Load current control circuit
View Patent ↗A system and method for operating one or more light emitting devices is disclosed. In one example, the intensity of light provided by the one or more light emitting devices is adjusted responsive to current feedback from the one or more light emitting devices.
1. A system for operating one or more light emitting devices, comprising:
a voltage regulator including a voltage feedback input receiving input from a voltage divider network electrically coupled to cathodes of the one or more light emitting devices, the voltage regulator in electrical communication with an input of a current controlling device and cathodes of the one or more light emitting devices, the voltage regulator including an error amplifier; and
a current sensing device positioned in a current path through which a current passes through the one or more light emitting devices, the current sensing device in electrical communication with a controller different than the voltage regulator, the controller including instructions to adjust light intensity of the one or more light emitting devices.
2. The system of claim 1 , where the controller instructions adjust lighting intensity via the current controlling device and where the voltage regulator further comprises a pulse width generator and a buck stage amplifier.
3. The system of claim 2 , where the current controlling device is a variable resistor.
4. The system of claim 3 , where the variable resistor is a FET.
5. The system of claim 1 , where the voltage regulator is a buck regulator.
6. The system of claim 1 , where the current sensing device is in electrical communication with the voltage feedback input.
7. The system of claim 1 , where the voltage feedback input is in direct electrical communication with an electrical node positioned between the one or more light emitting devices and a variable resistor, and where the variable resistor is positioned upstream of the current sensing device in the current path.
8. The system of claim 1 , where the voltage feedback input is a voltage input receiving a voltage at a cathode of the one or more light emitting devices.
9. A system for operating one or more light emitting devices, comprising:
a current controlled voltage regulator including a current feedback input, the current controlled voltage regulator in electrical communication with the one or more light emitting devices, the current controlled voltage regulator including an error amplifier that is electrically coupled to a pulse width modulation generator, and where an output of the pulse width modulation generator is input to a buck stage amplifier; and
a current sensing device positioned in a current path through which a current passes through the one or more light emitting devices, the current sensing device in direct electrical communication with the current feedback input.
10. The system of claim 9 , further comprising a controller including controller instructions to supply a reference signal to the error amplifier.
11. The system of claim 9 , where the error amplifier includes two amplifiers.
12. The system of claim 11 , where a first of the two amplifiers applies a gain to a voltage at cathodes of the one or more light emitting devices.
13. The system of claim 11 , where a second of the two amplifiers is in electrical communication with a comparator of the pulse width modulation generator.
14. The system of claim 9 , where the buck stage amplifier includes two switches.