Protection circuit for switching transistors in H-bridge circuit e.g. for model railway DC motor, sets transistors into off state if and as soon as voltage significantly different from half the motor operating voltage is detected

摘要

The protection circuit has a voltage detector (17) for motor (1) connection (2,3) voltages connected to a control unit (13). The motor connections are each connected via an equal resistance (14,15) to a connection of the voltage detector at a voltage equal to the mean of the voltages on the motor connections. The control unit sets at least some of the switching transistors (V1-V4) into the off state if and as soon as the voltage detector detects a voltage significantly different from half the operating voltage for the motor.