Patent ID: 7944162
Filing Date: 2011-05-17
Classification: H02P

Abstract:
1. A motor control device, comprising: a sensing circuit for sensing a motor to generate a sensing signal, wherein the sensing signal comprises a first sensing sub-signal and a second sensing sub-signal; a phase-shifting circuit electrically connected to the sensing circuit for receiving the sensing signal and generating a phase-shifting signal according to the sensing signal; a comparing circuit electrically connected to the phase-shifting circuit for receiving the phase-shifting signal and generating a comparing signal according to the phase-shifting signal; and a control circuit, electrically connected to the comparing circuit and the motor, for receiving the comparing signal and generating a control signal to control the rotation speed of the motor according to the comparing signal, wherein the phase-shifting circuit comprises a first phase-adjusting unit electrically connected to the sensing circuit for receiving the first sensing sub-signal and generating a first phase-shifting sub-signal according to the first sensing sub-signal, and the first phase-adjusting unit comprises: a first resistor having a first end electrically connected to the sensing circuit for receiving the first sensing sub-signal; a first capacitor having a first end electrically connected to the first end of the first resistor and a second end electrically connected to a second end of the first resistor; a second resistor having a first end electrically connected to the second end of the first resistor for transmitting the first phase-shifting sub-signal; a second capacitor having a first end connected to the first end of the second resistor and a second end electrically connected to a second end of the second resistor; and a third resistor having a first end electrically connected to the second end of the second resistor and a second end grounded.