Patent ID: 6486728
Filing Date: 2002-11-26
Classification: H02M

Abstract:
A charge pump comprising a lower voltage input and a higher voltage output, the charge pump comprising:a first charge pump stage comprising a first voltage input, a first voltage output, and a first clock input; a second charge pump stage comprising a second voltage input, a second voltage output, and a second clock input; each charge pump stage operative to pump charge from the respective voltage input to the respective voltage output in response to transitions of a respective clock signal applied to the respective clock input; said first voltage input connected to the second voltage output, and said first voltage output connected to the higher voltage output of the charge pump such that substantially all charge pumped by the second charge pump stage that reaches the higher voltage output is also pumped by the first charge pump stage; a control circuit operative to enable the first charge pump stage in a first mode of operation and to enable both the first and second charge pump stages in a second mode of operation; wherein a voltage of the higher voltage output of the charge pump is greater in the second mode than in the first mode.