Siemens Aktiengesellschaft

Robert Bleisteiner

Stefan Nowak

Helmut Lenz

A switching amplifier operable in a switched mode has a common-mode charging current which arises due to charge reversals in the conductor to ground and coupling capacitances. In order to make this charging current easily filterable, in a switching amplifier and a method for operating a switching amplifier, n successively connected cascade elements are provided n being odd and greater than equal to three, and a control unit drives comparable switch elements in the individual cascade elements so that these comparable switch elements are driven offset from cascade element-to-cascade element by 1/n times the switching period.

Switching amplifier and method for operating same

A power supply or converter has an AC-voltage source to which a number of rectifiers are connected, with at least one of the rectifiers having a switching stage by which, in a feedback mode, energy can be fed back to the AC-voltage source from a DC-voltage terminal and/or from a capacitor of the rectifier. Such an arrangement achieves an energy symmetry among a number of connected users, e.g. back-feeding output stages, with low losses and low cost in terms of circuitry.

Power supply

A DC chopper converter including four switching elements arranged in a four-arm or an H-bridge configuration between power supply terminals and on opposite sides of a load, each switching element having a free-wheeling diode connected parallel thereto, whereby at every load current direction, the two switching elements positioned diagonally opposite in the bridge are cyclically clocked such that the means value of the load current is defined by the overlap of the open times of the switching elements, while the two switching elements lying in series are clocked out of phase. Since all the switching elements are clocked, there is a steady transition during load current reversals such that the zero axis crossings of the load current need not be separately acquired for each reversal in the drive current.

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Dormitz, Germany

Robert Bleisteiner