DC2156A留学生讲解、Python，c++，Java程序设计辅导、讲解system monitor
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Description
LTC2946
Wide Range I2C Power,
Charge and Energy Meter
Demonstration circuit 2156A features the LTC 2946
rail-to-rail system monitor that measures current, voltage,
power, energy and charge. It features an operating
range of 2.7V to 100V and includes a shunt regulator for
operation from supplies above 100V to allow flexibility in
the selection of input supply. The current measurement
range of 0V to 100V is independent of the input supply.
An onboard, 0.4% accurate, 12-bit ADC measures load
current, input voltage and an auxiliary external voltage.
A 24-bit power value is generated by digitally multiplying
the measured 12-bit load current and input voltage data.
Energy andchargedata aregeneratedby integratingpower
and current. Minimum and maximum values are stored
and an overrange alert with programmable thresholds
minimizes the need for software polling. Data is reported
via a standard I2C interface. Shutdown mode reduces
power consumption to 20μA.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
QuikEval and Linduino are trademarks of Linear Technology Corporation. All other trademarks
are the property of their respective owners.
The demo board features nested pads for a range of sense
resistor package sizes to support currents of up to 15A
range. The full scale sense voltage is 102.4mV. A 20mΩ
sense resistor is populated on the board for 5.12A full
scale. The full scale current can be changed by populating
RSNS accordingly.
The DC2156A was designed to be connected to the DC590
andcontrolledthroughtheQuikEval? suiteof software. All
thresholds can be set and ADC registers read back through
the QuikEval interface, which provides a convenient way
to evaluate the LTC2946.
Figure 1. Typical Application Circuit
DEMO MANUAL DC2156A
DC2156A Pin and Jumper Definitions
Jumper Settings
JP1: Selects the VDD source. It can be set to VIN, INTVCC
or EXTVDD (which requires a voltage to be present at the
EXTVDD turret.) Please see Powering the DC2156A section
for examples of how these different settings are used.
JP2 (ADR0), JP3(ADR1): Selects the I2C slave address
of the LTC2946. Any changes here should also be made
inside of QuikEval for communications to persist. By
default, both jumpers are set to LOW which corresponds
to an address of 0xDE.
Turrets and Banana Jacks
Signal connections are made via the row of turret posts
along the edges of the board.
GND: (5 turrets, 2 banana jacks) These turrets are connected
directly to the ground planes.
VIN: Main Supply Input. The LTC2946 measures the current
flowing from VIN to VOUT.
VOUT: Supply Output to Load. The LTC2946 measures the
current flowing from VIN to VOUT.
INTVCC: Internal Low Voltage Supply Input/Output. This
turret is directly connected to the INTVCC pin. This turret is
used to power internal circuitry and can be configured as
a direct input, as a linear regulator from a higher voltage
connected to VDD or as a shunt regulator. In the default
configurationwithJP1 at VIN, INTVCCisinternallygenerated
and is 5V. Please see LTC2946 data sheet for more details.
EXTVDD: External Voltage Supply. This turret can be used
to power the LTC2946 independently of the VIN power
path. Connect to 4V to 100V external supply if this option
is selected through JP1.
ADIN: Input Measured by the Onboard ADC. Measures
between 0V to 2.048V. ADIN is loaded with a 140k and
3k resistive divider to allow voltage measurements of up
to 102.4V full scale.
VPU: Pull Up Voltage for the LEDs. Derived from a 5V
isolated supply on the DC590. It powers the GPIO LEDs
on the board. If a DC590 is not used and the DC2156A
is operated independently, a 2.5V to 5V supply must be
provided here, in order for the LEDs to work. 5V from
DC590 and the VPU turret input voltage are diode-ORed by
D6 to preclude back feeding from one source to the other.
SENSE+: Supply Voltage and Current Sense Input. Used
as a Kelvin input for the internal current sense amplifier.
The voltage at this pin is also monitored by the onboard
ADC with a full-scale input range of 102.4V. The full scale
current sense voltage is 102.4mV.
SENSE–: Current Sense Input. An external 20mΩ sense
resistor (RSNS) isconnectedbetweenSENSE+andSENSE–
to measure a full scale current of 5.12A. See Hardware
Setup section for details.
SCL: I2C Clock input.
SDA/SDAI: I2C Data Input. Connected to SDAO through
0Ω resistor R14. Remove R14 if opto-isolated I2C functionality
is desired.
SDAO: I2C Data Output. Connected to SDAI through 0Ω
resistor R14. Remove R14 if opto-isolated I2C functionality
is desired.
GPIO1: General Purpose Input/Output 1. Configurable
general purpose output and logic input. Configured by
default as General Purpose Output, pulls low to light D3.
GPIO2: General Purpose Input/Output 2. Configurable
general purpose output, logic input, and ACC control input
to gate internal accumulators. By default it is configured as
ACC input and pulled high so that the energy and charge
accumulation are active. If GPIO2 is configured as an
output, LED D4 lights up when GPIO2 is asserted low.
GPIO3: General Purpose Input/Output 3. Configurable
general purpose output, logic input, and ALERT# output.
By default it is configured as ALERT#. As ALERT#, it is
pulled to ground when a fault occurs to alert the host
controller. LED D5 lights when ALERT# is asserted low.3
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DEMO MANUAL DC2156A
Hardware Setup Options
Flexible Operating Modes of the LTC2946
The LTC2946 current sense inputs, SENSE+ and SENSE–
are used to make Kelvin connections to a current sense
resistor to measure the output current of a supply or the
current consumption of a load. They feature a common
mode range of 0V to 100V so that the output current of
either a positive or negative supply can be measured, as
well as current in either the positive or negative lead of the
load. Thus a potentially bewildering number of measurement
configurations are possible. To allow such flexibility,
the SENSE+ and SENSE– pins cannot be relied upon as
a source of power; the LTC2946 features a separate VDD
pin for this purpose.
Power to operate LTC2946 is obtained from the VDD pin
or the INTVCC pin (see the block diagram in Figure 2). If
a supply of 4V to 100V is available, VDD can be used and
an internal series regulator powers the device. If a supply
of 2.7V to 5.9V is available, power may be applied directly
to INTVCC. In the event that no supply of less than 100V
is available, the shunt regulator shown connected across
INTVCC can be used in conjunction with an external dropping
resistor to power the LTC2946.
Ringing
It comes as a surprise to many that seemingly innocent
acts, such as making a connection to a live supply, cause
ringing. Theory tells us that the amplitude of such ringing
reaches approximately 2x the input voltage, but in practice
this limit is sometimes exceeded. For general information
on ringing, see the LTC1647 data sheet.
Since the VDD pin current is small, ringing there is easily
suppressed by a 51Ω/100nF RC filter (R1 and C1) without
any compromise to the input voltage range. The SENSE+
and SENSE– pins however are not so easily protected.
To protect these pins and to prevent damage to the
LTC2946 that might arise from ringing, VIN is clamped by
an SMAT70A TVS (D1). D1 has a minimum breakdown
voltage of 77V at room temperature and thus VIN DC
input rating to 75V maximum. While D1 may be removed
to operate VIN up to 100V, always remember that any
excursion above this value may destroy the LTC2946.
DC2156A Pin and Jumper Definitions
Connectors
DC590 Connector (J5): J5 allows connection of the
DC2156A to the DC590 demo board through which the
Linear Technology? QuikEval software can communicate
with the board. When DC590 is connected, 5V is provided
to power the GPIO LEDs through this connector.
LED
INTVCC – D2:LightsupgreenwhenbothVPUandLTC2946
are powered.
ALERT# (GPIO3) – D5: Fault Alert Output. Lights up red
on an ALERT condition. Can also be monitored on the
ALERT (GPIO3) turret.
ACC (GPIO2) – D4:Will light up amberwhenACCis Low. By
DefaultGPIO2 is an input, pulled high to VPUby D4 and R7.
