Abstract: A power supply circuit includes a voltage conversion circuit, a signal path, a connector, and a feedback path. The voltage conversion circuit receives and converts an input voltage into an output voltage. A voltage drop is generated when the output voltage flows through the signal path. The connector is coupled to the voltage conversion circuit through the signal path, wherein the output voltage flows through the signal path then enters the connector as a connector voltage, which supplies power to an external device when the external device is connected to the connector. The feedback path is coupled to the voltage conversion circuit and the connector, wherein the connector voltage is fed back to the voltage conversion circuit as an induced voltage through the feedback path, and the voltage conversion circuit adjusts the output voltage according to the induced voltage.

Abstract: A projector includes a light source, a color wheel, a housing, a motor, a lens module, an optical detection module, and a feedback module. The light source is used for providing a light beam. The color wheel includes a plurality of optical filtering segments for generating light with a plurality of colors. The housing is connected to the color wheel. The housing has a timing mark. The motor is connected to the housing for rotating the color wheel through the housing. The lens module is used for outputting the light with the plurality of colors. When the housing is rotated, the optical detection module generates a pulse width modulation signal according variations of gray levels of the housing. The feedback module is coupled to the optical detection module for conditionally outputting an adjusted voltage to the optical detection module according to the pulse width modulation signal.

Abstract: A projector includes a light source, a color wheel, a housing, a motor, a lens module, an optical detection module, and a feedback module. The light source is used for providing a light beam. The color wheel includes a plurality of optical filtering segments for generating light with a plurality of colors. The housing is connected to the color wheel. The housing has a timing mark. The motor is connected to the housing for rotating the color wheel through the housing. The lens module is used for outputting the light with the plurality of colors. When the housing is rotated, the optical detection module generates a pulse width modulation signal according variations of gray levels of the housing. The feedback module is coupled to the optical detection module for conditionally outputting an adjusted voltage to the optical detection module according to the pulse width modulation signal.