This paper presents a high dynamic range imaging sensor for detection of low light level signals. The sensor
utilises a 12x12 array of large 150μm x 150μm pixels. The readout circuitry allows for multiple readout options
including; multiple sampling (which allows for techniques such as Correlated Double Sampling (CDS)) and Time
to Digital Conversion (TDC) techniques, operated both independently and under the same integration period.
Scope for test patterns is also present in the design. All samples taken from the pixels before during and after
exposure are converted digitally through the use of a single slope ADC utilising a 10 bit DAC and a comparator.
No sample and hold capacitor is present. 4x10 bit SRAMs (Static Random Access Memory) per pixel are utilised
to record multiple samples, or act as a counter for the TDC mode of operation. The large dynamic range of the
system is attributable to both the novel timing system implemented within the multiple sampling mode of
operation and the TDC mode of operation (operated independently or intermittently within the same
integration time), which combines the use of 4x10 bit SRAMs with the 10 bit DAC to produce a counter capable
of monitoring the pixel signal over extremely long integration times; in this case up to 30 seconds.