CLOCK-CONTROLLED PULSE WIDTH MODULATOR

摘要

A clock-controlled pulse width modulator comprises an integrator for receiving a variable input voltage and producing an output having a triangular waveform, the integrator including a capacitor which is charged at a rate proportional to the input voltage and discharged at a rate proportional to the difference between a reference voltage and the input voltage, the charging and discharging occurring during a time interval To, a clock pulse source for generating a continuous series of clock pulses, a counter receiving the clock pulses and producing a binary control signal which changes state in response to the counting of a preselected number of clock pulses, the control signal having a period To, and a control unit for terminating the charging of the capacitor and initiating the discharging of the capacitor in response to the first clock pulse following a selected transition in the control signal, and a device for terminating the discharging of the capacitor and initiating the charging of the capacitor in response to the first clock pulse following the discharge of the capacitor to a preselected threshold level.