a pixel circuit , and a method for operating a pixel circuit , to provide a multiple knee response characteristic . in one embodiment of the invention , one or more feed - through pulse signals are transmitted to an integration node to end a first linear integration time period . the ftp signal allows electrons to drain from the integration node to a reset node through a transfer gate . after the first integration period , a second linear integration period is conducted on the pixel circuit , where the photo conversion gain of the pixel circuit becomes reduced under higher illumination conditions due to the drained node . such operation creates a pixel with a photo response having multiple “ knee ” points , where each “ knee ” in the photo response curve will create separate regions whose photo sensitivities can be independently controlled with minimal thermal interference . by setting different voltage levels for the ftp signal and by controlling the integration time periods , the photo - response of the pixel circuit can be easily controlled .