Hi,
I try to understand how the Chip of Lineare technologie work .
I especially want to understand how this chip can transfrom tension as low as 20mV.
Thanks
Datasheet in Attachement
The 100:1 transformer on the input helps a lot. The block diagram on page 8 is where to look. C2 forms a resonant circuit with the transformer. The MOSFET connected to SW works as an amplifier, so that will oscillate at the resonant frequency.
C1 and the rectifiers tap off some of that power once it starts to oscillate.