The pulse width modulation circuit composed of 74HCUO4

Published:2011/7/17 20:46:00 Author:Borg | Keyword: pulse width, modulation circuit | From:SeekIC

In the figure is the pulse width modulation circuit composed of 74HCUO4. this is a multi-resonance oscillator composed of the Miller integrating circuit and time lag comparing circuit, if the rectangular wave duty cycle is changed by the input low frequency signal of R1, the pulse width can be modulated. C1 is the AC separation capacitor. The frequency of the rectangular wave is (1/4)[1/(R2C2)](R4/R3). According to the given element parameter, the frequency is about 900KHZ. R2 can compose a backward feedback, which is used to reduce the distortion. As the threshold voltage and output voltage amplitude are relevant to the power supply voltage, so S/N is affected by the power supply noise, which is to be noticed.



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