Patent ID: 8310300

Claim:
A charge pump comprising: a first counter having a control input for receiving a control signal, and an output for providing a first count value, wherein the first count value is incremented in response to the control signal being a first logic state and the first count value is decremented in response to the control signal being a second logic state; a pump stage having a variable capacitor, the variable capacitor having a control input coupled to the output of the first counter for receiving the first count value, wherein a capacitance value of the variable capacitor is changed in response to the first count value changing, and wherein the capacitance value is for determining a ramp-up rate of an output voltage at an output of the charge pump; a second counter having an output for providing a second count value; a digital-to-analog converter having an input coupled to the output of the second counter, and an output for providing an analog representation of the second count value; a comparator having a first input coupled to the output of the digital-to-analog converter, a second input coupled to the output of the charge pump, and an output for providing the control signal to the control input of the first counter; and a switch coupled between the output of the second counter and the input of the digital-to-analog converter, the switch having a control input for receiving a first clock signal.