LT4430HS6 LINER [Linear Technology], LT4430HS6 Datasheet - Page 13

• Manufacturer Part Number: LT4430HS6
• Description: Secondary-Side Opto-Coupler Driver Ground-Referenced Opto-Coupler Drive
• Manufacturer: LINER [Linear Technology]

APPLICATIONS INFORMATION
Generate a bias supply for a forward converter using similar
techniques to that of the fl yback converter. Figure 3a to 3c
detail the three common bias circuits for the synchronous
single-switch forward converter. In the fl yback converter
of Figure 1d, the bias supply is proportional to V
Figure 3b. Single-Switch Synchronous Forward Converter
with Tapped Secondary Bias Generator
V
IN
N = N1 + N2
• •
1:N
T1
•
•
N2
N1
Q1
FG
Q2
Figure 3a. Typical Single-Switch Synchronous Forward
Converter with Bias Generator
D1
V
CG
*OPTIONAL SEE TEXT
L1
IN
R1*
•
1:N
T1
C1
C
•
OUT
LT4430
V
Q1
V
BIAS
OUT
4430 F03b
IN
and
FG
Q2
V
decouples the bias supply from V
bias supply equals (V
supply equals (V
supply equals (V
OUT
D1
Figure 3c. Single-Switch Synchronous Forward Converter
with Preregulator Bias Generator
. However, in the forward converter, L1’s presence
CG
R1*
*OPTIONAL SEE TEXT
L1
V
IN
•
1:N
T1
C1
C
Z1
OUT
LT4430
V
V
IN
BIAS
•
OUT
4430 F03a
Q1
– V
• N1/N – V
IN
D1
F
).
• N – V
FG
R1*
C1
Q2
F
F
). In Figure 3c, the bias
). In Figure 3b, the bias
OUT
R2
CG
Z1
. In Figure 3a, the
R3*
L1
*OPTIONAL SEE TEXT
LT4430
QBS
C2
C
OUT
LT4430
V
V
BIAS
OUT
4430 F03c
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4430fb