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參數(shù)資料
| 型號： | SC4910A |
| 廠商： | Semtech Corporation |
| 英文描述： | High Performance Secondary Side Controller with Synchronous Rectifier |
| 中文描述： | 高性能二次側(cè)同步整流控制器 |
| 文件頁數(shù)： | 10/19頁 |
| 文件大?。?/td> | 330K |
| 代理商： | SC4910A |
10
2005 Semtech Corp.
www.semtech.com
SC4910A/B
POWER MANAGEMENT
Applications Information (Cont.)
This is the minimum external slope required to avoid sub-
harmonic oscillation at low input line.
With SC4910, the external slope is very easy to
implement. Referring to Figure 2, R12 is the current sense
resistor. R10 and the internal 20K
resistor divide the
internal slope 1.0V - 2.5V down to the required
compensation slope.
)
f
N
L
R
V
Se
(
)
0
5
(
20
)
f
N
L
R
V
Se
(
10
R
S
S
M
S
IN
S
S
M
S
IN
=
where:
LM - Power transformer magnetizing inductance
fS = Switching frequency
In the example,
=
100
100
=
240
)
3
E
250
6
E
450
21
36
085
.
(
)
0
5
(
20
)
3
E
250
6
E
450
21
36
085
.
(
10
R
R10
C36
R22
C22
C13
U5
SC4910
18
17
11
16
6
4
10
7
20
19
3
1
15
2
5
1
8
9
1
1
FB
COMP
OUTB
ISHARE
PHASE
CS
OUTA
A
RT1
RT2
SS
-SENSE
DELAY
SYNC/EN
VREF
A
P
P
P
P
R21
R12
R25
Figure 2
Closed-Loop Compensation
The simplified control-to-output transfer function for the
forward converter with current mode control, for small
value of external slope ( Se
≤
Sn, Sn is on-time slope of
sensed current waveform) is given by:
p
z
vgo
vg
s
1
s
1
G
G
ω
+
ω
+
=
where
closed
loop
current
with
stage
power
of
gain
DC
R
I
V
nN
G
S
O
O
S
vgo
=
closed
loop
current
with
stage
power
of
pole
ant
min
Do
RC
1
P
=
ω
stage
power
of
zero
ESR
C
R
1
ESR
Z
=
ω
where
R - Load resistance
C - Output capacitance
RESR - Output capacitors ESR
For the given example above, at low line and R = 0.165
,
C = 2 x 680uF = 1360uF, R
ESR
= 17m
, therefore:
dB
13
71
.
21
20
3
100
6
G
vgo
=
=
=
Hz
6887
s
/
rad
43253
6
E
1360
X
3
E
17
1
Hz
710
s
/
rad
4456
6
E
1360
X
165
.
1
Z
P
=
=
=
ω
=
=
=
ω
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| SC4910AITSTRT | High Performance Secondary Side Controller with Synchronous Rectifier |
| SC4910B | High Performance Secondary Side Controller with Synchronous Rectifier |
| SC4910BITSTRT | High Performance Secondary Side Controller with Synchronous Rectifier |
| SC4911 | Bias/Primary Side PWM Controller with Ultra Low Start-up Current |
| SC4911IMSTR | Bias/Primary Side PWM Controller with Ultra Low Start-up Current |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| SC4910AITSTR | 制造商:Semtech Corporation 功能描述:IC, PWM CONTROLLER, 12V, 20-TSSOP, Output Voltage:10V, Output Current:100mA, Sup |
| SC4910AITSTRT | 制造商:Semtech Corporation 功能描述:SC Series 18 V SMT High Performance Secondary Side Controller - TSSOP-20 |
| SC4910B | 制造商:SEMTECH 制造商全稱:Semtech Corporation 功能描述:High Performance Secondary Side Controller with Synchronous Rectifier |
| SC4910BITSTRT | 制造商:Semtech Corporation 功能描述:Secondary Side PWM Cntrlr SYNC POST REGUL 450KHz to 550KHz 20-Pin TSSOP T/R 制造商:Semtech Corporation 功能描述:ADV SCND SIDE CNTRL W/SYNCH RE |
| SC4911 | 制造商:SEMTECH 制造商全稱:Semtech Corporation 功能描述:Bias/Primary Side PWM Controller with Ultra Low Start-up Current |
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