GPIO1 – D3: General Purpose Output. Lights up green
when pulled low. Default state is low.
Figure 2. Simplified Supply Block Diagram
VDD
INTVCC
GND
735k
15k
5V LDO LTC2946
SENSE– SENSE+4
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DEMO MANUAL DC2156A
Hardware Setup Options
Powering The DC2156A
The LTC2946 offers great flexibility in terms of supply
options owing to its separate VDD and SENSE pins.
Jumper JP1 is used to select the source of power for VDD
andallowseasyconfigurationofthevarioussupplyoptions.
If JP1 is set to VIN, then VDD is powered from VIN (Figure?3a
and Figure?3b). In this configuration, sensing is done on
the same rail which is supplying power to the LTC2946.
Provide 4V to 75V at VIN in this configuration to power
the LTC2946. The 75V limitation is set by the zener clamp
D1 which protects the LTC2946 against voltage transients
exceeding 100V, while the 4V limitation is the minimum
operating voltage of the VDD pin. D1 can be removed if
the full voltage range of 100V is desired.
Figure 3a. DC2156A Is Powered from VIN
Figure 3b. LTC2946 Powered from VIN
SENSE– SENSE+ LOAD
LTC29465
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DEMO MANUAL DC2156A
Hardware Setup Options
If JP1 is set to EXTVDD then VDD is powered by the
EXTVDD turret (Figure 4a and Figure 4b). Provide
a separate 4V to 100V at the EXTVDD turret in this
configuration. The maximum input VIN is limited to
75V by D1. D1 can be removed if the full voltage range
of 100V is desired.
Figure 4a. DC2156A Powered from External VDD
Figure 4b. LTC2946 Powered from External VDD
SENSE– SENSE+ LOAD
LTC29466
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DEMO MANUAL DC2156A
If JP1 is settoINTVCC, thentheLTC2946’s internal circuitry
is powered from INTVCC. A low voltage supply (2.7V to
5.9V) connected to INTVCC helps minimize on-chip power
dissipation (Figure 5a and Figure 5b). The device can
also be used as a shunt regulator in this configuration to
monitor rails higher than 100V.
Regardlessofwhichconfigurationis selected, ifthe system
is connected properly, the green INTVCC LED should be lit.
By default the DC2156A is configured, with VIN providing
power to VDD.
In order to support a wide range of applications, the
LTC2946 demo board also features multiple nested sense
pads to support high current monitoring. These pads
are Kelvin sensed. By default the board supports current
monitoring of up to 5.12A. An appropriate sense resistor
can be used to support monitoring of desired current
levels up to 20A with an on-board sense resistor. The
SENSE+ and SENSE– turrets may be used to connect to
an external sense resistor and power path for any current
level. Remove RSNS in this case.
Figure 5a. DC2156A Powered from INTVCC
Figure 5b. LTC2946 Powered from INTVCC
LTC2946
Hardware Setup Options7
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DEMO MANUAL DC2156A
DC2156A Shunt Regulator
For supply voltages above 100V, the shunt regulator at
INTVCC can be used in both high and low side configurations
to provide power to the LTC2946 through an
external shunt resistor, RSHUNT. RSHUNT should be sized
according to the following equation:
VS(MAX) 5.9V
35mA
≤ RSHUNT ≤
VS(MIN) 6.7V
1mA +I
LOAD(MAX)
(1)
Figure 6a. Powering DC2156A from High Side Shunt Regulator to Allow for Input Voltage Higher than 100V
TO DC590
OR DC2026
+ LOAD –VIN
80V TO 200V
RSHUNT
Figure 6b. Powering LTC2946 from High Side Shunt Regulator to Allow for Input Voltage Higher than 100V
– SENSE– SENSE+ LOAD
LTC2946
where VS(MAX) and VS(MIN) are theoperatingmaximumand
minimum of the supply. ILOAD(MAX) is the maximum external
current load that is connected to the shunt regulator.
Figure 6a shows a high side power monitor with an input
monitoring range of 80V to 200V in a high side shunt
regulatorconfiguration. Thedevicegroundisseparatedfrom
circuit ground through RSHUNT and clamped at 6.3V below
the input supply, VIN. Note that due to the different ground
levels, the I2C signals from the LTC2946 need to be level
Hardware Setup Options8
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DEMO MANUAL DC2156A
Figure 7a. DC2156A Derives Power from Low Side Shunt Regulator in High Side Current Sense Topology
TO DC590
OR DC2026
LOAD
0V TO 75V
+
– 80V TO
200V
RSHUNT
5.1K
Figure 7b. DC2156A Derives Power from Low Side Shunt Regulator in High Side Current Sense Topology
SENSE– SENSE+ LOAD
LTC2946
Hardware Setup Options
shifted for communication with other ground referenced
components. The DC590, as well as the Linduino?, provide
the necessary isolation in this case. The bus voltage can be
measured with an appropriate external divider connected
to ADIN for full scale operation at 200V. Make sure to set
CA[7] intheCTRLAregister sothattheADCmeasuresADIN
with reference to INTVCC instead of the GND pin.
Figure 7a shows a high side rail-to-rail power monitor
which derives power from a greater than 100V secondary
supply. The voltage at INTVCC is clamped at 6.3V above
ground in a low side shunt regulator configuration to
power the part.9
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DEMO MANUAL DC2156A
Figure 8a. DC2156A Derives Power through Low Side Shunt Regulator in Low Side Current Sense Topology
VIN
80V TO
200V
RSHUNT
5.1k
+
– LOAD
TO DC590
OR DC2026
Figure 8b. LTC2946 Derives Power through Low Side Shunt Regulator in Low Side Current Sense Topology
SENSE+ SENSE–LOAD+
– LTC2946
RSNS
VIN
80V TO
200V
INTVCC
RSHUNT
5.1k
Hardware Setup Options
In low side power monitors, the device ground and the
current sense inputs are connectedtothenegative terminal
of the input supply as shown in Figure 8a. The low side
shunt regulator configuration allows operation with input
supplies above 100V by clamping the voltage at INTVCC.10
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DEMO MANUAL DC2156A
Figure 9a. Current Monitoring in a –48V System
–48V OUTPUT
–48V INPUT
RTN RTN
+
– LOAD
TO DC590
OR DC2026
Figure 9b. Current Monitoring in a –48V System
SENSE+ SENSE–+ LOAD ––48V RTN–48V INPUT –48V OUTPUT
LTC2946
RSNS
Hardware Setup Options
-48V System Monitoring
The DC2156A can also be configured to provide power
monitoring in -48V Telecom applications by setting JP1 to
EXTVDD, with the -48V input tied to VOUT and GND and the
-48V return tied to EXTVDD. The DC590 provides isolation
and level shifting, as the I2C interface is operating at -48V
with respect to -48V RTN, which is normally near earth
ground potential.11
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DEMO MANUAL DC2156A
Figure 10. Hardware Bench Setup
DC2156A
48V POWER SUPPLY
DC590
PC
GND VIN
5A ELECTRONIC LOAD
– +
– +
VOUT
GND
Quick Start Procedure
The various features of DC2156A can be demonstrated by
using Linear Technology’s QuikEval Software. QuikEval is
a USB-based product demonstration and data acquisition
software meant to be used in conjunction with the DC590
that connects to individual daughter cards for specific
Linear Technology products. This software can be found
on the Linear Technology website at:
http://ltspice.linear.com/software/ltcqev.exe
Connect the DC590 to the PC using the USB cable provided
with the DC590. Now, connect the DC590 to the DC2156A.
The setup should look like Figure 10.
Ensure power is applied to the DC2156A in any one of the
configurations described earlier in this manual and that a
load is connected to the board.
Oncesetupiscomplete, runtheQuikEvalSoftware. QuikEval
should auto-detect the DC2156A and provide the user with
a control panel.
