DC1697A - Demo Manual

DEMO MANUAL DC1697A
LTC2945
Wide Range I2C Power Monitor
DESCRIPTION
Demonstration circuit 1697A features the LTC2945. The
LTC2945 is a rail-to-rail system monitor that measures
current, voltage, and power. It features an operating range
of 2.7V to 80V and includes a shunt regulator for supplies
above 80V to allow flexibility in the selection of input supply. The current common mode measurement range of
0V to 80V is independent of the input supply. An onboard
0.75% 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. 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. The
demo board is populated for a 5A application. This can
be changed by populating R1 accordingly.
Design files for this circuit board are available at
http://www.linear.com/demo/DC1697A
L, LT, LTC, LTM, QuikEval, Linear Technology and the Linear logo are registered trademarks of
Linear Technology Corporation. All other trademarks are the property of their respective owners.
BOARD PHOTO
TO DC590
4V TO 80V
LOAD
dc1697A F01
Figure 1. Proper Test Equipment Setup
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1
DEMO MANUAL DC1697A
QUICK START PROCEDURE
Jumper Settings
VDD_SEL: 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 Hardware Setup section for examples of how these different jumper settings
are used.
SDA: Connects or separates the SDAI to SDAO pins. For use
with QuikEval™, leave it on TIE. The pins can be separated
in order to test applications using optoisolation.
ADIN: ADC input measured by the onboard ADC. Can
measure between 0V and 2.048V.
VPU: Pull up voltage for the ALERT LED. Connected on this
board to a 5V isolated supply on the DC590. If a DC590
is not used and the DC1697A is operated independently,
a 5V supply should be provided here.
Digital Connections
SCL: I2C Clock turret
ADR0, ADR1: Selects the I2C slave address of the LTC2945.
Any changes here should also be made inside of QuikEval
for communications to persist.
SDA/SDAI: I2C Bus Data input, can be tied to SDAO through
the SDA Jumper.
External Connections
ALERT: Fault Alert Output. Connected to ALERT LED. Open
Drain logic output that is pulled to ground after an event
resulting in a fault occurs.
Signal connections are made via the row of turret posts
along the edges of the board.
GND: (4 turrets)These turrets are connected directly to
the ground planes.
VIN: Used as a supply and current sense input for the
internal current sense amplifier. Depending on the
configuration of VDD_SEL, can also be tied to EXTVDD.
EXTVDD: High Voltage Supply Input. This pin powers an
internal series regulator with input voltages ranging from
5V to 80V and produces 5V for INTVCC when above 7V.
INTVCC: Internal Low Voltage Supply Input/Output. 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. Please
see LTC2945 data sheet for more details.
2
SDAO: I2C Bus Data output. Should be connected to SDAI.
LEDs
ALERT: Will light up red on an ALERT condition. Can also
be monitored on the ALERT turret.
INTVCC: Will light up green when INTVCC is providing
power.
Operating Principles
The DC1697A was designed to be connected to the DC590
and controlled through the QuikEval suite of software. All
thresholds can be set and ADC registers read back through
the QuikEval interface, which was designed to provide a
convenient way to evaluate the LTC2945.
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DEMO MANUAL DC1697A
HARDWARE SETUP
Due to having separate VDD and SENSE pins, the LTC2945
offers great flexibility in terms of supply options. The following are some examples of how to connect and set up the
DC1697A based on different supply input configurations.
In order for the DC1697A to function, power must be
applied. If the VDD_SEL jumper is set to VIN, then VDD and
VIN are connected as shown in Figure 2. At this point, as
long as 4V to 80V is provided at VIN the part will function
correctly. However, should VDD_SEL be tied to EXTVDD
then a separate voltage source should be provided at the
EXTVDD turret. Should VDD_SEL be tied to INTVCC then,
if VIN is less than 7V, a 5V supply should be provided at
the INTVCC turret.
If the system is connected properly, the INTVCC green
LED should be lit and the ALERT red LED should be off.
Jumper VDD_SEL Set to VIN to Tie VDD to VIN
4V TO 80V
LOAD
dc1697A F02
Figure 2. DC1697A Is Powered from Supply Being Monitored
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3
DEMO MANUAL DC1697A
HARDWARE SETUP
INTVCC can also be used as a 6.3V shunt regulator. For
supplies greater than 80V, simply connect power through
a shunt resister for high or low shunt configuration as
shown in Figure 3 and 4 respectively. For this configuration,
ensure VDD_SEL is set to INTVCC.
