- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄383777 > PS2603L (NEC Corp.) Optocoupler Applications PDF資料下載
參數(shù)資料
| 型號： | PS2603L |
| 廠商： | NEC Corp. |
| 英文描述： | Optocoupler Applications |
| 中文描述： | 光耦應(yīng)用 |
| 文件頁數(shù)： | 9/38頁 |
| 文件大?。?/td> | 223K |
| 代理商： | PS2603L |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁當(dāng)前第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁第33頁第34頁第35頁第36頁第37頁第38頁
8
STABILIZING OUTPUT LEVELS
When an optocoupler is used with the base pin of its phototransistor open, the collector dark current (I
CEO
) flows as a base
current. The current is amplified as a collector current and could make the output level of the phototransistor unstable. To
eliminate this unwanted base current and make the output level stable, flow the collector dark current (I
CEO
) through the base-
emitter resistor (R
BE
).
Fig 2-5 shows the I
CEO
vs. T
A
characteristics of a PS2601 optocoupler.
R
BE
=
8
I
F
= 0
V
CE
= 80V (40V for the
PS2603) 2601
Solid line: PS2601
Dotted line: PS2603
10000
R
BE
= 1M
R
BE
=100 M
1000
100
10
1
0.1
- 20
0
20
40
60
80
100
R
BE
=1M
C
C
Ambient Temperature T
A
(
°
C)
ELIMINATION OF INDUCED NOISE
Generally, machine-controlling equipment generates induced noise which may cause malfunctions. This unwanted noise in input
signals can be isolated by means of optocouplers. However, if the noise is too strong, it may be switched to the output through
the input-output capacitance C
1-2
of the optocoupler. This unwanted noise in the output can be removed in the following manner.
Insert a capacitor (preferably 100 pF) between the base and the emitter of the phototransistor of the optocoupler. This capacitor
delays response and suppresses malfunctions.
Graph 6-(a) to 6-(d) show how an external noise (surge voltage of 1000 V/
μ
s at rise time) is eliminated as the capacitance of the
base-emitter capacitor.
A fluctuation in the collector-emitter voltage caused by the on/off operation of a power switch at the output of the optocoupler
causes a base current to flow through the collector-base capacitor (C
CB
), which causes a malfunction.
In Fig. 2-7, for example, an instantaneous base current flows through the collector-base capacitor (C
CB
) of the optocoupler. The
current is multiplied by h
FE
(as a collector current) and causes an output voltage on both ends of the load resistance. It seems as
if an input signal was applied to the optocoupler. Graph 7-(a) shows the waveforms. This unwanted instantaneous induction
current can be eliminated by inserting a capacitor C
BE
between the emitter and the base of the phototransistor. Graph 7-(b)
shows the waveforms. Fig. 2-8 shows the output-voltage vs. C
BE
characteristics.
C
BE
V
o
R
L
Figure 2-6.
Figure 2-7.
PS2601 I
CEO
-T
A
Characteristics
Figure 2-5. I
CEO
vs. T
A
Characteristics
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| PS2604 | Optocoupler Applications |
| PS2604L | Optocoupler Applications |
| PS2602 | Optocoupler Applications |
| PS2602L | Optocoupler Applications |
| PS2605 | Optocoupler Applications |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| PS2604 | 制造商:California Eastern Laboratories (CEL) 功能描述:6pin DIP,Darlington Tr, DC, Coupler |
| PS2604L | 制造商:NEC 制造商全稱:NEC 功能描述:Optocoupler Applications |
| PS2605 | 制造商:California Eastern Laboratories (CEL) 功能描述:6pin DIP,Single Tr, AC, Base, Coupler |
| PS2605L | 制造商:NEC 制造商全稱:NEC 功能描述:Optocoupler Applications |
| PS2606 | 制造商:NEC 制造商全稱:NEC 功能描述:Optocoupler Applications |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。