Interfac ing with the DC2026
This board can also interface with the DC2026 Linduino
boardwhichispartoftheLinduinoFirmwareDevelopment
Program. The Linduino Firmware Development Program
provides users with convenient driver code, written in C,
for a wide range of LTC products. Please see the Linduino
page for more details.
The DC2026 comes preloaded with a DC590 emulator
firmware which allows easy interface with QuikEval. See
Figure 10 for connections but substitute the DC590 with
the DC2026. QuikEval will launch the GUI as it would with
the DC590. The DC2026 can also be used as a development
platform, example software along with drivers can
be found on the product landing page: http://www.linear.
com/product/LTC2946. 12
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DEMO MANUAL DC2156A
The DC2156A software user interface was designed to
allow the user to quickly evaluate the LTC2946. The user
has the ability to set fault thresholds, enable/disable and
clear alerts, change the source for the VIN measurement as
well asmonitor voltage, current, power, charge andenergy.
RSNS is set to 20mΩ by default on the DC2156A, should
any changes be made on the board, the corresponding
value should be entered into the software control panel.
By pressing Start, the software interface will begin using
the DC590 for data collection.
The LTC2946 software UI is split up into two main components.
The Data Acquisition Terminal and a Tabbed
Interface. A screen shot of the GUI is shown in Figure 11.
Figure 11. LTC2946 Software UI
DC2156A SOFTWARE USER INTERFACE
Data Acquisition Terminal
The Data Acquisition Terminal display is always in view of
the user, providing convenient controls to quickly perform
common functions and displaying real time voltage, current,
power, charge and energy data.
The Data Acquisition Terminal consists of the following
components.
Performance Graph
The performance graph plots data in real time for up to
the last minute. Older data, once scrolled off the screen,
is discarded. The user can choose to log all the data in a
.csv file by clicking on the logging checkbox which is also
found on the Data Acquisition Terminal.
The performance graph can plot any two quantities from
VIN, Current, ADIN, Power, Energy andCharge concurrently
on the same plot. Radio buttons located next to the plot
allowtheusertoselectwhichquantity toploton a particular
axis. The axes are color coded. The left axis will always be
plotted lime green and the right axis will always be plotted
in red. These color codes are conveniently placed next to
the radio buttons for user reference.13
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DEMO MANUAL DC2156A
Note: You cannot plot the same quantity on both axes. Attempting
to do so will result in the next available quantity
being selected instead.
Measurement Panel
The measurement panel provides text based output of VIN
and ADIN registers in volts, current registers in amperes
and power registers in watts. For each quantity this panel
displays the values of the maximum and minimum registers,
the high and low limit threshold registers and the
real time reading register. These values get updated with
each polling of the device if there is any change.
Figure 13. Measurement Panel
DC2156A SOFTWARE USER INTERFACE
Figure 12. Performance Graph14
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DEMO MANUAL DC2156A
Accumulator Panel
The onboard accumulators have their own dedicated panel
which displays the charge, energy and time base register
values. The GUI takes this one step further by providing
the user with two extra text boxes which depict the average
current and power from the time the control panel initiated
the polling of the device. These values get updated with
each polling of the device if there is any change.
Figure 14. Accumulator Panel
ADIN Resistor Panel
The ADIN pin on the demo board has a resistive divider, in
the form of R2 and R10, which allows the user to measure
voltages up to 102V. Since the ADIN pin has a full-scale
voltage of 2.048V, the voltage displayed is scaled internally
by the GUI based on the values entered in the R2 and R10
text boxes. If the values of the onboard resistors changed,
then these text boxes should be updated to reflect that
change to get proper scaling. If no scaling is desired or if
the ADIN pin is to be connected directly to a voltage source
of up to 2.048V then the “R2 = 0 Ohms” checkbox can be
checked to eliminate the internal scaling presentin theGUI.
Figure 15. Resistor Menu
Setup and Quick Controls Panel
The Setup and Quick Controls panel allows the user to
quickly change the sense resistor value (this must match
the sense resistor present on the board), clear fault registers
as well as the maximum and minimum registers of
all quantities, set the device address, perform ARA in the
case of an alert, as well as put the part in snapshot mode.
There are two special checkboxes present in the Setup and
Quick Controls panel which require further explanation.
DC2156A SOFTWARE USER INTERFACE
Figure 16. Setup and Quick Controls15
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DEMO MANUAL DC2156A
The Logging checkbox, once checked, will enable the GUI
to store VIN, ADIN, current, power, energy and charge
register values in a user defined .csv file. It will also log
the value of the fault register (in hexadecimal) so that the
user can see at what particular instant the fault register
changed valueduring a fault. Note thatthis checkbox greys
out once the start button is clicked and must be selected
before the start button is clicked if logging is desired.
The Restore Accumulators checkbox enables the user to
individually clear accumulator overflow faults while still
retaining values. Each accumulator in the LTC2946 has its
own dedicated status and fault bits. Status bits represent
real-time status of the part. If a fault occurs and then goes
away, the status bit would get set and then reset with the
fault event. The fault bit would stay latched. The accumulator
status bits behave slightly differently in the sense that
they stay latched once an accumulator overflows and do
not get reset until the accumulator itself is reset. This is
because an accumulator is still in overflow state once it
rolls over until it is reset. The only way to reset the accumulators
is by setting bits CB[1:0] to either 10 or 11.
This however resets ALL of the accumulator registers. To
prevent this from happening and to allow the user to only
reset a single accumulator fault, the Restore Accumulators
checkbox first stores the information from all the
accumulators, resets the accumulators and then restores
the accumulator values in the accumulator registers which
were not selected to be reset.
Alert/Fault Mask LEDs
In order to provide a friendly user interface, the LTC2946
abstracts the ALERT mask and FAULT registers from the
user in the form of clickable LEDs. Each LED maps to a
corresponding bit in the ALERT and FAULT registers. For
example, the POWER OVERVALUE LED maps to bit 7 in
the ALERT1 and FAULT1 registers. Similarly, the GPIO1
Input Fault LED maps to Bit 6 in the ALERT2 and FAULT2
registers and so forth.
Figure 17. Alert/Fault Mark LEDs
The LEDs have three states which indicate the status of
the FAULT and ALERT registers.
AninactiveLED, representedwith a greycolor, indicatesthat
neither the alert bit nor the corresponding fault bit is set.
An armed LED, represented with a green color, indicates
that the corresponding alert bit has been set, however no
fault event has occurred. This arms the ALERT# pin to pull
low if that particular fault event occurs.
A faulted LED, represented with a red color, indicates
that the corresponding fault bit has been set. Clicking on
a faulted LED will clear that fault by resetting the corresponding
fault bit. The LED will then return to its previous
state whether it was inactive or armed.
DC2156A SOFTWARE USER INTERFACE16
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DEMO MANUAL DC2156A
Tab Interfac e
The tabbed interface allows the user to cycle between the
various control and threshold registers of the LTC2946
without losing view of the data. It consists of the following
three tabs.
Control Register A
As the name suggests, this tab gives the user direct access
to the CTRLA register in the form of radio buttons.
Here, the user can configure the ADIN pin reference, offset
calibration, voltage channel as well as the duty cycle of
measurements easily.
Control Register B and GPIO Control
This tab provides access to the CTRLB and allows
control of the GPIO pins through registers GPIO_CFG
and GPIO3_CTRL.
TheCTRLBregister canbeusedtoputthepartinshutdown
mode as well as to configure handling of fault events. The
state of the individual GPIO pins can also be configured
through this tab.
DC2156A SOFTWARE USER INTERFACE
Figure 19. Control Register B and GPIO Control
Figure 18. Control Register A17
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DEMO MANUAL DC2156A
DC2156A SOFTWARE USER INTERFACE
Threshold and Initial Values
This tab provides access to the threshold registers within
theLTC2946. Theuser cansetthemaximumandminimum
thresholds of power, current, VIN and ADIN here by entering
the desired value and then clicking the corresponding
button. Once thebuttonis clicked, thedata is first validated.
