An example circuit includes a light detector and a biasing capacitor having (i) a first terminal that applies to the light detector an output voltage that can either bias or debias the light detector and (ii) a second terminal for controlling the output voltage. The circuit includes a first transistor connected to the second terminal of the biasing capacitor and configured to drive the output voltage to a first voltage level above a biasing threshold of the light detector and thereby biasing the light detector. The circuit includes a second transistor connected to the second terminal of the biasing capacitor and configured to drive the output voltage to a second voltage level below the biasing threshold of the light detector and thereby debiasing the light detector. The second voltage is a non-zero voltage that corresponds to a charge level of the biasing capacitor.