Japanese semiconductor manufacturer Renesas Electronics has announced its fourth-generation Li-ion battery management integrated circuit (IC). The company says its new ISL78714 IC provides accurate cell voltage and temperature monitoring, cell balancing, and extensive system diagnostics to protect 14-cell Li-ion battery packs, all while maximizing drive time and range for hybrid and electric vehicles.

The ISL78714 monitors and balances up to 14 series-connected cells with ±2mV accuracy across automotive temperature ranges. It includes a precision 14-bit analog-to-digital converter and associated data acquisition circuitry. The device also offers up to six external temperature inputs and includes fault detection and diagnostics for all key internal functions.

The device meets reliability and performance requirements of battery pack systems for all EV variants, including hybrids and plug-in hybrids, with safety features enabling automotive manufacturers to achieve the ISO 26262 automotive safety integrity level (ASIL D). The IC monitors and reads back over/under voltage, temperature, open wire conditions, and fault status for 112 cells in less than 10 milliseconds.

Multiple ISL78714 units can be connected together via a proprietary daisy chain that supports systems up to 420 cells (30 ICs). The ISL78714’s daisy-chain architecture uses low-cost capacitive or transformer isolation, or a combination of both, with twisted-pair wiring to stack multiple battery packs together while protecting against hot plug and high-voltage transients. A watchdog timer automatically shuts down a daisy-chained IC if communication with the master MCU is lost .

The device features a fully differential cell input range of ±5V that accommodates fuel cell and bus bar measurement requirements for aging battery packs and a 15-year board level accuracy (long term drift) of ±6 mV @ ±6σ.

Renesas Senior Director Niall Lyne said, “The ISL78714 battery management IC enables battery management systems with a best-in-class combination of battery pack monitoring accuracy, fast data acquisition, and fault checking features.”

Source: Renesas