JPH0576792B2 - - Google Patents

Info

Publication number
JPH0576792B2
JPH0576792B2 JP5573384A JP5573384A JPH0576792B2 JP H0576792 B2 JPH0576792 B2 JP H0576792B2 JP 5573384 A JP5573384 A JP 5573384A JP 5573384 A JP5573384 A JP 5573384A JP H0576792 B2 JPH0576792 B2 JP H0576792B2
Authority
JP
Japan
Prior art keywords
voltage
circuit
current
led
constant 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 - Lifetime
Application number
JP5573384A
Other languages
Japanese (ja)
Other versions
JPS60198872A (en
Inventor
Masaharu Ozaki
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.)
Seiko Instruments Inc
Original Assignee
Seiko Instruments 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
Application filed by Seiko Instruments Inc filed Critical Seiko Instruments Inc
Priority to JP59055733A priority Critical patent/JPS60198872A/en
Publication of JPS60198872A publication Critical patent/JPS60198872A/en
Publication of JPH0576792B2 publication Critical patent/JPH0576792B2/ja
Granted legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/30—Driver circuits
    • H05B45/395—Linear regulators
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/10—Controlling the intensity of the light
    • H05B45/14—Controlling the intensity of the light using electrical feedback from LEDs or from LED modules
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
    • Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Landscapes

  • Dot-Matrix Printers And Others (AREA)
  • Facsimile Heads (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
  • Control Of El Displays (AREA)
  • Led Devices (AREA)

Abstract

PURPOSE:To prevent the titled circuit from being affected by the fluctuation of supply voltage and the change of an ambient temperature by a method wherein the circuit is provided with a detecting element connected in series with an LED, a reference voltage output circuit and a current limiting element driving circuit and the LED is driven in constant current. CONSTITUTION:The driving current of an LED3, which has been limited by an MOS transistor (TR)4, runs through a resistor 5 and detecting voltage V1 generates on both ends of the resistor 5. On the other hand, drain current ID to run on an MOSTR7 fluctuates according to a temperature change without being affected by the terminal voltage V0 of a DC power source 2. Voltage Vr, whose current generates on both ends of a resistor 8, is impressed on a voltage comparator 6. Accordingly, output voltage, which corresponds to the component of a difference between the voltage V1 and the voltage Vr, is outputted from the output of the comparator 6 and the conductivity of the TR4 is controlled by this output voltage. As a result, current, which corresponds to the level of the voltage Vr, runs on the LED3 through the TR4 and the LED3 is driven in constant current. Accordingly, the LED3 is driven in constant current despite the fluctuation of the voltage V0 and when the ambient temperature changes, the change of the luminous efficiency is corrected.

Description

【発明の詳細な説明】 本発明はLEDを一定の輝度にて駆動すること
ができるようにした、特に、LEDプリンタ用の
LED駆動用集積回路として好適なLED駆動用
MOS集積回路に関する。[Detailed Description of the Invention] The present invention enables LEDs to be driven with constant brightness, and is particularly suitable for LED printers.
For LED driving, suitable as an integrated circuit for LED driving.
Regarding MOS integrated circuits.

例えば、LED素子を発光源として用いたLED
プリンタにあつては、多数個配設されている
LEDを選択的に点灯し、且つ点灯時における
LEDの輝度は所定の一定値に保たれる必要があ
る。しかしながら、従来から用いられてきている
この種のLED駆動回路においては、MOS出力ト
ランジスタのオン抵抗が温度によつて変化すると
共にLED素子自体の温度特性により、温度の上
昇に従つてLEDの輝度が低下するという問題点
を有していた。更に、MOSトランジスタを駆動
するための電圧の変動に左右されることも勿論で
ある。 For example, an LED that uses an LED element as a light source
For printers, there are many
Selectively light the LED and when it is lit
The brightness of the LED needs to be kept at a predetermined constant value. However, in this type of LED drive circuit that has been used conventionally, the on-resistance of the MOS output transistor changes depending on the temperature, and the brightness of the LED decreases as the temperature rises due to the temperature characteristics of the LED element itself. However, there was a problem in that it decreased. Furthermore, it goes without saying that it is influenced by fluctuations in the voltage for driving the MOS transistors.

