LM25115A,pdf datasheet (Second

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
Synchronous Buck 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.