EP0000844B1 - Semiconductor circuit arrangement for controlling a controlled device. - Google Patents

Semiconductor circuit arrangement for controlling a controlled device. Download PDF

Info

Publication number
EP0000844B1
EP0000844B1 EP19780300269 EP78300269A EP0000844B1 EP 0000844 B1 EP0000844 B1 EP 0000844B1 EP 19780300269 EP19780300269 EP 19780300269 EP 78300269 A EP78300269 A EP 78300269A EP 0000844 B1 EP0000844 B1 EP 0000844B1
Authority
EP
European Patent Office
Prior art keywords
transistor
current carrying
terminal
connected
high current
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.)
Expired
Application number
EP19780300269
Other languages
German (de)
French (fr)
Other versions
EP0000844A1 (en
Inventor
Howard Clayton Kirsch
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.)
Western Electric Co Inc
Original Assignee
Western Electric Co Inc
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
Priority to US05/823,729 priority Critical patent/US4160934A/en
Application filed by Western Electric Co Inc filed Critical Western Electric Co Inc
Publication of EP0000844A1 publication Critical patent/EP0000844A1/en
Application granted granted Critical
Publication of EP0000844B1 publication Critical patent/EP0000844B1/en
Priority to US823729 priority
Application status is Expired legal-status Critical

Links

Images

Classifications

    • GPHYSICS
    • G05CONTROLLING; REGULATING
    • G05FSYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F1/00Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
    • G05F1/10Regulating voltage or current
    • G05F1/46Regulating voltage or current wherein the variable actually regulated by the final control device is dc
    • G05F1/56Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices

