Image sensor with selective pixel binning

Abstract

An image sensor may include an array of imaging pixels. Each imaging pixel may have a photodiode that generates charge in response to incident light, a floating diffusion region, and a transfer transistor that transfers charge from the photodiode to the floating diffusion region. Each floating diffusion region may have an associated capacitance formed by a depletion region between n-type and p-type regions in a semiconductor substrate. To enable selective binning in the voltage domain, a number of transistors may be coupled to the floating diffusion capacitors. A first plurality of pixels may selectively couple the floating diffusion capacitors to ground. A second plurality of pixels may selective couple the floating diffusion capacitors to the floating diffusion capacitors of adjacent pixels. The voltages of multiple floating diffusion capacitors may be non-destructively binned on a single floating diffusion capacitor during readout.