Regulated Switched-Capacitor Doubler With Interleaving Control for Continuous Output Regulation

A dual-branch 1.8 V to 3.3 V regulated switched-capacitor voltage doubler with an embedded low dropout regulator is presented. For the power stage, the power switches are individually controlled by their phase signals using a phase-delayed gate drive scheme, and are turned on and off in proper sequence to eliminate both short-circuit and reversion currents during phase transitions. For the regulator, the two branches operate in an interleaving fashion to achieve continuous output regulation with small output ripple voltage. Dual-loop feedback capacitor multiplier is adopted for loop compensation and a P-switch super source follower with high current sinking capability is inserted to drive switching capacitive load, and push the pole at the gate of the output power transistor to high frequency for better stability. The regulated doubler has been fabricated in a 0.35 mum CMOS process. It operates at a switching frequency of 500 kHz with an output capacitor of 2 muF , and the maximum output voltage ripple is only 10 mV for a load current that ranges from 10 mA to 180 mA. The load regulation is 0.0043%/mA, and the load transient is 7.5 mus for a load change of 160 mA to 10 mA, and 25 mus for a load change of 10 mA to 160 mA.

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