Patent ID: 8174206
Filing Date: 2012-05-08
Classification: H05B

Abstract:
1. An encoding device for a light-emitting-diode (LED) lamp, said encoding device being adapted to receive an alternating current (AC) voltage input and display data related to a light-emitting operation, said encoding device comprising: a rectifier for rectifying the AC voltage input to result in a rectified signal; and an encoder for generating an encoded signal from the rectified signal and the display data, the encoded signal having an amplitude corresponding to a magnitude of the rectified signal, and a waveform corresponding to the display data, the encoded signal having a plurality of consecutive signal regions of equal time durations, each of the signal regions having one of first and second states, the waveform of the signal region having the first state being a positive half-cycle of an AC sinusoidal wave, the waveform of the signal region having the second state being a low potential waveform; the display data including a plurality of bits, wherein said encoding device further comprises a zero-crossing detecting circuit for detecting zero voltage points in the AC voltage input and for generating a first trigger signal having a plurality of pulses corresponding to the zero voltage points, said encoder processing one of the bits of the display data each time one of the pulses of the first trigger signal is received thereby; wherein said encoder includes a control circuit for selecting one of the first trigger signal and the low potential waveform for output as a control signal in accordance with the bit of the display data that is being processed, and a switch controlled by the control signal such that the state of the waveform of one of the signal regions of the encoded signal corresponds to the bit of the display data that is being processed.