Digital Motor Speed Control
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
A digital speed control is a pulse-width modulated drive system for either a brush or brushless DC motor. The motor is coupled to an emitter device which generates feedback signals indicative of motor movement. Referring to Figs. 1 and 2, the speed control operates as follows: When start line 10 is pulled down, both accelerate latch 11 and run latch 12 are set. This activates the motor drive input which will start the motor in the open-loop mode. As speed increases, emitter pulses are generated on line 13 to trigger 14 connected with trigger 15 in a manner which forms an edge-catcher circuit. The accurate edge of each emitter pulse will generate a narrow synchronized pulse E(P) on line 16 used to clear the speed reference counter 17 which starts counting up high speed clock pulses on line 18.