An apparatus includes a photodetector configured to generate an electrical current based on received illumination. The apparatus also includes a capacitor transimpedance amplifier (CTIA) unit cell having (i) an amplifier configured to receive the electrical current and a first reference voltage and generate a pre-integration voltage, (ii) a feedback capacitor coupled in parallel across the amplifier, (iii) a reset switch coupled in parallel across the feedback capacitor, and (iv) a coupling capacitor coupled to an output of the amplifier and configured to receive the pre-integration voltage and generate an integration voltage. The apparatus further includes a comparator configured to compare the pre-integration voltage and a second reference voltage, where generation of the integration voltage is modifiable based on the comparison.