Device for converting a photosignal into a voltage in image sensors with remote integrators

摘要

An image sensor with matrix readout includes a matrix of elementary photodetectors (P) connected through at least a bus (Bpel) to a remote integrator (I) which converts the signal of each elementary photodetector into a voltage. Provided between the end of the bus and the input of the integrator is an impedance matching device (D) with low output capacitance, delivering at its output, during the time for converting photodetector signal, a variation of charge which corresponds to an affine function of the charge present at the input of said matching device, wherein this charge variation is determined by: ${\int }_{t=0}^{t=\mathrm{Tconv}}\mathrm{Iinj}\left(t\right).dt={\int }_{t=0}^{t=\mathrm{Tconv}}I\mathrm{int}\left(t\right).dt$ where Iinj is the instantaneous current of the bus, injected at the input of the impedance matching device, Iint is the instantaneous current at the input of the integrator and Tconv is the conversion time.