本発明の目的は、従つて、複雑な回路構成を用
いることなしに、電源電圧及び周囲温度の変化が
あつてもLEDを一定輝度で駆動することができ
るようにしたLED駆動用MOS集積回路を提供す
ることにある。 Therefore, an object of the present invention is to provide a MOS integrated circuit for driving an LED that can drive an LED with constant brightness even when the power supply voltage and ambient temperature change without using a complicated circuit configuration. It is about providing.

本発明の構成は、直流電源により発光ダイオー
ドを駆動するためのLED駆動用MOS集積回路に
おいて、上記直流電源からLEDに流れる電流を
制御するためLEDと直列に接続された電流制御
素子と、LEDに流れる電流の大きさを検出する
ためLEDと直列に接続されている検出素子と、
上記直流電源から電力の供給を受け上記直流電源
の電圧レベル変動に拘らず所定レベルの基準電圧
を出力する回路と、上記検出素子からの検出電圧
と上記基準電圧とに応答して作動し上記LEDに
流れる駆動電流が所定値に維持されるよう上記電
流制限素子を駆動する回路とを備え、これにより
LEDが定電流駆動されるようにした点に特徴を
有する。 The configuration of the present invention is that, in an LED driving MOS integrated circuit for driving a light emitting diode with a DC power supply, a current control element connected in series with the LED to control the current flowing from the DC power supply to the LED, and A detection element connected in series with the LED to detect the magnitude of the flowing current,
a circuit that receives power from the DC power supply and outputs a reference voltage at a predetermined level regardless of voltage level fluctuations of the DC power supply; and a circuit that operates in response to the detection voltage from the detection element and the reference voltage; and a circuit that drives the current limiting element so that the drive current flowing through the current limiting element is maintained at a predetermined value.
The feature is that the LED is driven with a constant current.

多数のLEDを駆動する場合にあつては、基準
電圧を出力する回路は１つでよく、電流制御素
子、検出素子及び電流制御素子を駆動する回路
は、LED毎に設けられる。 When driving a large number of LEDs, only one circuit is required to output the reference voltage, and a circuit for driving the current control element, detection element, and current control element is provided for each LED.

以下、図示の実施例により、本発明を詳細に説
明する。 Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

第１図には、本発明によるLED駆動用MOS集
積回路一部分を示すの一実施例が示されている。
LED駆動用MOS集積回路１は、直流電源２によ
つて駆動される発光ダイオード３（以下、LED
という）に供給させる電力を、その輝度が所定値
を保つように制御するための回路であり、単一の
基板上に集積回路として形成されている。 FIG. 1 shows an embodiment of a portion of an LED driving MOS integrated circuit according to the present invention.
The LED driving MOS integrated circuit 1 includes a light emitting diode 3 (hereinafter referred to as LED) driven by a DC power supply 2.
This is a circuit for controlling the power supplied to the device so that its brightness remains at a predetermined value, and is formed as an integrated circuit on a single substrate.

この集積回路１は、LED３に流れる電流値を
制限する目的で、LED３と直列に接続される
MOSトランジスタ４が電流制限素子として設け
られており、MOSトラジスタ４は更に抵抗器５
を介して直流電源２の正極に接続されている。従
つて、MOSトランジスタ４によつて制限された
所要のLED駆動電流は、抵抗器５を介して流れ、
抵抗器５の両端には、LED３に流れる駆動電流
の大きさに従つたレベルの検出電圧V1が生じる。
検出電圧V1は、電圧比較器６の＋入力端子に印
加されている。 This integrated circuit 1 is connected in series with LED 3 for the purpose of limiting the current value flowing through LED 3.
A MOS transistor 4 is provided as a current limiting element, and the MOS transistor 4 is further connected to a resistor 5.
It is connected to the positive electrode of the DC power supply 2 via the terminal. Therefore, the required LED drive current limited by the MOS transistor 4 flows through the resistor 5 and
A detection voltage V 1 is generated across the resistor 5 at a level depending on the magnitude of the drive current flowing through the LED 3 .
The detection voltage V 1 is applied to the +input terminal of the voltage comparator 6.

