PWM STEP-DOWN DC-DC CONTROLLER

DESCRIPTION

The UTC UC4601/A is a PWM step-down DC/DC controller. It has a

low supply current. The step-down DC/DC converter with low ripple,

high efficiency performance is conveniently configured with additional

external components, such as a power-transistor, an inductor, a diode

and capacitors. The output voltage can be adjusted with external

components.

The UTC UC4601/A contains a high precision band-gap voltage

reference, a PWM control circuit, a soft-start circuit, a protection circuit,

an oscillator, an error amplifier with built-in compensation network and

input/output voltage detection circuits.

The UTC UC4601/A based DC/DC converter can performance well

when maintaining stability, which is due to its built-in state-of-art control

algorithm. Further, if the term of maximum duty cycle retains on a

certain time, the embedded protection circuits restart the operation with

soft-start and repeat until the maximum duty cycle condition is

released. Finally, the internal UVLO function blocks potentially unstable

output when the input voltage reaches the UVLO threshold or less. This

is aiming at making this circuit standby for low power consumption.

The UTC UC4601/A can be applied in battery-powered equipment,

hand-held communication equipment, cameras, video instruments

such as VCRs, camcorders, household electrical appliances.

FEATURES

* Input voltage varies from 2.3V to 15V

* Internal soft-start and protection function

* High efficiency up to 90% (TYP.)

* High output voltage accuracy: ±2%

* Standly current: 0.1μA (TYP.)

* CMOS output capability