Photoelectric detection circuit

Abstract

The invention provides a photoelectric detection circuit. The circuit comprises an electronic switch (1), an amplifying circuit (3), a biasing circuit (6), a selection circuit (7), a reference voltage generating circuit (8) and a comparison circuit (9). The circuit is characterized in that the circuit also comprises a photodiode (2), an integration capacitor (4) and a resistor (5); one end of the electronic switch (1) is connected with a power supply and the other end thereof is connected with the reverse end of the photodiode (2) and the reverse input ends of the integration capacitor (4) and the amplifying circuit (3); the in-phase end of the photodiode (2) is earthed; the other end of the integration capacitor (4) is connected with the output end of the amplifying circuit (3); the in-phase input end of the amplifying circuit (3) is connected with one end of the resistor (5); the other end of the resistor (5) is earthed; the biasing circuit (6) is connected to the biasing input end of the amplifying circuit (3); the selection circuit (7) is connected to the reference voltage generating circuit (8); the reference voltage generating circuit (8) is connected to one input end of the comparison circuit (9); and the other input end of the comparison circuit (9) is connected with the output end of the amplifying circuit (3).

Description

technical field [0001] The invention relates to a photoelectric detection circuit which can be completely implemented inside a CMOS integrated circuit and is used to ensure the safety of a non-contact CPU card chip. Background technique [0002] As a product series, contactless / contact CPU smart cards can be set with different functions, security performance, capacity and corresponding COS. The product application fields are becoming wider and wider, and the demand scale of different application fields is also increasing. Smart card controllers are usually made of silicon. The electrical properties of a silicon wafer will change with different voltages, temperature, light, ionizing radiation, and surrounding electromagnetic fields. Attackers will try to introduce some erroneous behavior by changing the power supply, electromagnetic induction, illuminating the surface of the smart card with visible light or radiating materials, or changing environmental parameters such as te...

AI Technical Summary

Problems solved by technology

The traditional light detection circuit adopts the form of discrete photodiodes, which has the disadvantages of high cost, difficult production and inconvenient use.

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