Maxim Integrated MAX17320 Li+ fuel gauge IC

The MAX17320 fuel-gauge and protection circuit, from Maxim Integrated Products, is designed to extend run time on multi-cell battery-powered products while also monitoring against self-discharge hazards.

The product is a pack-side fuel gauge and protector IC for 2 to 4 series (2S-4S) lithium-ion (Li+) cells and is equipped with Maxim Integrated’s ModelGauge m5 EZ algorithm; this is said to deliver 40% more accurate state-of-charge (SOC) readings than competitive offerings, eliminating the need for battery characterisation for most common Li+ cells. The fuel gauge offers low quiescent current (IQ) — claimed to be 85% lower than the nearest competitor — supporting long product shelf life.

Damaged or defective batteries may develop an internal cell leakage which can progressively get worse and can result in fire or explosion; however, until now there were no solutions for detecting self-discharge that develops during normal usage of the battery. The MAX17320 warns the system and disables a leaky battery before a potentially hazardous outcome. This is in addition to battery protection that allows fine tuning of voltage and current thresholds based on various temperature zones. The IC also provides a secondary protection scheme that permanently disables the battery by assisting a secondary protector or blowing a fuse in severe fault conditions.

The device is designed to ensure safe charging and discharging in 2S-4S Li+ battery applications by protecting against abnormal voltage, current and temperature conditions. Internal self-discharge detection provides systems with an early warning and cuts off potentially hazardous batteries. It delivers protection against cloning with SHA-256 authentication while providing a unique or dynamic key for every battery. It can run in an ultralow-power mode, enabling the system to read the SOC instantly as it wakes up without being disconnected from the battery cells during shipment or when stored on the shelf.