公开(公告)号：US11387813B2

公开(公告)日：2022-07-12

申请号：US17241044

申请日：2021-04-26

Applicant: MEDIATEK INC.

Inventor： Hsiu-Hsien Ting ,  Po-Chun Huang ,  Yu-Li Hsueh

IPC: H03K3/017 ,  H03K5/00 ,  H03K19/20 ,  G06F1/08

Abstract: A frequency multiplier and a delay-reused duty cycle calibration method thereof are provided. The frequency multiplier includes a first calibration circuit, a second calibration circuit and a controller. In a calibration mode of the frequency multiplier, an output terminal of a delay cell is coupled to an input terminal of the delay cell. The first calibration circuit repeatedly uses the delay cell M times for generating a first delayed signal. The controller controls the delay cell according to the first delayed signal, to find a delay of the delay cell which makes M times the delay be equal to one cycle period of an input clock signal. After the delay is found, the delay cell is repeatedly used M/2 times for generating a second delayed signal. The controller controls the second calibration circuit according to the second delayed signal to make an input calibration signal have a target duty cycle.

公开(公告)号：US20220069809A1

公开(公告)日：2022-03-03

申请号：US17241044

申请日：2021-04-26

Applicant: MEDIATEK INC.

Inventor： Hsiu-Hsien Ting ,  Po-Chun Huang ,  Yu-Li Hsueh

IPC: H03K3/017 ,  H03K5/00 ,  G06F1/08

Abstract: A frequency multiplier and a delay-reused duty cycle calibration method thereof are provided. The frequency multiplier includes a first calibration circuit, a second calibration circuit and a controller. In a calibration mode of the frequency multiplier, an output terminal of a delay cell is coupled to an input terminal of the delay cell. The first calibration circuit repeatedly uses the delay cell M times for generating a first delayed signal. The controller controls the delay cell according to the first delayed signal, to find a delay of the delay cell which makes M times the delay be equal to one cycle period of an input clock signal. After the delay is found, the delay cell is repeatedly used M/2 times for generating a second delayed signal. The controller controls the second calibration circuit according to the second delayed signal to make an input calibration signal have a target duty cycle.