SU815896A1 - Pulse-with modulator - Google Patents

Description

(54) WIDE-PULSE MODULATOR

the input signal, the second input is with a common bus, and the control input is with the output of the device and the output of the comparator, the first input of which is connected to the output of the sawtooth generator, an analog storage device is introduced, the information input of which is connected to the output of the operational amplifier, the output is the second input of the comparator, and the control input with the synchronization output of the saw-tooth generator, the input of which is connected to the thickness of the second input signal.

The drawing shows a functional diagram of a pulse width modulator.

The pulse width modulator contains an operational amplifier (op-amp) 1, the capacitor 2 is connected to the feedback circuit, the input is connected to the thickness 4 of the first input signal through a resistor 3, and to the output of a switch 6 through a resistor 5, the first input is connected to the second input is 7, the second input is with a common length, and the control input is with the output of the device and the output of the comparator 8, the first input of which is connected to the output of the sawtooth voltage generator 9, and the second input to the output of the analog storage device 10, input which This is connected to the output of operational amplifier 1, and the control input is connected to the synchronization output of the sawtooth generator.

In the simplest case, the analog storage device (CAM) may contain a capacitor connected between the common width and the output, and a control key connecting the input and output, and its control circuit is connected to the control input. In its simplest case, the sawtooth voltage generator may contain an operational amplifier, the feedback circuit of which includes a capacitor and a switch parallel to, the input through a resistor connected to pin 7, and the control input of the switch to the synchronization output of the sawtooth generator rectangular oscillations.

Pulse width modulator operates as follows.

In each cycle of the circuit, the duration of which is equal to the period T of the frequency generator of rectangular pulses, the voltage at the output of the sawtooth voltage generator (FPG) varies from zero at a speed proportional to the voltage removed from the bus 7 of the second input signal.

While the voltage at the output of the FPG is less than the voltage at the output of the CCD, the output of the comparator has a signal that sets the switch 6 to the position in which the shaft 7 is connected to its output, and the rest of the time the switch is in the position at which its output is connected to overall length. At the output GPN

In each period, a triangular voltage is formed.

Let at some point in time (at the beginning of the i-oro cycle) the signal changes abruptly and on pin 4 by the value of DU-. The voltage at the output of the CCD Uy in the next clock cycle will not change, which means that the pulse duration in this clock cycle will be kept. By the end of the i-oro cycle, the voltage at the output of the op-amp 1 will change by

D Uoy D Ui T / RC,

0 so in the tick i + 1

.T / RC,

 - (Ut / Ug) -T + (AUWAUi) T- (). If the condition RtCi RC is satisfied, where RI and C. are the resistance of the resistor and the capacitance of the capacitor installed in the FPG, then already in the i + 1 clock cycle the values of Uj and d correspond to the setting mode for the new value of the input signal (Ui + D Ui) and until the next change of one of the input signals.

Similarly, it can be shown that with a stepwise change in U2, the required output pulse duration is established already in the first clock cycle after the jump. Using a pulse-width modulator instead of the known ones will allow increasing the speed of systems using PWM modulation, while maintaining high accuracy and different ratios of the input signals.

Claims (2)

1. USSR author's certificate No. 567206, cl. H 03 K 13/20, 1977. 2. V. B. Smolov, E. Ugryumov. Time - impulse computing devices. Leningrad, “Energie, 1968, fig. 73 (prototype).