A photoelectric detection circuit with temperature compensation function

Abstract

The invention discloses a photoelectric detection circuit with a temperature compensation function. The photoelectric detection circuit comprises a photodiode converting optical signals into electric signals, a resistor used for converting a photoelectric current into a voltage signal, and a comparison circuit used for detecting the voltage signal. A first end of the photodiode is grounded or connected with a power supply voltage. A second end of the photodiode is connected with a first end of the resistor. A common node of the photodiode and the resistor is connected with a first signal input end of the comparison circuit. A second end of the resistor is connected with a second signal input end of the comparison circuit. The photoelectric detection circuit only comprises the photodiode, the resistor and the comparison circuit, and compared with a conventional photoelectric detection circuit, no operational amplifiers and reference voltage or reference current sources are needed, the complexity of the circuit is lowered, and the area and cost of the circuit are effectively reduced. The photoelectric detection circuit can be applied to the field of chip safety protection and the field of optical fiber communication.

Description

technical field [0001] The invention relates to the field of integrated circuits, in particular to a photoelectric detection circuit with temperature compensation function. Background technique [0002] Photoelectric detection technology is a technology that converts optical signals into electrical signals and performs subsequent processing on the electrical signals. Traditional photodetection circuits use photodiodes to convert light signals into current signals, and then use subsequent circuits to process the current signals, such as amplifying the current signals through amplifiers to detect or measure the amplified signals. [0003] figure 1 It is a circuit diagram of a traditional photodetection circuit, which includes a resistor 110, a photodiode 120, an amplifier 130, a reference voltage module 140, and a comparator 150; the resistor 110 and the amplifier 130 convert the photocurrent generated by the photodiode 120 into a voltage signal VA , the voltage value is the...

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Problems solved by technology

[0006] However, the photoelectric conversion efficiency of the photodiode itself is proportional to the temperature, and the dark current of the photodiode (when there is no light) is also proportional to the temperature, so the detection effect of the traditional photoelectric detection circuit will be different under different temperature conditions.

For the photoelectric cover opening detection circuit used for chip safety protection, under the limit operating temperature of the safety circuit, the traditional photoelectric cover opening detection circuit is likely to fail, and the chip is attacked at this time, and the photoelectric cover opening detection circuit cannot output an alarm signal. The data inside the chip will be stolen, which will cause serious consequences

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