Patent ID: 7012393

Claim:
A motor drive comprising: a first power semiconductor switching device having a pair of main current carrying terminals, the main current carrying terminals being coupled in series with a motor load; a first current control loop, the current control loop having a current sensor for the switching device for controlling the current through the switching device; a current limiting circuit driving the first current control loop to maintain the current in the switching device at a desired level, the current limiting circuit having first and second inputs; a speed regulation circuit having a first input coupled to a speed control input and a second input coupled to a feedback voltage from the motor representing the actual motor speed, the speed regulation circuit providing an output to the first input of the current limiting circuit to drive the motor to the desired motor speed; and a power limitation circuit for limiting the power consumed by the motor to a predetermined level and providing an output to the second input of the current limiting circuit, the power limitation circuit having an input coupled to receive the feedback voltage from the motor.