Description

  • This invention relates to a semiconductor circuit arrangement for controlling current transmitted through a controlled device.
  • In the prior art, the current in a controlled device such as a semiconductor light emitting diode (LED) has been regulated by a control circuit containing an insulated gate field effect transistor (IGFET) driver switch of relatively very large transconductance in series with a ballast resistor. The IGFET driver is typically formed in a semiconductive silicon chip in accordance with standard MOS (metal-oxide-semiconductor) technology. During operation, if the voltage drop across the IGFET driver in its "on" condition is relatively small compared with applied voltage, the brightness of the LED in its "on" condition is somewhat stabilized by the ballast resistor. However, such a control circuit suffers from poor current regulation, whereby the current in the LED during operation can fluctuate by as much as a factor of 3 when the voltage of the external power supply, of typically about 5 or 6 volts, fluctuates by only 20 percent. Although this fluctuation in current can be reduced by using larger voltages for the power supply in conjunction with a larger ballast resistor, such an approach to the current fluctuation problem still suffers from the requirement of a physically relatively large IGFET driver. This device, which consumes an undesirably large amount of semiconductive silicon chip area, is required in order to keep the driver resistance, and hence the driver voltage drop, relatively small (0.5 volt drop) for the desired LED operating current. Moreover, ordinary processing variations in the manufacture of the IGFET driver of the prior art circuit cause corresponding variations in the LED operating current, thereby adversely affecting either the brightness or the lifetime of the LED on account of, respectively, either too little or too much operating current. It would therefore be desirable to have a control circuit for stabilizing the operating current in an LED, which mitigates the shortcomings of this prior art.
  • In U.S. patent No. 3,903,454 there is disclosed a semiconductor circuit arrangement comprising first transistor switch means for controlling a controlled device when connected in series therewith in response to an input signal, and comparator feedback means operable on the control input of the first transistor switch means for controlling the current flowing through said transistor switch means in dependence upon a comparison of a voltage afforded by said transistor switch means and a reference potential, said comparator feedback means comprising first and second feedback terminals and second and third transistors each having a pair of high current carrying terminals and a low current carrying terminal, the first feedback terminal being connected to the control input of the first transistor switch means and the second feedback terminal being connected to a high current carrying terminal of said first transistor switch means, one of the high current carrying terminals of the second transistor being connected to one of the high current carrying terminals of the third transistor, the low current carrying terminal of the third transistor being connected to the second feedback terminal, and the other of the high current carrying terminals of the second transistor being connected to the first feedback terminal.
  • In accordance with the present invention the input signal to said arrangement is applied to the control input of said switch means, and the low current carrying terminal of the second transistor is connected to a terminal for the application thereto of a fixed reference potential (ground), the second feedback terminal being adapted to have the controlled device connected to it. In this way the transistor switch means can operate with a relatively large source-drain voltage, typically of about 5 volts; therefore, for a given operating current in the thereby controlled (LED) device the transistor switch means can now have a relatively high resistance, thereby reducing the required amount of semiconductor chip area therefor.
  • This invention together with its features, objects, and advantages will be better understood from the following exemplary embodiment which is described in conjunction with the accompanying single figure drawing which is a schematic circuit diagram of a semiconductor circuit arrangement for regulating the current in a semiconductor LED in accordance with a specific embodiment of the invention.
  • As shown in the drawing, a semiconductor LED 10 has one of its terminals connected to a voltage source VGG and another of its terminals connected to a ballast resistor R. As one example, the circuit parameters will be described in terms of P-MOS technology. Typically, the source VGG is approximately -12 volts, and the resistor R is approximately a thousand ohms. The LED is characterized by an operating "on" current of about 10 milliamperes with an operating voltage drop of about 2 to 3 volts. The LED and the resistor R are connected in series with the high current (i.e. source-drain) path of an IGFET driver 01 to another voltage source Vss of about +5 volt. In its "on" state, the driver 01 has a resistance advantageously equal to about R/2 or less.
  • As further shown in the drawing, the IGFETs Q3, Q4, Q5 and Q6 are in a comparator feedback network arrangement for stabilizing the voltage at node 11 located between R and Q,. For this purpose, the node 11 is connected to a low current (i.e. gate) terminal of 06 whose high current path connects VGG to a node 13. The node 13 is connected to Vss through the high current path of Q3 whose gate terminal is grounded (V=0). The gate terminal of the driver Q1 is connected to a node 12 which is connected through Q5 to VGG and through Q4 to the node 13. The IGFET Q5 is in a diode configuration; that is, the drain and gate terminals of Q5 are shorted together, so that Q5 behaves as a diode which tends to conduct current only in the direction toward the source VGG. On the other hand, the gate terminal of Q4 is connected to ground serving as a reference potential.
