PHASE DETECTION CIRCUITS AND METHODS

摘要

A phase detector circuit compares the phases of first and second periodic input signals to generate an output signal. The phase detector includes a circuit that makes two different combinations of the first and the second periodic input signals to generate third and fourth periodic signals. This circuit causes the third periodic signal to be based on a first combination of the first periodic signal and the second periodic signal that imparts a first relative phase shift. The circuit causes the fourth periodic signal to be based on a second combination of the first periodic signal and the second periodic signal to provide a different relative phase shift. The phase detector also includes a comparison circuit that compares a measure of the power of the third periodic signal to a measure of the power of the fourth periodic signal to generate the phase comparison output signal.