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 dc1697afa 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. dc1697afa 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 dc1697afa 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 dc1697afa 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 dc1697afa 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. dc1697afa 7 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 9 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 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 10 Linear Technology Corporation dc1697afa LT 0616 REV A • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 2013