principle of operation of hybrid voltage regulators?

Answer 1

I hope you really mean a hybrid voltage regulator, and not a voltage regulator for a hybrid car.....?!
If so, go to http://www.datasheet4u.com/html/S/T/R/STR-D1005T_Sankenelectric.pdf.html and doenload the PDF data sheet.
A hybrid is the in-between manufacturing technology between a circuitry made out of conventional electronic components on one hand, and an integrated circuit on the other.
Also known as thickfilm technology, it is relatively small in size, but cheaper to produce than an IC, especially in smaller quantities.
The circuit function could be anything; in this case it's a voltage regulator.