Improvement of Ir Proximity Sensor Based on Digital Simulation Mixed Subtraction Circuit

• Main Author: Wu JUNSHENG
• Format: Article
• Language: English
• Published: IFSA Publishing, S.L. 2013-12-01
• Series: Sensors & Transducers
• Subjects: Mixed digital simulation subtraction circuit; Ir proximity sensor; Ambient noise rejection.
• Online Access: http://www.sensorsportal.com/HTML/DIGEST/december_2013/PDF_vol_160/P_1575.pdf

This paper analyses the working principle of infrared proximity sensor, puts forward an efficient environmental noise suppression method for the problem that the test results are susceptible to environmental noise impact. The method is based on digital simulation mixed subtraction circuit, through the optical coating filter to filter out noise environment step by step, filtering background current and dark current in the total current of the PD from the IR LED so as to realize the accurate detection of the sensor. On the basis of detailed analysis of the method, this paper designs the related sensor circuit. The circuit can filter the ambient noise with maximum background light of 4000 lx and temperature of 85. Implements the accurate determination of proximity degree of the objects within the scope of 25 cm. Spectre simulation results show that after filtering out the noise, it is close to the detect output value and the ideal value (that is, the background light of 0 lx), and the error is less than 1 %. The designed circuit has been verified under 0. 35 ?m 3 V CMOS, the results meet the design targets. Keywords: Mixed d