Ambient light sensor circuitry includes a photodetector, a controllable current source, and control circuitry. The photodetector is coupled between a supply voltage and an intermediate node and configured to provide a photodetector current proportional to an amount of light detected thereby to the intermediate node. The controllable current source is coupled between the intermediate node and ground and configured to shunt a portion of the photodetector current from the intermediate node to ground based on a current control signal. The control circuitry is coupled to the intermediate node and the controllable current source and configured to provide the current control signal to the controllable current source, receive a measurement signal from the intermediate node, adjust the current control signal such that the measurement signal does not exceed a maximum input threshold of the control circuitry, and provide an ambient light measurement signal based on the current control signal.
