Patent ID: 7944257

Claim:
A charge pump for a phase-locked loop circuit, comprising: a sourcing current source providing a sourcing current, wherein the sourcing current source is coupled to a high-voltage voltage supply; a sourcing differential switch steering the sourcing current direction, wherein the sourcing differential switch is coupled between the sourcing current source and an output of the charge pump; a sourcing control circuit using a low-voltage sourcing control signal to selectively source the sourcing current to the output, wherein the sourcing control circuit receives a low-voltage charging-up signal from a phase frequency detector of the phase-locked loop circuit; a sinking switch; a sinking current source providing a sinking current, wherein the sinking current source is coupled between the output and the sinking switch; and a sinking control circuit using a low-voltage sinking control signal to selectively sink the sinking current to ground, wherein the sinking control circuit receives a low-voltage charging-down signal from the phase frequency detector of the phase-locked loop circuit.