Control circuit for balancing current and method thereof
AssigneesCoretronic Corporation, Young Lighting Technology Inc.
InventorsPei-Ting Chen, Chih-Tsan Huang, Tzu-Shou Kuo
Life of this patent
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Abstract
A control circuit for balancing current in a thin display device includes a light source, a power supply, and a control part. The light source includes a plurality of parallel light-emitting diode (LED) rows. The LED row includes at least one LED and a switch unit. The switch unit is in series connection with the LED. The switch unit has two working conditions, one is on and the other is off, to determine whether the current passes through the LED row. The power supply provides a working power for the LEDs. The control part detects the currents of the LED rows, controls the on-state timing ratio of the switch unit and controls the output power of the power supply.
Claims9
A control circuit for balancing current, employed in a thin display, comprising:
- a light source, which includes a plurality of parallel light-emitting diode (LED) rows, wherein each of the LED rows includes:
- at least one LED;
- and
- a first switch unit that is in series connection with the LED for determining whether a current passes through each of the LED rows;
- a power supply that is in series connection with the light source for providing the LEDs with a working power;
- a control part that detects the current of the LED rows, controls an on-state timing ratio of the first switch unit, and controls an output power of the power supply;
- and
- a short circuit connected in parallel with the LED for connecting two ends of an open circuit caused by a broken LED, wherein the short circuit comprises:
- a trigger part;
- and
- a second switch unit, wherein the trigger part detects the open circuit caused by the broken LED, and then the trigger part triggers the second switch unit to be at on-state for connecting the two ends of the open circuit.
A controlling method for balancing current, employed to balance currents of a plurality of parallel LED rows in a thin display device, comprising:
- increasing one of currents of the LED rows to a predetermined working current;
- selecting a minimum current of the currents of the LED rows;
- increasing the minimum current to the predetermined working current;
- and
- counting an on-state timing ratio of a current of each LED rows, and changing the currents of the LED rows according to the on-state timing ratio.
Dependencies are inferred from the claim text.