A transmitter drive circuit for a photoelectric sensor

Abstract

The invention discloses a photoelectric sensor transmitting terminal driving circuit, and aims to overcome the defect that an existing photoelectric sensor transmitting terminal driving circuit cannot make the driving current of an LED to be constant current, and cannot adjust the current magnitude through a compiled program. The photoelectric sensor transmitting terminal driving circuit comprises an LED driving chip TLC 5941 and a signal driving chip 74 HCT 245 which is connected with the LED driving chip TLC 5941 through signals; the signal driving chip 74 HCT 245 is used for driving the signals and guaranteeing the quality of the signals; the LED driving chip TLC 5941 is used for driving a transmitting terminal of a photoelectric sensor, can drive 16 sensor transmitting terminals simultaneously with the driving current being constant current, can allocate an internal memory register of the driving chip so as to achieve current adjustment, and can control the switch-on and switch-off of a current source. The photoelectric sensor transmitting terminal driving circuit can be applied to the transmitting terminal driving circuits of various photoelectric sensors.

Description

technical field [0001] The invention relates to a driving circuit, in particular to a driving circuit in a photoelectric sensor. Background technique [0002] Photoelectric sensors such as figure 1 The shown includes a transmitting end and a receiving end. Generally, the transmitting end is a light-emitting LED, and the light can be infrared light or light of other wavelengths. The receiving end is a photosensitive transistor. Its working principle is that the current flowing through the phototransistor is proportional to the received luminous flux. When the luminous flux received by the phototransistor is small, the current flowing between its collector and emitter is also small. When the phototransistor receives When the luminous flux is large, the current flowing between its collector and emitter will also increase. Photoelectric sensors can be used to detect the presence or absence of objects, passing states, running speeds, etc. For photoelectric sensors to be used n...

AI Technical Summary

Problems solved by technology

[0004] 1. The LED current is easy to change due to the change of the power supply, and the luminous brightness is unstable, which affects the accuracy of the detection at the receiving end;

[0005] 2. The LED current cannot be adjusted by programming. After long-term use, due to the pollution or aging of the sensor, it is often necessary to adjust the current of the LED light to make it still work normally, but this solution cannot achieve this function.

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