WO2007140167A2 - Smart talk backlighting system and method - Google Patents

Smart talk backlighting system and method Download PDF

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Publication number
WO2007140167A2
WO2007140167A2 PCT/US2007/069396 US2007069396W WO2007140167A2 WO 2007140167 A2 WO2007140167 A2 WO 2007140167A2 US 2007069396 W US2007069396 W US 2007069396W WO 2007140167 A2 WO2007140167 A2 WO 2007140167A2
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WO
WIPO (PCT)
Prior art keywords
circuit
driver
converter
display
voltage
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US2007/069396
Other languages
French (fr)
Other versions
WO2007140167A3 (en
Inventor
Dimitry Goder
Gi Young Lee
Quoi Van Huynh
Chris Tzuchun Lee
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Exar Corp
Sipex Corp
Original Assignee
Exar Corp
Sipex Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Exar Corp, Sipex Corp filed Critical Exar Corp
Priority to JP2009512247A priority Critical patent/JP2009538515A/en
Priority to CA002653251A priority patent/CA2653251A1/en
Priority to EP07784004A priority patent/EP2036073A4/en
Publication of WO2007140167A2 publication Critical patent/WO2007140167A2/en
Anticipated expiration legal-status Critical
Publication of WO2007140167A3 publication Critical patent/WO2007140167A3/en
Ceased legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes 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
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes 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 by control of light from an independent source
    • G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes 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 by control of light from an independent source using liquid crystals
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes 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
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes 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 by control of light from an independent source
    • G09G3/3406—Control of illumination source
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes 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
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G5/00—Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2330/00—Aspects of power supply; Aspects of display protection and defect management
    • G09G2330/02—Details of power systems and of start or stop of display operation
    • G09G2330/021—Power management, e.g. power saving
    • G09G2330/023—Power management, e.g. power saving using energy recovery or conservation

