Readout Circuit

A readout circuit for reading out an output current from a photoelectric conversion element which collectively outputs currents generated in a plurality of pixels, each of which includes an avalanche photodiode, includes a current mirror circuit configured to receive the output current and output first and second currents having magnitudes in proportion to the output current, a photon counting circuit configured to count the number of photons incident on the photoelectric conversion element on the basis of the first current, an integral circuit configured to integrate the second current to generate a voltage signal, and a signal processing unit configured to determine a magnitude of light incident on the photoelectric conversion element on the basis of a counting result output from the photon counting circuit and a magnitude of the voltage signal output from the integral circuit. 本发明涉及种读取电路，是读取来自将在分别包含雪崩光电二极管的多个像素中产生的电流并输出的光电转换元件的输出电流的电路，包括：接收上述输出电流，输出与上述输出电流成比例的大小的第1和第2电流的电流镜像电路；基于上述第1电流，进行入射至上述光电转换元件的光子的计数的