直流電源２の端子電圧V0のレベルに拘らず所
要の一定レベルの基準電圧を取出すため、ゲート
電極がソース電極に共通接続されているテプレツ
シヨン型MOSトランジスタ７のドレイン電極が
抵抗器８を介して直流電源２の正極に接続されて
いる。 In order to extract a reference voltage at a required constant level regardless of the level of the terminal voltage V0 of the DC power supply 2, the drain electrodes of the trenchment type MOS transistors 7 whose gate electrodes are commonly connected to the source electrodes are connected via a resistor 8. It is connected to the positive electrode of the DC power supply 2.

従つて、MOSトランジスタ７に流れるドレイ
ン電流IDは、MOSトランジスタ７のドレインに
印加されるVDに対して、第２図に示す如く変化
することになる。即ち、ドレイン電流IDの値は、
電圧VDの値が所定値以上であれば、電圧VDの値
にはほとんど依存せず、ドレイン電流IDは、温度
の変化に伴なうMOSトランジスタ７のスレシヨ
ールド電圧の変化と、MOSトランジスタ７のチ
ヤネル移動度の変化とのために変化するだけであ
る。 Therefore, the drain current I D flowing through the MOS transistor 7 changes as shown in FIG. 2 with respect to V D applied to the drain of the MOS transistor 7. That is, the value of drain current I D is
As long as the value of voltage V D is above a predetermined value, the drain current I D is almost independent of the value of voltage V D, and the drain current I D depends on the change in the threshold voltage of MOS transistor 7 due to temperature change and the change in the threshold voltage of MOS transistor 7 due to temperature change. It only changes due to the channel mobility change of 7.

即ち、ドレイン電圧IDは直流電源２の端子電圧
V0の変化によつては影響されず、温度変化によ
つて変動する。MOSトランジスタを流れる電流
の温度係数は上述したごとくスレツシヨールド電
圧の設定およびMOSトランジスタの移動度によ
り決まる。それゆえ、ドレイン電流IDの温度特性
を、即ち、温度の上昇に対してドレイン電流IDを
増大するようにMOSトランジスタ７のスレツシ
ヨールド電圧を任意に設定することができる。 In other words, the drain voltage I D is the terminal voltage of the DC power supply 2.
It is not affected by changes in V 0 and varies by changes in temperature. As described above, the temperature coefficient of the current flowing through the MOS transistor is determined by the setting of the threshold voltage and the mobility of the MOS transistor. Therefore, the threshold voltage of the MOS transistor 7 can be arbitrarily set so as to increase the temperature characteristics of the drain current ID , that is, the drain current ID as the temperature rises.

ドレイン電流IDが抵抗器８を流れることによつ
て抵抗器８の両端に生じる電圧Vrは、電圧比較
器６の一入力端子に印加されている。 A voltage Vr generated across the resistor 8 by the drain current I D flowing through the resistor 8 is applied to one input terminal of the voltage comparator 6 .

従つて、電圧比較器６の出力からは、検出電圧
V1と基準電圧Vrとの電圧差をゼロにするように
出力電圧Veが出力され、この出力電圧Veによつ
てトランジスタ４の導通度が制御される。この結
果、V1＜Vrとなると、出力電圧Veが正の方向に
増大してトランジスタ４のドレイン電流が増大
し、抵抗器５における電圧降下が増大する。即ち
検出電圧V1の値が増大する。逆に、V1＞Vrとな
ると、出力電圧Veが負の方向に増大してトラン
ジスタ４のドレイン電流が減少するので、抵抗器
５における電圧降下が減少する。即ち検出電圧
V1が減少する。このようにして、V1＝Vrとなる
ようにトランジスタ４の導通度が制御され、この
結果、基準電圧Vrのレベルに応じた電流がトラ
ンジスタ４を介してLED３に流れ、LED３は定
電流駆動される。 Therefore, from the output of the voltage comparator 6, the detected voltage
An output voltage Ve is output so as to make the voltage difference between V 1 and the reference voltage Vr zero, and the conductivity of the transistor 4 is controlled by this output voltage Ve. As a result, when V 1 <Vr, the output voltage Ve increases in the positive direction, the drain current of the transistor 4 increases, and the voltage drop across the resistor 5 increases. That is, the value of the detection voltage V1 increases. Conversely, when V 1 >Vr, the output voltage Ve increases in the negative direction and the drain current of the transistor 4 decreases, so the voltage drop across the resistor 5 decreases. That is, the detection voltage
V 1 decreases. In this way, the conductivity of the transistor 4 is controlled so that V 1 = Vr, and as a result, a current corresponding to the level of the reference voltage Vr flows through the transistor 4 to the LED 3, and the LED 3 is driven with a constant current. Ru.

