Charge pump circuit, PLL circuit, and, PLL frequency synthesizer

摘要

A charge pump circuit which may be used in a PLL includes a charge/discharge circuit, a detection circuit and an adjusting circuit. The charge/discharge circuit performs a charge operation in response to a first pulse signal and a discharge operation in response to a second pulse signal and outputs an output signal having a voltage based on the charge and the discharge operations. The detection circuit detects whether a charge operation or a discharge operation was performed and generates a control signal. The adjusting circuit adjusts the charge and discharge operations so that a charge amount and a discharge amount per unit time become substantially equal to each other.