LTC3901 Linear Technology, LTC3901 Datasheet - Page 11

• Manufacturer Part Number: LTC3901
• Description: Secondary Side Synchronous Driver for Push-Pull and Full-Bridge Converters
• Manufacturer: Linear Technology

APPLICATIO S I FOR ATIO
Figure 11. Full-Bridge Converter Switching Waveforms
SYNC
MD
MA
MB
MC
ME
MF
E
F
V
COMP
A
IN
FULL-BRIDGE CONTROLLER
V
B
U
FB
T3
LTC3722-1
MB
MA
U
C
E
W
D
F
T4
Figure 10. Simplified Isolated Full-Bridge Converter
MD
ISOLATION
MC
BARRIER
3901 F11
U
T2
T1
0V
MF
ME
the
In the first period, MB turns off, E goes low (followed by
MA turning on), and the LTC3901 forces ME to turn off.
The primary side delivers power to the load through
MOSFET MF, T1 and L1.
In the second period, MA remains on, MD turns off, and
MC turns on. E goes high and the LTC3901 forces both ME
and MF to conduct. This is the free-wheeling period with
the T1 secondary output shorted.
In the third period, MA turns off, F goes low (followed by
MB turning on), and the LTC3901 forces MF to turn off.
The primary side delivers power to the load through
MOSFET ME, T1 and L2.
Like the second period, the last period is a free-wheeling
period. MB remains on, MC turns off, MD turns on, F goes
high, and the LTC3901 forces both ME and MF to conduct.
The timeout and current sense operations are the same as
in the push-pull application.
11
14
12
6
3
5
9
CSE +
ME
CSE –
CSF +
MF
CSF –
SYNC
OUT
OPTOCOUPLER
DRIVER
LTC3901
TIMER
COMP
PGND
PV
GND
V
FB
CC
CC
16
8,10
1
4,13
7
L1
L2
+
3901 F10
C
OUT
LTC3901
V
OUT
11
3901f