CMOS IMAGE SENSOR WITH GLOBAL SHUTTER, ROLLING SHUTTER, AND A VARIABLE CONVERSION GAIN, HAVING PIXELS EMPLOYING SEVERAL BCMD TRANSISTORS COUPLED TO A SINGLE PHOTODIODE AND DUAL GATE BCMD TRANSISTORS FOR CHARGE STORAGE AND SENSING

摘要

The invention describes image sensor array pixels with global and rolling shutter capabilities that utilize multiple BCMD transistors for storing and sensing charge for a single photodiode. This configuration improves the Dynamic Range (DR) of the sensor, by allowing sensing different image signals from a single pixel without saturation, a low level signal with long integration time followed by a high level signal with short integration time. Signal processing circuits can process these signals into a single Wide Dynamic Range (WDR) output. Further disclosed are pixels that use multiple-gate BCMD transistors for charge storage and sensing having multiple concentric gates, which allows changing the conversion gain of the BCMD transistors. Variable conversion gain is a useful feature when building WDR sensors since low conversion gain and high well capacity allows detection of high level signals and, at the same time, low level signals with high conversion gain and low noise.

主权项

1. A CMOS image sensor pixel array that includes at least one pixel circuit, comprising:
at least one concentric dual gate Bulk Charge Modulated Device (BCMD) transistor coupled to a single photodiode, wherein the at least one concentric dual gate BCMD transistor is operable to store charge transferred from the photodiode for all the pixels of the array simultaneously, wherein the stored charge is accumulated in at least one integration time; and peripheral circuitry, wherein the at least one concentric dual gate BCMD transistors are additionally operable to be subsequently addressed and scanned in a row by row manner.