Li-ion management IC for batteries up to 25V

For Li-ion battery packs up to 25V, STMicroelectronics has introduced an IC for monitoring, balancing and protection, aiming at cordless power tools, back-up energy storage and medical devices.

Called L9961, its “built-in features include a dual pre-driver for controlling battery-pack safety relays, which can be programmed for high-side and low-side connection”, said ST. “An embedded non-volatile memory for configuration data relieves the microcontroller from reprogramming the device at each start-up. An I²C interface handles configuration and host communication to share battery state-of-charge and state-of-health.”

Through an ADC and current-sense amplifier, cell voltages are measured to ±15mV, and battery current to 0.25%. Through these, passive cell balancing and coulomb counting can be implemented.

Protections include over-voltage, under-voltage, balance under-voltage, over-current, and short-circuit-in-discharge.

With an optional thermistor, protection can be extended to pack over and under-temperature, and there is programmable output designed to blow a safety fuse via an optional external n-mosfet if certain conditions, classified as permanent failures, arise.

Hot plugging is supported.

Two power-saving modes cut the consumption – to 2μA in deep sleep and 5μA in stand-by.

A 3.3 V regulator is available for supplying external circuitry in both stand-by and normal operation modes.

Packaging is 5 x 5 x 1mm 32pad VFQFPN.

For more information, the L9961 product web page can be found on line here