Switching power supply for forming e.g. DC voltage step-up converter, has NMOS detection transistor comprising source connected to ground, drain connected to gate of PMOS transistor and gate connected to terminal of capacitor

摘要

The supply has a capacitor (C1) comprising a terminal connected to a terminal of an inductor (L). A resistor (R1) comprises a terminal connected to another terminal of the capacitor. A NMOS detection transistor (N2) has a source that is connected to the ground and a drain connected to a gate of a PMOS transistor (P1). The transistor (N2) has a gate connected to the latter terminal of the capacitor.