  • The node 12 is further connected to Vss through the high current path of Q2. The gate of Q2 is connected to an input signal source 20 which provides signals for turning Q2 "on" and "off". As more fully explained below, when Q2 is "on", then Q, is "off" and hence the LED 10 is also "off"; and when Q2 is "off", then Q1 is "on" and hence the LED 10 is also "on". Thus, the feedback arrangement acts as a signal inverter as well as a current stabilizer.
  • For optimum operation, the transconductance ratios B2, B3, B4, B5 and B6 of the IGFETs Q2, Q3, Q4, Q5 and Q6, respectively, should satisfy the following: B5 should be much less than B3; B3 should be much less than either B4 and B6; and B4 and B6 should be much less than B2. By "much less than" is meant less than by preferably a factor of 10, but in any event at least by a factor of 2 or 5. For example, by way of an illustrative example only, suitable approximate values for the B's are: B5=2× 10-6 mho/V; B3=15×10-6 mho/V; B4=B6=100×10-6 mho/V; and B2=250×10-6 mho/V. Moreover, the transistor Q1 is advantageously characterized by moderately high B1: for a 10 milliamp LED current, a suitable approximate value is B1=250×10-6 mho/volt. In the absence of the comparator feedback circuit, the required transconductance of the IGFET driver would be about 1,200×10-6 mho/volt. Operation of the circuit shown in the drawing can be understood from the following considerations. Starting from a condition in which the LED and the driver Q, are both "off" in the presence of a signal from the source 20 sufficient to maintain Q2 in its "on" state, it will first be shown that this condition is stable; and it will then be shown that a signal applied that is sufficient to switch and maintain Q2 in its "off" state will also switch and maintain both the driver Q, and the LED "on" in a stabilized current condition. In order to explain this operation, it is to be noted that when at first the input signal maintains Q2 in its "on" state, then the driver Q, will thus be in its "off" state and hence the LED will also be in its "off" state. Under these conditions, the node 12 tends to remain at essentially the potential Vss by virtue of the connection of this node to the source Vss through the relatively high B IGFET Q2. This connection is through the transistor of the highest B in the comparator circuit (Q3, Q5 and Q6 in particular). Thus, the node 12 remains in a stable condition at essentially Vss (the substrate of all transistors is connected to Vss as is ordinarily true in P-MOS integrated circuits). Accordingly, the voltage on the node 12 maintains the IGFET Q1 in its "off" state, thereby maintaining the LED 10 in its "off" state also. Meanwhile, since the node 11 is essentially at potential at VGG due to the path through R and the LED to the source VGG, the transistor Q6 is in its "on" state; so that the node 13 is essentially at potential VGG (except for a threshold of Q6 which, with the backgate bias effect, is about -5 or -6 volts). This is true even though Q3 is also "on" because of the high B6 of Q6 as compared with the low B3 of Q3. On the other hand, since node 13 is at essentially VGG while the node 12 is at Vss, Q4 is "on"; but this "on" condition of Q4 combined with the "on" conditions of Q5 and Q6 is not sufficient to pull the node 12 away from Vss, since Q2 has the highest transconductance B of all. Thus, the node 12 remains stably at Vss, thereby keeping Q, in its "off" state and hence the LED stably remains in its "off" state also.
  • When the input signal applied by the source 20 to the gate of Q2 is then switched to a value sufficient to turn Q2 "off", the potential of the node 12 tends toward VGG but without reaching it because the driver Q1 turns "on" before this node 12 reaches ground. As soon as the driver Q1 turns "on", however, the LED turns "on" also and the node 11, between Q, and R, goes from the potential VGG toward the potential Vss, since the "on" resistance of the driver is advantageously made sufficiently small compared with R, typically about R/2. As the node 11 goes toward Vss, the transistor Q6 allows the node 13 to go toward Vss by virtue of the "on" state of Q3. But when this node 13 reaches ground plus the threshold of 04, then Q4 turns "on", in the opposite direction with node 13 as its source and node 12 as its drain, thereby preventing the node 12 from going any further toward VGG. In this way, the node 12 is kept at a potential suitable for maintaining the driver Q, and the LED in their "on" states. In effect, the transistor arrangement of 03, Q4, Ql and Q6 acts as a feedback comparator for stabilizing, against fluctuations of either polarity, the voltage at node 11 essentially at the voltage applied to the gate of Q4, whenever the signal input turns Q2 "off". Thus, the LED remains "on" until the input signal is thereafter switched to a value sufficient to turn the transistor Q2 back to its "on" state.
  • Although the invention has been described in detail in terms of a specific embodiment, various modifications can be made without departing from the scope thereof. For example, N-MOS technology can be used instead of P-MOS; that is, all the transistors Q1―Q6 can be integrated in a P-type semiconductor chip with N+ type source and drain regions, with suitable modifications in Vss and VGG. Moreover, other types of transistors than IGFETs can be used, such as J-FETs or bipolar transistors. Also, a unidirectional current inhibiting diode element of conductance B5 in the forward direction can be used instead of the transistor Q5. Moreover, the voltages applied to gate electrode of Q4 and of Q3 can both be other than ground, in order to stabilize the voltage at node 11 during operation at a corresponding voltage other than essentially ground potential. In any event, however, it is preferred that the voltage difference (VSS―VGG) be at least three or more times the voltage drop across the LED in its "on" state, and that the voltage at node 11 be stabilized to a value that is sufficiently different from Vss to enable the use of a relatively small sized driver 01 of relatively high resistance, thereby to conserve semiconductor chip area.

