Method and apparatus for power feedback LED voltage control
AssigneeSct Ltd.
InventorsEric Li, Shean-Yih Chiou
Life of this patent
Estimating the term…
Abstract
An LED system includes an LED array, a plurality of driver circuits, a power supply, a bus and a feedback circuit. Each of the plurality of driver circuits is connected to and driving one of a plurality of LED subarrays in the LED array. Each of the plurality of driver circuits includes a comparator circuit, a local voltage register, and a global voltage register. The comparator circuit determines, as a local minimum voltage, a lowest voltage in the corresponding LED subarray. The global minimum voltage is determined by comparing all the local minimum voltages. The feedback circuit provides the power supply with a feedback signal reflecting the global minimum voltage and causes the power supply to adjust the voltage output to the LED array.
Claims18
An LED system, comprising:
- an LED array comprising a plurality of LED subarrays,
- a plurality of driver circuits, each connected to and driving one of the plurality of LED subarrays, wherein each of the plurality of driver circuits comprises a comparator circuit for determining, as a local minimum voltage, a lowest voltage in the corresponding LED subarray connected thereto, a local voltage register for storing the local minimum voltage, and a global voltage register for storing, as a global minimum voltage, a lowest voltage among the plurality of local minimum voltages in the plurality of LED subarrays;
- a power supply connected to and outputting a voltage to the LED array;
- a bus connecting the plurality of driver circuits;
- and
- a feedback circuit connected to the power supply and one or more of the global voltage registers in the plurality of driver circuits, wherein the feedback circuit provides the power supply with a feedback signal reflecting the global minimum voltage and causes the power supply to adjust the voltage output to the LED array.
A method for controlling voltage supplied to an LED system, wherein the LED system comprises a plurality of LED subarrays, the method comprising:
- applying an initial voltage to each of the plurality of LED subarrays in the LED system;
- determining a local minimum voltage for each of the plurality of LED subarrays to obtain a plurality of local minimum voltages;
- and
- determining a global minimum voltage amongst the plurality of local minimum voltages;
- adjusting the initial voltage using the global minimum voltage as a feedback to obtain an updated voltage to be applied to the plurality of LED subarrays in the LED system.
Dependencies are inferred from the claim text.