If it is out of range a message box will pop up and request
the user to enter data within the valid range. Once valid
data is sent to the part, the corresponding text box in the
MeasurementsPanelwillbeupdatedtoreflectthis change.
The user can also set the initial values for the accumulators
here. The time base is entered in hexadecimal format while
the charge and energy values are entered in coulombs and
joules, respectively. Similar to the threshold section, the
information must be sent by clicking on the corresponding
button so that the data is first validated and then sent
to the part.
This tab also allows the user to set the frequency of their
crystal oscillator if they are using one. The demo board
comes equipped with a 4MHz clock which is the default
value. If no external clock is desired, the crystal present on
the demo board can be removed and the “Use LTC2946’s
Internal Clock (5% Trimmed 250kHz)” checkbox can be
selected to use the part’s internal clock.
Figure 20. Threshold and Initial Values18
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DEMO MANUAL DC2156A
Parts List
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Required Circuit Components
1 1 C1 CAP., X7R 0.1μF 200V 10% 1206 AVX, 12062C104KAT2A
2 2 C2, C5 CAP., X5R 0.1μF 25V 10% 0603 AVX, 06033D104KAT2A
3 2 C3, C4 CAP., C0G, 36pF 25V 5% 0603 AVX, 06033A360JAT2A
4 1 D1 VOLTAGE SUPPRESSOR, 70V Diodes/Zetex, SMAT70A
5 2 D2, D3 LED, GRN PLCC-2 (B-SIZE) Vishay, VLMC3101-GS08
6 1 D4 LED, AMBER PLCC-2 (B-SIZE) Vishay, VLMH3100-GS08
7 1 D5 LED, RED PLCC-2 (B-SIZE) Vishay, VLMS3000-GS08
8 1 D6 DIODE, DUAL SCHOTTKY, SOT-23 Fairchild, BAT54C
9 4 E1, E2, E3, E4 TP, TURRET, .094" Mill-Max, 2501-2-00-80-00-00-07-0
10 15 E5–E19 TP, TURRET, .064" Mill-Max, 2308-2-00-80-00-00-07-0
11 3 JP1, JP2, JP3 HEADERS, DBL. ROW 2 X 3 2mm CTRS. Sullins, NRPN032PAEN-RC
12 4 J1, J2, J3, J4 BANANA JACK, NON-INSULATED Keystone, 575-4
13 1 J5 CONN., HEADER, 14 PIN, 2mm Molex, 87831-1420
14 1 Q1 MOSFET N-CHAN,60V 115MA SOT23 Diodes/Zetex, 2N7002-7-F
15 1 RSNS RES., LRC 0.020Ω 1.0W 1% 2010 IRC, LRF20 10LF-01-R020-F
16 1 R1 RES., CHIP 51Ω 0.1W 5% 0603 Vishay, CRCW060351R0JNEA
17 1 R2 RES., CHIP 147k 0.1W 1% 0603 Vishay, CRCW0603147KFKEA
18 4 R3, R5, R7, R9 RES., CHIP 3.3k 0.1W 5% 0603 Vishay, CRCW06033K30JNEA
19 3 R4, R6, R8 RES., CHIP 100k 0.1W 5% 0603 Vishay, CRCW0603100KJNEA
20 1 R10 RES., CHIP 3k 0.1W 1% 0603 Vishay, CRCW06033K00FKEA
21 0 R11, R12 RES, 0603 Opt
22 1 R14 RES, 0Ω, 0603 Vishay, CRCW0603000JNEA
23 3 R15, R16, R17 RES., CHIP 5.1k 0.1W 5% 0603 Vishay, CRCW06035K10JNEA
24 1 U1 I.C., POWER MONITOR, DFN16DE-4X3 Linear Technology, LTC2946IDE
25 1 U2 I.C., SERIAL EEPROM TSSOP-8 Microchip, 24LC025-I/ST
26 1 Y1 XTAL, 4 MHz, Y-ABLS Abracon Corp., ABLS-4.000MHz-B2-T
28 3 SHUNTS AS SHOWN ON ASSY DWG SHUNT, 2mm CTRS. Samtec 2SN-BK-G
29 4 MH1–MH4 STAND-OFF, NYLON 0.25" Keystone, 8831 (SNAP ON)19
dc2156af
DEMO MANUAL DC2156A
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation
that the interconnection of its circuits as described herein will not infringe on existing patent rights.
Figure 21. DC2156A Demo Circuit Schematic
Schematic Diagram
NOTES: UNLESS OTHERWISE SPECIFIED
1. ALL RESISTORS ARE IN OHMS, 0603.
ALL CAPACITORS ARE IN MICROFARADS, 0603.
2. INSTALL SHUNTS AS SHOWN.
NOTE: EEPROM FOR BOARD IDENTIFICATION
DC590 I2C INTERFACE
* DEFAULT
JUMPER POSITIONS
REMOVE R14 TO SEPERATE SDAI AND SDAO
TO DC590B
VOUT VIN
INTVCC
INTVCC
VGPIO
VGPIO
VPU
VPU
VPU
SIZE
DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. SCALE = NONE
www.linear.com
2 DEMO CIRCUIT 2156A
05/28/2014, 05:25 PM 1 1
WIDE RANGE I2C POWER MONITOR
N/A
LTC2946IDE
KIM T.
SAL H.
WITH ENERGY AND COULOMB METER
SIZE
DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. SCALE = NONE
www.linear.com
2 DEMO CIRCUIT 2156A
05/28/2014, 05:25 PM 1 1
WIDE RANGE I2C POWER MONITOR
N/A
LTC2946IDE
KIM T.
SAL H.
WITH ENERGY AND COULOMB METER
SIZE
DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. SCALE = NONE
www.linear.com
2 DEMO CIRCUIT 2156A
05/28/2014, 05:25 PM 1 1
WIDE RANGE I2C POWER MONITOR
N/A
LTC2946IDE
KIM T.
SAL H.
WITH ENERGY AND COULOMB METER
REVISION HISTORY
DESCRIPTION DATE APPROVED ECO REV
SAL H. PRODUCTION __ 2 05-28-14
REVISION HISTORY
DESCRIPTION DATE APPROVED ECO REV
SAL H. PRODUCTION __ 2 05-28-14
REVISION HISTORY
DESCRIPTION DATE APPROVED ECO REV
SAL H. PRODUCTION __ 2 05-28-14 E19
DEMO MANUAL DC2156A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com? LINEAR TECHNOLOGY CORPORATION 2014
LT 0814 ? PRINTED IN USA
DEMONSTRATION BOARD IMPORTANT NOTICE
Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions:
This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERINGDEVELOPMENT
OR EVALUATION PURPOSES ONLY and is not provided by LTC for commercial use. As such, the DEMO BOARD herein may not be complete
in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety
measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union
directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations.
If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date
of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU
OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS
FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR
ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES.
The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user releases LTC from all claims
arising from the handling or use of the goods. Due to the open construction of the product, it is the user’s responsibility to take any and all
appropriate precautions with regard to electrostatic discharge. Also be aware that the products herein may not be regulatory compliant or
agency certified (FCC, UL, CE, etc.).
No License is granted under any patent right or other intellectual property whatsoever. LTC assumes no liability for applications assistance,
customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind.
LTC currently services a variety of customers for products around the world, and therefore this transaction is not exclusive.
Please read the DEMO BOARD manual prior to handling the product. Persons handling this product must have electronics training and
observe good laboratory practice standards. Common sense is encouraged.
This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LTC application
engineer.
