High Precision PWM Wave Generating Circuit

Published:2011/7/22 21:39:00 Author:Michel | Keyword: High Precision, PWM Wave, Generating Circuit | From:SeekIC

The above picture is high precision PWM wave generating circuit.This circuit uses the number and data to control the dutyfactor accurately and constantly in 1%~99% range on the basis of 1% step.It can be used as calibration and adjustment PWM demodulation circuit or used as D/A converter sources D/A converter sources in PWM way.74 HC04 inverter and X1 (2 MHZ) constitute the crystal oscillator circuit and its work is very stable and the highest work frequency is 2MHZ.74 HHC190 (1) and 74 HCl90 (2) demodulate and get 20KHZ clock frequency.Once 74 HC190 (2) outputs 100 clock pulse it triggers the bistable multivibrator 74 HC74 one time.Reset method is that using comparators 74 HC85 (1) and (2) 74 HC85 to set.The clock pulse stops counting, circuit resets 74H04 outputs dutyfactor wave which is equal to setting value and the waveform resolution is 1%.



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