Driver for LED device, LED system, and adaptation method for LED device

Patent metadata

Field	Value
Publication number	US-12041701-B2
Application number	US-201917761258-A
Country	US
Kind code	B2
Filing date	Sep 17, 2019
Priority date	Sep 17, 2019
Publication date	Jul 16, 2024
Grant date	Jul 16, 2024

Abstract

A driver for a light-emitting diode (LED) device comprises: a rectifier, a current regulator and a detecting module. The rectifier is coupled to a ballast and configured to convert an alternating current from the ballast into a direct current. The current regulator is coupled between the rectifier and the LED device, and configured to receive the direct current from the rectifier and output a driving current to the LED device. The detecting module is configured to detect a signal indicating an output characteristic of the ballast, during a startup stage of the LED device. The current regulator is configured to convert the direct current from the rectifier into the driving current with a value equal to or less than a preset current threshold when the signal meets a preset condition, and the preset current threshold is less than a maximum current the LED device is able to carry without damage.

First claim

The invention claimed is:

1. A driver for a light-emitting diode (LED) device, configured to be coupled between a ballast and the LED device and adapt the LED device to the ballast, the driver comprising:
a rectifier, coupled to the ballast and configured to convert an alternating current from the ballast into a direct current;
a current regulator, coupled between the rectifier and the LED device, and configured to receive the direct current from the rectifier and output a driving current to the LED device; and
a detecting module operatively coupled to an output terminal of one of the ballast or the rectifier and configured to detect a signal indicating an output characteristic of the ballast during a startup stage of the LED device, and to output the detected signal to the current regulator;
wherein the current regulator converts the direct current from the rectifier into the driving current with a value equal to or less than a preset current threshold of the LED device when the detected signal meets a preset condition indicating that the output of the ballast cannot be adapted to the LED device.

2. The driver according to claim 1 , wherein the LED device comprises a plurality of LED chips coupled in series, and the maximum current is substantially equal to a rated current of the LED chip.

3. The driver according to claim 1 , wherein the LED device comprises N groups of LED chips, the N groups of LED chips are coupled in parallel with each other, each group comprises a plurality of LED chips coupled in series, and the maximum current is substantially equal to N times a rated current of the LED chip, wherein N is a natural number equal to or larger than 2.

4. The driver according to claim 1 , wherein the current regulator is configured to output the direct current from the rectifier to the LED device as the driving current when the signal does not meet the preset condition.

5. The driver according to claim 1 , wherein the signal comprises the alternating current outputted by the ballast, an alternating voltage outputted by the ballast, the direct current outputted by the rectifier, a direct voltage outputted by the rectifier, or a combination thereof.

6. The driver according to claim 5 , wherein the alternating current outputted by the ballast, the alternating voltage outputted by the ballast, the direct current outputted by the rectifier, the direct voltage outputted by the rectifier has a corresponding preset value range, and the preset condition is that: a value of the alternating current outputted by the ballast, the alternating voltage outputted by the ballast, the direct current outputted by the rectifier, the direct voltage outputted by the rectifier is out of the corresponding preset value range.

7. The driver according to claim 5 , wherein the preset condition is that: a frequency of the alternating current or the alternating voltage outputted by the ballast is lower than a preset frequency threshold.

8. The driver according to claim 1 , wherein the current regulator comprises a current scaling module configured to scale down the direct current to the value equal to or less than the preset current threshold if the signal meets the preset condition.

9. The driver according to claim 1 , wherein the current regulator comprises a constant-current control module configured to regulate the driving current to be substantially constant at the value equal to or less than the preset current threshold when the signal meets the preset condition.

10. The driver according to claim 1 , wherein the detecting module comprises:
a sampling circuit, configured to sample the signal; and
a judging circuit, configured to judge whether the signal sampled meets the preset condition, and output a judging result signal to the current regulator.

11. A light-emitting diode (LED) system, comprising:
an LED device; and
a driver for the LED device, configured to be coupled between a ballast and the LED device and adapt the LED device to the ballast, the driver comprising:
a rectifier, coupled to the ballast and configured to convert an alternating current from the ballast into a direct current;
a current regulator, coupled between the rectifier and the LED device, and configured to receive the direct current from the rectifier and output a driving current to the LED device; and
a detecting module operatively coupled to an output terminal of one of the ballast or the rectifier and configured to detect a signal indicating an output characteristic of the ballast during a startup stage of the LED device, and to output the detected signal to the current regulator;
wherein the current regulator converts the direct current into the driving current with a value equal to or less than a preset current threshold of the LED device if the detected signal meets a preset condition indicating that the output of the ballast cannot be adapted to the LED device.

12. A method for adapting an LED device to a ballast, comprising:
converting an alternating current from the ballast into a direct current by a rectifier;
receiving the direct current from the rectifier and outputting a driving current to the LED device by a current regulator;
detecting, by a detecting module operatively connected to an output terminal of one of the ballast or the rectifier, a signal indicating an output characteristic of the ballast during a startup stage of the LED device; and
converting, by the current regulator, the direct current from the rectifier into the driving current with a value equal to or less than a preset current threshold of the LED device if the detected signal meets a preset condition indicating that the output of the ballast cannot be adapted to the LED device.

13. The method according to claim 12 , comprising outputting the direct current from the rectifier to the LED device as the driving current if the signal does not meet the preset condition.

14. The method according to claim 12 , wherein the signal comprises the alternating current outputted by the ballast, an alternating voltage outputted by the ballast, the direct current outputted by the rectifier, a direct voltage outputted by the rectifier, or a combination thereof.

15. The method according to claim 14 , wherein the preset condition is that: a frequency of the alternating current or the alternating voltage outputted by the ballast is lower than a preset frequency threshold.

16. The method according to claim 12 , wherein the converting of the direct current comprises scaling down the direct current to the value equal to or less than the preset current threshold.

17. The method according to claim 12 , wherein the converting of the direct current comprises regulating the driving current to be substantially constant at the value equal to or less than the preset current threshold.

Assignees

• Savant Tech Llc

Inventors

• Zou Qiang
• Liu Zhichao
• Yan Qi

Classifications

• H05B45/305

  Frequency-control circuits · CPC title

• H05B45/345

  Current stabilisation; Maintaining constant current · CPC title

• H05B45/37 Primary

  Converter circuits · CPC title