Intersil introduced the ISL9214, a fully integrated low-cost single-cell Li-ion or Li-polymer battery charger. The ISL9214 is a charger for smart handheld devices that need to communicate with a personal computer via a USB. The charger accepts two power inputs, normally one from a USB (Universal Serial Bus) port and the other from a desktop cradle. 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 which protects the IC against over-temperature. If the die temperature rises above a typical value of +125°C, 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 CHG (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 CHG pin will indicate a logic HIGH signal. This status is latched and will be reset under one of these events: (1) the part is disabled and re-enabled; (2) the selected input source has been removed and reapplied, (3) the USBON turns LOW, or (4) the BAT pin voltage falls below the recharge threshold (~4.0V).
Key Features
- Complete charger for single-cell Li-ion/polymer batteries
- Dual input power sources for cradle and USB
- Integrated pass elements
- Fixed 380mA USB charge current
- Programmable cradle charge current
- Charge current
- Thermaguard for thermal protection
- 28V maximum voltages for cradle and USB inputs
- Adapter presence and charge indications
- Less than 0.5µA leakage current off the battery when no input power attached
- Programmable end-of-charge current
- Ambient temperature range: -40°C to +85°C
- No external blocking diode required
- Pb-free plus anneal available (RoHS compliant)
The ISL9214 is available now in a 10-lead DFN package and is priced at $1.25 in 1,000-unit quantities.