Definitions

  • the invention relates generally to backlight display driver circuits, and more particularly to backlight display driver circuits with feedback mechanisms
  • LCDs can be used for a number of applications such as in laptop and other computer displays, televisions, global positioning (GPS) units, and in personal data assistants ⁇ PDAs ⁇ , and for many other applications
  • LED Light Emitting Diodes
  • Conventional LCD backlighting suffers fiom a drawback, however The use of the LEDs increases power consumption, often to the point of eliminating the advantage of using LCD technology Accordingly, mechanisms for reducing the power consumed by LHDs used to backlight LCD displays are sought
  • Figure I illustrates an example of a driver circuit for driving LEDs used to backlight a.n LCD display.
  • Figure 2 illustrates an improved driver circuit
  • Figure 3 illustrates an improved driver circuit employing smart talk in an embodiment.
  • Figure 4A illustrates functionaiity of an embodiment employing power saving feedback from the driver to the DC -to- DC converter
  • Figure 4B illustrates functionality of an embodiment without power saving feedback from the driver to the DC-to-DC converter.
  • FIG. 1 shows a driver circuit 100, in which a driver device is used to drive LEDs used to backlight an LCD display.
  • the driver circuit 100 can include driver device 150, which may be an SP7617 backlight driver device made by SlPEX Corporation of Milpitas, California.
  • the SP7617 provides a four channel low side driver having maximum 6OmA current, current accuracy of about 2.5% and approximately 1% current matching between channels over a full temperature range, pulse width modulation and analog dimming control and short LED and thermal and over current protections
  • an input voltage Vin is applied to each channel, causing a current of Iled to flow through each channel and through the driver device 150, Current Iled causes a voltage drop of Vf across each LED 80, 90.
  • Vin 21 volts
  • Iled of 20 mA per channel and Vf of 3.5 volts
  • the power P dissipated by device driver is computed according to relationship (1 ):
  • FIG. 2 illustrates a modified driver circuit 200, in which a DC-to-DC converter 250 has been added in an effort to reduce power dissipation.
  • a DC-to-DC converter such as SP6125 by SIPEX Corporation, provides a relatively higher efficiency step down conversion from the Vin to a preferred Vcc.
  • Vin may be 21 volts and Vcc may be 9 volts and DC-to-DC converter 250 may have an efficiency of 90%, for example, an overall efficiency of approximately 70% may be achieved according to the relationship (2):
  • embodiments of the present invention are not limited to a step-down (buck) converter, such as the SP6125, but can also enable use of step-up (boost) converters as well. Additionally, embodiments may be realized using a pulse width modulator (PWM) as a specific implementation for the DC-to-DC converter.
  • PWM pulse width modulator
  • a power saving feedback from the driver to the DC-to-DC converter mechanism 350 (hereinafter, “smart talk mechanism") is coupled to the driver 150 in order to feed back adjustment information from the driver 150 to the DC-to-DC converter 250, enabling the DC-to-DC converter to adjust Vcc to reduce the Vcathode at the LEDs 80, 90.
  • Vcathode could be reduced to 7.3 volts by action of smart talk mechanism 350 and DC-to-DC converter 250. If the efficiency of the DC-to-DC converter 250 is approximately 93% and the efficiency of driver 150 and smart talk mechanism is about 96%, for example, an overall efficiency of approximately 90% may be achieved according to tile relationship (3);
  • FIG. 4 A - 4B illustrate a comparison of an embodiment employing power saving feedback from the driver to the DC-to-DC converter provided by a smart talk mechanism with an embodiment without the power saving feedback
  • smart talk mechanism 350 is coupled to the driver 150 in order to feed back adjustment information from the driver 150 to the DC-to-DC converter 250, [0018]
  • the DC-to-DC converter 250 by nature of its design, continuously adjusts its outputs voltage around an optimum feedback voltage.
  • the feedback voltage for the DC-to-DC converter 250 is a directly scaled version of the output voltage.
  • the smart talk mechanism will take the information of the anode voltage (at the driver output) and feed that back to the DC-to-DC converter 250. This information can be a direct anode voltage or a scaled version of it If this feedback voltage is high, then the DC-to-DC converter 250 will decrease it output to lower the cathode voltage and hence lower the anode voltage as well. If the feedback voltage is low, the then the DC-to- DC converter 250 will increase its output to raise the cathode voltage and hence raise the anode voltage as well.
  • the feedback enables the DC-to-DC converter to adjust Vcc to reduce the Vin at the cathode end of LED 80 from 9.0V, as shown by Figure 4B, to 7.3 V shown in Figure 4A.
  • the voltage drop across LEDs 80. 90 is reduced from a maximum value of 4.0V in Figure 4B to a nominal value of 3.5V in Figure 4 A.
  • voltage across a driver transistor within driver 1.50 can be dropped from 1.0V in Figure 4B to 0.3 V in Figure 4A.
  • Embodiments providing a larger quantity of channel drivers may be created using the techniques described above to reduce power dissipation in the device driver. For example, and without limitation, embodiments having four, eight or larger quantities of channel drivers may be realized in accordance with the techniques described herein.
  • input power is derived from one or more of a battery and an AC adapter
  • the efficiency of a backlight LED driver is increased from about 33% to about 90% and power dissipation is reduced by approximately 64%.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • Theoretical Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Nonlinear Science (AREA)
  • Mathematical Physics (AREA)
  • Optics & Photonics (AREA)
  • Liquid Crystal Display Device Control (AREA)
  • Dc-Dc Converters (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
  • Liquid Crystal (AREA)

Abstract

A smart talk mechanism provides feedback information from a driver to a DC-to-DC converter, enabling the DC-to-DC converter to adjust an input voltage for at least one illumination source backlighting the display for increasing the power efficiency.

