Driving integrated circuit and image display device including the same

• US 20100283773A1
• Filed: 05/05/2010
• Published: 11/11/2010
• Est. Priority Date: 05/08/2009
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Yong-Hun
• Application Number:
  US12/662,827
• Publication Number:
  US 20100283773A1
• Time in Patent Office: Days
• US Class Current: 345/211
• CPC Class Codes: G09G 2310/0278 Details of driving circuits arranged to drive both scan and data electrodes
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters

Abstract

A driving integrated circuit (IC) is provided. The driving IC includes a reference voltage setup circuit configured to output a reference voltage based on a test voltage and a load current control unit comparing a load voltage output from a load resistor with the reference voltage in response to a load current and maintaining the load current constant based on a result of the comparison.

Claims

1. A driving integrated circuit (IC), comprising:

a reference voltage setup circuit configured to output a reference voltage based on a test voltage; and

a load current control unit configured to compare a load voltage output from a load resistor with the reference voltage in response to a load current flowing in a load and maintain the load current constant based on a result of the comparison.

2. The driving IC as claimed in claim 1, further comprising a test resistor configured to output the test voltage in response to a test current.

3. The driving IC as claimed in claim 2, wherein the load resistor includes at least two unit resistors connected in parallel and the test resistor includes at least two unit resistors connected in series.

4. The driving IC of claim 2, wherein a resistance value of the test resistor is an N multiple of a resistance value of the load resistor where N is a natural number.

5. The driving IC as claimed in claim 2, wherein the test resistor is part of the load current control unit.

6. The driving IC as claimed in claim 2, wherein the load and test resistors are adjacent to one another on a semiconductor substrate.

7. The driving IC as claimed in claim 1, wherein the reference voltage setup circuit includes a calibration circuit configured to compare the test voltage with a calibration voltage and output at least one control signal according to a result of the comparison to control the load current control unit to maintain the load current constant.

8. The driving IC as claimed in claim 7, wherein the at least one control signal comprises:

a first current calibration control signal output to the load resistor to control a resistance value of the load resistor; and

a second current calibration control signal output to the reference voltage generator to control a magnitude of the reference voltage, wherein

the calibration circuit outputs one of the first and second current calibration control signals.

9. The driving IC as claimed in claim 7, further comprising:

a switch controller configured to output a plurality of switching signals based on the at least one current calibration control signal; and

a switching unit including a plurality of switches respectively connected with the first unit resistors, the switching unit configured to perform switching operation in response to the switching signals to control the resistance value of the load resistor.

10. The driving IC as claimed in claim 7, wherein the test voltage is an actual value output from a test resistor in response to a test current and the calibration voltage is a theoretical value calculated from the test current and a resistance value of the test resistor.

11. The driving IC as claimed in claim 1, wherein the load current control unit comprises:

a comparator configured to compare the load voltage with the reference voltage and output the comparison result; and

a controller connected with the load and configured to maintain a magnitude of the load current constant according to the comparison result output from the comparator.

12. The driving IC as claimed in claim 1, wherein the load comprises a plurality of light emitting diodes (LEDs) and the driving IC is an LED driving IC.

13. The driving IC as claimed in claim 2, further comprising a test current source connected to the test resistor supplying the test current.

14. The driving IC as claimed in claim 13, wherein the test current source is turned off when calibration is complete.

15. The driving IC as claimed in claim 1, wherein the reference voltage setup circuit includes a calibration circuit configured to receive the test voltage.

16. The driving IC as claimed in claim 15, wherein the reference voltage setup circuit includes a reference voltage generation circuit configured to output the reference voltage.

17. The driving IC as claimed in claim 16, wherein the reference voltage generation circuit is configured to output variable voltages to the calibration circuit and the calibration circuit includes a comparator comparing the variable voltages to the test voltage.

18. The driving IC as claimed in claim 17, wherein the load current control unit includes a comparator configured to compare the load voltage with the reference voltage and output the comparison, the comparator in the load current control unit being a same type as the comparator in the calibration circuit.

19. An image display device, comprising:

an image display unit configured to display an image signal;

a light source configured to provide light to the image display unit; and

a driving integrated circuit (IC) configured to maintain a load current applied from the outside to the light source constant, the driving IC including;

a reference voltage setup circuit configured to output a reference voltage based on a test voltage, and

a load current control unit configured to compare a load voltage output from a load resistor with the reference voltage in response to a load current flowing in a load and maintain the load current constant based on a result of the comparison.

20. The image display device as claimed in claim 19, wherein the image display unit is a large panel display unit.

21. The image display device as claimed in claim 20, wherein the light source includes a plurality of light sources arranged in a periphery of the large panel display unit.

22. The image display device as claimed in claim 20, wherein the light source includes a plurality of light sources arranged in a matrix adjacent the large panel display unit.

23. The image display device as claimed in claim 19, wherein the image display unit is a portable display unit.

24. The image display device as claimed in claim 23, wherein the light source includes a plurality of light sources arranged in a periphery of the portable display unit.

25. The image display device as claimed in claim 23, wherein the light source includes a plurality of light sources arranged in a matrix adjacent the portable display unit.

26. A back light unit for an image display device, comprising:

a light source configured to provide light to the image display device; and

a driving integrated circuit (IC) configured to maintain a load current applied from an outside to the light source constant, the driving IC including;

a reference voltage setup circuit configured to output a reference voltage based on a test voltage, and

a load current control unit configured to compare a load voltage output from a load resistor with the reference voltage in response to a load current flowing in a load and maintain the load current constant based on a result of the comparison.

27. The back light unit of claim 26, wherein the light source includes a plurality of light emitting diode (LED) sources arranged in a periphery of the back light unit.

28. The back light unit of claim 26, wherein the light source includes a plurality of light emitting diode (LED) sources arranged in a matrix.

29. The back light unit of claim 26, wherein the light source includes a light emitting diode (LED) source for a mobile device.

30. A multi-channel driving system, comprising:

a plurality of driving integrated circuits (ICs);

a reference voltage setup circuit adapted to supply respective reference voltages to each of the plurality of driving ICs, the reference voltage generation circuit including a reference voltage source adapted to supply source reference voltages based on test voltages; and

a calibration circuit configured to receive a sensed voltage from each of the driving ICs and to generate a respective reference voltages in accordance with each of the sensed voltages and a respectively selected one of the source reference voltages.

31. The multi-channel driving system as claimed in claim 30, wherein at least one of the reference voltage source and the calibration circuit are common to the plurality of driving ICs.

32. A method of driving a light source, comprising:

calibrating a reference voltage in accordance with a test voltage;

supplying the reference voltage to a current driver when calibrating is complete; and

driving the light source with the current driver.

33. The method as claimed in claim 32, further comprising, when calibrating is complete, stopping calibrating.

34. The method as claimed in claim 32, further comprising generating the test voltage using a test resistor, adjacent a resistor in the current driver, connected to a test current source.

35. The method as claimed in claim 34, further comprising turning off the test current source when calibrating is complete.