Patent ID: 9487124
Filing Date: 2016-11-08
CPC Classification: B60Q,B61L,F21S,H05B

Claim Text:
1. A locomotive headlight comprising: a light housing including a base and a lens, the base forming an internal cavity, with the lens covering and substantially closing the internal cavity; at least one light emitting diode (LED) mounted within the cavity, with the LED arranged to direct light generated thereby through the lens; a controller having an input lead that is coupled to a control switch, the control switch including an input node, an output node and at least two independently selectable current paths between the input node and the output node including high intensity and low intensity current paths, the input lead being coupled to the output node of the control switch, the controller to determine which of the high intensity and low intensity current paths is selected by deriving an estimated resistance value for the selected current path; a voltage sensor to sense the voltage at the output node, the controller to derive the estimated resistance value at least in part as a function of the sensed voltage; a current sensor to sense current at the output node, the controller to derive the estimated resistance value at least in part as a function of the sensed current; the controller programmed to generate a control signal indicating a high intensity and low intensity when the high intensity and low intensity current paths are selected, respectively; and a light driver coupled between the output node and the at least one LED, the light driver to receive the control signal and to adjust a current applied to the at least one LED as a function of the control signal.