AD8280:  Lithium Ion Battery Safety Monitor

The AD8280 is a hardware-only safety monitor for Lithium Ion battery stacks. The part has inputs to monitor six battery cells and two temperature sensors (either NTC or PTC thermistors). The part is designed to be daisy chained with additional AD8280’s to monitor a stack of significantly more than six cells, but without the need for numerous isolators. Its output can be configured for independent or shared alarm state.

The part functions independently from a primary monitor, such as the AD7280, containing its own reference and LDO, both of which are powered completely from the battery cell stack. The reference, in conjunction with external resistor dividers, is used to establish trip points for the over/under-voltages. Each cell channel contains programmable de-glitching (D/G) circuitry to avoid alarming from transient input levels.

The AD8280 also has two digital pins that can be used to select various combinations of the inputs in the case where there are less than six cells to be monitored. Most importantly, it has a self-test feature making it suitable for high-reliability applications, such as automotive hybrid electric vehicles. It can function over a temperature range of -40°C to +105°C.

• Lithium Ion Battery Back-up Monitor
• Ideally Suited for companion to AD7280 Primary Monitor
• Lithium Ion Battery Threshold Detection