R1282D002A Datasheet, PDF (1/18 Pages) RICOH electronics devices division – 2CH PWM DC/DC CONTROLLER

2CH PWM DC/DC CONTROLLER
R1282D002A SERIES
NO. EA-086-0502
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.
1