Claims (5)

1. Semiconductor circuit arrangement comprising first transistor switch means (Q1) for controlling a controlled device (10) when connected in series therewith in response to an input signal, and comparator feedback means operable on the control input of the first transistor switch means for controlling the current flowing through said transistor switch means in dependence upon a comparison of a voltage afforded by said transistor switch means and a reference potential, said comparator feedback means comprising first (12) and second feedback (11) terminals and second (Q4) and third (Q6) transistors each having a pair of high current carrying terminals and a low current carrying terminal, the first feedback terminal (12) being connected to the control input of the first transistor switch means (Q1) and the second feedback terminal being connected to a high current carrying terminal of said first transistor switch means, one of the high current carrying terminals of the third transistor (Q4) being connected to one of the high current carrying terminals of ghe third transistor (Q6), the low current carrying terminal of the third transistor being connected to the second feedback terminal, and the other of the high current carrying terminals of the second transistor being connected to the first feedback terminal, characterised in that the input signal to said arrangement is applied to the control input of said switch means (Q1), and in that the low current carrying terminal of the second transistor (Q4) is connected to a terminal for the application thereto of a fixed reference potential (ground), said second feedback terminal (11) being adapted to have said controlled device (10) connected to it.
2. Circuit arrangement as claimed in claim 1, comprising a fourth transistor (Q2) having a low current carrying terminal by means of which the input signal is applied to said switch means (01) and having a pair of high current carrying terminals, one of the said high current carrying terminals of the fourth transistor (Q2) being connected to the low current carrying terminal of said first transistor (Q,), a fifth transistor (Q3) having a low current carrying terminal and a pair of high current carrying terminals, one of the high current carrying terminals of the fifth transistor (Q3) being connected to the interconnected ones of the high current carrying terminals of the second (Q4) and third (Qg) transistors, and a unidirectional current inhibiting device (Q5) connected between the other high current carrying terminals of the second (Q4) and third (Q6) transistors.
3. Circuit arrangement as claimed in claim 2, in which the low current carrying terminal of the fifth (Q3) transistor is connected to a terminal for the application thereto of a reference potential, and in which the other high current carrying terminals of the fourth (Q2) and fifth (03) transistors are connected to terminals for connection thereto of a first voltage source, and the other high current carrying terminal of the third (Q6) transistor is connected to a terminal for connection thereto of a second, different voltage source to which the series connected controlled device (10) and ballast resistor (R) are connected.
4. Circuit arrangement as claimed in claim 2 or claim 3, in which the first (Q1), second (Q4), third (Q6), fourth (Q2) and fifth (Q3) transistors are field effect transistors and the current inhibiting device (05) is a sixth field effect transistor (Qs) the gate terminal of which is shorted to its drain terminal, and in which the second, third, fourth, fifth and sixth transistors respectively have transconductances B4, B6, B2, B3 and B5, respectively which satisfy the following conditions: B5 is less than B3; B3 is less than either B4 or B6; B4 and B6 are each less than B2.
5. Circuit arrangement as claimed in claim 4, in which B5 is less than B3 by a factor of at least 5; B4 and B6 are each less than B2 by a factor of at least 2.
EP19780300269 1977-08-11 1978-08-08 Semiconductor circuit arrangement for controlling a controlled device. Expired EP0000844B1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US05/823,729 US4160934A (en) 1977-08-11 1977-08-11 Current control circuit for light emitting diode
US823729 1986-01-29

Publications (2)

Publication Number Publication Date
EP0000844A1 EP0000844A1 (en) 1979-02-21
EP0000844B1 true EP0000844B1 (en) 1983-03-23

Family

ID=25239562

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19780300269 Expired EP0000844B1 (en) 1977-08-11 1978-08-08 Semiconductor circuit arrangement for controlling a controlled device.

