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参数资料
| 型号： | SG2845DM |
| 厂商： | MICROSEMI CORP-ANALOG MIXED SIGNAL GROUP |
| 元件分类： | 稳压器 |
| 英文描述： | CURRENT MODE PWM CONTROLLER |
| 中文描述： | 1 A SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDSO8 |
| 封装： | ROHS COMPLIANT, PLASTIC, SOIC-8 |
| 文件页数： | 11/12页 |
| 文件大小： | 216K |
| 代理商： | SG2845DM |
C
U R R E N T
-M
O D E
PWM C
O N T R O L L E R
SG1844/SG1845 Series
P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7
11
Copyright 2000
Rev. 1.4 4/00
P
R O D U C T I O N
D
A T A
S
H E E T
T Y P I C A L A P P L I C AT I O N C I R C U I T S
Pin numbers referenced are for 8-pin package and pin numbers in parenthesis are for 14-pin package.
FIGURE 17.
— ISOLATED MOSFET DRIVE
FIGURE 16.
— BIPOLAR TRANSISTOR DRIVE
Current transformers can be used where isolation is required
between PWM and Primary ground. A drive transformer is then
necessary to interface the PWM output with the MOSFET.
The 1844/45 output stage can provide negative base current to
remove base charge of power transistor (Q
) for faster turn off. This
is accomplished by adding a capacitor (C
) in parallel with a resistor
(R
1
). The resistor (R
1
) is to limit the base current during turn on.
FIGURE 14.
— CURRENT SENSE SPIKE SUPPRESSION
FIGURE 15.
— MOSFET PARASITIC OSCILLATIONS
A resistor (R
) in series with the MOSFET gate reduce overshoot and
ringing caused by the MOSFET input capacitance and any inductance
in series with the gate drive. (Note: It is very important to have a
low inductance ground path to insure correct operation of the I.C.
This can be done by making the ground paths as short and as wide
as possible.)
The RC low-pass filter will eliminate the leading edge current spike
caused by parasitics of Power MOSFET.
V
CC
V
IN
7 (12)
7 (11)
6 (10)
5 (8)
3 (5)
R
C
R
S
Q1
I
PK
I
PK(MAX)
=1.0V
R
S
SG1844/45
V
CC
V
IN
7 (12)
7 (11)
6 (10)
5 (8)
R
S
Q1
SG1844/45
3 (5)
R
1
SG1844/45
3 (5)
5 (8)
6 (10)
7 (11)
R
S
Q1
V
C1
C
1
R
1
R
2
V
IN
V
C
I
B
+
V
C
R
2
V
R
1
||R
2
_
V
CC
V
IN
7 (12)
7 (11)
6 (10)
5 (8)
3 (5)
SG1844/45
Isolation
Boundary
C
R
R
S
N
S
N
P
Q1
V
GS
Waveforms
+
_
50% DC
+
_
25% DC
I
PK
=
V (PIN 1) - 1.4
3R
S
N
P
N
S
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SG2845J | 制造商:Microsemi Corporation 功能描述:SG2845J - Bulk |
| SG2845M | 功能描述:IC PWM CURRENT MODE 8DIP RoHS:是 类别:集成电路 (IC) >> PMIC - AC-DC 转换器，离线开关 系列:- 标准包装:3,000 系列:- 输出隔离:隔离 频率范围:61kHz ~ 71kHz 输入电压:9.4 V ~ 28 V 输出电压:12V 功率（瓦特）:- 工作温度:-40°C ~ 125°C 封装/外壳:SC-74，SOT-457 供应商设备封装:6-TSOP 包装:带卷 (TR) |
| SG2845N | 制造商:Microsemi Corporation 功能描述:SG2845N - Bulk |
| SG2845Y | 制造商:Microsemi Corporation 功能描述:SG2845Y - Bulk |
| SG2846 | 制造商:MICROSEMI 制造商全称:Microsemi Corporation 功能描述:CURRENT MODE PWM CONTROLLER |
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