Short Circuit Detection for Lighting Circuits

This invention relates to control circuits for LED systems with a feedback loop to regulate a drive voltage. A controller for the system is proposed comprising a plurality of LED circuits and a controllable power source. The controller comprises a control unit configured to cause regulation of the drive voltage based on a determination of a plurality of feedback voltages and a fault condition detecting means. At least one of the LED circuits is determined as having a fault condition if the respective feedback voltage is below a fault threshold. In response to a detected fault condition, a test voltage is applied to a cathode of the fault circuit to confirm the presence of a fault condition.