JPS5954340A - Driving circuit of light emitting element - Google Patents

Abstract

PURPOSE:To attain ease of circuit integration, by connecting a field effect transistor (TR) for current limiting to a drain of a field effect TR so as to make the operation of a light emitting element stable at a small amplitude signal. CONSTITUTION:A signal source 14 is connected to a gate of an FET12 for voltage-current conversion. The source of the FET12 is connected to the light emitting element 11. The drain of the FET12 is connected to the source and the gate of an FET13 for current limiting. The drain of the FET13 is connected to the positive side of a power supply. An FET having a large saturated drain current and a large mutual conductance is selected as the FET12. An FET having a saturated drain current equal to a light emitting element drive current of the element 11 is selected as the FET13.

Description

[Detailed Description of the Invention] Technique of the Invention This invention No. 131, Stably driving a light emitting element with a small amplitude No. 171
19 no 3・r], 2 and so on, light emission that is easy to integrate (pa; child drive 11 s) times +, +8 +,;
Rumono-C A・8th crime.

Highlights between conventional technology! li 4 bodies! −・−(Drive circuit Otsu 3 of light emitting element such as J
1,i)′L,! 1 Nihai Bora 1-Hun, Star' (
This composition is 1.7 I) Ko, but 7, the oldest G, ■ (
：Details・; Forming a light emitting element on a semiconductor substrate 4-・Along with B, the driver constitutes one circuit. 1 to form, -, i, l, !, 4. s', 1t-C,
y). , Second, L Tsuna City y; 1 effect IO,・Nzo:! ,
:' The drive circuit according to l is, for example, (JFig.
Slip (J shoes 11.1 < T and abbreviation fV1, JK,
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, the l'=,',' IA, 1N41' on the j board
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, 2nd +/8+, ~1st input 1h pressure\'t;'
l'l output city flow I small flow l! 11μl 11;1's
21! J (,,221,-(Monotona?).?<OI
n! ', l saturation IL4>' current, V l) 4;i
t: ; ),' J-J-) Kozuki, vDi, issued)■
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11j]--(= Yes.

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Easy 1) 1. J, s, ki; pa, etc., J, ru light (dν ([7
] Output change iri 1 rotation pressure J-4 Tametsuko, 1・kawa ('!'
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, I entered the country for the first time, and the 1st charge was V +. (nono-
--1 Kozuki-) aL'r is to 0 □ V p's 1 'liX, ig, Kaname, l-'; l-, b j to1
1ノ, 10, ri: (-Z ``rii light,'+:
G requires a voltage equal to the sum of the forward voltage VD of J'1. Pin thousand off electric IJ-V +)&J,
Since the communication voltage is about -2 to -4 V, and the logic level of the high-speed digital circuit is t, +: l V, 1
Ii' l directly with the output signal of the 1-tracing statistical circuit
i' What drives 2, what 2 cannot do - (There was.

Also, the input signal voltage ■.

Since the current flowing through the light-emitting element 1, i.e., the train current i, varies linearly, it is necessary to specify the input signal level quite closely.
! 5 Selecting l''[5'F with a large saturation train current] (It is possible to drive the light emitting element with a small input signal voltage, but since the previous signal output will be largely dependent on the input voltage level, Applicable to transmission
It is something that cannot be done.

OBJECTS OF THE INVENTION The present invention provides a method for stably driving a light emitting element with a small amplitude signal such as an output signal of a 1J speed digital circuit, and also provides a light emitting element driving circuit that can be easily integrated into an integrated circuit. This is what IBI provides.Examples will be described below.

Embodiment of the invention Figure 3 &j Actual journey of the invention (911 times +?: J, diagram, game) - 1 concubine #, toM L
Saw 1・゛I charge Ti2 is 1・゛l for heavy pressure-current change.
In general, connect 18 light-emitting elements II to the source of 1 and 12 from 1 and 1, and connect 7, I and I for current limiting.
Connect the source and gate of Iu'l'13 and connect its F
Connect a small power supply to the Ruin of E Tl 3. I”IE
In TI 2, the saturation 1, Shi -in -L -in Lan + 10 is thick (11 41 mouth 1-1kktance: 7 + 11 people 1, I 'I''', J Tatsumi 1 scale, I- ' : 'l'
l 3 L, l, 'c) fed (IJ F le-(
The current 102 is the light emitting element i' I I o) The light emitting current 102 and the dynamic current 21.

i” by ’t531 shakuj゛.

Figure 4 shows 1・'tEi'12 of Figure 3. I・'Ig
Shizuka from TI 3? ) The curve d is 1, and the curve d is ■
・'lff'F12, curve [) is l” Ij TI 3
Regarding ``(later ζ), VD is the forward voltage of the light emitting element 11, V pυ is the 1-pin 1000-off voltage.

