DC motor drive control device

摘要

A DC motor is connected across the mid-points of a bridge circuit which includes a switching device in each leg of the bridge. A forward or reverse motor direction drive current flows through the motor depending on the conducting states of the switching devices. A motor drive control device operates to produce either forward or reverse drive signals for controlling the conductivities of the bridge switching devices to thereby produce a forward or reverse motor direction drive current in response to a forward or reverse drive signal respectively. The drive control device detects and measures the level of the motor drive current and when it exceeds a predetermined target value, orders a gating circuit in the path of the forward and reverse drive signals, to invert the forward and reverse drive signals to thereby reverse the direction of the motor direction drive current. This produces a braking action. The gating circuit is preferably constructed of a plurality of EXCLUSIVE OR circuits.