Duty-cycle correction circuit and method for differential clocking

Abstract

A completely differential approach to correcting duty-cycle distortions of a differential clock signal propagating through a differential amplifier. A duty-cycle distortion correction (DCDC) differential amplifier circuit / device is provided with a differential amplifier whose output wires are coupled to a correction circuit. The correction circuit comprises a differential low pass filter and a differential correction amplifier. The differential correction amplifier's output is dotted back into the output of the amplifier. The differential output of the amplifier is passed through the low pass filter, which provides differential DC output signals that triggers respective correction amplifier transistors to generate an inverted correction current that is added back to respective differential output pulse. The DCDC differential amplifier provides a completely differential approach to correction of duty-cycle distortions within the differential output.

Description

technical field [0001] The present invention relates generally to circuit devices, and more particularly to signal propagation through circuit devices. More specifically, the present invention relates to methods and circuit devices for correcting duty cycle distortion in a signal propagating through a circuit device. Background technique [0002] Duty cycle in a circuit device is a measure of the rise pulse time of a clock signal propagating through the device compared to the cycle time. For many current device implementations, these clock signals are differential clock signals (rather than single-ended clock signals), and their duty cycles tend to exhibit distortion as they propagate through the device. [0003] For example, a conventional circuit device such as an ASIC (Application Specific Integrated Circuit) receives and propagates a differential clock input signal with rising and falling pulses through a differential clock tree consisting of a series of amplifiers (or ...

AI Technical Summary

Problems solved by technology

However, these single-ended feedback circuits are prone to noise and require additional circuitry to convert between differential and single-ended signaling

In addition, the design requires a large area due to the use of replicators and other feedback conversion devices

In summary, these circuits have inherent problems of poor noise rejection, duty cycle distortion, higher power and larger area

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