PWM control of TDA5142T output stage

Speed ​​digital control circuit. The external PWM signal is input from pin 17.
OTA acts as a level converter to control external transistors. What needs to be pointed out here is that the PWM voltage cannot be directly added to the motor winding like
the general DC motor PWM control . Otherwise, the PWM signal will seriously interfere with the back electromotive force waveform, making the zero-crossing point impossible to detect. Therefore, after amplification by an external transistor, a filter composed of an inductor and a capacitor is connected to control the VMOT power supply end of the integrated circuit at one level. That is to say, the motor windings are still controlled by analog mode.     The braking of the motor is performed by pin 8. When the voltage of pin 8 is lower than 2.3V, the motor brakes ; when it is floating or greater than 2.7V, the motor operates normally.