Design Of Infrared Proximity Sensor PX3062with Environment Noise Suppression

With the development of electronic products towards the intellectualized direction,light sensor presents robust momentum of growth, which is widely used in mobileproducts, computer products, consumer electronic products, industry, medical,automobile, and so on. The present research situation on light sensor is not optimistic inChina although it is widely used. It is of great practical significance to study anddevelop domestic light sensor, which can not only explore domestic market, but also fillgaps in this product area of our state.The design in the paper is based on the project “Theoretical Research on the KeyTechnique and the Design for Light Sensor” in the Institute of Electronic CAD inXidian University. This paper presents the fundamentals of infrared proximity sensors,which describes the system scheme and key functional modules’ circuit design ofproximity sensor PX3062, and the functional and performance simulation results aregiven. The infrared proximity sensor cannot sense proximity correctly with the effect ofenvironment noise, such as the interfere of sunlight, light and temperature change. Akind of highly effective method of environment noise suppression is proposed based onthe problem, which employs optical filming filter and sequential controllingdigital-analog mixed subtraction circuit to remove environment noise step by step,achieving the purpose of accurate proximity sensing. Moreover, the sensor circuit isdesigned, which can sense the proximity of object at a distance up to25cm away fromthe sensor under the environment of the sunlight and temperature lower than85℃. Inaddition, this proximity sensor can work in the power down mode, which means whenthe proximity sensor is out of work the power dissipation can decrease to near zero,while in the normal working mode, the power consumption can also be reduced byconfiguration of sleep time. The designed proximity sensor could be easily used for itsbuilt-in ADC(Analog-to-Digital Converter), LED(Light Emitting Diode) driver, I2Cinterface, interrupt pin, and ability of programming.The designed circuit is verified by Spectre simulation in3.3V0.35μmCMOS(Complementary Metal Oxide Semiconductor) process. The simulation resultsshow that under the given noise environment the sense error is less than1%.