Application of TL494 as current regulator

In the double closed-loop speed control system of a DC motor (a brushless DC motor)
, the output of the speed regulator is a torque (or current) given signal,'.
The TL494 can be used as a current regulator and current limiter (see Figure 10-3). The current feedback detection
signal is input from pin 1, and the command current J' is input from pin 2. This error amplifier is connected to
work as a PI regulator to generate a PWM signal. The sawtooth waveform is used as a comparison
waveform here, and its effect is better than that of the triangle wave, because the back edge of the sawtooth waveform is very steep, which avoids the phenomenon of multiple on and off of the PWM
signal caused by current fluctuations at the switching moment .