Pixel with Switchable High Gain and High Capacity Modes

摘要

Provided herein is a novel pixel circuit for image sensors such as IR ROIC image sensors. The design provides a switchable pixel with two modes. In the first mode, the pixel performs in-pixel correlated double sampling to remove reset noise. In the second mode, the pixel is configured in a high-capacity mode to avoid saturation. The pixel may be dynamically switched between modes, for example in response to lighting conditions in the scene to be imaged.

主权项

1. A charge transimpedance amplifier readout circuit which can be alternately switched between a correlated double sampling configuration and a high capacity configuration, wherein
the charge transimpedance amplifier readout circuit comprises a single output differential amplifier, wherein the positive input of the amplifier is a reset voltage source and the negative input is the output of a photodetector; wherein a feedback capacitor is present in a feedback loop between the amplifier output and the negative amplifier input; wherein a reset switch can be closed to short the amplifier output to its negative input and the two plates of the feedback capacitor to each other; wherein the circuit comprises a clamping voltage source which can be connected or disconnected to the circuit by a clamping voltage switch; wherein the circuit comprises a dual-use capacitor which can be connected to the circuit in alternate configurations by the action of switches; wherein the correlated double sampling configuration comprises the dual-use capacitor being connected in series between the amplifier output and transiently being connected to the clamping voltage source, such that the dual-use capacitor may store a reset value for correlated double sampling operation; and wherein the high capacity configuration comprises the dual-use capacitor being connected in parallel with the feedback capacitor, increasing the total feedback capacitance and decreasing the gain of the amplifier.