Second Generation High Voltage Battery Stack MonitorSecond Generation High Voltage Battery Stack Monitor

Linear Technology's LTC 6803 is a second generation highvoltage battery monitor for hybrid/electric vehicle (HEVs), electric vehicles(EVs) and other high voltage, high performance battery systems. The LTC6803 isa complete battery measuring IC that includes a 12-bit ADC, a precision voltagereference, a high voltage input multiplexer and a serial interface. EachLTC6803 can measure up to 12 individual battery cells in series. The device'sproprietary design enables multiple LTC6803s to be stacked in series withoutoptocouplers or isolators, permitting precision voltage monitoring of everycell in long strings of series-connected batteries. The LTC6803 follows theLTC6802 with the same functionality and pinout, plus a number of significantperformance enhancements.

The maximum total measurementerror of the LTC6803 is guaranteed to be less than 0.25 percent from -40 to125C. The LTC6803 offers an extended cell measurement range from -300mV to 5V,enabling the LTC6803 to monitor a wide range of battery chemistries, as well assupercapacitors. Each cell is monitored for undervoltage and overvoltageconditions, and an associated MOSFET is available to discharge overchargedcells. Added functionality is provided by an onboard 5V regulator, temperaturesensor, GPIO lines and thermistor inputs.

For long-term battery packstorage, the current consumed by the integrated BMS can potentially unbalancethe cells. The LTC6803 addresses this concern with a standby mode that drawsless than 12uA. The power input of the LTC6803 is isolated from the stack,allowing the LTC6803 to draw current from an independent source. When poweringfrom this input, the current draw on the pack is reduced to less than 1AmuA.

Second Generation High Voltage Battery Stack Monitor