A dark current compensation circuit comprises a first comparator having inputs for a detection signal and a first voltage, and a second comparator having inputs for the detection signal and a second voltage. The dark current compensation circuit also comprises a controller coupled to the first and second comparators, which has an input for an event signal. An adjustable current source is coupled to the controller and configured to generate a compensation current. The controller adjusts a value of the compensation current based on the first and second comparator outputs and maintains a constant value in response to the event signal indicating photons incident on a photon detector. In some implementations, the dark current compensation circuit further comprises an analog sub-circuit coupled to the adjustable current source and configured to receive the detection signal. The analog sub-circuit generates an analog compensation current in response to the detection signal.