Dual-input charger chip is well protected

The ISL9214 is an ideal charger for smart handheld devices that need to communicate with a personal computer via a USB.

Intersil has introduced a fully integrated low-cost single-cell Li-ion or Li-polymer battery charger.

Because the ISL9214 provides dual input power sources for desktop cradle and USB, minimal components are necessary, offering the customer cost and board space savings.

The ISL9214 is an ideal charger for smart handheld devices that need to communicate with a personal computer via a USB.

Due to the 28V-rated inputs for the cradle and USB, the ISL9214 offers an extra level of protection to a Li-ion battery from charging system failures.

With its 28V input rating, large, low-cost output tolerance adapters can be used safely.

When both inputs are powered, the cradle input is used to charge the battery.

The ISL9214's charge current is programmable for the cradle input with a small resistor.

The end-of-charge current is also programmable by another external resistor.

The charger incorporates Thermaguard that protects the IC against overtemperature.

If the die temperature rises above a typical value of +125C, a thermal foldback function reduces the charge current automatically to prevent further temperature rise.

The charger has two indication pins.

The PPR (power present) pin outputs an open-drain logic low when either the cradle or the USB input power is attached.

The charge pin is also an open-drain output that indicates a logic low when the charge current is above a minimum current level.

When the charge current of the ISL9214 is below the preset minimum current, the charge pin will indicate a logic high signal.

This status is latched and will be reset under one of these events: the part is disabled and re-enabled; the selected input source has been removed and reapplied; the USB on turns low; or the battery pin voltage falls below the recharge threshold (4.0V).

Other key features include integrated pass elements, a fixed 380mA USB charge current, less than 0.5uA leakage current off the battery when no input power attached, an ambient temperature range of -40 to +85C, and no external blocking diode is required.

Target applications for the ISL9214 include smart handheld devices, cellphones, PDAs, MP3 players, digital still cameras and handheld test equipment.

The ISL9214 is available now in a 10-lead DFN package.

Pb-free plus anneal is also available (RoHS compliant).

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