Abstract: A pulse width modulation control circuit includes a pulse width modulator which supplies a signal to a power switch tying together a DC signal generator and a motor and various sensing circuit including a control voltage disabler circuit. All of the sensing circuits are appropriately designed to ensure that the various components of the circuit are not damaged under abnormal conditions whether due to motor loads heavier than rated or undesired changes in AC current input or control voltages.

Abstract: A pulse width modulation control circuit includes a pulse width modulator which supplies a signal to a power switch tying together a d.c. signal generator and a motor and various sensing circuit including a control voltage disabler circuit, a motor voltage and current feedback circuit, and a low control voltage disabler circuit. All of the sensing circuits are appropriately designed to ensure that the various components of the circuit are not damaged under abnormal conditions whether due to motor loads heavier than rated or undesired changes in a.c. current input or control voltages.