A charge pump (140) having a differential current amplifier with a current source (151) that sources output current (155) in response to a first bias point (141), and a current sink (152) that sinks current in response to a second bias point (142) is provided. The charge pump includes a first level translator (131) that monitors a high range of an output voltage (156) of the differential current amplifier and self-adjusts the first bias point to extend the output voltage to a higher range, and a second level translator (132) that monitors a low range of the output voltage of and self-adjusts the second bias point to extend the output voltage to a lower range. The charge pump keeps the output current constant between the higher range and the lower range. A sensing transistor increases an output impedance of the differential current amplifier and reduces output loading.