Pulse-width modulation pixel sensor

A method of operation of a pulse-width modulation (PWM) image sensor, the method comprising:

• during a detection period, receiving a number of photons at a PWM pixel of the PWM image sensor;
• converting the number of photons into a photocurrent as the number of photons is received;
• accumulating a number of electrons at a sense node during the detection period, the number of electrons accumulated in response to the sense node receiving the photocurrent;
• during and in synchronization with the detection period, incrementing a count non-linearly, each value of the count synchronized with a non-linear time reference;
• and
• when the accumulated number of electrons reaches a threshold number of electrons, latching a value of the count in a memory of a time-to-digital converter (TDC) circuit.