12 Channel Multicell Battery Monitor with Daisy Chain Interface, Generation 1

The LTC6802-1 is a complete battery monitoring IC that includes a 12-bit ADC, a precision voltage reference, a high voltage input multiplexer and a serial interface. Each LTC6802-1 can measure up to 12 series connected battery cells with an input common mode voltage up to 60V. In addition, multiple LTC6802-1 devices can be placed in series to monitor the voltage of each cell in a long battery string. The unique level-shifting serial interface allows the serial ports of these devices to be daisy-chained without optocouplers or isolators.

When multiple LTC6802-1 devices are connected in series they can operate simultaneously, permitting all cell voltages in the stack to be measured within 13ms.

To minimize power, the LTC6802-1 offers a measure mode, which simply monitors each cell for overvoltage and undervoltage conditions. A standby mode is also provided.

Each cell input has an associated MOSFET switch for discharging overcharged cells.

For large battery stack applications requiring individually addressable serial communications, see the LTC6802-2.

SPI Interface

Features

LTC6802-1

Daisy Chain

Multiple devices can be connected in serial fashion without digital isolation

LTC6802-2

Addressable

Parallel addressed SPI interface - each device in a chain communicates with a control processor in parallel via external digital isolators

Applications

* Electric and Hybrid Electric Vehicles

* High Power Portable Equipment

* Backup Battery Systems

* High Voltage Data Acquisition Systems

* Qualified for Automotive Applications

* Measures Up to 12 Li-Ion Cells in Series (60V Max)

* Stackable Architecture Enables >1000V Systems

* 0.25% Maximum Total Measurement Error

* 13ms to Measure All Cells in a System

* Cell Balancing:

* On-Chip Passive Cell Balancing Switches

* Provision for Off-Chip Passive Balancing