Intersil’s highly-integrated Li-ion charger safeguards battery in automotive eCall systems



ISL78692, a 4.1V single-cell battery charger

Intersil, a leading provider of innovative power management and precision analog solutions, announced the ISL78692, a 4.1V single-cell battery charger designed to extend the life of lithium-ion (Li-ion) batteries in automotive emergency call (eCall) systems. The ISL78692 battery charger dissipates lower leakage current (3uA) than competing solutions, allowing the backup battery to remain charged for a longer period of time. Lower charging voltage also extends battery life while the device’s small footprint reduces total solution size.

Vehicles equipped with eCall systems automatically place a call to an emergency service center in the event of an accident. The ISL78692 Li-ion battery charger is designed to support emerging worldwide emergency call systems such as Europe’s eCall initiative, which brings rapid assistance to motorists involved in a collision anywhere in the European Union, and OnStar®, which provides a safety and security service in the United States.

The ISL78692 charger’s ability to monitor the battery’s temperature and its low, 4.1V output voltage both help to extend the life of popular LiFeP04 batteries. Highly integrated, the ISL78692 requires only five external components to program the charging current. When combined with the charger’s compact 3mm x 3mm DFN package, the complete solution easily fits on space-constrained PCBs. The ISL78692 also offers a unique charge current thermal foldback feature that prevents overheating by automatically reducing the battery charging current, creating a very robust, small footprint design.

“OEMs want an automotive-qualified battery charger that prevents rapid discharging of the vehicle’s backup battery when parked for an extended period of time,” said Philip Chesley, vice president of Intersil’s Precision Products. “The ISL78692 leverages Intersil’s proprietary power management technology to deliver a solution with the industry’s lowest leakage current and most optimized feature set for eCall automotive applications.”

Features and Specifications:
• Complete charger for single-cell Lithium batteries
• 3uA leakage (max) over -40°C to 85°C temperature range increases the duration the backup battery remains charged when Vin supply is off
• Up to 1A programmable charging current, allows trade-off of battery charging time against heat dissipation and expected battery lifetime
• Guaranteed operation down to 2.65V after start-up, preventing shut off during cold-crank start
• 1% initial voltage accuracy provides precise control of charging level to extend operating lifetime of battery
• Integrated power transistor and current sensor
• 10% trickle charge preconditions fully drained battery until it reaches 2.8V minimum charge level
• NTC thermistor input protects battery by monitoring temperature and shuts off charger when battery is outside the specified charging temperature
• AEC-Q100 grade 3 qualified

The ISL78692 Li-ion battery charger is available now in a 10-pin, 3mm x 3mm DFN package and is priced at $0.99 USD in 1k quantities. The ISL78692 is supported by the ISL78692EVAL1Z evaluation board, which is available for $56 USD each.

ISL78692 Li-ion battery charger