lm5045sqx National Semiconductor Corporation, lm5045sqx Datasheet - Page 5

• Manufacturer Part Number: lm5045sqx
• Description: Full-bridge Pwm Controller With Integrated Mosfet Drivers
• Manufacturer: National Semiconductor Corporation

TSSOP
23, 20
25, 18
26, 17
27, 16
Pin
19
21
22
24
28
LLP Pin
19, 16
21, 14
22, 13
23, 12
15
17
18
20
24
LO1, LO2 Low Side Output Driver
BST1,2
PGND
HO1,2
Name
HS1,2
VCC
SR2
SR1
VIN
Synchronous Rectifier Driver
Output of Start-Up Regulator
Power Ground
Synchronous Rectifier Driver
Gate Drive Bootstrap
High Side Output Driver
Switch Node
Input Power Source
Description
5
Control output for synchronous rectifier gate. Capable of peak
sourcing 100mA and sinking 400mA.
The output voltage of the start-up regulator is initially regulated to
9.5V. Once the secondary side soft-start (SSSR pin) reaches 1V,
the VCC output is reduced to 7.7V. If an auxiliary winding raises
the voltage on this pin above the regulation set-point, the internal
start-up regulator will shutdown, thus reducing the IC power
dissipation.
Connect directly to Analog Ground
Alternating output of the PWM gate driver. Capable of 1.5A peak
source and 2A peak sink current.
Control output for synchronous rectifier gate. Capable of peak
sourcing 100mA and sinking 400mA.
Bootstrap capacitors connected between BST1,2 and SW1,2
provide bias supply for the high side HO1,2 gate drivers. External
diodes are required between VCC and BST1,2 to charge the
bootstrap capacitors when SW1,2 are low.
High side PWM outputs capable of driving the upper MOSFET of
the bridge with 1.5A peak source and 2A peak sink current.
Common connection of the high side FET source, low side FET
drain and transformer primary winding.
Input to the Start-up Regulator. Operating input range is 14V to
100V. For power sources outside of this range, the LM5045 can
be biased directly at VCC by an external regulator.
Application Information
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