Description

SMART TALK BACKLIGHTING SYSTEM AND METHOD
CLAIM OF PRIORlTY [0001] U S Patent Application No 1 1 /440,757 entitled SMART T ALK BACKLIGHTING SYSTEM AND METHOD, by Dϊmitry Goder et al., filed May 25, 2006 {Attorney Docket No SIPEX-01006US0)
COPYRIGHT NOTICE [0002] A portion of the disclosυre of this patent document contains material that is subject to copyright protection The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the U S Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever
FIELD OF THE INVENTION
[0003} The invention relates generally to backlight display driver circuits, and more particularly to backlight display driver circuits with feedback mechanisms
BACKGROUND
[0004} Liquid Crystal Displays (LCDs) can be used for a number of applications such as in laptop and other computer displays, televisions, global positioning (GPS) units, and in personal data assistants {PDAs}, and for many other applications Conventionally , Light Emitting Diodes (LED) may be used to backlight the LCD display for greater brilliance Conventional LCD backlighting suffers fiom a drawback, however The use of the LEDs increases power consumption, often to the point of eliminating the advantage of using LCD technology Accordingly, mechanisms for reducing the power consumed by LHDs used to backlight LCD displays are sought
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] Preferred embodiment(s) of the present invention will be described in detail based on the following figures, wherein [ [0006] Figure I illustrates an example of a driver circuit for driving LEDs used to backlight a.n LCD display.
[0007 ] Figure 2 illustrates an improved driver circuit,
[0008] Figure 3 illustrates an improved driver circuit employing smart talk in an embodiment.
[0009] Figure 4A illustrates functionaiity of an embodiment employing power saving feedback from the driver to the DC -to- DC converter,
[0010] Figure 4B illustrates functionality of an embodiment without power saving feedback from the driver to the DC-to-DC converter.
DETAILED DESCRIPTION
[0011] Figure 1 shows a driver circuit 100, in which a driver device is used to drive LEDs used to backlight an LCD display. The driver circuit 100 can include driver device 150, which may be an SP7617 backlight driver device made by SlPEX Corporation of Milpitas, California. While many embodiments can be prepared incorporating a variety of other driver devices, the SP7617 provides a four channel low side driver having maximum 6OmA current, current accuracy of about 2.5% and approximately 1% current matching between channels over a full temperature range, pulse width modulation and analog dimming control and short LED and thermal and over current protections In operation, an input voltage Vin is applied to each channel, causing a current of Iled to flow through each channel and through the driver device 150, Current Iled causes a voltage drop of Vf across each LED 80, 90. In an example operational context having values of Vin of 21 volts, Iled of 20 mA per channel and Vf of 3.5 volts, the power P dissipated by device driver is computed according to relationship (1 ):
P - [21 V - (2.5V x 2)] x (20mA x 4) = 1.12 Watts ( 1 )
[0012] Figure 2 illustrates a modified driver circuit 200, in which a DC-to-DC converter 250 has been added in an effort to reduce power dissipation. As shown by Figure 2, a DC-to-DC converter, such as SP6125 by SIPEX Corporation, provides a relatively higher efficiency step down conversion from the Vin to a preferred Vcc. In an operational context, Vin may be 21 volts and Vcc may be 9 volts and DC-to-DC converter 250 may have an efficiency of 90%, for example, an overall efficiency of approximately 70% may be achieved according to the relationship (2):
Eoverall - 90% x 78% = 70% (2)
