Synchronous time-to-charge converter

Abstract

A time-to-charge converter (TCC) includes a phase detector configured to receive a first clock and a second clock and output a phase error signal indicative of the time difference between the second clock and the first clock; a current source configured to generate a tail current; a current directing network configured to direct the tail current towards either a first node or a second node based on the phase error signal; a synchronous clock generator configured to receive the first clock and generate a third clock that is synchronous to the first clock but has an independently determined duty cycle; an integration capacitor having a top plate connected to the second node and a bottom plate driven by an inversion of the third clock; a switch positioned between a third node and the second node, controlled by the third clock; and a load capacitor attached to the third node.