Country Status (4)

Country Link
US (1) US4160934A (en)
EP (1) EP0000844B1 (en)
JP (1) JPS5430456A (en)
DE (1) DE2862207D1 (en)

Families Citing this family (84)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2415332B1 (en) * 1978-01-20 1980-08-22 Thomson Csf
US4346343A (en) * 1980-05-16 1982-08-24 International Business Machines Corporation Power control means for eliminating circuit to circuit delay differences and providing a desired circuit delay
US4504776A (en) * 1980-11-12 1985-03-12 Bei Electronics, Inc. Power saving regulated light emitting diode circuit
US4383216A (en) * 1981-01-29 1983-05-10 International Business Machines Corporation AC Measurement means for use with power control means for eliminating circuit to circuit delay differences
US4403157A (en) * 1982-02-08 1983-09-06 Teledyne Industries, Inc. Control circuit for light emitting diode
US4717868A (en) * 1984-06-08 1988-01-05 American Microsystems, Inc. Uniform intensity led driver circuit
DE3427498C2 (en) * 1984-07-26 1986-08-07 Ifm Electronic Gmbh, 4300 Essen, De
US4656637A (en) * 1985-02-14 1987-04-07 Sundstrand Data Control, Inc. Multiple ring laser gyro power supply
DE3519711C2 (en) * 1985-06-01 1988-10-20 Richard Hirschmann Radiotechnisches Werk, 7300 Esslingen, De
GB2236414A (en) * 1989-09-22 1991-04-03 Stc Plc Controlled electronic load circuit
JP2518525B2 (en) * 1993-06-28 1996-07-24 日本電気株式会社 Radio selective call receiver
US5929568A (en) * 1997-07-08 1999-07-27 Korry Electronics Co. Incandescent bulb luminance matching LED circuit
US5998928A (en) * 1997-11-03 1999-12-07 Ford Motor Company Lighting intensity control system
DE19828516C1 (en) 1998-06-26 2000-03-16 Qvf Pilot Tec Gmbh Glued glass pressure-resistant body consists of two hemispheres, method of assembling such a glass body, and their use
US6388390B2 (en) 1999-04-06 2002-05-14 Erwin J. Rachwal Flashlight
US7262752B2 (en) * 2001-01-16 2007-08-28 Visteon Global Technologies, Inc. Series led backlight control circuit
US6717559B2 (en) 2001-01-16 2004-04-06 Visteon Global Technologies, Inc. Temperature compensated parallel LED drive circuit
US6697130B2 (en) 2001-01-16 2004-02-24 Visteon Global Technologies, Inc. Flexible led backlighting circuit
US6930737B2 (en) 2001-01-16 2005-08-16 Visteon Global Technologies, Inc. LED backlighting system
US6392359B1 (en) 2001-01-22 2002-05-21 Gelcore, L.L.C. System and method for reducing wavelength variations between light emitting diodes
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
US20070189001A1 (en) * 2002-12-11 2007-08-16 Safeexits, Inc. Multi-functional ballast and location-specific lighting
US20080197790A1 (en) * 2002-12-11 2008-08-21 Mangiaracina Anthony A Lighting utilizing power over the ethernet
TWI260572B (en) 2003-03-07 2006-08-21 Hon Hai Prec Ind Co Ltd Variable driving apparatus for light emitting diode
CA2443206A1 (en) 2003-09-23 2005-03-23 Ignis Innovation Inc. Amoled display backplanes - pixel driver circuits, array architecture, and external compensation
CA2472671A1 (en) 2004-06-29 2005-12-29 Ignis Innovation Inc. Voltage-programming scheme for current-driven amoled displays
EP1774834A1 (en) 2004-07-23 2007-04-18 Magna International Inc Power supply system and method for automative led lighting systems
KR20070101275A (en) 2004-12-15 2007-10-16 이그니스 이노베이션 인크. Method and system for programming, calibrating and driving a light emitting device display
US9275579B2 (en) 2004-12-15 2016-03-01 Ignis Innovation Inc. System and methods for extraction of threshold and mobility parameters in AMOLED displays
