Patent ID: 8552649

Claim:
A lamp head configured to be electrically coupled solely to a power-supply element and a return element, a power voltage carried by the power-supply element being regulated by a control element, the lamp comprising: at least one LED configured to emit light; and a first circuit coupled to the at least one LED and configured to adjust the brightness of the light emitted by the at least one LED solely in response to adjustments made to the power voltage by the control element, wherein the first circuit comprises: a second circuit coupled to the power-supply and return elements, the second circuit configured to generate a first reference voltage; a third circuit coupled to the second circuit, the power-supply element and the return element, the third circuit configured to determine a difference between the first reference voltage and the power voltage and generate a first signal based on the determined difference; and a fourth circuit coupled to the third circuit, the fourth circuit configured to generate a second reference voltage based on the first signal.