LTC4230

With switching frequency as high as 500kHz, The LTC4230 current mode PWM battery charger is the smallest, sim-plest, most efficient solution to fast-charge modern re-chargeable batteries including lithium-ion (Li-Ion), nickel-metal-hydride (NiMH)* and nickel-cadmium (NiCd)* that require constant-current and/or constant-voltage charg-ing. The internal switch is capable of delivering 1.5A DC current (2A peak current). The 0.1Ω onboard current sense resistor of LTC4230 makes the charging current programming very simple. One resistor (or a programming current from a DAC) is required to set the full charging current (1.5A) to within 5% accuracy. The LTC4230 with 0.5% reference voltage accuracy meets the critical constant-voltage charg-ing requirement for lithium cells.

The LTC4230 can charge batteries ranging from 2V to 20V. Ground sensing of current is not required and the battery's negative terminal can be tied directly to ground. A saturat-ing switch running at 200kHz (500kHz for LT1510-5) gives high charging efficiency and small inductor size. A block-ing diode is not required between the chip and the battery because the chip goes into sleep mode and drains only 3µA when the wall adaptor is unplugged. Soft start and shutdown features are also provided. The LTC4230 is available in a 16-pin fused lead power SO package with a thermal resistance of 50°C/W, an 8-pin SO and a 16-pin PDIP.