Sensortek Technology Corp.

Wen-Cheng Chen

Ming-Huang Liu

Jer-Hau Hsu

Kai-Hsiang Chan

Sheng-Wen Huang

Tso-Sheng Tsai

The present application discloses a light sensor circuit, which comprises a photodiode and a capacitor unit. The cathode of the photodiode is controlled by a capacitive unit to maintain the same or close voltage level as the anode of the photodiode, which significantly reduces the effect of the dark current of the photodiode. Thus, the light sensor circuit can effectively maintain the performance and accuracy of an analog-to-digital converter applying the light sensor circuit. The circuit design difficulty and manufacturing cost are also significantly reduced.

Light sensor circuit

An analog-to-digital module includes a sampling unit, for generating an output voltage between a positive output end and a negative output end according to a positive input voltage of a positive input end and a negative input voltage of a negative input end; a comparing unit, for generating a digital output signal according to magnitude relationship between the output voltage and a reference voltage; a variable current source, for generating a variable current according to the digital output signal at the negative input end in a first period according to a control signal; a measured current source, for generating a measured current at the negative input end; and an adjusting unit, for adjusting the output voltage according to the digital output signal in a second period according to the control signal; wherein the first period does not overlap the second period.

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Hsinchu County, Taiwan

Wen-Cheng Chen