STMicroelectronics has priced its new 10-cell battery-management IC, the L9962, at $2.89 each in 1,000-unit orders. The device packs a 12-bit analog-to-digital converter, cell balancing at up to 70mA, and 0.25% current-measurement accuracy into a 7mm x 7mm 48-pin TQFP package.

The L9962 targets lithium-ion and lithium-polymer packs with up to 10 series-connected cells. ST positions it in cordless power tools and other portable and semi-portable equipment. The listed applications include medical devices, light electric vehicles such as e-bikes and scooters, and backup energy storage such as UPS systems.

What does the chip actually do?

The core job is measurement. The L9962 reads individual cell voltages on a continuous cycle with a programmable loop time. When it detects overvoltage or undervoltage, it activates balancing and protection functions. A plausibility check compares the total stack voltage against the number of cells, which helps catch wiring faults and failed readings.

The device also holds its voltage-measurement accuracy across the full operating-temperature range. That matters because cell voltages must remain tightly aligned for a pack to deliver its rated lifetime. In plain terms: better measurement keeps cells from drifting apart, and drifting cells are what kill packs early.

How does it track current and heat?

A high-accuracy current-sense amplifier supports Coulomb counting, the standard method for estimating remaining charge. By watching pack current closely, the chip can flag excessive charge and discharge currents and provide short-circuit discharge protection. ST specifies 0.25% current-measurement accuracy over the full temperature range.

Thermal monitoring uses an NTC thermistor with ratiometric measurement. This detects both over-temperature and under-temperature conditions at the pack level. The takeaway: voltage, current and temperature are measured on one die, so a pack designer needs fewer external parts to build a complete safety case.

How does it cut the bill of materials?

ST has integrated several functions that normally require separate components:

• Battery-pack fuse management
• Configurable high-side and low-side pre-drivers for pack relays
• A 3.3V low-dropout regulator that stays on in standby, powering an external MCU or indicator LEDs

An I2C interface lets the host configure parameters such as the voltage-measurement interval and read back state-of-charge and state-of-health data. Each integration removes a part from the board, and at a $2.89 price point the argument is volume-driven simplicity.

Where does the power budget go?

Quiescent current is the spec that decides shelf life. The L9962 draws 5µA in standby and 2µA in deep-sleep, a mode intended for products in transit. For a pack that may sit in a warehouse or a shipping container for months, that 2µA figure is the difference between arriving charged and arriving flat.

ST claims the ultra-low quiescent current maximizes runtime and enables these power-saving modes without giving up monitoring capability. The plain version: the chip watches the battery while barely drawing from it.

For designers of mid-size packs in power tools, light mobility and backup storage, the L9962 offers a single-chip monitoring, balancing and protection path with a published price, which should sharpen competition in the sub-$3 battery-management segment.