Systems and methods for controlling power factors of LED lighting systems

Patent metadata

Field	Value
Publication number	US-12457670-B2
Application number	US-202418639870-A
Country	US
Kind code	B2
Filing date	Apr 18, 2024
Priority date	Apr 13, 2020
Publication date	Oct 28, 2025
Grant date	Oct 28, 2025

Abstract

System and method for controlling a bleeder current to increase a power factor of an LED lighting system without any TRIAC dimmer. For example, the system for controlling a bleeder current to increase a power factor of an LED lighting system without any TRIAC dimmer includes: a first current controller configured to receive a rectified voltage generated by a rectifier that directly receives an AC input voltage without through any TRIAC dimmer; and a second current controller configured to: control a light emitting diode current flowing through one or more light emitting diodes that receive the rectified voltage not clipped by any TRIAC dimmer; and generate a sensing voltage based at least in part upon the light emitting diode current, the sensing voltage representing the light emitting diode current in magnitude.

First claim

What is claimed is:

1. A controller system for controlling a bleeder current of an LED lighting system, the controller system comprising:
a current controller configured to receive a rectified voltage generated by a rectifier that receives an AC input voltage;
wherein the current controller is further configured to:
receive a sensing voltage representing a light emitting diode current flowing through one or more light emitting diodes; and
generate a bleeder current based at least in part on the sensing voltage;

wherein the current controller is further configured to:
in response to the light emitting diode current being larger than zero in magnitude, generate the bleeder current equal to zero in magnitude; and
in response to the light emitting diode current being equal to zero in magnitude,
generate the bleeder current larger than zero in magnitude; and
change the bleeder current with the changing rectified voltage in magnitude;

wherein the current controller is further configured to, with the light emitting diode current being equal to zero in magnitude:
increase the bleeder current with the increasing rectified voltage in magnitude; and
decrease the bleeder current with the decreasing rectified voltage in magnitude.

2. The controller system of claim 1 wherein a sum of the bleeder current and the light emitting diode current is equal to, in magnitude, a rectifier current generated by the rectifier.

3. The controller system of claim 2 wherein, with the light emitting diode current being equal to zero in magnitude, the rectified voltage and the rectifier current contribute to an active power to increase a power factor of the LED lighting system.

4. The controller system of claim 1 wherein the sensing voltage is directly proportional to the light emitting diode current in magnitude.

5. The controller system of claim 1 wherein:
in response to the light emitting diode current increasing from being equal to zero to being larger than zero, a rectifier current increases from a first magnitude to a second magnitude; and
in response to the light emitting diode current decreasing from being larger than zero to being equal to zero, the rectifier current decreases from the second magnitude to a third magnitude;
wherein:
the first magnitude is larger than zero;
the second magnitude is larger than zero; and
the third magnitude is larger than zero.

6. The controller system of claim 5 wherein the first magnitude and the third magnitude are equal.

7. The controller system of claim 1 wherein:
each cycle of the AC input voltage includes two half cycles of the AC input voltage; and
one half cycle of the AC input voltage starts at a first time, passes a second time and a third time, and ends at a fourth time;
wherein:
the first time precedes the second time;
the second time precedes the third time; and
the third time precedes the fourth time.

8. The controller system of claim 7 wherein:
the rectified voltage is equal to zero in magnitude at the first time and at the fourth time; and
after the first time but before the fourth time, the rectified voltage is larger than zero in magnitude during an entire duration from the first time to the fourth time.

9. The controller system of claim 8 wherein:
the rectified voltage becomes larger than a threshold voltage in magnitude at the second time; and
the rectified voltage becomes smaller than the threshold voltage in magnitude at the third time.

10. The controller system of claim 9 wherein:
after the first time but before the second time,
the light emitting diode current is equal to zero in magnitude; and
the bleeder current is larger than zero in magnitude;

after the second time but before the third time,
the light emitting diode current is larger than zero in magnitude; and
the bleeder current is equal to zero in magnitude; and

after the third time but before the fourth time,
the light emitting diode current is equal to zero in magnitude; and
the bleeder current is larger than zero in magnitude.

11. The controller system of claim 10 wherein:
from the first time to the second time, a rectifier current increases to a first magnitude;
from the second time to the third time, the rectifier current remains at a second magnitude; and
from the third time to the fourth time, the rectifier current decreases from a third magnitude.

12. The controller system of claim 11 wherein:
at the second time, the rectifier current rises from the first magnitude to the second magnitude; and
at the third time, the rectifier current drops from the second magnitude to the third magnitude;
wherein:
the first magnitude is larger than zero;
the second magnitude is larger than zero; and
the third magnitude is larger than zero.

13. The controller system of claim 12 wherein the first magnitude and the third magnitude are equal.

14. The controller system of claim 7 wherein, after the first time but before the second time:
the rectified voltage remains larger than zero in magnitude;
a rectifier current remains larger than zero in magnitude; and
the rectified voltage and the rectifier current contribute to an active power to increase a power factor of the LED lighting system.

15. The controller system of claim 14 wherein, after the third time but before the fourth time:
the rectified voltage remains larger than zero in magnitude;
the rectifier current remains larger than zero in magnitude; and
the rectified voltage and the rectifier current contribute to the active power to increase the power factor of the LED lighting system.

16. A method for controlling a bleeder current of an LED lighting system, the method comprising:
receiving a rectified voltage generated by a rectifier that receives an AC input voltage;
receiving a sensing voltage representing a light emitting diode current flowing through one or more light emitting diodes; and
generating a bleeder current based at least in part on the rectified voltage and the sensing voltage;
wherein the generating a bleeder current based at least in part on the rectified voltage and the sensing voltage includes:
in response to the light emitting diode current being larger than zero in magnitude, generating the bleeder current equal to zero in magnitude; and
in response to the light emitting diode current being equal to zero in magnitude,
generating the bleeder current larger than zero in magnitude; and
changing the bleeder current with the changing rectified voltage in magnitude;

wherein the generating a bleeder current based at least in part on the rectified voltage and the sensing voltage further includes, with the light emitting diode current being equal to zero in magnitude:
increasing the bleeder current with the increasing rectified voltage in magnitude; and
decreasing the bleeder current with the decreasing rectified voltage in magnitude.

17. The method of claim 16 wherein a sum of the bleeder current and the light emitting diode current is equal to, in magnitude, a rectifier current generated by the rectifier.

18. The method of claim 17 wherein, with the light emitting diode current being equal to zero in magnitude, the rectified voltage and the rectifier current contribute to an active power to increase a power factor of the LED lighting system.

19. The method of claim 16 wherein the sensing voltage is directly proportional to the light emitting diode current in magnitude.

20. The method of claim 16 , and further comprising:
in response to t

Assignees

• On Bright Electronics Shanghai Co Ltd

Inventors

• Zhu Liqiang
• Fang Qian
• Fan Zhilin
• Li Ke

Classifications

• H05B45/14

  using electrical feedback from LEDs or from LED modules · CPC title

• H05B45/355 Primary

  Power factor correction [PFC]; Reactive power compensation · CPC title