MC4044-MC4344 direct pulse width application circuit

VOUT can also be used to control switching power amplifiers and drive DC motors. It is suitable
for larger power control and has higher efficiency. There is a more simplified solution that only
uses U. of MC4044 phase comparator 1. The output directly controls the power switch. When U,
is L, the switch is turned on and the motor accelerates. After reaching the predetermined speed, U. Change to H,
turn off the switch and let the motor slow down. In steady state, V lags behind a certain phase difference to
maintain the motor operating at a predetermined speed. Due to the limited loop gain, this phase difference will be
relatively large. At this time, the motor works in the width modulation mode of the reference frequency fR.
The inertia of the electromechanical system acts as a low-pass filter . This direct pulse width modulation is applied as long as
the load changes are limited so that the duty cycle is within. ． Within 15-0. 85, the system can work stably
. The schematic block diagram of this system is shown in the figure.