Renesas Electronics ISL78714 Li-Ion Battery Management ICs
Renesas Electronics ISL78714 Lithium-Ion (Li-Ion) Battery Management ICs provide accurate cell voltage and temperature monitoring, cell balancing, and extensive system diagnostics to protect 14-cell Li-ion battery packs while maximizing driving time and range for hybrid and electric vehicles (HEV/MHEV/PHEV/BEV). The feature-rich Renesas ISL78714 monitors and balances up to 14 series-connected cells with ±2mV accuracy across automotive temperature ranges, letting system designers make informed decisions based on absolute voltage levels. The ISL78714 includes a precision 14-bit analog-to-digital converter and associated data acquisition circuitry. The device also offers up to six external temperature inputs (two available from GPIOs), including fault detection and diagnostics for all key internal functions. The ISL78714 comes in a 64-lead TQFP package and offers unmatched lifetime accuracy.
The ISL78714 meets the stringent reliability and performance requirements of battery pack systems for all EV variants, including HEV/PHEV, with safety features enabling automotive manufacturers to achieve the ISO 26262 automotive safety integrity level (ASIL D). In addition, the ISL78714 monitors and reads back over/under voltage, temperature, open-wire conditions, and fault status for 112 cells in less than 10ms or 70 cells in 6.5ms.
Multiple ISL78714 can be connected via a proprietary daisy chain that supports 420 cells (30 ICs) systems that provide industry-leading transient and EMC/EMI immunity, exceeding automotive requirements. 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 the hot plug and high-voltage transients. A watchdog timer automatically shuts down a daisy-chained IC if communications are lost with the master MCU.
A battery management system (BMS) reference design, including five ISL78714 ICs and an RH850/P1M MCU, is available to form a complete 70-cell evaluation platform for external balancing. The reference design kit provides setup and data logging via CAN and UART. Also provided are a GUI, Altium layout files, and low-level drivers for the RH850 peripherals and ISL78714. Hardware, software, and interface reference manuals are included, along with an EMC report.
Features
- Monitors and manages up to 14 cell voltages with ±2mV measurement accuracy
- Robust two-wire daisy chain communications system using a capacitor or transformer coupling up to 1Mbps
- Fully differential cell input range of ±5V accommodates fuel cell and bus bar measurement requirements for aging battery packs
- 15-year board-level accuracy (long-term drift) of ±6mV at ±6σ
- High diagnostic coverage for cell voltage and temperature measurements
- AEC-Q100 Grade-2 qualified and specified for operation from -40°C to +105°C
Applications
- Hybrid electric vehicle (HEV), plug-in hybrid (PHEV), and electric vehicle (EV) battery packs
- Electric motorcycle battery packs
- Backup battery and energy storage systems
- Portable and semi-portable equipment
Typical Application
Associated Solution
Renesas Electronics Automotive Battery Management
Designed to exceed electric vehicles' rigorous safety, reliability, and performance standards.