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US 10,757,775 B2Granted
N-color scalable LED driver
AssigneeRensselaer Polytechnic Institute
InventorsKumar Modepalli, Leila Parsa
Life of this patent
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Abstract
Light-emitting diode (LED) driver systems that are scalable and can be used for N-color LED systems are provided. An LED system having N LED strings of different color can be efficiently driven with independently controllable constant current sources for each string from a single power source. The driver system can include a power converter having an inductor.
Claims13
A light-emitting diode (LED) driving system, comprising:
- a power converter comprising an inductor and configured to provide a direct current (DC) output;
- a control circuit configured to receive input signals and provide output control signals to the power converter;
- and
- a load connected to the power converter and receiving the DC output from the power converter,
- wherein the load comprises:
- a first LED string for a first LED of a first color;
- and
- a second LED string for a second LED of a second color different from the first color,
- wherein the first LED is a higher-voltage LED than is the second LED, and
- wherein the second LED string comprises a first switch in series with the second LED;
- and
- wherein the controller is configured to implement a control scheme comprising the following steps:
- i) setting all switches in the strings ON;
- ii) measuring individual switch currents for all switches in the strings;
- iii) integrating these switch currents;
- iv) once an integrated current in the LED string that has the lowest-voltage LED of all present current strings that have a switch that is ON reaches a predetermined reference value for that LED string, switching the switch in that LED string to OFF;
- v) repeating step iv) until all series switches in the strings are OFF.
14 more elements
Dependencies are inferred from the claim text.