Patent ID: 8810136

Claim:
An LED drive circuit comprising: a plurality of LEDs that are connected in series; a first DC power supply that is connected in series to the plurality of LEDs so as to apply a forward bias to the plurality of LEDs; a second DC power supply that is connected in series to the first DC power supply and is connected to the plurality of LEDs so as to apply a forward bias to the plurality of LEDs; a coil that is connected in series with the plurality of LEDs and can accumulate energy from current generated by the first DC power supply and the second DC power supply; a rectifying element whose cathode is connected between the first DC power supply and the second DC power supply, wherein the rectifying element is configured to allow current to flow from the plurality of LEDs to between the first DC power supply and the second DC power supply; a transfer switching element that is connected to an anode of the rectifying element, wherein the transfer switching element is configured to connect the plurality of LEDs and the first power supply when the transfer switching element is switched on and is configured to allow current to flow from the plurality of LEDs to the rectifying element when the transfer switching element is switched off; and a control unit for controlling the transfer switching element, wherein a first closed circuit is formed by the plurality of LEDs, the first DC power supply, the second DC power supply, and the coil when the transfer switching element is switched on under control of the control unit, and a second closed circuit is formed by the plurality of LEDs, the second DC power supply, the coil, and the rectifying element when the transfer switching element is switched off under control of the control apparatus.