To provide an LED lamp which continues to stably light without twinkling even if a voltage of a commercial electric power source to be practically supplied has an asymmetric waveform in up and down, fluctuates in its frequency or has a messy waveform with a noise component being applied.
A constant voltage generation circuit, which operates to generate a target voltage from an electric power source with its voltage changing with time, comprises constant voltage generation means 22 and selection output means 23. The constant voltage generation means 22 takes a drive state or a non-drive state in accordance with magnitude of a voltage inputted from the electric power source so as to output a predetermined voltage in the drive state, and the selection output means 23 operates to select and output an output voltage when the constant voltage generation means 22 is in the drive state and to select and output a voltage of the electric power source when the voltage generation means 22 is in the non-drive state.
OGURO MASAKI
YOSHIZAWA FUMIO
本多 章悟
樺山 亨
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