OUTLINE

The R1282D002A is a CMOS-based 2-channel PWM Step-up (as Channel 1)/Step-down (as Channel 2) DC/DC converter controller.

The R1282D002A consists of an oscillator, a PWM control circuit, a reference voltage unit, an error amplifier, a reference current unit, a protection circuit, and an under voltage lockout (UVLO) circuit. A high efficiency Step-up/Step-down DC/DC converter can be composed of this IC with inductors, diodes, power MOSFETs, resisters, and capacitors. Each output voltage and maximum duty cycle can be adjustable with external resistors, while soft-start time can be adjustable with external capacitors and resistors.

As for a protection circuit, if Maximum duty cycle of either Step-up DC/DC converter side or Step-down DC/DC converter side is continued for a certain time, the R1280D002A latches both external drivers with their off state by its Latch-type protection circuit. Delay time for protection is internally fixed typically at 100ms. To release the protection circuit, restart with power-on (Voltage supplier is equal or less than UVLO detector threshold level).

FEATURES

? Input Voltage Range .........................................2.5V to 5.5V

? Built-in Latch-type Protection Function by monitoring duty cycle (Fixed Delay Time Typ. 100ms)

? Oscillator Frequency.........................................700kHz

? High Accuracy Voltage Reference ....................±1.5

? U.V.L.O. Threshold............................................Typ. 2.2V (Hysteresis: Typ. 0.2V)

? Small Package ..................................................thin SON-10 (package thickness Max. 0.9mm)

APPLICATIONS

? Constant Voltage Power Source for Portable Equipment.

? Constant Voltage Power Source for LCD and CCD.