Patent ID: 6169444
Filing Date: 2001-01-02
Classification: H02M

Abstract:
A circuit for regulating a charge pump receiving an input signal across an input terminal and a common terminal and producing an output signal across an output terminal and the common terminal, wherein the input signal has an input voltage and the output signal has an output voltage and the charge pump includes an input capacitor connected across the input terminal and the common terminal, and an output capacitor connected across the output terminal and the common terminal, and a flying capacitor having a first side and a second side, the circuit comprising: an oscillator which, when enabled by an enable signal, produces an oscillator signal that alternates between a first state and a second state; a detection sub-circuit producing an error signal when the output voltage deviates from a desired output voltage, wherein said error signal has voltage representative of how much the output voltage differs from said desired output voltage; a channel-switch sub-circuit suitable for connecting the flying capacitor across the common terminal and the input terminal when said oscillator signal is in said first state, and alternately connecting the flying capacitor across the common terminal and the output terminal when said oscillator signal is in said second state; said channel-switch sub-circuit further suitable for controllably setting resistance to the flying capacitor responsive to voltage in said error signal when said oscillator signal is in said first state; and an enable sub-circuit producing said enable signal when said error signal has voltage exceeding said desired output voltage by a preset amount, for regulating the charge pump by enabling said oscillator to operate said channel-switch sub-circuit to alternately charge the flying capacitor at a rate controlled by resistance set by said channel-switch sub-circuit from the input terminal and to discharge the flying capacitor via the output terminal into the output capacitor.