Mailing Address:
Linear Technology
1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright 2004, Linear Technology Corporation
Description
LTC2946
Wide Range I2C Power,
Charge and Energy Meter
Demonstration circuit 2156A features the LTC 2946
rail-to-rail system monitor that measures current, voltage,
power, energy and charge. It features an operating
range of 2.7V to 100V and includes a shunt regulator for
operation from supplies above 100V to allow flexibility in
the selection of input supply. The current measurement
range of 0V to 100V is independent of the input supply.
An onboard, 0.4% accurate, 12-bit ADC measures load
current, input voltage and an auxiliary external voltage.
A 24-bit power value is generated by digitally multiplying
the measured 12-bit load current and input voltage data.
Energy andchargedata aregeneratedby integratingpower
and current. Minimum and maximum values are stored
and an overrange alert with programmable thresholds
minimizes the need for software polling. Data is reported
via a standard I2C interface. Shutdown mode reduces
power consumption to 20μA.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
QuikEval and Linduino are trademarks of Linear Technology Corporation. All other trademarks
are the property of their respective owners.
The demo board features nested pads for a range of sense
resistor package sizes to support currents of up to 15A
range. The full scale sense voltage is 102.4mV. A 20mΩ
sense resistor is populated on the board for 5.12A full
scale. The full scale current can be changed by populating
RSNS accordingly.
The DC2156A was designed to be connected to the DC590
andcontrolledthroughtheQuikEval? suiteof software. All
thresholds can be set and ADC registers read back through
the QuikEval interface, which provides a convenient way
to evaluate the LTC2946.
Figure 1. Typical Application Circuit
DEMO MANUAL DC2156A
DC2156A Pin and Jumper Definitions
Jumper Settings
JP1: Selects the VDD source. It can be set to VIN, INTVCC
or EXTVDD (which requires a voltage to be present at the
EXTVDD turret.) Please see Powering the DC2156A section
for examples of how these different settings are used.
JP2 (ADR0), JP3(ADR1): Selects the I2C slave address
of the LTC2946. Any changes here should also be made
inside of QuikEval for communications to persist. By
default, both jumpers are set to LOW which corresponds
to an address of 0xDE.
Turrets and Banana Jacks
Signal connections are made via the row of turret posts
along the edges of the board.
GND: (5 turrets, 2 banana jacks) These turrets are connected
directly to the ground planes.
VIN: Main Supply Input. The LTC2946 measures the current
flowing from VIN to VOUT.
VOUT: Supply Output to Load. The LTC2946 measures the
current flowing from VIN to VOUT.
INTVCC: Internal Low Voltage Supply Input/Output. This
turret is directly connected to the INTVCC pin. This turret is
used to power internal circuitry and can be configured as
a direct input, as a linear regulator from a higher voltage
connected to VDD or as a shunt regulator. In the default
configurationwithJP1 at VIN, INTVCCisinternallygenerated
and is 5V. Please see LTC2946 data sheet for more details.
EXTVDD: External Voltage Supply. This turret can be used
to power the LTC2946 independently of the VIN power
path. Connect to 4V to 100V external supply if this option
is selected through JP1.
ADIN: Input Measured by the Onboard ADC. Measures
between 0V to 2.048V. ADIN is loaded with a 140k and
3k resistive divider to allow voltage measurements of up
to 102.4V full scale.
VPU: Pull Up Voltage for the LEDs. Derived from a 5V
isolated supply on the DC590. It powers the GPIO LEDs
on the board. If a DC590 is not used and the DC2156A
is operated independently, a 2.5V to 5V supply must be
provided here, in order for the LEDs to work. 5V from
DC590 and the VPU turret input voltage are diode-ORed by
D6 to preclude back feeding from one source to the other.
SENSE+: Supply Voltage and Current Sense Input. Used
as a Kelvin input for the internal current sense amplifier.
The voltage at this pin is also monitored by the onboard
ADC with a full-scale input range of 102.4V. The full scale
current sense voltage is 102.4mV.
SENSE–: Current Sense Input. An external 20mΩ sense
resistor (RSNS) isconnectedbetweenSENSE+andSENSE–
to measure a full scale current of 5.12A. See Hardware
Setup section for details.
SCL: I2C Clock input.
SDA/SDAI: I2C Data Input. Connected to SDAO through
0Ω resistor R14. Remove R14 if opto-isolated I2C functionality
is desired.
SDAO: I2C Data Output. Connected to SDAI through 0Ω
resistor R14. Remove R14 if opto-isolated I2C functionality
is desired.
GPIO1: General Purpose Input/Output 1. Configurable
general purpose output and logic input. Configured by
default as General Purpose Output, pulls low to light D3.
GPIO2: General Purpose Input/Output 2. Configurable
general purpose output, logic input, and ACC control input
to gate internal accumulators. By default it is configured as
ACC input and pulled high so that the energy and charge
accumulation are active. If GPIO2 is configured as an
output, LED D4 lights up when GPIO2 is asserted low.
GPIO3: General Purpose Input/Output 3. Configurable
general purpose output, logic input, and ALERT# output.
By default it is configured as ALERT#. As ALERT#, it is
pulled to ground when a fault occurs to alert the host
controller. LED D5 lights when ALERT# is asserted low.3
dc2156af
DEMO MANUAL DC2156A
Hardware Setup Options
Flexible Operating Modes of the LTC2946
The LTC2946 current sense inputs, SENSE+ and SENSE–
are used to make Kelvin connections to a current sense
resistor to measure the output current of a supply or the
current consumption of a load. They feature a common
mode range of 0V to 100V so that the output current of
either a positive or negative supply can be measured, as
well as current in either the positive or negative lead of the
load. Thus a potentially bewildering number of measurement
configurations are possible. To allow such flexibility,
the SENSE+ and SENSE– pins cannot be relied upon as
a source of power; the LTC2946 features a separate VDD
pin for this purpose.
Power to operate LTC2946 is obtained from the VDD pin
or the INTVCC pin (see the block diagram in Figure 2). If
a supply of 4V to 100V is available, VDD can be used and
an internal series regulator powers the device. If a supply
of 2.7V to 5.9V is available, power may be applied directly
to INTVCC. In the event that no supply of less than 100V
is available, the shunt regulator shown connected across
INTVCC can be used in conjunction with an external dropping
resistor to power the LTC2946.
Ringing
It comes as a surprise to many that seemingly innocent
acts, such as making a connection to a live supply, cause
ringing. Theory tells us that the amplitude of such ringing
reaches approximately 2x the input voltage, but in practice
this limit is sometimes exceeded. For general information
on ringing, see the LTC1647 data sheet.
Since the VDD pin current is small, ringing there is easily
suppressed by a 51Ω/100nF RC filter (R1 and C1) without
any compromise to the input voltage range. The SENSE+
and SENSE– pins however are not so easily protected.
To protect these pins and to prevent damage to the
LTC2946 that might arise from ringing, VIN is clamped by
an SMAT70A TVS (D1). D1 has a minimum breakdown
voltage of 77V at room temperature and thus VIN DC
input rating to 75V maximum. While D1 may be removed
to operate VIN up to 100V, always remember that any
excursion above this value may destroy the LTC2946.
DC2156A Pin and Jumper Definitions
Connectors
DC590 Connector (J5): J5 allows connection of the
DC2156A to the DC590 demo board through which the
Linear Technology? QuikEval software can communicate
with the board. When DC590 is connected, 5V is provided
to power the GPIO LEDs through this connector.
LED
INTVCC – D2:LightsupgreenwhenbothVPUandLTC2946
are powered.
ALERT# (GPIO3) – D5: Fault Alert Output. Lights up red
on an ALERT condition. Can also be monitored on the
ALERT (GPIO3) turret.
ACC (GPIO2) – D4:Will light up amberwhenACCis Low. By
DefaultGPIO2 is an input, pulled high to VPUby D4 and R7.
GPIO1 – D3: General Purpose Output. Lights up green
when pulled low. Default state is low.
