Patent ID: 6690218
Filing Date: 2004-02-10
Classification: H03K

Abstract:
A method of performing duty cycle correction of an input signal having a non-uniform duty cycle using a capacitor-degenerating differential pair circuit comprising:a step for inputting to the circuit the input signal having the non-uniform duty cycle; a step for forming a DC voltage across one or more capacitors in the circuit which is representative of the difference in duration between positive and negative portions of the input signal duty cycle; a step for deriving a DC switching level from the DC voltage; a step for forming, through a switching action of the differential pair circuit, an output signal having a duty cycle, whereby durations of positive and negative portions of the output signal duty cycle are defined by crossover points between the input signal and the DC switching level; a step for adjusting the DC voltage until the output signal duty cycle is at least substantially uniform; wherein the capacitor-degenerating differential pair circuit comprises one or more capacitors coupled between the emitters of a differential pair of bipolar transistors.