The 1-rain current i of FET is generally expressed as:

in = ID (1-(VG /Vp))2...
(+1 Also, the light emission drive current of light emitting element 1 is FE Tl 3
FI when it becomes almost equal to the saturation train current 1, 2 of
ETI 20) 'y' -1-voltage vG I is VG
1 = V)) (1--'6 2/+01)
・It is expressed as (2). (The input signal voltage e for driving the light emitting element 11 (jff) is expressed by the following equation.

e〒-Vp seeing〒〒7i] Me vpf kenr〒] horse] ...(3) Nopuo Wg+
``I・'' I 巳′ ``12 Kate width, WB2 is F 巳 1'
The gate width is 13, and the saturation drain current is approximately proportional to the gate width.

For example, Vp = 2V, ID 1 = 120mA.

If 1o2=20mA, the input signal voltage e is approximately 0
．． It becomes 8v. This is equivalent to the output signal level of a normal high-speed digital circuit, so the high-speed Tinkle circuit (-h
Is it possible to drive it oil-wetted with the output signal of ?

FIG. 5 4J is a curve diagram for explaining the above-mentioned operation, in which a train current i (1) tries to flow along the zll characteristic curve a of the FET 12 due to the input signal voltage e, but the current limiting F
Since ET13 is connected in series with Nj5, its saturation leakage current 1a2Ju, J-'s train 1M flow will not flow, and the level of Equation (3) C (not shown) is higher than the human power input death voltage e'-. Even if a signal is input manually, a constant level of current will be supplied to the light emitting element 11.

FIG. 6 is a circuit diagram of another embodiment of the present invention - with ζ, and a light emitting element 21. I"l-, i'22. Is ζ for l+ equal to 1.0ζ as in the example shown in FIG. 3?
The saturation l rain current of r 23 is made jγ constant J to the same extent as the light emission driving j current of the light emitting element 421.
Kino. In case of illusion, set resistance 25 to I”IE
T23's source Ruko is connected, and alcoholic C1 river pa1i'
There is a saturation of 23 where the rain current 'IAL is combined with the light emission drive current of the light emitting element 21. As a result, 1・'E
'F22 is a low level human power signal from Shinbage Gen 24.
) and the current LAFIE T 2 flows through the light emitting element 21.
3 limited by J′1. Then, it is possible to supply a light emission drive current of -.

Figure 7 shows the input signal type 17V1 of 1.''E'F, paired with (
1. Characteristic curve 1'1' (Yes, 1・1・
:'l'23 source (”-IRGA shik 11-t
IJl 25G song (li R'Cshow'J' a:,
fia ) u l:' Iy (2'i city current \1 [, tea -2), the 81st interest's 1-source voltage V
DS 11 and in current i n'l! +11 curve diagram Q
As shown in 1, the saturated F'L-in current 102 and the ? The U flow limit can be changed to i]-゛), 2, or (').

m 9 l! l +4 shots) ll', tJ' l 10)
Bar 1' I), 1jjl road mome/s actual times 1
Figure 18 shows -4-1) -(-, F" IF, '
Fl! 7G light emission through i 111.1: Hf as electric current rA, i B can be supplied. , 2'I'', T
15), ζ.1- A constant high voltage or a return voltage of 11N is applied to stabilize the light-emitting element 11 in 1). 1.2,
l't,'4. Current IO is supplied via T13.

No. 101R+ is a characteristic curve diagram of the light-emitting element-r, and the horizontal axis is the current and the output power (11 output 1).Light-emitting element 1
To the current 18 near the dark value of F, T12.
Through FIE 'VI 3, input the password to phantom 1i+,'
, the input signal waveform 6. is generated every time the current ID is changed to 1?1 and flows into the light emitting element 11. An optical signal with a Z-centered waveform is output.

Figure 11 No. J Figure 0 circuit configuration +, 4S bond circuit,
Approximate situation; bribe j;・l? t7. IXI, ;(λ,
121-1 is the city 1/cane arrangement anst figure on the side:
(I O-1+!'f+ Ill, anti-HaCtj;+△・1
Layer 1.゛(2 is Q LIA s IH, 336J: l
) Δr7(,; rr /”l s lTh1 (
3 A 4: I n ,”
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1ζ Electric Small J111's △R (to Sra 8s/Ji l!l
li”i, :I 51,1.' n Δe (J
2J to more (Clara)-)1shii), 36 L;
l', n'' to ano\S group 1k,; (7C31 electrode, 3 ε( is 7. n l wide (1 pa (ni) Shigeru,
4 (l L, 1. n −: rΔs li,
41 kl electrode (2 and 7; 4 bodies 1. ---ri (h formation)
2. Life 1!1. : #j 3・1 or C:・Turn it to the arrow (2 points shown)・---relight or output #'l-6.

