Common-mode feedback method using a current starved replica biasing

A method, system, and circuit design product for setting the common-mode voltage level of a charge pump to yield low duty cycle distortion from a voltage controlled oscillator (VCO). Differential charge pumps utilize common-mode feedback (CMF) networks to control the common-mode voltage level. A replica circuit of a current starved delay cell from a VCO replaces the unity gain buffering circuit within a common-mode feedback circuit. Inserting the current starved delay cell replica circuit permits adequate negative feedback compensation, while allowing a phase locked loop (PLL) to operate with a wide bandwidth. As a result of utilizing the replica circuit of a current starved delay cell from a VCO, the common-mode voltage level is optimally centered to interface with the VCO, thereby minimizing duty cycle distortion.