[0013] It is noteworthy that embodiments of the present invention are not limited to a step-down (buck) converter, such as the SP6125, but can also enable use of step-up (boost) converters as well. Additionally, embodiments may be realized using a pulse width modulator (PWM) as a specific implementation for the DC-to-DC converter. [0014] Efficiencies greater than those provided by the architectures shown in Figure 1 and Figure 2 are desired. Addition of a power saving feedback from the driver to the DC- to-DC converter mechanism would result in an advantageous efficiency improvement over the architectures of Figure 1 and Figure 2. [0015] In one embodiment shown in Figure 3, a power saving feedback from the driver to the DC-to-DC converter mechanism 350 (hereinafter, "smart talk mechanism") is coupled to the driver 150 in order to feed back adjustment information from the driver 150 to the DC-to-DC converter 250, enabling the DC-to-DC converter to adjust Vcc to reduce the Vcathode at the LEDs 80, 90. In an operational example, Vcathode could be reduced to 7.3 volts by action of smart talk mechanism 350 and DC-to-DC converter 250. If the efficiency of the DC-to-DC converter 250 is approximately 93% and the efficiency of driver 150 and smart talk mechanism is about 96%, for example, an overall efficiency of approximately 90% may be achieved according to tile relationship (3);
Eoverall = 93% x 96% - 90% (3)
[0016) The operation of smart talk mechanism 350 can provide improved efficiency over the circuits illustrated by Figure 1 and Figure 2. Functionality of a smart talk mechanism suitable for use in the back light, display driver of Figure 3 will now be described in further detail with reference to Figures 4 A - 4B. [0017) Figures 4 A - 4B illustrate a comparison of an embodiment employing power saving feedback from the driver to the DC-to-DC converter provided by a smart talk mechanism with an embodiment without the power saving feedback, As shown by Figure 4 A, smart talk mechanism 350 is coupled to the driver 150 in order to feed back adjustment information from the driver 150 to the DC-to-DC converter 250, [0018] In an embodiment, the DC-to-DC converter 250, by nature of its design, continuously adjusts its outputs voltage around an optimum feedback voltage. Normally, the feedback voltage for the DC-to-DC converter 250 is a directly scaled version of the output voltage. The smart talk mechanism will take the information of the anode voltage (at the driver output) and feed that back to the DC-to-DC converter 250. This information can be a direct anode voltage or a scaled version of it If this feedback voltage is high, then the DC-to-DC converter 250 will decrease it output to lower the cathode voltage and hence lower the anode voltage as well. If the feedback voltage is low, the then the DC-to- DC converter 250 will increase its output to raise the cathode voltage and hence raise the anode voltage as well. This mechanism will ensure the anode voltage to be at an optimum voltage which maximizes the intended power to the LEDs and reduces the power loss inside the driver. [0019] The feedback enables the DC-to-DC converter to adjust Vcc to reduce the Vin at the cathode end of LED 80 from 9.0V, as shown by Figure 4B, to 7.3 V shown in Figure 4A. The voltage drop across LEDs 80. 90 is reduced from a maximum value of 4.0V in Figure 4B to a nominal value of 3.5V in Figure 4 A. Finally, voltage across a driver transistor within driver 1.50 can be dropped from 1.0V in Figure 4B to 0.3 V in Figure 4A. These and other benefits provided by embodiments employing a smart talk mechanism can improve efficiency, reduce power dissipation, enhance battery life and so forth. [0020] Embodiments providing a larger quantity of channel drivers may be created using the techniques described above to reduce power dissipation in the device driver. For example, and without limitation, embodiments having four, eight or larger quantities of channel drivers may be realized in accordance with the techniques described herein. In embodiments, input power is derived from one or more of a battery and an AC adapter According to embodiments, the efficiency of a backlight LED driver is increased from about 33% to about 90% and power dissipation is reduced by approximately 64%. [0021 ] The foregoing description of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations will be apparent to the practitioner skilled in the art. Particularly, it will be evident that the above- described features of detecting and ranking images with numerical ranks in order of usefulness based on vignette scare can be incorporated into other types of software applications beyond those described. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention for various embodiments and with various modifications that are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents

