Current splitter for LED lighting system
View Patent ↗Systems and methods for controlling a light emitting diode (LED) system having a plurality of LED arrays are provided. The lighting system can include a dimmable LED driver circuit configured to provide a driver output suitable for providing a driver current to the LED arrays. A current splitter circuit can be provided between the LED driver circuit and the plurality of LED arrays to control the ratio of current from the driver output provided to each of the plurality of LED arrays. The current splitter circuit can be configured to control the current ratio provided to the plurality of LED arrays independently of the driver output according to a current ratio control curve based at least in part on a variable reference signal provided at the current splitter circuit.
1. A lighting emitting diode (LED) system, comprising:
a first LED array having one or more LED devices;
a second LED array having one or more LED devices;
a dimmable driver circuit configured to provide a driver output; and
a current splitter circuit configured to receive the driver output and to provide a first current to the first LED array and a second current to the second LED array;
an interface provided at the current splitter circuit configured to receive a variable reference signal;
wherein the current splitter circuit is configured to control a current ratio of the first current and the second current according to a non-linear current ratio control curve, the non-linear current ratio control curve specifying the current ratio as a function of at least the variable reference signal.
2. The LED system of claim 1 , wherein the non-linear current ratio control curve comprises super-linear, parabolic, logarithmic, asymptotic, or exponential relationship between the current ratio and the variable reference signal.
3. The LED system of claim 1 , wherein the non-linear current ratio control curve comprises a step function defined at least in part on the variable reference signal.
4. The LED system of claim 1 , wherein the current splitter circuit comprises:
a first switching element coupled to the first LED array;
a second switching element coupled to the second LED array; and
one or more control devices configured to control the first switching element to provide the first current to the first LED array and to control the second switching element to provide the second current to the second LED array.
5. The LED system of claim 4 , wherein the first switching element and the second switching element each comprise a current sensing MOSFET.
6. The LED system of claim 1 , wherein the interface is configured to receive the variable reference signal from an external dimmer circuit.
7. The LED system of claim 1 , wherein the variable reference signal is a 0V to 10V lighting control signal, a DALI lighting control signal, or a DMX lighting control signal.
8. The LED system of claim 1 , further comprising an optical sensor coupled to the current splitter circuit, the optical sensor configured to provide a feedback signal indicative of a light output of the LED system to the current splitter circuit, the current splitter circuit configured to control the current ratio based at least in part on the feedback signal.
9. The LED system of claim 1 , wherein the dimmable driver circuit comprises a line dimming driver.
10. The LED system of claim 1 , further comprising a dimming control interface configured to receive a dimming control signal, the driver output being dependent on the dimming control signal.
11. The LED system of claim 10 , wherein the dimming control interface is provided at the driver circuit.
12. The LED system of claim 10 , wherein the dimming control interface is provided at the current splitter circuit.
13. The LED system of claim 1 , wherein the first LED array is associated with a different color temperature than the second LED array such that adjustment of the variable reference signal facilitates adjustment of the color temperature of the LED system.