- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄364679 > AN5001 Use of the VTO. rT on-state characteristic model PDF資料下載
參數(shù)資料
| 型號(hào)： | AN5001 |
| 英文描述： | Use of the VTO. rT on-state characteristic model |
| 中文描述： | 使用仇。反T的狀態(tài)特征模型 |
| 文件頁(yè)數(shù)： | 1/5頁(yè) |
| 文件大小： | 83K |
| 代理商： | AN5001 |
1/5
AN5001 Application Note
www.dynexsemi.com
The use of the V
, r
on-state characteristic model and a
more accurate alternative.
The inclusion of the theoretical terms V
TO
and r
T
in power
semiconductor data sheets allows a simple means of calculating
power loss, but this can lead to many incorrect assumptions.
The terms in question are the two coefficients of a simple straight
line model of the device on-state characteristic curve. To
calculate the power the following formula is used:
P = V
T0
I
T(AV)
+ r
T
k
2
I
T(AV)
where k is the current waveform form factor, eg 1.57 for half
sine wave.
2
[1]
The use of V
TO
and r
T
to approximate to the forward volt drop
curve of a power semiconductor originates from pre-computer
days when engineers used slide rules, calculators and, later
on, simple computers for their calculations. The use of modern
computers means that better approximations to the characteristic
can easily be used. The most popular of these is the model
proposed by General Electric:
V
TM
= A + B*lnI + C*I + D*sqrt(I)
[2]
where A, B, C and D are constants with values specific to the
device in question.
The use of this model is described below.
V
T0
, r
T
DEFINITIONS
Although the straight line model is basically simple, variations in
definition can lead to significant differences in calculated powers.
Different manufacturers of power semiconductors have defined
V
T0
and r
T
in different ways. Here are 4 variations:
1) As fig. 1, where the line is the tangent to the V
TM
vs I
T
curve
at the average current.
2) As fig. 2, where a chord is drawn through I
T(AV)
and 3xI
T(AV)
.
This variation is the one used by Dynex for the calculation of
data sheet power losses and current ratings. The definition
is commonly used for thyristors. For rectifier diodes a chord
through 3xI
T(AV)
and 5xI
T(AV)
sometimes gives a better result.
3) A variation of 2 which uses two straight lines instead of one
to approximate to the true curve. In this version the lines
I
T
I
T(AV)
V
T
V
TO
r
T
I
T
I
T(AV)
V
TM
V
TO
r
T
3x I
T(AV)
AN5001
Use Of The V
TO
, r
T
On-state Characteristic Model
Application Note
AN5001-7.0 February 2004
Replaces February 2003 version, AN5001-6.0
Fig.1
Fig.2
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| AN5111 | TV Sound and Video Receiver Circuit |
| AN5112 | Analog IC |
| AN5120N | TV Video Receiver Circuit |
| AN5135NK | RF inductor, ceramic core, 5% tol, SMT, RoHS |
| AN5136K | TV Sound and Video Receiver Circuit |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| AN-5001 | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:LVX Low Voltage Dual Supply CMOS Translating Transceivers |
| AN500-10-12 | 制造商:AN# - MILITARY 功能描述: |
| AN-5002 | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:GTLP: Single vs. Multiple Output Switching Technical Discussion |
| AN500-4-3 | 制造商:SOCKET SCREWS 功能描述: |
| AN500-4-6 | 制造商:AN# - MILITARY 功能描述: |
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。