Figure 2. Simplified Supply Block Diagram
VDD
INTVCC
GND
735k
15k
5V LDO LTC2946
SENSE– SENSE+4
dc2156af
DEMO MANUAL DC2156A
Hardware Setup Options
Powering The DC2156A
The LTC2946 offers great flexibility in terms of supply
options owing to its separate VDD and SENSE pins.
Jumper JP1 is used to select the source of power for VDD
andallowseasyconfigurationofthevarioussupplyoptions.
If JP1 is set to VIN, then VDD is powered from VIN (Figure?3a
and Figure?3b). In this configuration, sensing is done on
the same rail which is supplying power to the LTC2946.
Provide 4V to 75V at VIN in this configuration to power
the LTC2946. The 75V limitation is set by the zener clamp
D1 which protects the LTC2946 against voltage transients
exceeding 100V, while the 4V limitation is the minimum
operating voltage of the VDD pin. D1 can be removed if
the full voltage range of 100V is desired.
Figure 3a. DC2156A Is Powered from VIN
Figure 3b. LTC2946 Powered from VIN
SENSE– SENSE+ LOAD
LTC29465
dc2156af
DEMO MANUAL DC2156A
Hardware Setup Options
If JP1 is set to EXTVDD then VDD is powered by the
EXTVDD turret (Figure 4a and Figure 4b). Provide
a separate 4V to 100V at the EXTVDD turret in this
configuration. The maximum input VIN is limited to
75V by D1. D1 can be removed if the full voltage range
of 100V is desired.
Figure 4a. DC2156A Powered from External VDD
Figure 4b. LTC2946 Powered from External VDD
SENSE– SENSE+ LOAD
LTC29466
dc2156af
DEMO MANUAL DC2156A
If JP1 is settoINTVCC, thentheLTC2946’s internal circuitry
is powered from INTVCC. A low voltage supply (2.7V to
5.9V) connected to INTVCC helps minimize on-chip power
dissipation (Figure 5a and Figure 5b). The device can
also be used as a shunt regulator in this configuration to
monitor rails higher than 100V.
Regardlessofwhichconfigurationis selected, ifthe system
is connected properly, the green INTVCC LED should be lit.
By default the DC2156A is configured, with VIN providing
power to VDD.
In order to support a wide range of applications, the
LTC2946 demo board also features multiple nested sense
pads to support high current monitoring. These pads
are Kelvin sensed. By default the board supports current
monitoring of up to 5.12A. An appropriate sense resistor
can be used to support monitoring of desired current
levels up to 20A with an on-board sense resistor. The
SENSE+ and SENSE– turrets may be used to connect to
an external sense resistor and power path for any current
level. Remove RSNS in this case.
Figure 5a. DC2156A Powered from INTVCC
Figure 5b. LTC2946 Powered from INTVCC
LTC2946
Hardware Setup Options7
dc2156af
DEMO MANUAL DC2156A
DC2156A Shunt Regulator
For supply voltages above 100V, the shunt regulator at
INTVCC can be used in both high and low side configurations
to provide power to the LTC2946 through an
external shunt resistor, RSHUNT. RSHUNT should be sized
according to the following equation:
VS(MAX) 5.9V
35mA
≤ RSHUNT ≤
VS(MIN) 6.7V
1mA +I
LOAD(MAX)
(1)
Figure 6a. Powering DC2156A from High Side Shunt Regulator to Allow for Input Voltage Higher than 100V
TO DC590
OR DC2026
+ LOAD –VIN
80V TO 200V
RSHUNT
Figure 6b. Powering LTC2946 from High Side Shunt Regulator to Allow for Input Voltage Higher than 100V
– SENSE– SENSE+ LOAD
LTC2946
where VS(MAX) and VS(MIN) are theoperatingmaximumand
minimum of the supply. ILOAD(MAX) is the maximum external
current load that is connected to the shunt regulator.
Figure 6a shows a high side power monitor with an input
monitoring range of 80V to 200V in a high side shunt
regulatorconfiguration. Thedevicegroundisseparatedfrom
circuit ground through RSHUNT and clamped at 6.3V below
the input supply, VIN. Note that due to the different ground
levels, the I2C signals from the LTC2946 need to be level
Hardware Setup Options8
dc2156af
DEMO MANUAL DC2156A
Figure 7a. DC2156A Derives Power from Low Side Shunt Regulator in High Side Current Sense Topology
TO DC590
OR DC2026
LOAD
0V TO 75V
+
– 80V TO
200V
RSHUNT
5.1K
Figure 7b. DC2156A Derives Power from Low Side Shunt Regulator in High Side Current Sense Topology
SENSE– SENSE+ LOAD
LTC2946
Hardware Setup Options
shifted for communication with other ground referenced
components. The DC590, as well as the Linduino?, provide
the necessary isolation in this case. The bus voltage can be
measured with an appropriate external divider connected
to ADIN for full scale operation at 200V. Make sure to set
CA[7] intheCTRLAregister sothattheADCmeasuresADIN
with reference to INTVCC instead of the GND pin.
Figure 7a shows a high side rail-to-rail power monitor
which derives power from a greater than 100V secondary
supply. The voltage at INTVCC is clamped at 6.3V above
ground in a low side shunt regulator configuration to
power the part.9
dc2156af
DEMO MANUAL DC2156A
Figure 8a. DC2156A Derives Power through Low Side Shunt Regulator in Low Side Current Sense Topology
VIN
80V TO
200V
RSHUNT
5.1k
+
– LOAD
TO DC590
OR DC2026
Figure 8b. LTC2946 Derives Power through Low Side Shunt Regulator in Low Side Current Sense Topology
SENSE+ SENSE–LOAD+
– LTC2946
RSNS
VIN
80V TO
200V
INTVCC
RSHUNT
5.1k
Hardware Setup Options
In low side power monitors, the device ground and the
current sense inputs are connectedtothenegative terminal
of the input supply as shown in Figure 8a. The low side
shunt regulator configuration allows operation with input
supplies above 100V by clamping the voltage at INTVCC.10
dc2156af
DEMO MANUAL DC2156A
Figure 9a. Current Monitoring in a –48V System
–48V OUTPUT
–48V INPUT
RTN RTN
+
– LOAD
TO DC590
OR DC2026
Figure 9b. Current Monitoring in a –48V System
SENSE+ SENSE–+ LOAD ––48V RTN–48V INPUT –48V OUTPUT
LTC2946
RSNS
Hardware Setup Options
-48V System Monitoring
The DC2156A can also be configured to provide power
monitoring in -48V Telecom applications by setting JP1 to
EXTVDD, with the -48V input tied to VOUT and GND and the
-48V return tied to EXTVDD. The DC590 provides isolation
and level shifting, as the I2C interface is operating at -48V
with respect to -48V RTN, which is normally near earth
ground potential.11
dc2156af
DEMO MANUAL DC2156A
Figure 10. Hardware Bench Setup
DC2156A
48V POWER SUPPLY
DC590
PC
GND VIN
5A ELECTRONIC LOAD
– +
– +
VOUT
GND
Quick Start Procedure
The various features of DC2156A can be demonstrated by
using Linear Technology’s QuikEval Software. QuikEval is
a USB-based product demonstration and data acquisition
software meant to be used in conjunction with the DC590
that connects to individual daughter cards for specific
Linear Technology products. This software can be found
on the Linear Technology website at:
http://ltspice.linear.com/software/ltcqev.exe
Connect the DC590 to the PC using the USB cable provided
with the DC590. Now, connect the DC590 to the DC2156A.
The setup should look like Figure 10.
Ensure power is applied to the DC2156A in any one of the
configurations described earlier in this manual and that a
load is connected to the board.
Oncesetupiscomplete, runtheQuikEvalSoftware. QuikEval
should auto-detect the DC2156A and provide the user with
a control panel.
