Light emitting diode power supply apparatus

Patent metadata

Field	Value
Publication number	US-9258856-B2
Application number	US-201314029386-A
Country	US
Kind code	B2
Filing date	Sep 17, 2013
Priority date	Jun 28, 2013
Publication date	Feb 9, 2016
Grant date	Feb 9, 2016

Abstract

There is provided a light emitting diode power supply apparatus capable of limiting a rise in a voltage level of a power supplied to a light emitting diode even in the case in which driving of the light emitting diode is stopped for a long period of time. The light emitting diode power supply apparatus includes: a power supply unit supplying a driving power set under a control to a light emitting diode; and a controlling unit selecting one of a detection voltage obtained by detecting a current flowing to the light emitting diode and a voltage provided according to an operation state of the light emitting diode to control a power supply operation of the power supply unit.

First claim

What is claimed is:

1. A light emitting diode power supply apparatus comprising:
a power supply unit supplying a driving power set under a control to a light emitting diode; and
a controlling unit controlling power supply operation of the power supply unit based on a detection voltage obtained by detecting a current flowing to the light emitting diode during a period in which the light emitting diode is operated and controlling the power supply operation of the power supply unit based on a voltage provided, when the operation of the light emitting diode is stopped.

2. The light emitting diode power supply apparatus of claim 1 , further comprising a feedback voltage forming unit detecting the driving power of the power supply unit to form a feedback voltage.

3. The light emitting diode power supply apparatus of claim 2 , wherein the voltage provided is one of the feedback voltage detected by the feedback voltage forming unit and a fixed voltage having a preset voltage level.

4. The light emitting diode power supply apparatus of claim 2 , wherein the controlling unit includes:
a first comparator comparing the detection voltage and a voltage of a dimming signal with each other;
a second comparator comparing the feedback voltage and a preset reference voltage with each other;
a current mirror mirroring a current according to the comparison result of the first or second comparator to control a frequency of a reference frequency signal required for the power supply operation of the power supply unit;
a third comparator comparing a preset operating power and a voltage of the comparison result of the first or second comparator with each other to control the current mirroring of the current mirror; and
a buffer buffering the comparison result input thereinto.

5. The light emitting diode power supply apparatus of claim 4 , wherein the controlling unit further includes:
a first switch switching an output of the comparison result of the first comparator according to a preset pulse width modulation (PWM) reset signal; and
a second switch switching an output of the comparison result of the second comparator according to a preset reset signal.

6. The light emitting diode power supply apparatus of claim 5 , wherein the controlling unit further includes:
a setter setting an output condition of the comparison results of the first and second comparators; and
a multiplexer outputting the comparison result of the first or second comparator according to the output condition set by the setter.

7. The light emitting diode power supply apparatus of claim 5 , wherein the controlling unit further includes:
a first multiplexer selecting and outputting one of the comparison result of the first comparator and a preset fixed voltage according to a preset abnormal operation condition; and
a second multiplexer selecting one of the output of the first multiplexer and the comparison result of the second comparator according to a voltage level of the feedback voltage to be provided to the buffer.

8. The light emitting diode power supply apparatus of claim 5 , wherein the controlling unit further includes a selector selecting and outputting a comparison result having a lower voltage level in the comparison results of the first and second comparators in the case in which a preset abnormal operation condition is satisfied.

9. The light emitting diode power supply apparatus of claim 1 , wherein the controlling unit includes:
a first comparator comparing the detection voltage and a voltage of a dimming signal with each other;
a first switch switching an output of the comparison result of the first comparator according to a preset PWM reset signal;
a setter setting an output condition;
a multiplexer outputting the comparison result of the first comparator or a preset fixed voltage according to the output condition set by the setter;
a current mirror mirroring a current according to the output signal of the multiplexer to control a frequency of a reference frequency signal required for the power supply operation of the power supply unit;
a third comparator comparing a preset operating power and the output signal of the multiplexer with each other to control the current mirroring of the current mirror; and
a buffer buffering the output signal of the multiplexer.

10. The light emitting diode power supply apparatus of claim 1 , further comprising a transferring unit electrically insulated to transfer a control signal of the controlling unit to the power supply unit.

11. A light emitting diode power supply apparatus comprising:
a power supply unit switching an input power to supply a driving power to a light emitting diode; and
a controlling unit controlling a power supply operation of the power supply unit based on a detection voltage obtained by detecting a current flowing to the light emitting diode during a period in which the light emitting diode is operated and controlling the power supply operation of the power supply unit based on a voltage provided, when the operation of the light emitting diode is stopped.

12. The light emitting diode power supply apparatus of claim 11 , further comprising a feedback voltage forming unit detecting the driving power of the power supply unit to form a feedback voltage.

13. The light emitting diode power supply apparatus of claim 12 , wherein the voltage provided is one of the feedback voltage detected by the feedback voltage forming unit and a fixed voltage having a preset voltage level.

14. The light emitting diode power supply apparatus of claim 12 , wherein the controlling unit includes:
a first comparator comparing the detection voltage and a voltage of a dimming signal with each other;
a second comparator comparing the feedback voltage and a preset reference voltage with each other;
a current mirror mirroring a current according to the comparison result of the first or second comparator to control a frequency of a reference frequency signal required for the power supply operation of the power supply unit;
a third comparator comparing a preset operating power and a voltage of the comparison result of the first or second comparator with each other to control the current mirroring of the current mirror; and
a buffer buffering the comparison result input thereinto.

15. The light emitting diode power supply apparatus of claim 14 , wherein the controlling unit further includes:
a first switch switching an output of the comparison result of the first comparator according to a preset PWM reset signal; and
a second switch switching an output of the comparison result of the second comparator according to a preset reset signal.

16. The light emitting diode power supply apparatus of claim 15 , wherein the controlling unit further includes:
a setter setting an output condition of the comparison results of the first and second comparators; and
a multiplexer outputting the comparison result of the first or second comparator according to the output condition set by the setter.

17. The light emitting diode power supply apparatus of claim 15 , wherein the controlling unit further includes:
a first multiplexer selecting and outputting one of the comparison result of the first comparator and a preset fixed voltage according to a preset abnormal operation condition; and
a second multiplexer selecting one of the output of the first multiplexer and the comparison result of the second comparator according to a voltage level of the feedback voltage to be provided to the buffer.

18. The light emitting diode power supply apparatus of cl

Assignees

• Samsung Electro Mech

Inventors

• Han Dae Hoon
• Kim Seo Hyung
• Kwon Jung Sun
• Park Jung Eui
• Lee Jin Soo
• Hwang Bo Hyun

Classifications

• H05B45/50 Primary

  responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits · CPC title

• H05B45/44

  with an active control inside an LED matrix · CPC title

• H05B45/37 Primary

  Converter circuits · CPC title

• H05B33/0824

  Electricity · mapped topic

• H05B33/0815 Primary

  Electricity · mapped topic