Clock signal duty ratio adjusting circuit

Abstract

A clock signal duty ratio adjusting circuit comprises a time delay circuit, an AND gate circuit, a square wave generating circuit, an OR gate circuit, and a charge pump. The input end of the charge pump is coupled to the output end of the OR gate circuit, and the output end is coupled to a first input end of the time delay circuit. A second input end of the time delay circuit inputs a clock signal of preset first duty ratio, and the output end is coupled to a second input end of the AND gate circuit. A first input end of the AND gate circuit inputs the clock signal of preset first duty ratio, and the output end is coupled to the clock input end of the square wave generating circuit and a first input end of the OR gate circuit and outputs a duty ratio adjusted clock signal. The output end of the square wave generating circuit is coupled to a second input end of the OR gate circuit, and the square wave generating circuit is suitable for generating a square wave of preset second duty ratio. By using the adjusting circuit, the problem that the output clock signal is unstable during clock signal duty ratio adjustment is avoided effectively.

Description

technical field [0001] The invention relates to the field of clock adjustment, in particular to a clock signal duty ratio adjustment circuit. Background technique [0002] In practical applications, the duty cycle of the clock signal generated by the usual clock generation circuit is 50%. In some special application scenarios, clock signals with other duty ratios are required, for example, the duty ratio of the input clock signal is 25%. [0003] The existing clock duty ratio adjustment generally adopts a method combining a delay circuit and an AND gate circuit. However, although the above solution is relatively easy to implement, there are large errors because the parameters of the delay circuit itself change with changes in process, temperature, voltage and other environmental factors. In order to overcome the above problems, another clock duty ratio adjustment circuit appears, including: AND gate circuit, low-pass filter, error amplifier and voltage control delay circui...

AI Technical Summary

Problems solved by technology

[0004] However, in the above clock duty ratio adjustment method, the low-pass filter is connected to the operational amplifier. Since both the low-pass filter and the operational amplifier have corresponding poles, the above method has the problem of unstable output clock signal.

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