The 5k shunt resistor shown provides 15mA to INTVCC at
80V. The allowable range of resistance for a given input
range is given by the following formula:
VS(MAX) – 5.9V
VS(MIN) – 6.7V
≤ RSHNT ≤
35mA
1mA +ILOAD(MAX)
The DC590 provides isolation and level shifting, as the
I2C interface is operating at 5.9V to 6.7V below the supply
being monitored.
Jumper VDD_SEL Set to INTVCC With A Resistor Connected from DC1697 GND to Circuit Ground
> 80V
dc1697A F03
5k
Figure 3. Powering DC1697A Using High-Side Shunt Regulator to Allow for Input Voltage Higher Than 80V
4
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DEMO MANUAL DC1697A
HARDWARE SETUP
Jumper VDD_SEL Set to INTVCC with a Resistor Connected to INTVCC
0V TO 80V
LOAD
> 80V
5k
dc1697A F04
Figure 4. Powering DC1697A Through Low-Side Shunt Regulator in High-Side Current Sense Topology
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5
DEMO MANUAL DC1697A
HARDWARE SETUP
–48V systems can also be monitored by simply setting
VDD_SEL to EXTVDD with the –48V input tied to VIN 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 at earth ground potential.
TO DC590 (PROVIDES ISOLATION)
–48V RETURN
–48V INPUT
LOAD
–48V RETURN
dc1697A F05
Figure 5. Current Monitoring in a –48V System with the DC590 Providing Isolation
6
dc1697afa
DEMO MANUAL DC1697A
SOFTWARE SETUP
Figure 6.
The DC1697A control panel was designed to allow the user
to quickly evaluate the LTC2945. The user has the ability
to set fault thresholds, enable/disable and clear alerts as
well as change the source for the VIN measurement. Rsens
is set to 20mΩ by default on the DC1697A, should any
changes be made to the board, the corresponding value
should be entered into the software GUI. By pressing
RUN, the software interface will begin using the DC590
for data collection.
The Alert Persist option modifies how the ALERT pin and
LED on the board react. With Alert Persist checked, on
an ALERT the corresponding FAULT button will light up
red on the software GUI. The ALERT LED should also be
red on the DC1697A itself. Click the Clear Alerts button
to clear all alerts.
With Alert Persist not enabled, an alert event will still light
up the corresponding FAULT button, however the ALERT
LED on the board will turn on briefly before turning off due
to a read by the GUI from the Fault Register. The QuikEval
GUI constantly polls registers in order to properly graph
and monitor the part. In a real world situation, these repeated reads are not necessary. The Alert Persist option
was designed to simulate real world behavior while still
providing a friendly interface.
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DEMO MANUAL DC1697A
PARTS LIST
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
1
2
1
C1
Cap., X7R, 0.1µF, 100V, 10%, 1206
AVX 12061C104KAT2A
1
C2
Cap., X7R, 1000pF, 100V, 10%, 0603
AVX 06031C102KAT2A
MURATA, GRM188R72A102KA01D
3
2
C3, C4
Cap., X5R, 0.1µF, 25V, 20%, 0603
AVX 06033D104KAT2A
4
1
D1
Voltage Supressor, 75V
DIODES/ZETEX SMAJ75A-13-F
5
1
D2
LED, GRN PLCC-2 (B-Size)
VISHAY VLMC3101-GS08
6
1
D3
LED, RED PLCC-2 (B-Size)
VISHAY VLMS3000-GS08
7
4
E1, E2, E3, E4
Turret, Testpoint .062 Thick Brd.
MILL-MAX 2501-2-00-80-00-00-07-0
8
10
E5-E14
Turret, Testpoint 0.063"
MILL-MAX 2308-2-00-80-00-00-07-0
9
1
JP1
CONN., HDR., MALE, 2 × 3, 2mm, THT, STRT
SULLINS, NRPN032PAEN-RC
10
1
JP2
CONN., HDR., MALE, 1 × 3, 2mm, THT, STRT
SULLINS, NRPN031PAEN-RC
11
2
JP3, JP4
CONN., HDR., MALE, 1 × 4, 2mm, THT, STRT
SULLINS, NRPN041PAEN-RC
12
1
J1
Header, 2 mm CTRS
MOLEX, 878 31-1420
13
1
Q1
N-Channel, MOSFET SOT23
DIODES/ZETEX. 2N7002-7-F
14
1
R1
Res., LRC 0.020, 1.0W, 1%, 2010
IRC LRF20 10LF-01-R020-F
15
1
R2
Res., Chip 51, 0.1W, 5%, 0603
VISHAY CRCW060351R0JNEA
16
1
R3
Res., Chip 10k, 0.1W, 5%, 0603
VISHAY CRCW060310K0JNEA
PANASONIC, ERJ3GEYJ103V
17
0
R4, R5 (OPT)
Res., 0603
OPT.