従つて、抵抗器５，８の値を適宜に設定して、
所要の駆動電流がLED３に供給されるようにす
れば、LEDは直流電源２の電圧V0の変動に拘ら
ず常に一定の電流で駆動され、所定の輝度を維持
することができる。 Therefore, by appropriately setting the values of resistors 5 and 8,
If the required drive current is supplied to the LED 3, the LED is always driven with a constant current regardless of fluctuations in the voltage V0 of the DC power supply 2, and a predetermined brightness can be maintained.

その上、温度が上昇すると、上述した如く、
MOSトランジスタ７のIDが増大するので基準電
圧Vrも上昇し、温度上昇により低下するLED３
の発光効率の変化を補正する。すなわち、この補
正を行わないと、LED３の発行が弱くなり、印
字が薄くなつてしまう。一方、温度が低下する
と、基準電圧Vrも低下し、この場合にも温度変
化による発光効率の変化を補正することができ
る。 Moreover, as the temperature increases, as mentioned above,
As ID of MOS transistor 7 increases, reference voltage Vr also increases, and LED 3 decreases due to temperature rise.
to compensate for changes in luminous efficiency. In other words, if this correction is not performed, the light emitted from the LED 3 will become weaker and the print will become lighter. On the other hand, when the temperature decreases, the reference voltage Vr also decreases, and in this case as well, changes in luminous efficiency due to temperature changes can be corrected.

本実施例において、抵抗器５，８は、例えば拡
散抵抗又はポリシリコン抵抗として同時に形成さ
れるため、抵抗器５，８の抵抗比を所望の値に設
定することが比較的容易であり、LED３の駆動
電流を所定の設定値に比較的正確に設定すること
ができる。 In this embodiment, the resistors 5 and 8 are formed simultaneously as, for example, a diffused resistor or a polysilicon resistor, so it is relatively easy to set the resistance ratio of the resistors 5 and 8 to a desired value, and the LED 3 The drive current can be relatively accurately set to a predetermined set value.

第３図には、多数のLED３1，３2，３3…を選
択的に点滅させることができるようにした本発明
の他の実施例が示されている。第３図に示す
LED駆動用MOS集積回路は、例えばLEDプリン
タに好適である。このLED駆動用MOS集積回路
１１においては、第１図に示した各部に対応する
部分には同一の符号を付し、その説明を省略す
る。 FIG. 3 shows another embodiment of the present invention in which a large number of LEDs 3 1 , 3 2 , 3 3 . . . can be selectively blinked. Shown in Figure 3
The LED driving MOS integrated circuit is suitable for, for example, an LED printer. In this LED driving MOS integrated circuit 11, parts corresponding to those shown in FIG. 1 are denoted by the same reference numerals, and their explanations will be omitted.

第３図の実施例では、各LED３1，３2，３3…
を選択的に点滅することができるよう、トランジ
スタ４の各ゲートとアースとの間にスイツチング
トランジスタ１２1，１２2，１２3…が設けられ
ており、別途設けられた制御回路１３からの制御
信号C1，C2，C3…により、各スイツチングトラ
ンジスタ１２1，１２2，１２3…がオン、オフさ
れ、これにより各LEDの点滅を制御する構成と
なつている。 In the embodiment shown in FIG. 3, each LED 3 1 , 3 2 , 3 3 . . .
Switching transistors 12 1 , 12 2 , 12 3 . . . are provided between each gate of the transistor 4 and the ground so that the switching transistors can be selectively blinked. The switching transistors 12 1 , 12 2 , 12 3 . . . are turned on and off by the signals C 1 , C 2 , C 3 . . . , thereby controlling the blinking of each LED.

