Key features of the RAJ240090- and RAJ240100-based battery management IC solutions:

(1) Integrated microcontroller (MCU) that enables flexible support for a wide variety of industrial battery system specifications
The new solutions are the industry’s first (Note 1) Li-ion battery management ICs for industrial equipment supporting three to ten cells to feature an integrated low-power RL78 MCU. They integrate the remaining capacity measurement and safety monitoring functions, such as overvoltage and overcurrent, and Renesas’ low-power RL78 MCU into a single package to provide flexible support for a wide variety of industrial battery system specifications. This provides a high-precision A/D converter (required for battery control voltage measurement) and MCU that have been matched and adjusted beforehand, thereby contribute to substantially reducing the need for calibration. In addition, the peripheral functions required by industrial applications, including power supply, field effect transistor (FET) driver, and real-time clock, are included on-chip. This can reduce the BOM cost of the battery management system block by approximately 30 percent compared to other Renesas products.

(2) Rich design support tools that enable even beginners to easily implement battery systems with a high level of safety

Renesas plans to release development startup support tools, such as reference software, reference circuit diagrams, and setup manuals. The support tools will enable changes to parameter setting and simplify Li-ion battery pack design, and to enable faster solutions for battery management.

(3) Maintenance of high safety level through constant safety monitoring in ultra-low-power mode, with the ability to safely shut down the system if a problem occurs

The RAJ240090 and RAJ240100 support a ultra-low-power mode, which reduces current consumption to only 25 µA. This allows battery monitoring functions to operate constantly, even when the system is powered off. A record-keeping function can store information such as battery history to monitor deterioration and store system faults in the MCU memory. The MCU can issue an alarm and disable battery to prevent Li-ion battery failure.

In addition, the battery management ICs support a system configuration in which N-channel MOSFETs are positioned at the positive poles of the battery cells (Note 2). This means that if the battery management IC fails, the system can be shut down safely. If, on the other hand, the MCU enters a runaway state, the battery protection function of the analog front-end block can continue to operate independently, providing failsafe for enhanced system safety.