18
3
R6, R7, R8
Res., Chip 5.1k, 0.1W, 5%, 0603
VISHAY CRCW06035K10JNEA
19
2
R9, R10
Res., Chip 3.3k, 0.1W, 5%, 0603
VISHAY, CRCW06033K30JNEA
NIC, NRC06J332TRF
PANASONIC, ERJ3GEYJ332V
20
0
TP1 (OPT)
CONN., HDR., MALE,1X2, 2mm, THT, STRT
SULLINS, NRPN021PAEN-RC
IC, Wide Range I2C Power Monitor, QFN-12(UD)
LINEAR TECHNOLOGY CORP. LTC2945CUD
21
1
U1
22
1
U2
I.C., Serial EEPROM TSSOP-8
MICROCHIP 24L C025-I/ST
23
4
SHUNTS AS SHOWN ON
ASSY DWG
Shunt, 2mm CTRS.
SAMTEC 2SN-BK-G
8
dc1697afa
D
C
B
A
E14
E13
JP3
ADR0
4
3
2
1
VIN
HI
LO
FLOAT
JP4
ADR1
4
3
2
1
C2
1000pF
100V
D1
SMAJ75A-13-F
R2
51
4
3
2
1
WP
SCL
A1
A2
1
(OPT)
SDA
VSS
24LC025-I/ST
TP1
VCC
A0
U2
8
5
6
7
R6
5.1K
R7
5.1K
JP1
6
5
2
4
3
1
VDD_SEL
HIGH VOLTAGE LINES
C4
0.1uF
R8
5.1K
QUICK EVAL DEMO ONLY
LO
ADIN
GND
E8
E6
E2
E1
FLOAT
HI
INTVCC
EXTVDD
GND
VIN
0V - 80V
VIN
2
14
12
11
9
10
5
7
4
6
2
1
EXTVDD
INTVCC
J1
NC
EEGND
EESCL
EESDA
EEVCC
MISO
SDA/MOSI
SCK/SCL
CS
5V
VUNREG
MOLEX
TO DC590B
C3
0.1uF
C1
0.1uF
100V
1206
87831-1420
INTVCC
GND
2
GND
13
GND
8
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.
3
1
3
2
1
13
6
SCL
SDAI
SDAO
ALERT
SENSE-
CUSTOMER NOTICE
VPU
SCL
5
GND EP
EXPOSED PAD
U1
9
R3
7
8
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
3
/ALERT
INTVCC
1
SDA
TIE
0603
R5
(OPT)
PRODUCTION
R10
3.3K
VOUT
5
3
2
Q1
2N7002
VLMC3101
D2
GRN
INTVCC
R9
3.3K
0603
UNTIE
R4
(OPT)
JP2
/ALERT
VLMS3000
D3
RED
ALERT
4
SCALE = NONE
MARK T.
KIM T.
APPROVALS
DATE:
N/A
SIZE
E12
VPU
E11
SCL
IC NO.
LTC2945CUD
DEMO CIRCUIT 1697A
10/26/2012, 06:09 PM
5
SHEET
1
OF
4
1
REV.
WIDE RANGE I2C POWER MONITOR
TITLE: SCHEMATIC
TECHNOLOGY
SDAI
SDAO
E10
GND
E9
E7
ALERT
DATE
10-26-12
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900 www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
1. ALL RESISTORS ARE IN OHMS, 0603.
ALL CAPACITORS ARE IN MICROFARADS, 0603.
2. INSTALL SHUNTS AS SHOWN.
NOTES: UNLESS OTHERWISE SPECIFIED
10K
E5
GND
VOUT
5A
MARK T.
APPROVED
REVISION HISTORY
DESCRIPTION
E4
10
4
REV
E3
LTC2945CUD
SDA/SDAI
4
ADIN
11
SENSE+
__
ECO
0.020
1%
2010
4
R1
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES.
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APP ENG.
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
ADR0
ADR1
INTVCC
VDD
12
3
D
C
B
A
DEMO MANUAL DC1697A
SCHEMATIC DIAGRAM
dc1697afa
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DEMO MANUAL DC1697A
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 ENGINEERING DEVELOPMENT
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
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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
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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
10 Linear Technology Corporation
dc1697afa
LT 0616 REV A • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
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