POWER SUPPLY UNIT AND ORGANIC LIGHT EMITTING DISPLAY INCLUDING THE SAME

• US 20130235017A1
• Filed: 06/28/2012
• Published: 09/12/2013
• Est. Priority Date: 03/07/2012
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Mobile Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Park, Sung-Cheon
• Granted Patent: US 9,514,671 B2
• Time in Patent Office: Days
• US Class Current: 345/212
• CPC Class Codes: G05F 1/40 using discharge tubes or semiconductor devices as final control devices
• CPC Class Codes: G05F 1/62 using bucking or boosting dc sources
• CPC Class Codes: G09G 2330/028 Generation of voltages supplied to electrode drivers in a matrix display other than LCD
• CPC Class Codes: G09G 3/3208 organic, e.g. using organic light-emitting diodes [OLED]

Abstract

Disclosed is a power supply unit including a DC-DC converter including an output terminal and resistor coupling terminal and an external resistor coupled to the resistor coupling terminal, where the DC-DC converter includes a first power generation unit which outputs a predetermined current to the output terminal, and a sensing circuit unit that includes a sensing resistor located between the first power generation unit and the output terminal and stops an operation of the first power generation unit depending on a current value flowing in the sensing resistor. A power supply unit and an organic light emitting display including the power supply unit include a sensing circuit unit that stops operation of the power supply unit to prevent an additional damage when an abnormal current occurs.

Claims

1. A power supply unit including:

a DC-DC converter including a first power generation unit, an output terminal, a sensing circuit unit between the first power generation unit and the output terminal, and a resistor coupling terminal, wherein the sensing circuit includes a sensing resistor; and

an external resistor coupled to the resistor coupling terminal,

wherein the first power generation unit is configured to output a current to the output terminal, the sensing circuit unit is configured to cause a stop in operation of the first power generation unit based on a value of a current flowing in the sensing resistor exceeding a predetermined value, and wherein the output terminal is configured to output a first power.

2. The power supply unit according to claim 1, wherein the sensing circuit unit further includes:

a first resistor connected to a common node between the first power generation unit and the sensing resistor, and a first node,

a first transistor connected to the first node and the resistor coupling terminal,

an operational amplifier configured to control the first transistor using an input reference voltage and a voltage input to the first node, and

a comparator configured to supply a driving stop signal to the first power generation unit if both a voltage of the output terminal and a voltage input to the first node are identical.

3. The power supply unit according to claim 2, wherein the operational amplifier comprises a non-inverting terminal with the reference voltage input thereto, an inverting terminal with the voltage of the resistor coupling terminal input thereto, and an output terminal connected to a gate electrode of the first transistor.

4. The power supply unit according to claim 1, wherein the sensing circuit unit further includes:

a first resistor connected to a common node between the first power generation unit and the sensing resistor, and a first node,

a first transistor connected to the first node and a first reference current source,

a second resistor connected to the output terminal and a second node,

a second transistor connected to the second node and a second reference current source,

a third transistor connected to the first node and the resistor coupling terminal, and having a gate electrode connected to a common node between the first transistor and the first reference current source, and

a comparator configured to supply a driving stop signal to the first power generation unit if both a reference voltage and a voltage input to the resistor coupling terminal are identical.

5. The power supply unit according to claim 4, wherein a gate electrode of the second transistor is coupled to a gate electrode of the first transistor and to the second reference current source.

6. The power supply unit according to claim 4, wherein the first resistor and the second resistor have a same resistance.

7. The power supply unit according to claim 4, wherein the first transistor and the second transistor are P-type transistors.

8. The power supply unit according to claim 7, wherein the third transistor is N-type transistor.

9. The power supply unit according to claim 4, wherein a current value supplied by the first reference current source and a current value supplied by the second reference source are identical.

10. The power supply unit according to claim 1, wherein the DC-DC converter further includes an input terminal electrically coupled to a power unit.

11. The power supply unit according to claim 10, further comprising a first inductor connected between the power unit and the input terminal.

12. The power supply unit according to claim 11, wherein the first power generation unit includes:

a fourth transistor connected to the input terminal and a ground power,

a fifth transistor connected to the input terminal and the sensing resistor, and

a first switching control unit configured to control the fourth transistor and the fifth transistor.

13. The power supply unit according to claim 1, wherein the DC-DC converter is implemented by an integrated chip.

14. An organic light emitting display including:

a plurality of pixels supplied with each of a scan signal, a data signal and a first power;

a scan driving unit for supplying the scan signal to the pixels through a scan line;

a data driving unit for supplying the data signal to the pixels through a data line; and

a power supply unit including a DC-DC converter including a first power generation unit, an output terminal, a sensing circuit unit between the first power generation unit and the output terminal, a resistor coupling terminal, and an external resistor coupled to the resistor coupling terminal, the first power generation unit configured to output a current to the output terminal, the sensing circuit unit including a sensing resistor and configured to cause a stop in operation of the first power generation unit based on a value of a current flowing in the sensing resistor exceeding a predetermined value, the output terminal configured to output the first power, the resistor coupling terminal configured to supply the first power to the pixels,

15. The organic light emitting display according to claim 14, wherein the sensing circuit unit further includes:

a first resistor connected between a common node between the first power generation unit and the sensing resistor, and a first node,

a first transistor connected between the first node and the resistor coupling terminal,

an operational amplifier configured to control the first transistor using a reference voltage and a voltage of the first node which are input, and

a comparator configured to supply a driving stop signal to the first power generation unit if a voltage input to the output terminal and a voltage input to the first node are identical.

16. The organic light emitting display according to claim 15, wherein the operational amplifier includes a non-inverting terminal having the reference voltage input thereto, an inverting terminal having the voltage of the resistor coupling terminal input thereto, and an output terminal connected to a gate electrode of the first transistor.

17. The organic light emitting display according to claim 14, wherein the sensing circuit unit further includes:

a first resistor connected between a common node between the first power generation unit and the sensing resistor, and a first node,

a first transistor connected between the first node and a first reference current source,

a second resistor connected between the output terminal and a second node,

a second transistor connected between the second node and a second reference current source,

a third transistor connected between the first node and the resistor coupling terminal, and having a gate electrode connected to a common node of the first transistor and the first reference current source, and

a comparator configured to supply a driving stop signal to the first power generation unit if both an input reference voltage and a voltage input to the resistor coupling terminal are identical.

18. The organic light emitting display according to claim 17, wherein a gate electrode of the second transistor is coupled to a gate electrode of the first transistor and the second reference current source.

19. The organic light emitting display according to claim 17, wherein the first resistor and the second resistor have a same resistance.

20. The organic light emitting display according to claim 17, wherein the first transistor and the second transistor are P-type transistors.

21. The organic light emitting display according to claim 20, wherein the third transistor is N-type transistor.

22. The organic light emitting display according to claim 17, wherein the current value supplied by the first reference current source and the current value supplied by the second reference source are identical.

23. The organic light emitting display according to claim 14, wherein the DC-DC converter further includes an input terminal electrically coupled to a power unit.

24. The organic light emitting display according to claim 14, further comprising a first inductor connected between the power unit and the input terminal.

25. The organic light emitting display according to claim 24, wherein the first power generation unit includes:

a fourth transistor connected between the input terminal and a ground power,

a fifth transistor connected between the input terminal and the sensing resistor, and

a first switching control unit configured to control the fourth transistor and the fifth transistor.

26. The organic light emitting display according to claim 14, wherein the DC-DC converter is implemented by an integrated chip.