Patent attributes
The present invention discloses a negative charge pump feedback circuit, wherein the feedback circuit is connected between an AND gate and the output terminal of the negative charge pump, and a clock signal is connected to the negative charge pump through the AND gate and under the control of the feedback signal, with the feedback circuit including a switch-capacitor circuit and a comparator; a first terminal of a first capacitor of the switch-capacitor circuit is connected to the output terminal of the negative charge pump through a first switch, and grounded through a second switch; a first terminal of a second capacitor is connected to a second terminal of the first capacitor, grounded though a third switch, and connected to the comparator though a fourth switch; an adjustable capacitor is connected in parallel to both terminals of the second capacitor; a positive-phase input terminal of the comparator is connected to a reference voltage. The switch-capacitor circuit is made to switch constantly between two states by the control of four control signals over the four switches, achieving voltage division and positive/negative voltage conversion simultaneously. The present invention can reduce the circuit area, increase the feedback speed, and reduce the output voltage ripple of the charge pump.