Reduced-Ripple p-Channel Metal-Oxide-Semiconductor Field-Effect Transistor Charge Pump Circuit with Small Filtering Capacitance

摘要

This paper presents a two-stage, two-phase, p-channel metal-oxide-semiconductor field-effect transistor (PMOSFET) charge pump with special two-step clocks for ripple reduction. The ripple voltage can be reduced by adjusting the overdrive voltage during charge transfer. The charge pump including the circuit of the proposed clocks and 5_pF boosting capacitance was fabricated using 0.35um complementary metal-oxide-semiconductor field-effect transistor (CMOSFET) technology in an area of 0.182mm~2. With the new clock scheme, high voltage gain and driving capacity without overstress of the transistors are preserved. The experimental results reveal that the output voltage ripple is reduced from 23.2 to 12.8mV for an output current of 36uA at a frequency of 10 MHz and a supply voltage of 1.8 V, which indicates a 45% ripple reduction without increasing filtering capacitance.