	US 11,916,557 B2
	Clock spread spectrum circuit, electronic equipment, and clock spread spectrum method
Xiangye Wei, Beijing (CN); Liming Xiu, Beijing (CN); and Yuhai Ma, Beijing (CN)
Assigned to BEIJING BOE TECHNOLOGY DEVELOPMENT CO., LTD., Beijing (CN); and BOE TECHNOLOGY GROUP CO., LTD., Beijing (CN)
Filed by BEIJING BOE TECHNOLOGY DEVELOPMENT CO., LTD., Beijing (CN); and BOE TECHNOLOGY GROUP CO., LTD., Beijing (CN)
Filed on Jun. 9, 2022, as Appl. No. 17/836,419.
Application 17/836,419 is a continuation of application No. 16/980,930, granted, now 11,381,229, previously published as PCT/CN2019/083901, filed on Apr. 23, 2019.
Prior Publication US 2022/0302911 A1, Sep. 22, 2022
Int. Cl. H03K 5/1252 (2006.01); G06F 1/04 (2006.01); H03K 5/00 (2006.01)

CPC H03K 5/1252 (2013.01) [G06F 1/04 (2013.01); H03K 5/00006 (2013.01)]

10 Claims

1. A clock spread spectrum circuit, comprising:

a control circuit, configured to generate a frequency control word according to a modulation parameter, wherein the frequency control word changes discretely with time; and

a signal generation circuit, configured to receive the frequency control word and generate and output a spread spectrum output signal that is spectrum-spread according to the frequency control word, wherein the spread spectrum output signal corresponds to the frequency control word;

wherein the signal generation circuit comprises:

a base time unit generation sub-circuit, configured to generate and output a base time unit; and

a spread spectrum sub-circuit, configured to generate and output the spread spectrum output signal according to the frequency control word and the base time unit;

the spread spectrum sub-circuit is a time average frequency direct period synthesizer;

wherein the frequency control word is expressed as:

F(t)=I+r(t),

wherein F(t) is the frequency control word, I is an integer part of the frequency control word, I is a constant and an integer, r(t) is a decimal part of the frequency control word, r(t) is a decimal and discretely changes with the time, and t represents the time;

wherein the modulation parameter comprises a spread spectrum depth coefficient, a spread spectrum reference value, a modulation rate, and a modulation mode, which correspond to the spread spectrum output signal,

the control circuit comprises: a decimal generation sub-circuit, configured to generate the decimal part according to the spread spectrum depth coefficient, the spread spectrum reference value, the modulation mode, and the modulation rate;

wherein the decimal generation sub-circuit comprises:

a frequency modulation control module, configured to generate a frequency modulation clock signal according to the modulation rate to control a rate of change of the frequency control word; and

a decimal generation module, configured to generate and output the decimal part to a synthesis sub-circuit according to the modulation mode, the spread spectrum depth coefficient, and the spread spectrum reference value under control of the frequency modulation clock signal;

wherein the decimal generation module comprises a selection sub-module and a plurality of modulation mode sub-modules corresponding to a plurality of modulation modes,

the plurality of modulation modes comprise at least two modulation modes selected from a group consisting of a triangle modulation mode, a sawtooth modulation mode, a sinusoidal modulation mode, and a random modulation mode,

each modulation mode sub-module of the plurality of modulation mode sub-modules is configured to generate a middle decimal part corresponding to a modulation mode corresponding to the modulation mode sub-module according to the modulation mode corresponding to the modulation mode sub-module, the spread spectrum depth coefficient, and the spread spectrum reference value;

the selection sub-module is configured to select one of a plurality of middle decimal parts generated by the plurality of modulation mode sub-modules as the decimal part according to the modulation mode.