Single-cell charger

Intersil’s new ISL9204 is a single-cell Li-ion battery charger chip with a 28V input voltage rating that eliminates the over-voltage protection circuit normally required in low-input chargers.

The charger accepts input voltages up to 28V but is disabled when the input voltage exceeds the OVP (over-voltage protection) threshold minimum of 10V, enhancing system protection.

The device is optimised for smaller cell capacities by setting the trickle charge threshold at 2.7V (recommended by small cell manufacturers) and offering charge current accuracy of 10% between 75mA and 150mA.

‘Intersil’s ISL9204 addresses the charging requirements of low-capacity 1-cell Li-ion applications such as Bluetooth headsets and small portable multimedia players,’ said Andrew Baker, product marketing manager of Intersil’s Handheld Power product group. ‘Its tiny 2x3 mm DFN (dual flat no-lead) package enables it to be used in space-constrained and thermally sensitive applications.’

The device performs the constant current/constant voltage (CC/CV) charge function required by Li-ion batteries. The charge current and end-of-charge (EOC) current are programmable with external resistors. When the charge current reduces to the programmable EOC current level during the constant voltage (CV) charge phase, an EOC indication is provided by the charge (CHG) pin, which is an open-drain output. Two indication pins, power present (PPR) and CHG, allow simple interface to a microprocessor or LEDs.