PROXIMITY SENSING DEVICE AND OPTICAL SENSING CIRCUIT HAVING PROXIMITY SENSING FUNCTION

摘要

Differing from conventional optical sensing device used in smart phones often lacks self-calibration function, a novel proximity sensing device having self-calibration function is disclosed by the present invention, and comprises: a driving module, a lighting element, a first a light receiving module, a conversion module, a judge circuit, a synchronous sequential module, an analog front-end module, and an analog-to-digital convertor. When executing a noise calibration process, a sensing signal outputted from the first light receiving module is converted to a voltage signal by the conversion signal comprising a signal-amplifying MOSFET, a current mirror circuit, N number of cascode MOSFET pairs, and a current-to-voltage converting resistor. After that, the voltage is transmitted to the judge circuit, and then the noise calibration process would be completed under the cooperation of the judge circuit, the synchronous sequential module, and the analog front-end module.