LTC6812-1 15-Cell Battery Stack Monitor with Daisy Chain Interface FEATURES DESCRIPTION n Measures Up to 15 Battery Cells in Series The LTC 6812-1 is a multicell battery stack monitor that n 2.2mV Maximum Total Measurement Error measures up to 15 series connected battery cells with n Stackable Architecture for High Voltage Systems a total measurement error of less than 2.2mV. The cell n Built-In isoSPI Interface measurement range of 0V to 5V makes the LTC6812-1 n 1Mb Isolated Serial Communications suitable for most battery chemistries. All 15 cells can be n Uses a Single Twisted Pair, Up to 100 Meters measured in 245s, and lower data acquisition rates can n Low EMI Susceptibility and Emissions be selected for high noise reduction. n Bidirectional for Broken Wire Protection Multiple LTC6812-1 devices can be connected in series, n 245s to Measure All Cells in a System permitting simultaneous cell monitoring of long, high n Synchronized Voltage and Current Measurement voltage battery strings. Each LTC6812-1 has an isoSPI n 16-Bit Delta-Sigma ADC with Programmable interface for high speed, RF immune, long distance com- Noise Filter munications. Multiple devices are connected in a daisy n Engineered for ISO 26262-Compliant Systems chain with one host processor connection for all devices. n Passive Cell Balancing Up to 200mA (Max) with This daisy chain can be operated bidirectionally, ensuring Programmable Pulse-Width Modulation communication integrity, even in the event of a fault along n 9 General Purpose Digital I/O or Analog Inputs the communication path. n Temperature or Other Sensor Inputs 2 n Configurable as an I C or SPI Master The LTC6812-1 can be powered directly from the battery n 6A Sleep Mode Supply Current stack or from an isolated supply. The LTC6812-1 includes n 64-Lead eLQFP Package passive balancing for each cell, with individual PWM duty n AEC-Q100 Qualified for Automotive Applications cycle control for each cell. Other features include an on- board 5V regulator, nine general purpose I/O lines and a sleep mode, where current consumption is reduced to 6A. APPLICATIONS All registered trademarks and trademarks are the property of their respective owners. Protected n Electric and Hybrid Electric Vehicles by U.S. patents, including 8908779, 9182428, 9270133. n Backup Battery Systems n Grid Energy Storage n High Power Portable Equipment Cell 15 Measurement Error TYPICAL APPLICATION vs Temperature 2.0 15-Cell Monitor and Balance IC CELL VOLTAGE = 3.3V 1.5 5 TYPICAL UNITS 1.0 + CELL 15 0.5 ISOLATED + 0 CELL 14 DATA WITH LTC6812-1 WIRE BREAK 0.5 PROTECTION + 1.0 CELL 2 + 1.5 CELL 1 68121 TA01a 2.0 50 25 0 25 50 75 100 125 TEMPERATURE (C) 68121 TA01b Rev. B 1 Document Feedback For more information www.analog.com MEASUREMENT ERROR (mV)LTC6812-1 TABLE OF CONTENTS Features ..................................................... 1 Discharge Timer Monitor ........................................35 2 Applications ................................................ 1 I C/SPI Master on LTC6812-1 Using GPIOs ............36 Typical Application ........................................ 1 S Pin Pulsing Using the S Pin Control Settings ......39 Description.................................................. 1 S Pin Muting ........................................................... 41 Absolute Maximum Ratings .............................. 3 Serial Interface Overview ........................................ 41 Order Information .......................................... 3 4-Wire Serial Peripheral Interface (SPI) Physical Pin Configuration .......................................... 3 Layer .......................................................................42 Electrical Characteristics ................................. 4 2-Wire Isolated Interface (isoSPI) Physical Layer ...42 Typical Performance Characteristics ................... 9 Data Link Layer .......................................................52 Pin Functions .............................................. 15 Network Layer ........................................................52 Block Diagram ............................................. 16 Applications Information ................................ 69 Improvements from the LTC6811-1 .................... 17 Providing DC Power ................................................69 Operation................................................... 18 Internal Protection and Filtering ..............................70 State Diagram ......................................................... 18 Cell Balancing .........................................................73 Core LTC6812-1 State Descriptions ........................ 18 Discharge Control During Cell Measurements ........ 74 isoSPI State Descriptions ....................................... 19 Digital Communications ..........................................77 Power Consumption ............................................... 19 Enhanced Applications ............................................85 ADC Operation ........................................................20 Reading External Temperature Probes ....................87 Data Acquisition System Diagnostics .....................25 Package Description ..................................... 88 Watchdog and Discharge Timer ..............................32 Revision History .......................................... 89 Reset Behaviors ......................................................34 Typical Application ....................................... 90 S Pin Pulse-Width Modulation for Cell Balancing ...35 Related Parts .............................................. 90 Rev. B 2 For more information www.analog.com