Avalanche photo diode (APD) bias voltage adjustment circuit based on negative voltage adjustment

Abstract

The invention discloses an avalanche photo diode (APD) bias voltage adjustment circuit based on negative voltage adjustment. The circuit includes a pixel outside bias voltage generating module and a pixel inside bias voltage adjustment module. The pixel outside bias voltage generating module uses a first operational amplifier and a second operational amplifier to clamp source voltages of a secondPMOS tube and a fourth PMOS tube to stepping voltage and 0V. The pixel inside bias voltage adjustment module uses a first current mirror unit and a first PMOS tube in the pixel outside bias voltage generating module to form a proportional current mirror structure, different proportions of mirroring are realized through controlling switches, and thus floating ground voltage is adjusted to an integer multiple of the stepping voltage. The pixel inside bias voltage adjustment module uses a second current mirror unit and a third PMOS tube in the pixel outside bias voltage generating module to forma current mirror structure, the floating ground voltage is clamped to 0V when all the switches in the first current mirror unit are turned off, and stepping adjustment of APD bias voltage is realized.A manner of negative voltage adjustment is adopted to expand an adjustment range of the APD bias voltage, and improvement of detection sensitivity of an APD array is facilitated.

Description

technical field [0001] The invention belongs to the fields of integrated circuits and optoelectronics, and relates to a circuit for adjusting the bias voltage of an avalanche photodiode based on a negative power supply voltage. Background technique [0002] Single photon detection technology is a new detection technology based on single photon that has just been developed in recent years. It can detect extremely weak light signals. Among the currently used photodetectors, there are mainly two types of detectors capable of single photon detection, namely photomultiplier tube (Photo Multiplier Tube, PMT) and avalanche photodiode (Avalanche Photo Diode, APD). Among them, the avalanche photodiode APD (hereinafter referred to as APD) has the advantages of low power consumption, small size, large operating spectrum range, and low operating voltage in the infrared band, so it is widely used. Avalanche photodiode APD detectors can be divided into two working modes, linear and Geige...

AI Technical Summary

Problems solved by technology

[0005] Aiming at the deficiencies in the traditional APD bias voltage adjustment method, such as large area, inability to realize the adjustment of a single pixel, and low voltage stability, the present invention proposes a method for adjusting the APD bias voltage of an avalanche photodiode, which is based on negative voltage. Adjustment, expands the adjustment range of APD bias voltage, and can achieve pixel-by-pixel adjustable APD charging and setting voltage, which is conducive to improving the detection sensitivity of APD array, and has the advantages of small area, fast response speed, and high voltage accuracy.

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