Battery-pack monitor safeguards hybrid and electric vehicle power systems

Intersil has introduced the ISL78610, a new 12-cell lithium-ion (Li-ion) battery-pack monitor. The device provides cell balancing and accurate voltage and temperature monitoring to safeguard Li-ion battery packs in hybrid electric vehicles, plug-in hybrid electric vehicles, and electric vehicles. System designers can use the ISL78610 as a standalone battery-pack monitor or as a redundant back-up device when combined with the high accuracy ISL78600 multi-cell battery manager. This powerful combination enables automobile manufacturers to achieve the higher ISO 26262 automotive safety integrity level (ASIL) D rating. The feature-rich ISL78610 monitors and balances up to 12 cells with accurate voltage readings and diagnostics. This lets system designers make informed decisions based on absolute voltage levels rather than simply receiving a “system not OK” signal indicating an out-of-range condition. The ISL78610 includes a voltage reference, 14-bit analog-to-digital converter and registers for control and data, while connecting directly to a microcontroller through its 2Mbps SPI interface. The device also offers four external temperature inputs, and includes fault detection and diagnostics for all key internal functions. The battery monitoring and management ICs meet the stringent safety, reliability and performance requirements of next generation automotive battery pack systems. Together, the ISL78610 and ISL78600 offer internal and external fault detection such as open wire, over and under voltage as well as temperature and cell balancing faults to mitigate battery pack failures. Multiple devices can be daisy-chained together to support systems with up to 168 cells using a proprietary communications system that provides industry-leading transient and EMC/EMI immunity, which exceeds carmaker requirements. Intersil’s daisy-chain architecture uses low-cost capacitive isolation with twisted pair wiring to stack multiple battery packs together, while the ICs internal protection guards against hot plug and high voltage transients. A watchdog timer automatically shuts down a daisy-chained IC if communications is lost with the master microcontroller. “The ISL78610 battery pack monitor provides customers the right combination of Li-ion battery pack monitoring and control features,” said Philip Chesley, senior vice president, precision products, Intersil. “Teaming the monitor with the ISL78600 battery manager also gives carmakers the robustness, accuracy and redundancy required to achieve an ASIL-D compliant battery management system.”