Control circuit for a DC motor.

摘要

A DC power supply (Vcc) for a DC motor (2) is controlled by a drive transistor (3). An "ON" state of the drive transistor (3) is maintained by a comparator (8) or means which compares a terminal voltage (VT) at a point (4) between the DC motor (2) and the drive transistor (3) with a reference voltage (VR) supplied from the power supply. A clock pulse (P2) is applied to the drive transistor (3) to make it periodically turn off in order to detect an induced voltage depending upon rotation rate of the DC motor (2). The drive transistor (3) remains turned off upon stopping the rotating DC motor (2) by force. A rotation rate control means (41) is also provided. One particular application for the control circuit disclosed is as the drive means for a powered window for an automobile.