Abstract: A pulsating circuit suppling a pulsating voltage to a load when a capacitor is not discharged, and a control circuit which controls discharging the capacitor. The control circuit includes a smoothing circuit, and a voltage detection circuit. The voltage detection circuit includes a first switch that is turned off by detecting the pulsating voltage is in a voltage range; a second switch connected to the first switch and is turned on when the first switch is turned off; and a third switch connected to the second switch and is turned on when the second switch is turned on When the pulsating voltage is not in the discharge voltage range of the capacitor, the first switch is turned on and the second and third switches are turned off. A discharge voltage of the capacitor is set within a range that is slightly higher than a lower limit of a voltage.

Abstract: Each of blocks includes an arbitrary number of series connections of LEDs. A current signal for controlling operation of the LEDs in the blocks is divided into plural signal currents. An allowable forward current having a duty cycle corresponding to a division number is caused to flow through the LEDs in one block for an allowable time, using one of the signal currents. A rated forward current that does not cause destruction of LEDs is caused to flow through the LEDs in the other blocks, using the other of the signal currents. The LEDs in the blocks are driven by causing the allowable forward current and the rated forward current to flow periodically. The rated forward current is caused to flow through at least one additional LED, whereby a difference between respective voltages corresponding to the allowable forward current and the rated forward current is produced.

Abstract: Each of blocks includes an arbitrary number of series connections of LEDs. A current signal for controlling operation of the LEDs in the blocks is divided into plural signal currents. An allowable forward current having a duty cycle corresponding to a division number is caused to flow through the LEDs in one block for an allowable time, using one of the signal currents. A rated forward current that does not cause destruction of LEDs is caused to flow through the LEDs in the other blocks, using the other of the signal currents. The LEDs in the blocks are driven by causing the allowable forward current and the rated forward current to flow periodically. The rated forward current is caused to flow through at least one additional LED, whereby a difference between respective voltages corresponding to the allowable forward current and the rated forward current is produced.