Boost convertor steps up handheld voltages

A novel monolithic, micropower, high-frequency step-up DC/DC switching convertor boosts the voltage from one or two NiMH or NiCd cells up to a usable level of 1.8 or 3.3V.

The NCP1423 is a monolithic, micropower, high-frequency step-up DC/DC switching convertor that boosts the voltage from one or two nickel metal-hydride (NiMH) or nickel cadmium (NiCd) cells up to a usable level of 1.8 or 3.3V.

This new device is specifically designed for battery-operated portable electronic products, supplying up to 400mA load - including wireless optical mice and keyboards, wireless headsets, audio players, PDAs and other handheld devices.

The NCP1423 integrates synchronous rectification to improve efficiency and to eliminate the external Schottky diode.

Its high switching frequency (up to 600kHz) allows for a low profile, small-sized inductor and output capacitor to be used.

When the device is disabled, the internal conduction path from the LX or bat pin to the out pin is fully blocked - and the out pin is isolated from the battery.

This true-cutoff function effectively reduces the shutdown current.

A ring-killer feature has also been integrated to eliminate the high-frequency ringing in discontinuous conduction mode.

Additional features - such as a low-battery detector, cycle-by-cycle current limit and thermal shutdown - provide other benefits for various battery-operated applications.

For example, with all these functions enabled, the quiescent supply current is typically only 9.0uA, thereby minimising battery current drain.

The NCP1423DMR2 is available in a Micro-10 package and prices at $0.95 per unit in 10,000-unit quantities.

Back to top