Switching power supply unit

Abstract

A switching power supply having at least one switch (S) controlled by a control circuit (AST), by means of which an input direct voltage (UV) is switched, whereby a thermal model (THM) is implemented in a control (STE), by means of which the temperature of at least one component (S; D3, D4, UET) can be calculated or estimated, and at least one current value that is load-dependent is made available as an electrical quantity to the thermal model, the control (STE) is directed at outputting at least one limiting signal (abs, ala) when a limiting value or a function of multiple limiting values depending on calculated or estimated temperature values is reached, which is usable in the sense of an action to reduce temperature, and which produces at least one limiting signal (abs) to the control circuit in the sense of a temperature reduction and thus a power reduction.

Dependencies are inferred from the claim text.