Patent attributes
A charge pump includes a resistor divider connected between an output voltage node and ground and a comparator inputting a reference voltage at one input, and a divided voltage from the resistor divider at another input. A digital control circuit is enabled by the comparator. A first transistor and a second transistor are in series between an input voltage node and the ground, both transistors controlled by the digital control circuit. A pump capacitor is connected between to the output voltage node and between the first and second transistor, and being charged by turning the first and second transistors on and off. A first diode is between the pump capacitor and the input voltage node. A second diode between the pump capacitor and the output voltage node. A reservoir capacitor between the output voltage node and ground. The digital control circuit comprises a first shift register. The first transistor comprises a first plurality of parallel transistors, the first shift register includes any of a first plurality of DQ, RS or JK flip flops connected in series, and outputs of the flip flops control gates of the first plurality of parallel transistors.
