Patent ID: 8305005

Claim:
An integrated circuit for driving high-voltage LED lamps applied with a full-wave rectified power, the integrated circuit comprising: a plurality of LED stacks connected in series, each of the LED stacks including a first side and a second side, the second side of an LED stack being electrically connected to the first side of a next LED stack in the series; a control unit; a plurality of current-clamping units electrically connected to the control unit and LED stacks; and at least one current-sensing unit electrically connected to the current-clamping units and the control unit; wherein a first current-clamping units is electrically connected to the second side of the first LED stack and the first side of the second LED stack, and a last current-clamping unit is electrically connected to the second side of a last LED stack, when an electrical current flowing through the current-clamping unit is greater than a default current, a respective current-sensing unit outputs a logical high signal to the control unit, and when the electrical current flowing through the current-clamping unit is not greater than the default current, the respective current-sensing unit outputs a logical low signal to the control unit, and wherein the control unit is configured to turn off the first (N-1) current-clamping units when the control unit is informed from the logical high and low signals that the full-wave rectified power is larger enough to drive the first N LED stacks in the LED stack series, wherein N is an integer number larger than 1.