LIGHT-EMITTING MODULE

• US 20170127486A1
• Filed: 03/23/2015
• Published: 05/04/2017
• Est. Priority Date: 03/31/2014
• Status: Active Grant

• Current Assignee: Suzhou Lekin Semiconductor Company Limited
• Original Assignee: LG Innotek Company Limited (LG Corporation)
• Inventors: KANG, Il Yeong, LEE, Sang Hoon, JOO, Keun Tak, CHOI, Tae Young, JEON, Jong Won
• Granted Patent: US 9,775,204 B2
• Time in Patent Office: Days
• CPC Class Codes: H05B 45/48 having LEDs organised in strings and incorporating parallel shunting devices
• CPC Class Codes: H05B 45/50 responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits
• CPC Class Codes: H05B 45/59 for reducing or suppressing flicker or glow effects

Abstract

The light-emitting module according to one embodiment comprises first to Nth light-emitting element packages (wherein N is a positive integer greater than or equal to 1), which are connected in series to one another, and a current level regulator for regulating the level of current flowing through the Nth light-emitting element package. Each of the first to Nth light-emitting element packages comprises a light-emitting cell comprising a plurality of sub-cells, which comprise at least one light-emitting element and are connected in series or parallel to one another, and a flicker control unit, which is connected between the plurality of sub-cells and selectively forms the path or current flowing through the light-emitting cell according to the level of an external driving voltage. At least one of the first to Nth light-emitting element packages further comprises a first current control resistor connected to the output of the light-emitting cell.

Claims

1. A light emitting module, comprising:

first to N-th (where N being a positive integer equal to or greater than

     1) light emitting element packages connected to each other in series; and

a current level regulator regulating a level of current flowing in the N-th light emitting element package,

wherein each of the first to N-th light emitting element packages includes;

a light emitting cell, each of the light emitting cell including at least one light emitting element and including a plurality of sub cells connected to each other in series or in parallel; and

an ON/OFF controller connected between the plurality of sub cells and selectively forming a path, through which current flows, in the light emitting cell according to a level of an external driving voltage,

wherein at least one of the first to N-th light emitting element packages further includes a first current regulation resistor connected to an output of the light emitting cell,

wherein the ON/OFF controller comprises a first reference voltage generator generating a first reference voltage using a voltage between a node between the sub cells and an output terminal of the ON/OFF controller, and

wherein the ON/OFF controller selectively forms the path, through which current flows, in the light emitting cell by using the first reference voltage.

2. The light emitting module according to claim 1, wherein the ON/OFF controller further includes a first current control integrated circuit (IC) for controlling current flowing in the light emitting cell.

3. The light emitting module according to claim 1, further comprising a first surge protection unit disposed between the N-th light emitting element package and the current level regulator to protect the light emitting module from a surge voltage less than or equal to a predetermined voltage.

4. The light emitting module according to claim 3, wherein:

the first surge protection unit includes a field effect transistor,

the field effect transistor includes;

a drain connected to the N-th light emitting element package;

a gate receiving the external driving voltage; and

a source connected to the current level regulator.

5. The light emitting module according to claim 1, further comprising a rectifier rectifying the alternating current (AC) external driving voltage and supplying the rectified external driving voltage to the first to N-th light emitting element packages.

6. The light emitting module according to claim 5, further comprising a second surge protection unit connected to the rectifier in parallel to protect the light emitting module from a surge voltage greater than the predetermined voltage.

7. The light emitting module according to claim 6, wherein the second surge protection unit includes a varistor connected to the rectifier in parallel.

8. The light emitting module according to claim 5, further comprising a fuse disposed between the AC external driving voltage and the rectifier.

9. The light emitting module according to claim 5, further comprising:

a Zener resistor having one side connected to a first node between the rectifier and the first light emitting element package; and

a Zener diode having an anode connected to the other side of the Zener resistor and a cathode connected to the current level regulator.

10. The light emitting module according to claim 1, wherein the plurality of sub cells includes:

a first sub cell having a plurality of light emitting elements connected to each other in parallel; and

a second sub cell connected to the first sub cell in series and having a plurality of light emitting elements connected to each other in parallel.

11. The light emitting module according to claim 1, wherein the ON/OFF controller further includes:

a first switching element connected between a node between the plurality of sub cells and an output terminal of the light emitting cell to perform switching in response to a first switching control signal;

a first comparator comparing a voltage of the output terminal of the light emitting cell and the first reference voltage, and outputting a comparison result as the first switching control signal;

a first current source connected between the output terminal of the light emitting cell and the output terminal of the ON/OFF controller.

12. The light emitting module according to claim 11, wherein the ON/OFF controller further includes a first mode selector controlling current of the first current source.

13. The light emitting module according to claim 4, wherein the current level regulator includes:

a second current regulation resistor;

a second switching element connected between the source and one side of the second current regulation resistor to perform switching in response to a second switching control signal;

a second comparator comparing a voltage of one side of the second current regulation resistor with a second reference voltage, and outputting a comparison result as the second switching control signal;

a second reference voltage generator generating the second reference voltage using a voltage between the source and the other side of the second current regulation resistor; and

a second current source connected between both sides of the second current regulation resistor.

14. The light emitting module according to claim 13, further comprising a second mode selector controlling current of the second current source.

15. The light emitting module according to claim 5, further comprising a valley-fill circuit reducing and outputting a level difference between a maximum value and a minimum value of the rectified external driving voltage.

16. The light emitting module according to claim 15, wherein the valley-fill circuit includes:

a first diode having an anode connected to a low potential of the rectified external driving voltage;

a first capacitor connected between a high potential of the rectified external driving voltage and a cathode of the first diode;

a second diode having an anode connected to the cathode of the first diode;

a third diode having an anode and a cathode respectively connected to the cathode of the second diode and the high potential of the rectified external driving voltage; and

a second capacitor connected between the cathode of the second diode and the low potential of the rectified external driving voltage.

17. The light emitting module according to claim 15, further comprising a first surge protection circuit disposed between the valley-fill circuit and the first light emitting element package to protect the light emitting module from a surge voltage equal to or less than a predetermined voltage.

18. The light emitting module according to claim 1, further comprising a first surge protection circuit disposed between the first light emitting element package and the second light emitting element package to protect the light emitting module from a surge voltage equal to or less than a predetermined voltage.

19. The light emitting module according to claim 15, wherein the level difference is reduced by a predetermined level and the predetermined level is 40% to 50% of the level difference.

20. A light emitting module comprising:

first to N-th (where N being a positive integer equal to or greater than

     1) light emitting element packages electrically connected to each other;

a rectifier rectifying an alternating current (AC) external driving voltage; and

a valley-fill circuit reducing a difference between a maximum value and a minimum value of the external driving voltage rectified by the rectifier, and outputting the external driving voltage having the reduced level to the first to N-th light emitting element packages,

wherein each of the first to N-th light emitting element packages includes;

a light emitting cell, each of the light emitting cell including at least one light emitting element and including a plurality of sub cells connected to each other in series or in parallel; and

an ON/OFF controller connected between the plurality of sub cells and selectively forming a path in which current flows in the light emitting cell according to the reduced level of the external driving voltage.,

wherein the ON/OFF controller comprises a first reference voltage generator generating a first reference voltage using a voltage between a node between the sub cells and an output terminal of the ON/OFF controller, and

wherein the ON/OFF controller selectively forms the path, through which current flows, in the light emitting cell by using the first reference voltage.