Patent ID: 8519634

Claim:
Drive circuitry for driving a plurality of solid state light emitters coupled between a first node and a second node, a first voltage level provided at the first node being higher than a second voltage level provided at the second node, the drive circuitry comprising: a switching regulator having a switch and an inductive element coupled between the switch and the second node to electrically connect the switch to the second node, a controller for controlling the switch in accordance with an output signal produced by the solid state light emitters to drive the solid state light emitters, input power supply circuitry for supplying an input power supply signal to provide the first voltage level at the first node, the input power supply circuitry being configured for supplying the controller with a first power supply signal produced based on the input power supply signal, operation power supply circuitry electrically connected to the second node for supplying the controller with a second power supply signal when the second voltage level developed at the second node is sufficient to support operation of the controller, a first unidirectional conduction device configured for providing the first power supply signal from the input power supply circuitry to the controller, and a second unidirectional conduction device configured for providing the second power supply signal to the controller, wherein: the first unidirectional conduction device is in an on state, and the second unidirectional conduction device is in an off state when the second voltage level at the second node is not sufficient to support operation of the controller, and the first unidirectional conduction device is turned into an off state, and the second unidirectional conduction device is turned into an on state when the second voltage level at the second node becomes sufficient to support operation of the controller.