Interfac ing with the DC2026
This board can also interface with the DC2026 Linduino
boardwhichispartoftheLinduinoFirmwareDevelopment
Program. The Linduino Firmware Development Program
provides users with convenient driver code, written in C,
for a wide range of LTC products. Please see the Linduino
page for more details.
The DC2026 comes preloaded with a DC590 emulator
firmware which allows easy interface with QuikEval. See
Figure 10 for connections but substitute the DC590 with
the DC2026. QuikEval will launch the GUI as it would with
the DC590. The DC2026 can also be used as a development
platform, example software along with drivers can
be found on the product landing page: http://www.linear.
com/product/LTC2946. 12
dc2156af
DEMO MANUAL DC2156A
The DC2156A software user interface was designed to
allow the user to quickly evaluate the LTC2946. The user
has the ability to set fault thresholds, enable/disable and
clear alerts, change the source for the VIN measurement as
well asmonitor voltage, current, power, charge andenergy.
RSNS is set to 20mΩ by default on the DC2156A, should
any changes be made on the board, the corresponding
value should be entered into the software control panel.
By pressing Start, the software interface will begin using
the DC590 for data collection.
The LTC2946 software UI is split up into two main components.
The Data Acquisition Terminal and a Tabbed
Interface. A screen shot of the GUI is shown in Figure 11.
Figure 11. LTC2946 Software UI
DC2156A SOFTWARE USER INTERFACE
Data Acquisition Terminal
The Data Acquisition Terminal display is always in view of
the user, providing convenient controls to quickly perform
common functions and displaying real time voltage, current,
power, charge and energy data.
The Data Acquisition Terminal consists of the following
components.
Performance Graph
The performance graph plots data in real time for up to
the last minute. Older data, once scrolled off the screen,
is discarded. The user can choose to log all the data in a
.csv file by clicking on the logging checkbox which is also
found on the Data Acquisition Terminal.
The performance graph can plot any two quantities from
VIN, Current, ADIN, Power, Energy andCharge concurrently
on the same plot. Radio buttons located next to the plot
allowtheusertoselectwhichquantity toploton a particular
axis. The axes are color coded. The left axis will always be
plotted lime green and the right axis will always be plotted
in red. These color codes are conveniently placed next to
the radio buttons for user reference.13
dc2156af
DEMO MANUAL DC2156A
Note: You cannot plot the same quantity on both axes. Attempting
to do so will result in the next available quantity
being selected instead.
Measurement Panel
The measurement panel provides text based output of VIN
and ADIN registers in volts, current registers in amperes
and power registers in watts. For each quantity this panel
displays the values of the maximum and minimum registers,
the high and low limit threshold registers and the
real time reading register. These values get updated with
each polling of the device if there is any change.
Figure 13. Measurement Panel
DC2156A SOFTWARE USER INTERFACE
Figure 12. Performance Graph14
dc2156af
DEMO MANUAL DC2156A
Accumulator Panel
The onboard accumulators have their own dedicated panel
which displays the charge, energy and time base register
values. The GUI takes this one step further by providing
the user with two extra text boxes which depict the average
current and power from the time the control panel initiated
the polling of the device. These values get updated with
each polling of the device if there is any change.
Figure 14. Accumulator Panel
ADIN Resistor Panel
The ADIN pin on the demo board has a resistive divider, in
the form of R2 and R10, which allows the user to measure
voltages up to 102V. Since the ADIN pin has a full-scale
voltage of 2.048V, the voltage displayed is scaled internally
by the GUI based on the values entered in the R2 and R10
text boxes. If the values of the onboard resistors changed,
then these text boxes should be updated to reflect that
change to get proper scaling. If no scaling is desired or if
the ADIN pin is to be connected directly to a voltage source
of up to 2.048V then the “R2 = 0 Ohms” checkbox can be
checked to eliminate the internal scaling presentin theGUI.
Figure 15. Resistor Menu
Setup and Quick Controls Panel
The Setup and Quick Controls panel allows the user to
quickly change the sense resistor value (this must match
the sense resistor present on the board), clear fault registers
as well as the maximum and minimum registers of
all quantities, set the device address, perform ARA in the
case of an alert, as well as put the part in snapshot mode.
There are two special checkboxes present in the Setup and
Quick Controls panel which require further explanation.
DC2156A SOFTWARE USER INTERFACE
Figure 16. Setup and Quick Controls15
dc2156af
DEMO MANUAL DC2156A
The Logging checkbox, once checked, will enable the GUI
to store VIN, ADIN, current, power, energy and charge
register values in a user defined .csv file. It will also log
the value of the fault register (in hexadecimal) so that the
user can see at what particular instant the fault register
changed valueduring a fault. Note thatthis checkbox greys
out once the start button is clicked and must be selected
before the start button is clicked if logging is desired.
The Restore Accumulators checkbox enables the user to
individually clear accumulator overflow faults while still
retaining values. Each accumulator in the LTC2946 has its
own dedicated status and fault bits. Status bits represent
real-time status of the part. If a fault occurs and then goes
away, the status bit would get set and then reset with the
fault event. The fault bit would stay latched. The accumulator
status bits behave slightly differently in the sense that
they stay latched once an accumulator overflows and do
not get reset until the accumulator itself is reset. This is
because an accumulator is still in overflow state once it
rolls over until it is reset. The only way to reset the accumulators
is by setting bits CB[1:0] to either 10 or 11.
This however resets ALL of the accumulator registers. To
prevent this from happening and to allow the user to only
reset a single accumulator fault, the Restore Accumulators
checkbox first stores the information from all the
accumulators, resets the accumulators and then restores
the accumulator values in the accumulator registers which
were not selected to be reset.
Alert/Fault Mask LEDs
In order to provide a friendly user interface, the LTC2946
abstracts the ALERT mask and FAULT registers from the
user in the form of clickable LEDs. Each LED maps to a
corresponding bit in the ALERT and FAULT registers. For
example, the POWER OVERVALUE LED maps to bit 7 in
the ALERT1 and FAULT1 registers. Similarly, the GPIO1
Input Fault LED maps to Bit 6 in the ALERT2 and FAULT2
registers and so forth.
Figure 17. Alert/Fault Mark LEDs
The LEDs have three states which indicate the status of
the FAULT and ALERT registers.
AninactiveLED, representedwith a greycolor, indicatesthat
neither the alert bit nor the corresponding fault bit is set.
An armed LED, represented with a green color, indicates
that the corresponding alert bit has been set, however no
fault event has occurred. This arms the ALERT# pin to pull
low if that particular fault event occurs.
A faulted LED, represented with a red color, indicates
that the corresponding fault bit has been set. Clicking on
a faulted LED will clear that fault by resetting the corresponding
fault bit. The LED will then return to its previous
state whether it was inactive or armed.
DC2156A SOFTWARE USER INTERFACE16
dc2156af
DEMO MANUAL DC2156A
Tab Interfac e
The tabbed interface allows the user to cycle between the
various control and threshold registers of the LTC2946
without losing view of the data. It consists of the following
three tabs.
Control Register A
As the name suggests, this tab gives the user direct access
to the CTRLA register in the form of radio buttons.
Here, the user can configure the ADIN pin reference, offset
calibration, voltage channel as well as the duty cycle of
measurements easily.
Control Register B and GPIO Control
This tab provides access to the CTRLB and allows
control of the GPIO pins through registers GPIO_CFG
and GPIO3_CTRL.
TheCTRLBregister canbeusedtoputthepartinshutdown
mode as well as to configure handling of fault events. The
state of the individual GPIO pins can also be configured
through this tab.
DC2156A SOFTWARE USER INTERFACE
Figure 19. Control Register B and GPIO Control
Figure 18. Control Register A17
dc2156af
DEMO MANUAL DC2156A
DC2156A SOFTWARE USER INTERFACE
Threshold and Initial Values
This tab provides access to the threshold registers within
theLTC2946. Theuser cansetthemaximumandminimum
thresholds of power, current, VIN and ADIN here by entering
the desired value and then clicking the corresponding
button. Once thebuttonis clicked, thedata is first validated.
