Patent ID: 6201929
Filing Date: 2001-03-13
Classification: H02P

Abstract:
A multistage rotating speed control circuit for a DC motor which is connected between a positive and a negative DC supply voltages and controls the rotating speed of the motor, said multistage rotating speed control circuit comprising:a digital control circuit which receives a digital signal set and delivers a corresponding current based on the digital signal set;a driving circuit connected to said digital control circuit, which controls the rotating speed of the DC motor based on the output current of said digital control circuit,an input voltage modifying circuit which delivers an output voltage;a reference voltage generating circuit which provides a fixed number of reference voltages; anda comparing circuit including the fixed number of comparators, each of which receives the output voltage from said input voltage modifying circuit at its first end and a different reference voltage generated by said reference voltage generating circuit at its second end, and delivers an output digital signal based on the comparison result of the two input signals, these output digital signals collectively making up an input digital signal set of said digital control circuit.