Patent ID: 9084330
Filing Date: 2015-07-14
Classification: H05B

Abstract:
1. A fault-tolerant controller for a lighting system comprising a plurality of LED circuits and a controllable power source providing a drive voltage to power the plurality of LED circuits, the fault-tolerant controller comprising: a control unit configured to cause regulation of the drive voltage based on a determination of a plurality of feedback voltages, one feedback voltage for each of the plurality of LED circuits; and a fault condition detecting means configured to identify one or more fault conditions from the plurality of feedback voltages, wherein at least one of the LED circuits is determined as a fault circuit having a fault condition for which the respective feedback voltage is below a first fault circuit condition threshold, wherein the fault condition detecting means is further configured, in response to a detected fault condition, to apply a test voltage to a cathode of the fault-circuit and, if the feedback voltage of the fault circuit remains below a second fault circuit condition threshold, the fault circuit is determined to have a short circuit condition, wherein the fault condition detecting means comprises a plurality of pull-up circuits, each pull-up circuit provided between ground voltage and a cathode for each LED circuit, wherein each pull-up circuit comprises a voltage source and a switch, the fault condition detecting means being configured to cause closing of the switch associated with the fault circuit upon detecting a fault condition to apply the test voltage to the cathode of the fault circuit.