STEP-UP DC/DC CONTROLLER
The R1212D is a CMOS-based PWM step-up DC/DC controller with low supply current. Internally, the R1212D consists of an oscillator, a PWM comparator circuit, a reference voltage unit, an error amplifier, a reference current unit, a protection circuit, and an under voltage lockout (UVLO) circuit. A low ripple, high efficiency stepup DC/DC converter can be composed of this IC with some external components, or an inductor, a diode, a power MOSFET, divider resistors, and capacitors.
The maximum duty cycle and the soft start time are easily adjustable with external resistors and capacitors. In terms of maximum duty cycle, with or without internal limit can be set by mask options. As for the protection circuit, after the soft-starting time, if the maximum duty cycle is continued for a certain period, the R1212D latches the external driver with its off state, or the latch-type protection circuit works. The delay time for latch the state can be set with an external capacitor. To release the protection circuit, restart with power-on (Voltage supplier is equal or less than UVLO detector threshold level).
|Input Voltage Range||2.2V to 5.5V|
|Built-in Latch-type Protection Function (Output Delay Time can be set with an external capacitor)|
|Two Options of Basic Oscillator Frequency||700kHz, 1.4MHz, 300kHz|
|Maximum Duty Cycle/Soft-start time||Adjustable with external capacitors
(If internal limit is set by version, Typ. 90% or Typ. 91.5%)
|High Reference Voltage Accuracy||±1.5%|
|UVLO Threshold level||Typ.1.9 V/ 2.1 V/ 2.8 V by mask option|
|Small Temperature Coefficient of Reference Voltage||Typ. ±150ppm/°C|
- ・Constant Voltage Power Source for portable equipment.
- ・Constant Voltage Power Source for LCD and CCD.
|Data Sheet||Flyer||Package Info.||Mark Info.||Quality Assurance Data|
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