US Patent 8946640 Unit cells with avalanche photodiode detectors

Various techniques are disclosed for providing reference signals to image detectors in accordance with one or more embodiments of the invention. For example, in one or more embodiments, switched capacitors may be used to provide bias voltages to individual unit cells of a focal plane array such that the bias voltages are held by the unit cells over one or more integration periods while the unit cells are decoupled from an input line. As a result, the bias voltages may be free from noise incident on the input line and thus may more accurately bias the individual unit cells.