Patent ID: 8427208
Filing Date: 2013-04-23
Classification: H03K,H03L,H04L

Abstract:
1. A phase interpolator, comprising: a selector that supplies four-phase clock signals to a first mixer and a second mixer; the first mixer that generates a first clock signal having a first phase lead angle and a second clock signal having a phase lead angle of 180 degrees with respect to the first clock signal on the basis of the clock signals supplied from the selector according to a first control signal defining the first clock signal and the second clock signal to be generated and the first phase lead angle to be given to the clock signals; the second mixer that generates a third clock signal having a phase lead angle of 90 degrees with respect to the first clock signal and a fourth clock signal having a phase lead angle of 270 degrees with respect to the first clock signal on the basis of the clock signals supplied from the selector according to a second control signal defining the third clock signal and the fourth clock signal to be generated and the second phase lead angle to be given to the clock signals; a first phase detector that computes an exclusive OR of the first clock signal output from the first mixer and the third clock signal output from the second mixer; a second phase detector that computes an exclusive OR of the second clock signal output from the first mixer and the fourth clock signal output from the second mixer; a first charge pump circuit that converts the exclusive OR output from the first phase detector to a first voltage signal; a second charge pump circuit that converts the exclusive OR output from the second phase detector to a second voltage signal; an analog digital converter that generates a digital signal from a signal generated on the basis of a composite signal of the first voltage signal output from the first charge pump circuit and the second voltage signal output from the second charge pump circuit; and an adder that adds the digital signal output from the analog digital converter to the first control signal to generate the second control signal and supplies the second control signal to the second mixer.