Transimpedance amplification circuit and photosensitive chip

Abstract

The invention discloses a transimpedance amplification circuit and a photosensitive chip, the transimpedance amplification circuit comprises a first photosensitive diode, a second photosensitive diode, a first feedback resistor, a second feedback resistor and a transimpedance amplification unit, the anode of the first photosensitive diode is grounded, and the cathode of the first photosensitive diode is coupled with the first input end of the transimpedance amplification unit; the anode of the second photosensitive diode is grounded, and the cathode of the second photosensitive diode is coupled with the second input end of the transimpedance amplification unit; the first end of the first feedback resistor is coupled with the first input end of the transimpedance amplification unit, and the second end of the first feedback resistor is coupled with the first output end of the transimpedance amplification unit; the first end of the second feedback resistor is coupled with the second input end of the transimpedance amplification unit, and the second end of the second feedback resistor is coupled with the second output end of the transimpedance amplification unit; and the surface of the second photosensitive diode is covered with a light blocking layer, and the intrinsic current of the second photosensitive diode is used for compensating the intrinsic current of the first photosensitive diode. According to the scheme, the common-mode interference resistance of the transimpedance amplification circuit can be improved.

Description

technical field [0001] The invention relates to the field of electronic technology, in particular to a transimpedance amplifier circuit and a photosensitive chip. Background technique [0002] Transimpedance amplifier circuit is the key circuit to realize photoelectric conversion. In the traditional transimpedance amplifier circuit, the current source is usually used as the steady-state compensation of the transimpedance amplifier circuit. refer to figure 1 , a schematic diagram of the structure of an existing transimpedance amplifier circuit is given. [0003] figure 1 In the above, the photosensitive diode PD generates a photosensitive current of μA (microampere) level after receiving light, and the photosensitive current is amplified and output by the transimpedance amplification unit. The first input terminal "+" of the transimpedance amplifying unit and the first output terminal V O1 connected between a load resistor R F , the second input terminal "-" and the sec...

AI Technical Summary

Problems solved by technology

[0004] However, since the current source I TH The magnitude of the current is usually preset and inconsistent with the intrinsic current of the photodiode PD

In addition, limited by the process, the current source I TH The output current itself will also have certain fluctuations

In the prior art, limited by the current source I TH , the anti-common-mode interference ability of the transimpedance amplifier circuit is poor

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