各LED３1，３2，３3…を駆動する回路は、基
準電圧を発生する回路が共通になつている点を除
けば第１図の場合と全く同様である。この第３図
に示す本発明のLED駆動用MOS集積回路は温度
特性回路であるMOSトランジスタ７が１個で済
むので、ICチツプの面積を小さくできる効果が
ある。 The circuits for driving the LEDs 3 1 , 3 2 , 3 3 . . . are exactly the same as those shown in FIG. 1, except that the circuit for generating the reference voltage is common. Since the LED driving MOS integrated circuit of the present invention shown in FIG. 3 requires only one MOS transistor 7, which is a temperature characteristic circuit, it has the effect of reducing the area of the IC chip.

また、このMOSトランジスタ７は各LED３1、
LED３2、LED３3に共通なので全てのLED３1、
LED３2、LED３3がすべて同じ温度特性となるよ
うに制御でき、このLED３1〜３3間に、発光のバ
ラツキがない効果を有する。さらに、このLED
がLEDプリンターである場合には、印字のムラ
が発生しない効果を有する。 Furthermore, this MOS transistor 7 connects each LED 3 1 ,
It is common to LED3 2 and LED3 3 , so all LED3 1 ,
The LED 3 2 and the LED 3 3 can be controlled so that they all have the same temperature characteristics, and there is no variation in light emission between the LEDs 3 1 to 3 3 . Additionally, this LED
When the printer is an LED printer, it has the effect of preventing uneven printing.

本発明によれば、上述の如く、LEDを定電流
駆動とする構成としたので、電源電圧の変動によ
りLEDの輝度が影響を受けることがなく、極め
て安定した駆動を行なうことができ、また、
LEDの温度特性の補正をも比較的簡単に行なえ
る等の利点を有している。 According to the present invention, as described above, since the LED is configured to be driven with a constant current, the brightness of the LED is not affected by fluctuations in the power supply voltage, and extremely stable driving can be performed.
It has the advantage that the temperature characteristics of the LED can be corrected relatively easily.

【図面の簡単な説明】[Brief explanation of drawings]

第１図は本発明によるLED駆動用MOS集積回
路の一部分を示す一実施例を示す回路図、第２図
は第１図に示した装置の作動を説明するための特
性図、第３図は本発明によるLED駆動用MOS集
積回路の他の実施例を示す回路図である。 １，１１……LED駆動用MOS集積回路、２…
…直流電源、３，３1，３2，３3……発光ダイオ
ード（LED）、４……トランジスタ、５，３……
抵抗器、７……MOSトランジスタ。 FIG. 1 is a circuit diagram showing an embodiment of a part of an LED driving MOS integrated circuit according to the present invention, FIG. 2 is a characteristic diagram for explaining the operation of the device shown in FIG. 1, and FIG. FIG. 3 is a circuit diagram showing another embodiment of the LED driving MOS integrated circuit according to the present invention. 1, 11...LED driving MOS integrated circuit, 2...
...DC power supply, 3, 3 1 , 3 2 , 3 3 ... Light emitting diode (LED), 4 ... Transistor, 5, 3 ...
Resistor, 7...MOS transistor.

