Patent ID: 9674471
Date: 2017-06-06
CPC Classifications: H03K,H04N

Claim:
1. A digital unit cell comprising: an integrator circuit configured to accumulate charge in response to radiation incident on the integrator circuit over an integration period; a dynamic comparator coupled to the integrator circuit, the dynamic comparator including a first output and a second output and configured to compare an integration voltage of the integrator circuit with a reference voltage over the integration period, provide a first pulse signal to the first output each time a determination is made that the integration voltage is less than the reference voltage, and provide a second pulse signal to the second output each time a determination is made that the integration voltage exceeds the reference voltage; a multiplexer coupled to the first output and the second output of the dynamic comparator and configured to receive a count direction control signal; and a counter element coupled to the multiplexer and configured to increment a count value each time the first pulse signal or the second pulse signal is received from the dynamic comparator over the integration period, wherein the multiplexer is configured to couple the first output of the dynamic comparator to the counter element in response to the count direction control signal being in a first state, and to couple the second output of the dynamic comparator to the counter element in response to the count direction control signal being in a second state.