Closed-loop step-down fractional charge pump converter in 0.18um CMOS technology

This paper presents a digitally controlled closed-loop step-down charge pump converter with fractional conversion ratios, implemented in TSMC 0.18um 1P6M CMOS technology. A simple and area-efficient implementation of charge-pump converter with low ripple output voltage and fast settling time response implementation is achieved. The feedback loop configuration provides the circuit load protection from overvoltage. Moreover, this converter can function at 1 MHz operational frequency having a 2.2V to 3.3V input voltage suitable for battery applications. A regulated 1.1V output voltage with 10mA load current is achieved, with 10mV output voltage ripple, 82.9μs settling time, and 83.39% peak efficiency.