LM5115
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SNVS343E –MARCH 2005–REVISED MARCH 2013
LM5115 Secondary Side Post Regulator / Synchronous Buck Controller
Check for Samples: LM5115
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FEATURES
DESCRIPTION
The LM5115 is
a versatile switching regulator
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Self-Synchronization to Main Channel Output
Standalone DC/DC Synchronous Buck Mode
Leading Edge Pulse Width Modulation
controller. It has two main application configurations.
The first is utilizing the Secondary Side Post
Regulation (SSPR) technique to implement multiple
output power converters. In the second configuration,
it can be used as a standalone synchronous buck
Voltage-Mode Control with Current Injection
and Input Line Feed-Forward
controller
(Please
see
Standalone
DC/DC
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Operates from AC or DC Input up to 75V
Wide 4.5V to 30V Bias Supply Range
Wide 0.75V to 13.5V Output Range.
Top and Bottom Gate Drivers Sink 2.5A Peak
Adaptive Gate Driver Dead-Time Control
Wide Bandwidth Error Amplifier (4MHz)
Programmable Soft-Start
Synchronous Buck Mode for more details). The
SSPR technique develops a highly efficient and well
regulated auxiliary output from the secondary side
switching waveform of an isolated power converter.
Regulation of the auxiliary output voltage is achieved
by leading edge pulse width modulation (PWM) of the
main channel duty cycle. Leading edge modulation is
compatible with either current mode or voltage mode
control of the main output. The LM5115 drives
external high side and low side NMOS power
switches configured as a synchronous buck regulator.
Thermal Shutdown Protection
TSSOP-16 or Thermally Enhanced WSON-16
Packages
A
current sense amplifier provides overload
protection and operates over a wide common mode
input range. Additional features include a low dropout
(LDO) bias regulator, error amplifier, precision
reference, adaptive dead time control of the gate
signals and thermal shutdown.
Typical Application Circuit
Phase Signal
Main
Output
3.3V
FEEDBACK
INPUT
Main Converter
PWM Controller
Sync
HB
V
CC
+12V
LM5115HO
R
S
Auxiliary
Output
2.0V
V
BIAS
HS
LO
RAMP
SS
CO
COMP
FB
CS
V
OUT
PGND AGND
Figure 1. Simplified Multiple Output Power Converter Utilizing SSPR Technique
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PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
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