15-Cell Battery Stack Monitor with Daisy Chain Interface

The LTC6812-1 is a multicell battery stack monitor that measures up to 15 series connected battery cells with a total measurement error of less than 2.2mV. The cell measurement range of 0V to 5V makes the LTC6812-1 suitable for most battery chemistries. All 15 cells can be measured in 245μs, and lower data acquisition rates can be selected for high noise reduction.

Multiple LTC6812-1 devices can be connected in series, permitting simultaneous cell monitoring of long, high voltage battery strings. Each LTC6812-1 has an isoSPI interface for high speed, RF immune, long distance communications. Multiple devices are connected in a daisy chain with one host processor connection for all devices. This daisy chain can be operated bidirectionally, ensuring communication integrity, even in the event of a fault along the communication path.

The LTC6812-1 can be powered directly from the battery stack or from an isolated supply. The LTC6812-1 includes passive balancing for each cell, with individual PWM duty cycle control for each cell. Other features include an onboard 5V regulator, nine general purpose I/O lines and a sleep mode, where current consumption is reduced to 6μA.

Applications

* Electric and Hybrid Electric Vehicles

* Backup Battery Systems

* Grid Energy Storage

* High Power Portable Equipment

* Measures Up to 15 Battery Cells in Series

* 2.2mV Maximum Total Measurement Error

* Stackable Architecture for High Voltage Systems

* Built-In isoSPI™ Interface

* 1Mb Isolated Serial Communications

* Uses a Single Twisted Pair, Up to 100 Meters

* Low EMI Susceptibility and Emissions

* Bidirectional for Broken Wire Protection

* 245μs to Measure All Cells in a System

* Synchronized Voltage and Current Measurement