Patent ID: 7667414

Claim:
An LED lighting apparatus comprising: a plurality of LEDs connected in series including a first LED and a last LED, the first LED including an anode and a cathode, and the last LED including an anode and a cathode; a boosting circuit configured to supply electricity to the anode of the first LED; a current detection circuit configured to detect a LED current of the plurality of LEDs connected in series, the current detection circuit connected between the boosting circuit and the anode of the first LED; an inverted boosting circuit configured to supply electricity to the cathode of the last LED; and a dual PWM control IC with two output terminals and two feedback terminals, a first output terminal of the two output terminals connected to an input of the boosting circuit, and a corresponding feedback terminal of the two feedback terminals connected to an output of the current detection circuit, the other output terminal of the two output terminals connected to an input of the inverted boosting circuit, and a corresponding second feedback terminal of the two feedback terminals connected to an output of the inverted boosting circuit, wherein the dual PWM control IC is configured to control the boosting circuit and the inverted boosting circuit in accordance with the LED current detected by the current detection circuit, such that the LED current is substantially constant during operation of the apparatus.