DRIVE CIRCUIT FOR A DC MOTOR, COMPRISING AN H-BRIDGE AND A MOTOR BRAKING CIRCUIT

摘要

A drive circuit for a DC drive motor (1) of an actuator in a vehicle, in particular an actuator of a steering lock in which a gear component driven by the motor can move toward a mechanical end stop, comprising four circuit components (6-9) controlled by a control circuit (14), wherein a first circuit component (6) couples a first connection (4) of the motor to a supply voltage (2), a second circuit component (7) couples the first connection (4) to ground (3), a third circuit component (8) couples a second connection (5) of the motor to the supply voltage and a fourth circuit component (9) couples the second connection (5) to ground (3). The circuit components each comprise a control connection and are switched off when the drive fails. The control circuit (14) applies a control voltage to the control connections (10, 13) of the first and fourth circuit components (6, 9) in order to drive the motor in one direction and applies a control voltage to control the connections (11, 12) of the second and third circuit components (7, 8) in order to drive the motor in the opposite direction. A motor braking circuit is provided for temporarily supplying the control connections (11, 13) of the second and fourth circuit component (7, 9) with a control voltage for turning on the circuit components as soon as the supply voltage (2) drops off, wherein the control voltage is provided from an energy storage medium (16) that is charged while the supply voltage (2) is applied.