M FI et al'12. I.l.113. 11- (J i, lAS layer ζ
, :l 4.1,')-1 electric t7i 42 .~44 or j'1. ing. 45~51! ;I: l Wiring for concubine, 61- and 3 are one ink basso)-(there is
1HVi of luminescent element rII 411 r・' I-i soi
+2. +・'LC'l' I 5's source S is connected, sales 1'lI+portion! it 45, 49-(If
;l'＞'e, 1・゛Big゛I for 2 of 11,・inl
') and 1-' I about 1' l 3's source S and connection wiring lit 4 '7 are connected, l' l et al.'l' I
3 no Tsuno-1 Ichigoku 43 and sauce S limited edition, FL
: 'I' l 3's 1・l, in one and 1・゛1尤'
l' l 5 no 1/fnl) or connection wiring 48゛C
Connected41. ing. Also, bonding x 1 (11 and [P) + 20 gate electrode 42 etc.) is connected with Y + 'ri 46, pon) - r nk x 1
(+2 and F I->'I゛I 5 no 1-shi in 1)
Connect with I/concubine wiring 51, Ij'C 411, hon.
-i' □(Nkupano [[)3 and F I尤'I']
5'J-1□ rli pole 4 poles 41/g pile wiring 50
The input signal from the (A signal ν) source is added to the input signal 62 (
(Ha) The voltage at the center of gravity is applied, and the Hongdae ink is 163
4.: 11 bias electric moon is added. Therefore, the fifth]
The J circuit configuration shown in the figure is realized as an integrated circuit "ζ," and the voltage-current conversion I" lu '[' I2 turns on and off the light emission drive J\a flow of the light emitting element 1 control the light emission drive 1]iJ+ current F Ij TI 3-
The bias current of the dark value current of the light emitting element 11 can be supplied by the FI 5.

car number'@1-IE-FI for current conversion 112-1
If the circuit configuration is such that the light emitting element 11 is connected to the inner side, the electrode 37 and I
Tl, 5 cJ) i' L in 1) should not be connected to C, 111 * 14j () to surface -1- () wiring connection) hC purchase. (Kinaimono 1L), 5"ru. Also, No. 11134 shows the case of meza type, or the separation between elementary J' 4-1-) and a = soleno-type configuration and 1-ru L' T) Dekini].

Effects of the invention ↓ Yuju explained 2 noko, -1, uni, the present invention (,,!, electric 1.1 - electric c'JIC conversion 1.1 et al'I'12.I
・li:'l'220 + light emitting element f-11,2x in source
Set jijV, blue, l・+<′+゛l 2 , +−
゛+rei 1' 22-1, electric θ; control (1υ
11 l・I': T13. l・' +5 Tshi) 3 to 1
Continuation Lノ;=, second. I, I, 1st grade student 'l'ilf's human power trust ζ light emitting element! 51st movement', 2, etc., and transmit the output of the connected isotal circuit;
Sub-control nυ11 1・'L: T13゜1・Nz′l−1
1: The number is Js1jJj's 1! Bao [1” Ruin′”U1’
1) Select 'j'l-1'iij for 4), above), which is good, so it can be easily formed as ii,
) Pine Taha Irisa “Yumi (light)′Cba・、I jl;l
1.1, link 1-link etc. Ly
Lj′,! 'i'sa11.ノ9L Imitsunobu ``・;'' can be outputted.
ls has the advantage of being easy to convert into a Tril path.

[Brief explanation of the drawing]

No. 11, 1, conventional j5) (dynamic circuit, Fig. 2, 4J human power signal' output current characteristic curve diagram, Fig. 3, circuit 1y1 of an embodiment of the present invention, Fig. 4, 3 Each FI' in the figure,
Figure 5 is a curve diagram for explaining the operation of Embodiment 1 of the present invention. Figure 6 is a circuit diagram of another embodiment of the present invention. 7 and 8 are diagrams showing the characteristics of the rain current in Figure 6 (1) 1) for explaining the operation, Figure 9 is a circuit diagram of a dimensional embodiment of the present invention, and Figure 10 is the characteristic of a light emitting element. 111 explanatory diagram, Figure 11 is the circuit of Figure 10 (11\
Figure 12 is a schematic perspective view of the structure as a multilayer circuit, and Figure 12 is a schematic -1-plane view showing the electrodes and wiring. ], I1.21 is the light emitting element, 2.12.22 is 1·18T for voltage-electricity/11L conversion, 13.2:N; FI for current limiting, 25LJ ton current control + i1V ! It is a resistor for llIrlIr person applicant person stock i℃ meeting - 1 representative patent attorney Kugo Tamamushi E3 and 3 others Fig. 1 - Fig. 3 Fig. 2 D ■ DI - Fig. 4 T ■ p Fig. 9 Fig. 6 Fig. 6 Fig. 7 Fig. 8 VG l) S Fig. 9 Fig. 10

Claims (1)

[Claims] ? lil lower - current change 1 leaf, + i 了 and 7 electric field sentence) 1 ri 1 - ra〉 4 - using the source G of the field effect 1 non-so star G this light emission 7 Zheng j' is connected tp L1-7 (originated)
j' Drive, Se I, h4 in the circuit, 11;
Sato 1 Funsosta is connected,,'c Jino Kogomi-'I?' i
F and J-ro light emitting element 1WD 4!1j circuit.