Analysis of working principle of LED infrared receiving head

- May 30, 2019-

The semiconductor material used in the infrared emission tube is usually gallium arsenide (GaAs), gallium arsenide (GaAlAs), etc., and is packaged in a transparent or light blue, black resin. At present, the application of infrared emission tube is mainly the signal source of various photoelectric detectors, specifically used in remote control, alarm and wireless communication, such as the dark red translucent sphere we see at the front end of the transmission equipment such as TV remote control. The device is an LED infrared emission tube.

During the use, the surface of the LED infrared receiving head tube should be kept clean, and the external surface should not be rubbed and damaged. Otherwise, the emitted infrared light will be reflected or scattered, which directly affects the use effect. This is also our work and use. .

The LED infrared emission tube must be used together with the LED infrared receiving head. Therefore, when selecting the type, pay special attention to whether the wavelength parameters of the infrared light signals they emit match (preferably ordered from the same manufacturer), otherwise the sensitivity of the reception will be affected.

Infrared receiver working principle

There are also many types of LED infrared receivers. There are generally three pins, including power supply pins, grounding and signal output pins. Usually, the manufacturer integrates the infrared receiver and circuit into a single component to form an integrated device. The internal circuits include LED infrared receivers, amplifiers, limiters, bandpass filters, integration circuits and comparators. The LED infrared receiving head receives the infrared signal, and then sends the signal to the amplifier and the limiter. The limiter functions to control the pulse amplitude within a certain level (because the distance of the LED infrared transmitting tube is uncertain), the AC signal Then enter the bandpass filter (can pass the load wave from 30khz to 60khz), then enter the comparator through the demodulation circuit and the integration circuit, and the signal output from the comparator output is reduced to the transmitter.

The infrared remote control device in the household appliance is a typical daily application of the LED infrared emitting tube and the receiving head. Its advantages are good anti-interference, simple and easy to implement circuit, low power consumption and low cost, and now almost all home appliance remote control devices This device is used.