Patent ID: 8380138

Claim:
An apparatus for adjusting a duty cycle of a periodic signal to generate an adjusted signal, the adjusted signal being alternately high (HI) and low (LO) over each cycle, the apparatus comprising: a dual-phase charge pump configured to, during a first phase, supply current to a charge pump node when the adjusted signal is HI and to sink current from the charge pump node when the adjusted signal is LO, the dual-phase charge pump further configured to, during a third phase, supply current to the charge pump node when the adjusted signal is LO and to sink current from the charge pump node when the adjusted signal is HI; a charge and sample module comprising an integration capacitor having first and second terminals, the charge and sample module configured to: during the first phase, couple the first terminal of the integration capacitor to the charge pump node, the second terminal of the integration capacitor being coupled to ground; during a second phase, sample a voltage across the integration capacitor using a second sampling capacitor; during the third phase, couple the second terminal of the integration capacitor to the charge pump node, the first terminal of the integration capacitor being coupled to a supply voltage; during a fourth phase, sample the voltage across the integration capacitor using a first sampling capacitor; and a de-skew module for adjusting the duty cycle of the periodic signal to generate an adjusted periodic signal, the duty cycle of the periodic signal adjusted according to a voltage across the first sampling capacitor.