US9280933B2 (en) 2004-12-15 2016-03-08 Ignis Innovation Inc. System and methods for extraction of threshold and mobility parameters in AMOLED displays
US10013907B2 (en) 2004-12-15 2018-07-03 Ignis Innovation Inc. Method and system for programming, calibrating and/or compensating, and driving an LED display
US10012678B2 (en) 2004-12-15 2018-07-03 Ignis Innovation Inc. Method and system for programming, calibrating and/or compensating, and driving an LED display
CA2496642A1 (en) 2005-02-10 2006-08-10 Ignis Innovation Inc. Fast settling time driving method for organic light-emitting diode (oled) displays based on current programming
US20140111567A1 (en) 2005-04-12 2014-04-24 Ignis Innovation Inc. System and method for compensation of non-uniformities in light emitting device displays
JP5355080B2 (en) 2005-06-08 2013-11-27 イグニス・イノベイション・インコーポレーテッドIgnis Innovation Incorporated Method and system for driving a light emitting device display
CA2518276A1 (en) 2005-09-13 2007-03-13 Ignis Innovation Inc. Compensation technique for luminance degradation in electro-luminance devices
TWI291771B (en) * 2005-09-16 2007-12-21 Innolux Display Corp Light emitting diode flexible printed circuit
US8477121B2 (en) 2006-04-19 2013-07-02 Ignis Innovation, Inc. Stable driving scheme for active matrix displays
US7456586B2 (en) * 2006-01-31 2008-11-25 Jabil Circuit, Inc. Voltage controlled light source and image presentation device using the same
CA2556961A1 (en) 2006-08-15 2008-02-15 Ignis Innovation Inc. Oled compensation technique based on oled capacitance
US20080266849A1 (en) * 2007-04-30 2008-10-30 Nielson Lyman O Fluorescent lighting conversion to led lighting using a power converter
CA2669367A1 (en) 2009-06-16 2010-12-16 Ignis Innovation Inc Compensation technique for color shift in displays
US10319307B2 (en) 2009-06-16 2019-06-11 Ignis Innovation Inc. Display system with compensation techniques and/or shared level resources
CA2688870A1 (en) 2009-11-30 2011-05-30 Ignis Innovation Inc. Methode and techniques for improving display uniformity
US9311859B2 (en) 2009-11-30 2016-04-12 Ignis Innovation Inc. Resetting cycle for aging compensation in AMOLED displays
US9384698B2 (en) 2009-11-30 2016-07-05 Ignis Innovation Inc. System and methods for aging compensation in AMOLED displays
US8803417B2 (en) 2009-12-01 2014-08-12 Ignis Innovation Inc. High resolution pixel architecture
CA2687631A1 (en) 2009-12-06 2011-06-06 Ignis Innovation Inc Low power driving scheme for display applications
US20140313111A1 (en) 2010-02-04 2014-10-23 Ignis Innovation Inc. System and methods for extracting correlation curves for an organic light emitting device
US10089921B2 (en) 2010-02-04 2018-10-02 Ignis Innovation Inc. System and methods for extracting correlation curves for an organic light emitting device
US9881532B2 (en) 2010-02-04 2018-01-30 Ignis Innovation Inc. System and method for extracting correlation curves for an organic light emitting device
CA2692097A1 (en) 2010-02-04 2011-08-04 Ignis Innovation Inc. Extracting correlation curves for light emitting device
US10176736B2 (en) 2010-02-04 2019-01-08 Ignis Innovation Inc. System and methods for extracting correlation curves for an organic light emitting device
US10163401B2 (en) 2010-02-04 2018-12-25 Ignis Innovation Inc. System and methods for extracting correlation curves for an organic light emitting device
CA2696778A1 (en) 2010-03-17 2011-09-17 Ignis Innovation Inc. Lifetime, uniformity, parameter extraction methods