Claims

CLAIMSWhat is claimed is:
1 . A circuit to drive a backlight for a display comprising: a backlight device driver; a DC-to-DC converter; and a smart talk mechanism to feed back adjustment information from the driver to the DC-to-DC converter, thereby enabling the DC-to-DC converter to adjust an input voltage for at least one illumination source backlighting the display for increasing the power efficiency.
2. The circuit of claim 1, wherein the backlight device driver drives a light emitting diode (LED) back light for a liquid crystal display (LCD).
3 The circuit of claim 1 , wherein the smart talk mechanism enables adjusting the voltage applied to at least one light emitting diode (LED) backlighting the display,
4. The circuit of claim 3, wherein the smart talk mechanism enables adjusting the voltage applied to the cathode of at least one light emitting diode (LED) backlighting the display
5. The circuit of claim 1, further comprising the smart talk mechanism sensing at least one of power dissipation, current and voltage of the driver
6. The circuit of claim 5, further comprising determining by the smart talk mechanism an appropriate feedback to the DC-to-DC converter based upon the at least one of power dissipation, current and voltage of the driver.
7. The circuit of claim 1, wherein the display includes a liquid crystal display (LCD).
8. The circuit of claim 1 , wherein the driver comprises a multi -channel driver,
9 The circuit of claim 1, wherein the DC-to-DC converter adjusts a voltage to the backlight of the display.
10. The circuit of claim 1, wherein input power is derived from at least one of a battery and an AC adapter.
1 1 . The circuit of claim 1 , wherein the DC-to-DC converter comprises a pulse width modulator (PWM).
PCT/US2007/069396 2006-05-25 2007-05-21 Smart talk backlighting system and method Ceased WO2007140167A2 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
JP2009512247A JP2009538515A (en) 2006-05-25 2007-05-21 Smart talk backlight system and method
CA002653251A CA2653251A1 (en) 2006-05-25 2007-05-21 Smart talk backlighting system and method
EP07784004A EP2036073A4 (en) 2006-05-25 2007-05-21 Smart talk backlighting system and method

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US11/440,757 US7589704B2 (en) 2006-05-25 2006-05-25 Smart talk backlighting system and method
US11/440,757 2006-05-25

Publications (2)

Publication Number Publication Date
WO2007140167A2 true WO2007140167A2 (en) 2007-12-06
WO2007140167A3 WO2007140167A3 (en) 2009-04-16

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US (1) US7589704B2 (en)
EP (1) EP2036073A4 (en)
JP (1) JP2009538515A (en)
KR (1) KR20090035664A (en)
CN (1) CN101496091A (en)
CA (1) CA2653251A1 (en)
WO (1) WO2007140167A2 (en)

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CN102098828A (en) * 2009-12-11 2011-06-15 富准精密工业(深圳)有限公司 Lamp control system

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040252096A1 (en) 2003-05-21 2004-12-16 Der-Jiunn Wang Dual panel display backlight power controller chip for handheld apparatus
EP1619656A2 (en) 2004-07-12 2006-01-25 Sony Corporation Display unit and backlight unit

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Publication number Priority date Publication date Assignee Title
JP2002351417A (en) * 2001-05-24 2002-12-06 Internatl Business Mach Corp <Ibm> Driving power supply circuit which generates driving power supply voltage of driver circuit used in display device and reference voltage used in the driver circuit to generate gradation voltage, driver circuit voltage generating method to generate the driving power supply voltage and the reference voltage and display device having the driving power supply circuit
JP3939517B2 (en) * 2001-08-24 2007-07-04 東光株式会社 Dimming control circuit
JP4177022B2 (en) * 2002-05-07 2008-11-05 ローム株式会社 LIGHT EMITTING ELEMENT DRIVE DEVICE AND ELECTRONIC DEVICE HAVING LIGHT EMITTING ELEMENT
JP4306657B2 (en) * 2004-10-14 2009-08-05 ソニー株式会社 Light emitting element driving device and display device

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Publication number Priority date Publication date Assignee Title
US20040252096A1 (en) 2003-05-21 2004-12-16 Der-Jiunn Wang Dual panel display backlight power controller chip for handheld apparatus
EP1619656A2 (en) 2004-07-12 2006-01-25 Sony Corporation Display unit and backlight unit

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP2036073A4

Also Published As

Publication number Publication date
EP2036073A2 (en) 2009-03-18
CN101496091A (en) 2009-07-29
JP2009538515A (en) 2009-11-05
US7589704B2 (en) 2009-09-15
US20070273676A1 (en) 2007-11-29
KR20090035664A (en) 2009-04-10
EP2036073A4 (en) 2010-07-14
CA2653251A1 (en) 2007-12-06
WO2007140167A3 (en) 2009-04-16

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