A light emitting diode (LED) controller for controlling a plurality of LED channels includes channel select circuitry, detection circuitry, and error processor circuitry. The channel select circuitry is configured to drive N−1 LED channels of a plurality of (N) LED channels at a nominal modulation frequency and to selectively drive a selected one of the N LED channels at a probe modulation frequency. The detection circuitry is configured to receive a composite brightness signal corresponding to brightness signals from the N LED channels. The detection circuitry is further configured to filter the composite bright signal and generate a selected brightness signal corresponding to a brightness of the selected LED channel at the probe modulation frequency. The error processor circuitry is configured to compare the selected brightness signal to user defined and/or preset photometric quantities and generate a control signal for adjusting the brightness of the selected LED channel.