Secondary Side Post Regulator Controller - National Semiconductor
Description
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LM25115 Secondary Side Post Regulator Controller
November 2005
LM25115 Secondary Side Post Regulator Controller
General Description
The LM25115 controller contains all of the features necessary to implement multiple output power converters utilizing the Secondary Side Post Regulation (SSPR) technique.
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 LM25115 drives external high side and low side NMOS power switches configured as a synchronous buck regulator.
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.
Features
n n n n n n n n n n n n n Self-synchronization to main channel output Free-run mode for buck regulation of DC input Leading edge pulse width modulation Voltage-mode control with current injection and input line feed-forward Operates from AC or DC input up to 42V 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 Thermal shutdown protection TSSOP-16 or thermally enhanced LLP-16 packages
Typical Application Circuit
20172601
FIGURE 1.
Simplified Multiple Output Power Converter Utilizing SSPR Technique
© 2005 National Semiconductor Corporation
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LM25115
Connection Diagram
20172602
16-Lead TSSOP, LLP See NS Package Numbers MTC16 and SDA16A
Ordering Information
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