专利名称：OPTICAL SENSOR CALIBRATION USING
HIGH FREQUENCY PULSE WIDTHMODULATION
发明人：Michael J. Lorello,Gary S. Jacobson,George J.
Doutney
申请号：US12971053申请日：20101217
公开号：US20120152696A1公开日：20120621
专利附图：
摘要：A system and method for adjusting the LED current of an optical sensor that
does not decrease the effectiveness of the optical sensor or the length of its operatinglife, or significantly increase the cost due to hardware requirements. The LED current ofan optical sensor is adjusted using a high frequency pulse-width modulated signalgenerated from a microcontroller. Based on feedback provided by the photo-detector,the duty cycle of the signal can be adjusted by the microcontroller. The signal passesthrough a low pass filter which averages the modulated signal into a DC voltage, which isthen used to control a current amplifier circuit that provides current to the LED of theoptical sensor. This adjustability enables the system to compensate for variations insensor LED's and the LED brightness reduction to due aging and/or build-up ofcontaminants on the photo-detector and/or LED.
申请人：Michael J. Lorello,Gary S. Jacobson,George J. Doutney
地址：Guilford CT US,Norwalk CT US,Sandy Hook CT US
国籍：US,US,US
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