Integrated multi-cell battery pack monitor enables smallest designs

March 13, 2017 // By Nick Flaherty
ISL94202 battery pack monitor
Intersil, now a subsidiary of Renesas Electronics, has launched a 3-to-8 cell battery pack monitor that supports lithium-ion (Li-ion) and other battery chemistries for vacuum cleaners, lawn equipment, handheld power tools, e-bikes, scooters, toys, and energy storage systems.

The highly integrated ISL94202 battery pack monitor enables ultra-small 2-terminal designs, and accurately monitors, protects and cell balances rechargeable battery packs to ensure safe operation and charging. 

The monitor operates as a stand-alone battery protection system using an internal state machine with five pre-programmed modes for accurately balancing and controlling each battery cell. It monitors and protects the battery pack from catastrophic events such as hardware faults, short circuit conditions, and cell voltage overcharge/over-discharge and meets the UL2054, UL2271/72 and IEC62133 specified pack safety requirements.

Designers can program the ISL94202 battery monitor’s protection settings to enable the industry’s smallest, low-cost battery packs without requiring an external microcontroller. If required, the ISL94202 can also communicate with an external microcontroller via I2C serial bus to provide additional fuel gauge measurements, including state of charge and state of health information. Precise fuel gauge status is provided by the device’s high-side current measurement feature.

The ISL94202 integrates high-side charge/discharge FET drive circuitry, which makes it easy to interface to tools or electric motor equipment. The device also controls external passive cell balancing switches to ensure good cell energy matching while protecting the pack’s cell life from chronic undercharging. In addition, the ISL94202 can withstand factory pack assembly hot plug events, which greatly simplifies manufacturing.