R1211D101A Datasheet | RICOH

R1211x SERIES STEP-UP DC/DC CONTROLLER NO.EA-088-0604 OUTLINE The R1211x Series are CMOS-based PWM step-up DC/DC converter controllers with low supply current. Each of the R1211x Series 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 low ripple, high efficiency step-up DC/DC converter can be posed of this IC with some external ponents, or an inductor, a diode, a power MOSFET, divider resisters, and capacitors. Phase pensation has been made internally in the R1211x002B/D Series, while phase pensation can be made externally as for R1211x002A/C Series. B/D version has stand-by mode. Max duty cycle is internally fixed typically at 90%. Soft start function is built-in, and Soft-starting time is set typically at 9ms(A/B, 700k Hz version) or 10.5ms(C/D, 300k Hz version). As for the protection circuit, after the soft-starting time, if the...