Patent ID: 6329872
Filing Date: 2001-12-11
Classification: H03L

Abstract:
A charge pump circuit for sourcing current to and sinking current from an external circuit, the charge pump circuit comprising:first transistor means comprising first and second transistors, each having an input control electrode and two other electrodes, the other two electrodes of both transistors being connected in series, the series-connected first and second transistors causing a first current to flow therein upon application of operating voltage to the first transistor means which develops a first voltage in response to the first current;second transistor means comprising third and fourth transistors, each having an input control electrode and two other electrodes, the other two electrodes of both transistors being connected in series, upon application of the operating voltage, the second transistor means causing a second current to flow in the third transistor and a third current to flow in the fourth transistor, a second voltage being developed across the external circuit in response to the second or third current;first feedback means for providing a first signal in response to the first and second voltages, the first signal being fed to the input control electrode of the first transistor;second feedback means for providing a second signal in response to a reference voltage and a third voltage, the second signal being fed to the input control electrode of the second transistor;first feeding means for feeding the first signal to the input control electrode of the third transistor in response to a first input signal;second feeding means for feeding the second signal to the input control electrode of the fourth transistor in response to a second input signal; andstart-up means for initializing the first transistor means so that a start-up current flows therein wherein the sourcing current is the second current, the sinking current is the third current, and the third voltage is from the first transistor means.