RP400xxx1B Series are high efficiency, step-up DC/DC converter ICs packaged in compact 5pin SOT23 or 6pin DFN(PLP). This converter starts up of low voltage (Typ.0.7V) operation from one to two alkaline or a nickel-metal-hydride (NiMH) or one-cell Lithium-ion (Li+) battery.
This IC consists of a reference voltage unit with soft start, an error amplifier, hase compensation circuits, a slope circuit, a PWM control circuit, a start-up circuit, a PWM/VFM mode control circuit, internal switches and a protection circuit. As a protection circuit, RP400xxx1B has a current limit circuit which limits the peak current of the inductor at each clock cycle.
A low ripple high efficiency step up DC/DC converter can be composed of RP400xxx1B Series with only an inductor, a diode and capacitors. This converter is based on a fixed frequency current mode PWM control which goes to power save mode (VFM mode) at light load automatically. RP400xxx1B Series has built-in Anti-ringing switch to prevent switching node from ringing, when the converter enters the discontinuous current mode.
The output voltage of RP400K001B can be set within 1.8~5.0V (recommended range of output voltage) by external divider resistors.