Efficient differential charge pump with sense and common mode control

摘要

A differential charge pump circuit for use in a phase-locked loop (PLL) circuit is disclosed. The circuit includes a reference current, two sense amplifiers, a common mode control amplifier, and an h-bridge circuit. The h-bridge circuit is coupled to the reference current and the common mode control amplifier. The reference current drives a first portion of the h-bridge circuit and the common mode control amplifier controls a second portion of the h-bridge circuit. The h-bridge circuit also includes first and second nodes. The circuit controls a voltage at the first node so that it is substantially equal to a voltage at the second node for a plurality of voltages at the second node.