US8907991B2 (en) 2010-12-02 2014-12-09 Ignis Innovation Inc. System and methods for thermal compensation in AMOLED displays
CN102566626B (en) * 2010-12-28 2014-01-22 鸿富锦精密工业(深圳)有限公司 Temperature monitoring circuit
CN102693609A (en) * 2011-03-22 2012-09-26 鸿富锦精密工业(深圳)有限公司 Electronic device with high temperature alarm function
US9799246B2 (en) 2011-05-20 2017-10-24 Ignis Innovation Inc. System and methods for extraction of threshold and mobility parameters in AMOLED displays
US9171500B2 (en) 2011-05-20 2015-10-27 Ignis Innovation Inc. System and methods for extraction of parasitic parameters in AMOLED displays
US9530349B2 (en) 2011-05-20 2016-12-27 Ignis Innovations Inc. Charged-based compensation and parameter extraction in AMOLED displays
US8576217B2 (en) 2011-05-20 2013-11-05 Ignis Innovation Inc. System and methods for extraction of threshold and mobility parameters in AMOLED displays
US8599191B2 (en) 2011-05-20 2013-12-03 Ignis Innovation Inc. System and methods for extraction of threshold and mobility parameters in AMOLED displays
US9466240B2 (en) 2011-05-26 2016-10-11 Ignis Innovation Inc. Adaptive feedback system for compensating for aging pixel areas with enhanced estimation speed
CN103562989B (en) 2011-05-27 2016-12-14 伊格尼斯创新公司 System and method for the compensation of ageing of displayer
US10089924B2 (en) 2011-11-29 2018-10-02 Ignis Innovation Inc. Structural and low-frequency non-uniformity compensation
US8937632B2 (en) 2012-02-03 2015-01-20 Ignis Innovation Inc. Driving system for active-matrix displays
US9747834B2 (en) 2012-05-11 2017-08-29 Ignis Innovation Inc. Pixel circuits including feedback capacitors and reset capacitors, and display systems therefore
US8922544B2 (en) 2012-05-23 2014-12-30 Ignis Innovation Inc. Display systems with compensation for line propagation delay
US9336717B2 (en) 2012-12-11 2016-05-10 Ignis Innovation Inc. Pixel circuits for AMOLED displays
US9786223B2 (en) 2012-12-11 2017-10-10 Ignis Innovation Inc. Pixel circuits for AMOLED displays
WO2014108879A1 (en) 2013-01-14 2014-07-17 Ignis Innovation Inc. Driving scheme for emissive displays providing compensation for driving transistor variations
US9830857B2 (en) 2013-01-14 2017-11-28 Ignis Innovation Inc. Cleaning common unwanted signals from pixel measurements in emissive displays
EP3043338A1 (en) 2013-03-14 2016-07-13 Ignis Innovation Inc. Re-interpolation with edge detection for extracting an aging pattern for amoled displays
US9324268B2 (en) 2013-03-15 2016-04-26 Ignis Innovation Inc. Amoled displays with multiple readout circuits
DE112014003719T5 (en) 2013-08-12 2016-05-19 Ignis Innovation Inc. compensation accuracy
US9761170B2 (en) 2013-12-06 2017-09-12 Ignis Innovation Inc. Correction for localized phenomena in an image array
US9741282B2 (en) 2013-12-06 2017-08-22 Ignis Innovation Inc. OLED display system and method
US9502653B2 (en) 2013-12-25 2016-11-22 Ignis Innovation Inc. Electrode contacts
US10192479B2 (en) 2014-04-08 2019-01-29 Ignis Innovation Inc. Display system using system level resources to calculate compensation parameters for a display module in a portable device
CA2879462A1 (en) 2015-01-23 2016-07-23 Ignis Innovation Inc. Compensation for color variation in emissive devices
CA2889870A1 (en) 2015-05-04 2016-11-04 Ignis Innovation Inc. Optical feedback system
CA2892714A1 (en) 2015-05-27 2016-11-27 Ignis Innovation Inc Memory bandwidth reduction in compensation system
CA2900170A1 (en) 2015-08-07 2017-02-07 Gholamreza Chaji Calibration of pixel based on improved reference values

