Battery pack monitor IC for multi-cell Li-ion batteries

August 25, 2015 // By Graham Prophet
Intersil's ISL94203 is a 3-to-8 cell battery pack monitor that supports lithium-ion (Li-ion) and other battery chemistries used in medical mobility carts, wheelchairs, e-bikes, handheld power tools, vacuum cleaners and solar or renewable energy storage systems.

The device has been designed to accurately monitor, protect and cell-balance rechargeable battery packs to maximise battery life and ensure safe charging and system operation. It functions as a stand-alone battery management system for rechargeable Li-ion battery packs. Its internal state machine has five pre-programmed stages that accurately control each cell of a battery pack to extend operating life. The IC integrates high-side charge/discharge FET drive circuitry, which allows customers to securely ground-reference the battery pack to their designs.

The ISL94203 includes several programmable protection and monitoring features to safeguard battery packs from catastrophic events such as short circuit conditions and cell voltage shorts. It has an open wire check to ensure the IC is securely connected to the battery pack. The device also has a special protection feature that blows a polyfuse to render the battery pack inoperable in the event of a catastrophic failure. In addition to delivering diagnostic information, the ISL94203 can withstand battery pack hot plug events and support the full range of Li-ion chemistries.

The company says the combination of features simplifies design of Li-ion rechargeable battery management systems. Features include:

  1. Integration of cell voltage level shift, automatic cell balance, 14-bit ADC, current sense monitor, power FET control, temperature sensor interface;
  2. Eight cell voltage monitors support Li-ion CoO2, Li-ion Mn2O4, Li-ion phosphate and other battery chemistries;
  3. Operates as a standalone solution or with a microcontroller;
  4. Integrated charge pump controls cutoff FETs used to charge/discharge battery pack;
  5. Multiple cell voltage protection options up to 4.8V;
  6. Programmable detection/recovery times for over-voltage, under-voltage, over-current and short circuit conditions;
  7. Open wire detection;
  8. EEPROM storage for device configuration;
  9. Power saving algorithm activated when battery pack is not in use.

In a 6 x 6 mm, 48-lead TQFN package, the part is priced at $2.19 (1000). The ISL94203EVKIT1Z evaluation kit is priced at $328, and includes an evaluation board, interface board with USB to I²C interface, and software GUI that supports