US 12,432,475 B2
Digital pixel architecture supporting low power and high dynamic range operation having a counter that stops counting pulses in response to detecting a voltage on a capacitor exceeding a threshold
Zhenwu Wang, Moorpark, CA (US); and Angelika Rutz, Newbury Park, CA (US)
Assigned to Raytheon Company, Arlington, VA (US)
Filed by Raytheon Company, Waltham, MA (US)
Filed on Apr. 18, 2023, as Appl. No. 18/302,641.
Prior Publication US 2024/0357261 A1, Oct. 24, 2024
Int. Cl. H04N 5/335 (2011.01); H04N 25/76 (2023.01); H04N 25/77 (2023.01); H04N 25/78 (2023.01)
CPC H04N 25/78 (2023.01) [H04N 25/77 (2023.01); H04N 25/7795 (2023.01)] 20 Claims
OG exemplary drawing
 
1. An apparatus comprising:
a photodetector configured to generate an electrical current based on received illumination;
a capacitor configured to be charged by the electrical current and generate a voltage;
a controller configured to detect whether the voltage on the capacitor exceeds a threshold during a sampling period; and
a timer configured to generate an estimate or measure of an amount of time within the sampling period during which the voltage on the capacitor does not exceed the threshold;
wherein the timer comprises a counter configured to count a number of pulses in a clock signal and to stop counting the pulses in the clock signal in response to the controller detecting that the voltage on the capacitor exceeds the threshold, the pulses in the clock signal having an exponentially-increasing spacing during the sampling period.