High voltage step down DC converter

摘要

A DC converter for stepping down DC voltage having two input terminals (E1, E2) to be connected to an input DC voltage source with a high voltage level; two output terminals (A1, A2) for taking a regulated low output DC voltage; a coil (TS) having a center tap (MA) and connected at one end (TA1) with a first one (E1) of the input terminals via an electronic switch device (MOS) and at the other end (TA2) with the second input terminal (E2) via a first capacitor (C1); the charging voltage of the first capacitor (C1) forming the output DC voltage; a second capacitor (C6) connected at one end with a node located between switching device (MOS) and coil (TS) and at the other end with the center tap (MA) via a first diode (D2); a control device (EV, PWM for comparing the charging voltage of the second capacitor (C6) with a reference voltage (REF) and rendering the switch device (MOS) conductive and non-conductive with a pulse-frequency modulated and/or pulse-width modulated switching pulse sequence depending on the result of comparison; and a second diode (D1) connected between the center tap (MA) and the second input terminal (E2); the two diodes (D1, D2) being poled to conduct current toward the second capacitor (C6) or away from the second input terminal (E2) with respect to the potential occurring on the center tap (MA) when the switch device (MOS) is nonconductive.