Simple Permanent Magnet Motor Speed Control Circuit
Original Publication Date: 1981-May-01
Included in the Prior Art Database: 2005-Feb-11
An arrangement is described which dynamically controls the speed of a motor by the use of a switched power control and a feedback loop which monitors the back EMF (electromotive force) of the motor. The motor is alternately connected to a power supply and sample and hold circuit under the control of a pulsewidth modulator. The width of the pulses of the modulator output are dependent upon the voltage fed back from the motor.