Drop-In Upgrade: ST Launches New Automotive Battery Management IC

STMicroelectronics has introduced the L9963F, a new automotive battery-management IC designed for lithium-ion battery packs in electric vehicles, hybrid systems, and industrial energy storage applications. The new L9963F IC is essentially an upgrade to the company’s existing L9963E platform, adding monitoring, balancing, and functional safety capabilities.

STMicroelectronics’ L9963F battery-management IC supports lithium-ion monitoring and balancing for EV and energy storage systems. 

The L9963F (datasheet linked) supports monitoring of four to 14 battery cells per IC and can scale to systems containing up to 434 series-connected cells through daisy-chained devices. ST is targeting EV battery packs, 48-V systems, UPS systems, industrial storage, e-bikes, and e-scooters where accurate cell monitoring, synchronized measurements, and functional safety are critical to battery reliability and vehicle operation.

Fully Compatible Upgrade to the L9963E Platform

Rather than introducing an entirely new IC format, STMicroelectronics designed the L9963F IC as a direct replacement for the earlier L9963E. Existing users can upgrade their current systems without making any major changes to PCB layouts or software.

Typical application of the L9963F. See page 4 of the datasheet for an enlarged image. 

The IC monitors between four and 14 stacked lithium-ion cells and can support larger battery arrays by simply connecting multiple devices into the existing daisy chain. Working systems can scale up to 31 battery packs and 434 total series-connected cells while also maintaining synchronized communication and measurement timing across the chain. That scalability is important in automotive power design because battery pack assemblies vary significantly between 48-V mild hybrids, full EV platforms, and stationary storage systems. 

High-Accuracy Monitoring and Synchronized Sampling

The L9963F integrates a 16-bit ADC with a maximum voltage measurement error of ±2 mV across a 0.5-V to 4.3-V range. STMicroelectronics has also implemented fully synchronized current and voltage sampling with 0-µs desynchronization delay between samples, which helps improve state-of-charge calculations, balancing accuracy, and fault detection in larger battery systems. The L9963F will also include coulomb counting for pack current monitoring and overcurrent detection during both ignition-on and ignition-off conditions.

Block diagram of the L9963F. See page 5 of the datasheet for an enlarged image.

Communication between stacked L9963F devices uses a 2.66-Mbps isolated serial interface with less than 4-µs latency between the first and 31st device in a chain. ST says full conversion and readout times remain below 16 ms even in systems monitoring up to 434 cells. The L9963F also supports passive balancing currents up to 200 mA per cell in both normal and silent-balancing modes, allowing balancing functions to continue during low-power operation while minimizing battery drain.

Functional Safety and Fault Protection

The L9963F adds several safety and diagnostic features for automotive battery systems, including a redundant cell-measurement path with ADC swap capability to support fault tolerance and limp-home operation. The L9963F is designed for ISO 26262 and ASIL-D systems and includes redundant fault reporting through both SPI communication and a dedicated FAULT line. ST also integrated nine GPIOs, support for up to seven NTC temperature sensors, programmable balancing control, dual 5-V regulators, automatic diagnostics, and hot-plug protection without requiring external zener components across cells.

With the new L9963F IC, STMicroelectronics expands its battery-management portfolio while keeping compatibility with the earlier L9963E platform. This gives end users a combination of scalable cell monitoring, synchronized sampling, isolated communication, passive balancing, and ASIL-D support that targets EVs, hybrid vehicles, and energy-storage systems.

All images used courtesy of STMicroelectronics.