The principle of the optical infrared receiver head circuit

Billion-ray infrared receiver is mainly used in set-top boxes, infrared remote control system, billion light agent Super-Yi Electronics to explain the working principle of the receiving head, from the circuit, PD chip and amplification circuit analysis of the principle of billion-ray infrared receiver head.

First of all, let's look at the system framework of the billion-ray infrared receiver head:

From PD (photodiode) and its bias circuit analysis of the billion-ray infrared receiver head working principle:

PD Wafer

The sensor signals the infrared light to convert the received light signal into a current signal.

The bias circuit of the infrared receiver head

Providing PD with reasonable direction bias conditions, the effect of variable impedance on the signal, eliminating the interference signal, and most of the signals are transmitted to the back-stage amplifier.

TA (Impedance transform amplification circuit)

An impedance conversion between PD and a post-stage amplifier is applied to transform the current signal into a voltage signal and to separate the AC and DC components of the induced current.

IR Receiver Head CGA (controllable gain amplification circuit)

Provides the main gain of the entire module (50-80db), can accept instructions to change the gain, is controlled by AGC (automatic gain control).

BF (band-pass filter)

According to the frequency domain characteristic of the signal to eliminate the jamming means, can eliminate the interference signal from various interference sources;

The width of the pass band is 4KHz;

The optimal value is above 7-10;

Center frequency in the IC factory Si cho Good, there are a variety of center frequency for selection.

AGC (Automatic gain control circuit)

According to the time-domain characteristics of the signal to eliminate the interference, can eliminate the different time characteristic parameters of the interference signal;

Based on the parameters such as the gap time between the pulse cluster time and the pulse cluster, the useful signal or interference signal is judged, and the different types of IC have different basis for judging the time parameters.

When encountering disturbance, the gain of CGA is adjusted to the minimum, so that the interference signal is not passed;

Does not affect the reception of useful signals;

In a dark environment, AGC controls the CGA gain to a large number, but ensures no spontaneous output.

The above is the work principle of the infrared receiver head, according to the circuit analysis of the infrared receiver head, million light agent super-Yi Electronic main push infrared receiver Head IRM3638 series, if the infrared receiver head of the technical advice, can directly consult customer service, we will provide you with technical support and application information.

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The principle of the optical infrared receiver head circuit