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2014351A1 (en) * 1970-03-25 1971-11-11 Siemens Ag
US3736522A (en) * 1971-06-07 1973-05-29 North American Rockwell High gain field effect transistor amplifier using field effect transistor circuit as current source load
JPS5121781B2 (en) * 1973-05-02 1976-07-05
US3925690A (en) * 1974-09-30 1975-12-09 Rockwell International Corp Direct drive circuit for light emitting diodes
US3955103A (en) * 1975-02-12 1976-05-04 National Semiconductor Corporation Analog switch
US4017847A (en) * 1975-11-14 1977-04-12 Bell Telephone Laboratories, Incorporated Luminous indicator with zero standby power

Also Published As

Publication number Publication date
DE2862207D1 (en) 1983-04-28
US4160934A (en) 1979-07-10
JPS5430456A (en) 1979-03-06
EP0000844A1 (en) 1979-02-21

Similar Documents

Publication Publication Date Title
US4779037A (en) Dual input low dropout voltage regulator
US6922321B2 (en) Overcurrent limitation circuit
US4683382A (en) Power-saving voltage supply
US5666044A (en) Start up circuit and current-foldback protection for voltage regulators
US3806742A (en) Mos voltage reference circuit
US6046577A (en) Low-dropout voltage regulator incorporating a current efficient transient response boost circuit
US6720754B2 (en) Voltage regulator
KR100264718B1 (en) Regulator circuit and semiconductor integrated circuit device having the same
US7119526B2 (en) Processor based integrated circuit with a supply voltage monitor using bandgap device without feedback
US6583644B2 (en) Output buffer for reducing slew rate variation
US7142044B2 (en) Voltage regulator
US7116129B2 (en) Temperature-compensated output buffer method and circuit
US6236194B1 (en) Constant voltage power supply with normal and standby modes
US6703813B1 (en) Low drop-out voltage regulator
US7339416B2 (en) Voltage regulator with low dropout voltage
US4584492A (en) Temperature and process stable MOS input buffer
US4430582A (en) Fast CMOS buffer for TTL input levels
EP0079937B1 (en) Semiconductor current regulator and switch
KR920001634B1 (en) Inter-mediate potential generation circuit for generating a potential intermediate between a power source potential and ground potential
US7215183B2 (en) Reference voltage generator circuit
US6700363B2 (en) Reference voltage generator
DE69530905T2 (en) Circuit and method for voltage regulation
US6222357B1 (en) Current output circuit with controlled holdover capacitors
US6756839B2 (en) Low voltage amplifying circuit
US6861832B2 (en) Threshold voltage adjustment for MOS devices

Legal Events

Date Code Title Description
AK Designated contracting states:

Designated state(s): DE FR GB

17P Request for examination filed
AK Designated contracting states:

Designated state(s): DE FR GB

REF Corresponds to:

Ref document number: 2862207

Country of ref document: DE

Date of ref document: 19830428

Format of ref document f/p: P

ET Fr: translation filed
PGFP Postgrant: annual fees paid to national office

Ref country code: DE

Payment date: 19840628

Year of fee payment: 07

PGFP Postgrant: annual fees paid to national office

Ref country code: FR

Payment date: 19840703

Year of fee payment: 07

PG25 Lapsed in a contracting state announced via postgrant inform. from nat. office to epo

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19880429

PG25 Lapsed in a contracting state announced via postgrant inform. from nat. office to epo

Ref country code: DE

Effective date: 19880503

GBPC Gb: european patent ceased through non-payment of renewal fee
REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

PG25 Lapsed in a contracting state announced via postgrant inform. from nat. office to epo

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19881117