1FEATURES

2? Power-up/Power-down Tracking

? Self-synchronization to Main Channel Output

? Leading Edge Pulse Width Modulation

? Valley Current Mode Control

? Standalone DC/DC Synchronous Buck Mode

? 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 package

DESCRIPTION

The LM25115A controller contains all of the features

necessary to produce multiple tracking outputs using

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. LM25115A can be also used as a

standalone DC/DC synchronous buck controller

(Refer to Standalone DC/DC Synchronous Buck

Mode section). 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 LM25115A 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.