Digital speed control system with current feedback

Digitally controlled speed system composed of L291 and L292:
  The circuit diagram is shown in the figure. In this example, the digital speed command is a binary number,
  input from L291. Measure the generator output voltage and input it from pin 12, N. is the error amplifier.
  The motor steering is determined by the logic level of pin 7 . Utilizing L291 internal amplifier N. Introduce current
  feedback. It is slightly different from the upward inversion. Since N, only the inverting input terminal can be used,
  the circuit is a little more complicated. The current feedback signal is obtained from the potentiometer RP and the sliding contact.
  The
  the potentiometeradjustment RP, so that the motor speed is zero.
    6． Expansion of L292 drive power The maximum drive capacity of the L292 PWM driver
  is 36V, 2A, and can be used to control low-voltage DC motors below approximately 60W. When used in high-power
systems such as   robots and machine tool feed systems, larger power   transistors can be connected externally to expand their driving power.