Infrared proximity transducer capable of inhibiting environmental noise

Abstract

The invention discloses an infrared proximity transducer capable of inhibiting an environmental noise. In the prior art, there are problems of poor capability for inhibition of environmental noises and high fallout ratio on the condition of strong background light and high temperature; however, the above-mentioned problems are solved by utilizing the infrared proximity transducer. The infrared proximity transducer comprises a photodiode circuit, an infrared emitting diode, a current control circuit, an analog to digital conversion circuit, a digital to analog conversion circuit, a time sequence control circuit and a data storage circuit. The photodiode circuit converts a detected optical signal to a current signal; the current signal passes through the current control circuit and is output to the analog to digital conversion circuit; the digital to analog conversion circuit converts an output of the analog to digital conversion circuit into a current signal and then the current signalis feedbacked to an input terminal of the analog to digital conversion circuit; the output of the analog to digital conversion circuit is sent to an external microprocessor through the data storage circuit; and the time sequence control circuit provides a time sequence control signal for all circuits. According to the invention, an effect of filtering and removing environmental noises is good; and a degree of closeness of an object can be accurately detected in the environment of strong background light and high temperature; therefore, the infrared proximity transducer can be applied to intelligent control of electronic products.

Description

technical field [0001] It relates to an optical digital-analog hybrid integrated circuit, especially an infrared proximity sensor with environmental noise suppression capability, which can be used for intelligent control of electronic products. Background technique [0002] Proximity sensors are divided into inductive, capacitive, magnetic induction, photoelectric and ultrasonic according to their basic principles. Infrared proximity sensor, as a kind of photoelectric proximity sensor, has become extremely widely used in portable handheld devices such as mobile phones and PDAs, and has become a research hotspot. For example, when people put a mobile phone with proximity sensing function close to their ears and start making a call, the mobile phone will automatically detect this close action, and automatically turn off the backlight of the mobile phone and the touch screen keyboard to save power and prevent misuse; After the flip cover is opened to a certain angle, the backl...

AI Technical Summary

Problems solved by technology

However, when the background light is strong, the current is still very large, and optical coating filtering alone cannot meet the demand; at the same time, as the ambient temperature rises, the dark current index of the PD increases. Since the dark current and photocurrent cannot be distinguished, the sensor also detection error

In order to improve the environmental noise caused by background light and dark current, infrared proximity sensors are usually designed with large PD area and high-current drive IR LEDs, but this kind of infrared proximity sensors cannot meet the requirements of low power consumption and small size for consumer electronics products. area requirements, and cannot be used in a continuously high temperature environment

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