DC motor drive circuit composed of integrated voltage stabilizing circuit

There are many cases where the motor is driven by an integrated voltage regulator circuit. Unlike the direct drive of a general three-terminal voltage regulator, the circuit in the figure below allows the motor to obtain a driving voltage from 0V to 7V, thus having low-voltage speed regulation performance. IC1 is a fixed voltage regulator with positive output, and IC2 is a four-terminal voltage regulator with adjustable negative output. By adjusting Rl, the motor can obtain zero voltage. Since the heat sink of IC2 is internally connected to the input terminal, IC1 and IC2 can use a common heat sink to adapt to low-voltage operation.