1. A phase lock loop comprising: a controlled oscillator responsive to a control voltage for producing an output signal of some output frequency; a comparator responsive to a feedback signal derived from the output signal and to a reference signal for producing at least one error signal; a charge pump circuit comprising multiple pairs of unidirectional current sources; a control circuit responsive to at least one control signal and to said at least one error signal for activating one or more pairs of unidirectional current sources, at the same time deactivating one or more pairs of unidirectional current sources; and a loop filter responsive to the multiple pairs of unidirectional current sources for producing said control voltage.