Claims (1)

【特許請求の範囲】 １ 抵抗とMOSトランジスタとの直列接続回路
からなる基準電圧発生回路と、 電流制御素子と発光ダイオードとの直列回路か
らなる定電流回路と、 上記MOSトランジスタの電位を基準電位とし
て、上記電流制御素子の制御端子に、上記定電流
回路の電流を一定値に制御する制御信号を出力す
る制御信号発生回路とからなり、 上記基準電圧発生回路と定電流回路とは、直流
電源に接続されて並列回路を構成し、 上記MOSトランジスタは、ゲート電極がソー
ス電極に共通接続されたデプレツシヨン型である
ことを特徴とするLED駆動用MOS集積回路。 ２ 上記定電流回路は、複数固並列に配列され、
各定電流回路を構成する電流制御素子の制御端子
には、上記制御信号発生回路の出力がそれぞれ入
力されることを特徴とする特許請求の範囲第１項
記載のLED駆動用MOS集積回路。[Scope of Claims] 1. A reference voltage generation circuit consisting of a series connection circuit of a resistor and a MOS transistor, a constant current circuit consisting of a series circuit of a current control element and a light emitting diode, and a potential of the MOS transistor as a reference potential. , a control signal generation circuit that outputs a control signal for controlling the current of the constant current circuit to a constant value to the control terminal of the current control element, and the reference voltage generation circuit and the constant current circuit are connected to a DC power supply. A MOS integrated circuit for driving an LED, wherein the MOS transistors are connected to form a parallel circuit, and the MOS transistors are of a depletion type in which a gate electrode is commonly connected to a source electrode. 2 The constant current circuits are arranged in plural fixed parallels,
2. The LED driving MOS integrated circuit according to claim 1, wherein the outputs of the control signal generation circuits are input to the control terminals of the current control elements constituting each constant current circuit.
JP59055733A 1984-03-23 1984-03-23 Mos integrated circuit for led driving Granted JPS60198872A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP59055733A JPS60198872A (en) 1984-03-23 1984-03-23 Mos integrated circuit for led driving

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP59055733A JPS60198872A (en) 1984-03-23 1984-03-23 Mos integrated circuit for led driving

Publications (2)

Publication Number Publication Date
JPS60198872A JPS60198872A (en) 1985-10-08
JPH0576792B2 true JPH0576792B2 (en) 1993-10-25

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Application Number Title Priority Date Filing Date
JP59055733A Granted JPS60198872A (en) 1984-03-23 1984-03-23 Mos integrated circuit for led driving

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Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1988007729A1 (en) * 1987-04-01 1988-10-06 Eastman Kodak Company Printer apparatus
JPH078213Y2 (en) * 1987-09-22 1995-03-01 富士ゼロックス株式会社 LED printer head
JPS6450948U (en) * 1987-09-24 1989-03-29
JP2539508B2 (en) * 1989-02-13 1996-10-02 株式会社日立製作所 Optical recording head
JPH04348964A (en) * 1991-05-27 1992-12-03 Kyocera Corp Image forming device
JP3985763B2 (en) * 1997-03-12 2007-10-03 セイコーエプソン株式会社 Display device and electronic device
EP0923067B1 (en) 1997-03-12 2004-08-04 Seiko Epson Corporation Pixel circuit, display device and electronic equipment having current-driven light-emitting device
JP3988707B2 (en) * 1997-03-12 2007-10-10 セイコーエプソン株式会社 Pixel circuit, display device, and electronic device
TW550530B (en) 2000-10-27 2003-09-01 Semiconductor Energy Lab Display device and method of driving the same
CN100419837C (en) * 2002-08-21 2008-09-17 皇家飞利浦电子股份有限公司 Display device
CN101976668B (en) * 2010-09-27 2012-11-28 复旦大学 Device for controlling light-emitting diode (LED) by silicon-based MOS tube, array and manufacturing method thereof
ITCS20110016A1 (en) * 2011-06-17 2012-12-18 E D P Srl ELECTRONIC SYSTEM FOR POWER SUPPLY AND ADJUSTMENT OF THE CURRENT FOR LED LAMPS

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5229084B2 (en) * 1972-04-06 1977-07-30
JPS551147A (en) * 1978-06-19 1980-01-07 Nec Corp Stabilized luminous source

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5229084U (en) * 1975-08-20 1977-03-01

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5229084B2 (en) * 1972-04-06 1977-07-30
JPS551147A (en) * 1978-06-19 1980-01-07 Nec Corp Stabilized luminous source

Also Published As

Publication number Publication date
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