If it is out of range a message box will pop up and request
the user to enter data within the valid range. Once valid
data is sent to the part, the corresponding text box in the
MeasurementsPanelwillbeupdatedtoreflectthis change.
The user can also set the initial values for the accumulators
here. The time base is entered in hexadecimal format while
the charge and energy values are entered in coulombs and
joules, respectively. Similar to the threshold section, the
information must be sent by clicking on the corresponding
button so that the data is first validated and then sent
to the part.
This tab also allows the user to set the frequency of their
crystal oscillator if they are using one. The demo board
comes equipped with a 4MHz clock which is the default
value. If no external clock is desired, the crystal present on
the demo board can be removed and the “Use LTC2946’s
Internal Clock (5% Trimmed 250kHz)” checkbox can be
selected to use the part’s internal clock.
Figure 20. Threshold and Initial Values18
dc2156af
DEMO MANUAL DC2156A
Parts List
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Required Circuit Components
1 1 C1 CAP., X7R 0.1μF 200V 10% 1206 AVX, 12062C104KAT2A
2 2 C2, C5 CAP., X5R 0.1μF 25V 10% 0603 AVX, 06033D104KAT2A
3 2 C3, C4 CAP., C0G, 36pF 25V 5% 0603 AVX, 06033A360JAT2A
4 1 D1 VOLTAGE SUPPRESSOR, 70V Diodes/Zetex, SMAT70A
5 2 D2, D3 LED, GRN PLCC-2 (B-SIZE) Vishay, VLMC3101-GS08
6 1 D4 LED, AMBER PLCC-2 (B-SIZE) Vishay, VLMH3100-GS08
7 1 D5 LED, RED PLCC-2 (B-SIZE) Vishay, VLMS3000-GS08
8 1 D6 DIODE, DUAL SCHOTTKY, SOT-23 Fairchild, BAT54C
9 4 E1, E2, E3, E4 TP, TURRET, .094" Mill-Max, 2501-2-00-80-00-00-07-0
10 15 E5–E19 TP, TURRET, .064" Mill-Max, 2308-2-00-80-00-00-07-0
11 3 JP1, JP2, JP3 HEADERS, DBL. ROW 2 X 3 2mm CTRS. Sullins, NRPN032PAEN-RC
12 4 J1, J2, J3, J4 BANANA JACK, NON-INSULATED Keystone, 575-4
13 1 J5 CONN., HEADER, 14 PIN, 2mm Molex, 87831-1420
14 1 Q1 MOSFET N-CHAN,60V 115MA SOT23 Diodes/Zetex, 2N7002-7-F
15 1 RSNS RES., LRC 0.020Ω 1.0W 1% 2010 IRC, LRF20 10LF-01-R020-F
16 1 R1 RES., CHIP 51Ω 0.1W 5% 0603 Vishay, CRCW060351R0JNEA
17 1 R2 RES., CHIP 147k 0.1W 1% 0603 Vishay, CRCW0603147KFKEA
18 4 R3, R5, R7, R9 RES., CHIP 3.3k 0.1W 5% 0603 Vishay, CRCW06033K30JNEA
19 3 R4, R6, R8 RES., CHIP 100k 0.1W 5% 0603 Vishay, CRCW0603100KJNEA
20 1 R10 RES., CHIP 3k 0.1W 1% 0603 Vishay, CRCW06033K00FKEA
21 0 R11, R12 RES, 0603 Opt
22 1 R14 RES, 0Ω, 0603 Vishay, CRCW0603000JNEA
23 3 R15, R16, R17 RES., CHIP 5.1k 0.1W 5% 0603 Vishay, CRCW06035K10JNEA
24 1 U1 I.C., POWER MONITOR, DFN16DE-4X3 Linear Technology, LTC2946IDE
25 1 U2 I.C., SERIAL EEPROM TSSOP-8 Microchip, 24LC025-I/ST
26 1 Y1 XTAL, 4 MHz, Y-ABLS Abracon Corp., ABLS-4.000MHz-B2-T
28 3 SHUNTS AS SHOWN ON ASSY DWG SHUNT, 2mm CTRS. Samtec 2SN-BK-G
29 4 MH1–MH4 STAND-OFF, NYLON 0.25" Keystone, 8831 (SNAP ON)19
dc2156af
DEMO MANUAL DC2156A
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation
that the interconnection of its circuits as described herein will not infringe on existing patent rights.
Figure 21. DC2156A Demo Circuit Schematic
Schematic Diagram
NOTES: UNLESS OTHERWISE SPECIFIED
1. ALL RESISTORS ARE IN OHMS, 0603.
ALL CAPACITORS ARE IN MICROFARADS, 0603.
2. INSTALL SHUNTS AS SHOWN.
NOTE: EEPROM FOR BOARD IDENTIFICATION
DC590 I2C INTERFACE
* DEFAULT
JUMPER POSITIONS
REMOVE R14 TO SEPERATE SDAI AND SDAO
TO DC590B
VOUT VIN
INTVCC
INTVCC
VGPIO
VGPIO
VPU
VPU
VPU
SIZE
DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. SCALE = NONE
www.linear.com
2 DEMO CIRCUIT 2156A
05/28/2014, 05:25 PM 1 1
WIDE RANGE I2C POWER MONITOR
N/A
LTC2946IDE
KIM T.
SAL H.
WITH ENERGY AND COULOMB METER
SIZE
DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. SCALE = NONE
www.linear.com
2 DEMO CIRCUIT 2156A
05/28/2014, 05:25 PM 1 1
WIDE RANGE I2C POWER MONITOR
N/A
LTC2946IDE
KIM T.
SAL H.
WITH ENERGY AND COULOMB METER
SIZE
DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. SCALE = NONE
www.linear.com
2 DEMO CIRCUIT 2156A
05/28/2014, 05:25 PM 1 1
WIDE RANGE I2C POWER MONITOR
N/A
LTC2946IDE
KIM T.
SAL H.
WITH ENERGY AND COULOMB METER
REVISION HISTORY
DESCRIPTION DATE APPROVED ECO REV
SAL H. PRODUCTION __ 2 05-28-14
REVISION HISTORY
DESCRIPTION DATE APPROVED ECO REV
SAL H. PRODUCTION __ 2 05-28-14
REVISION HISTORY
DESCRIPTION DATE APPROVED ECO REV
SAL H. PRODUCTION __ 2 05-28-14 E19
DEMO MANUAL DC2156A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com? LINEAR TECHNOLOGY CORPORATION 2014
LT 0814 ? PRINTED IN USA
DEMONSTRATION BOARD IMPORTANT NOTICE
Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions:
This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERINGDEVELOPMENT
OR EVALUATION PURPOSES ONLY and is not provided by LTC for commercial use. As such, the DEMO BOARD herein may not be complete
in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety
measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union
directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations.
If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date
of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU
OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS
FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR
ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES.
The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user releases LTC from all claims
arising from the handling or use of the goods. Due to the open construction of the product, it is the user’s responsibility to take any and all
appropriate precautions with regard to electrostatic discharge. Also be aware that the products herein may not be regulatory compliant or
agency certified (FCC, UL, CE, etc.).
No License is granted under any patent right or other intellectual property whatsoever. LTC assumes no liability for applications assistance,
customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind.
LTC currently services a variety of customers for products around the world, and therefore this transaction is not exclusive.
Please read the DEMO BOARD manual prior to handling the product. Persons handling this product must have electronics training and
observe good laboratory practice standards. Common sense is encouraged.
This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LTC application
engineer.
Mailing Address:
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Milpitas, CA 95035
Copyright 2004, Linear Technology Corporation