Organic light emitting display having DC-DC converter

• US 8,334,824 B2
• Filed: 12/28/2007
• Issued: 12/18/2012
• Est. Priority Date: 01/22/2007
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Park, Sungcheon
• Primary Examiner(s): CERULLO, LILIANA P
• Application Number:
  US11/966,797
• Publication Number:
  US 20080174287A1
• Time in Patent Office: 1,817 Days
• Field of Search: 345/82, 345/83, 345/204, 345211-213, 341 50-107
• US Class Current: 345/82
• CPC Class Codes: H02M 1/009 having two or more independently controlled outputs for DC-DC converter with intermediate AC H02M3/33561
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load
• CPC Class Codes: H05B 45/60 Circuit arrangements for operating LEDs comprising organic material, e.g. for operating organic light-emitting diodes [OLED] or polymer light-emitting diodes [PLED]
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

An organic light emitting display having a DC-DC converter with freewheel diodes replaced by switches integrated into a switching controller. This way, power consumption is reduced by truly shutting down a current path when the DC-DC converter does not operate, and the size and weight of the DC-DC converter may be reduced. One embodiment of the DC-DC converter has a boost converter with a first switch coupled to a power supplier and a second switch, functioning as a freewheel diode, coupled to an organic light emitting display panel, and an inverter with a third switch coupled to the power supplier and a fourth switch, functioning as a freewheel diode, coupled to the organic light emitting display panel. A switching controller is coupled to the boost converter and the inverter. The second and fourth switches, which function as the freewheel diodes, are integrated into the switching controller.

Claims

1. An organic light emitting display having a power supplier, a DC-DC converter, a scan driver, a data driver, and an organic light emitting display panel, wherein the DC-DC converter comprises:

a boost converter comprising a first switch electrically coupled to the power supplier and a second switch electrically coupled to the power supplier, the first switch, and the organic light emitting display panel, the second switch being configured to output a positive power voltage to the organic light emitting display panel;

an inverter comprising a third switch electrically coupled to the power supplier and a fourth switch electrically coupled to the third switch and the organic light emitting display panel; and

a switching controller electrically coupled to the boost converter and the inverter,

wherein the boost converter and the inverter are adapted such that at any one time, no more than one of the first switch or the third switch is turned on, and

wherein power from the power supplier is not supplied to the organic light emitting display panel when the second switch and the fourth switch are both turned off.

2. The organic light emitting display as claimed in claim 1,

wherein the first switch, the second switch, the third switch, and the fourth switch are integrated with the switching controller.

3. The organic light emitting display as claimed in claim 1,

wherein the boost converter further comprises a first inductor electrically coupled to the power supplier, the first switch, and the second switch.

4. The organic light emitting display as claimed in claim 1,

wherein the boost converter further comprises a first capacitor electrically coupled to the second switch and the organic light emitting display panel.

5. The organic light emitting display as claimed in claim 1,

wherein the inverter further comprises a second inductor electrically coupled to the first switch, the third switch, and the fourth switch.

6. The organic light emitting display as claimed in claim 1,

wherein the inverter further comprises a second capacitor electrically coupled to the fourth switch and the organic light emitting display panel.

7. The organic light emitting display as claimed in claim 1,

wherein the second switch is coupled to a first resistor and a second resistor in series;

and

a node between the first resistor and the second resistor is electrically coupled to the switching controller.

8. The organic light emitting display as claimed in claim 7,

wherein the switching controller comprises a first comparator electrically coupled to the node between the first resistor and the second resistor.

9. The organic light emitting display as claimed in claim 1,

wherein the fourth switch is coupled to a third resistor and a fourth resistor in series;

and

a node between the third resistor and the fourth resistor is electrically coupled to the switching controller.

10. The organic light emitting display as claimed in claim 9,

wherein the switching controller comprises a second comparator electrically coupled to the node between the third resistor and the fourth resistor.

11. The organic light emitting display as claimed in claim 1,

wherein the switching controller has an enable terminal;

and

wherein the switching controller is adapted to turn off the second switch and the fourth switch when a disable signal is input to the switching controller through the enable terminal.

12. The organic light emitting display as claimed in claim 1,

wherein the first switch comprises an N-channel field-effect transistor having a control electrode, and the second switch comprises a P-channel field-effect transistor having a control electrode.

13. The organic light emitting display as claimed in claim 12,

wherein the switching controller comprises a first driver, which supplies a same control signal to the first switch and the second switch.

14. The organic light emitting display as claimed in claim 1,

wherein the third switch comprises a P-channel field-effect transistor having a control electrode, and the fourth switch comprises an N-channel field-effect transistor having a control electrode.

15. The organic light emitting display as claimed in claim 14,

wherein the switching controller comprises a second driver, which supplies a same control signal to the third switch and the fourth switch.

16. The organic light emitting display as claimed in claim 1,

wherein the boost converter is adapted such that at any one time, no more than one of the first switch or the second switch is turned on.

17. The organic light emitting display as claimed in claim 1,

wherein the inverter is adapted such that at any one time, no more than one of the third switch or the fourth switch is turned on.

18. The organic light emitting display as claimed in claim 1,

wherein the fourth switch outputs a negative power voltage to the organic light emitting display panel.

19. The organic light emitting display as claimed in claim 1,

wherein the organic light emitting display panel comprises:

a switch electrically coupled to the scan driver and the data driver, through a scan line and a data line, respectively;

a capacitor electrically coupled to the switch;

a driving transistor electrically coupled to the capacitor; and

an organic light emitting diode electrically coupled to the driving transistor.

20. The organic light emitting display as claimed in claim 19,

wherein the driving transistor and the organic light emitting diode are electrically coupled to the DC-DC converter.

21. The organic light emitting display as claimed in claim 19,

wherein the driving transistor is electrically coupled to the boost converter, and the organic light emitting diode is electrically coupled to the inverter.