Siemens Aktiengesellschaft

Walter Burger

Helmut Lenz

Klaus Porzelt

The embodiments relate to a method and to a device having at least one source, (in particular, having a source for a magnetic resonance imaging system), wherein the device is designed to select a supply voltage of the source on the basis of a load voltage of a load supplied with current and/or voltage from the source.

Adaptive pin diode drive circuit with minimized power loss

A device for monitoring chip temperature of a switch output stage having a switch element (100, 106) that has a first circuit (10) for generating a signal (pv.sub.on) corresponding to the dissipated power of the switch element (100-106) during an on state. The device has a second circuit (20) for generating a signal (pv.sub.1, pv.sub.2 ; pv'.sub.1) corresponding to the dissipated power of the switch element (100-106) during a turn-on and/or turn-off event. The device further has a summer (40) that sums the signals (pv.sub.on, pv.sub.1, pv.sub.2 ; pv.sub.on pv'.sub.1) of the first and second circuits (10, 20) in weighted fashion and outputs a sum signal (pv.sub.sum) corresponding to the dissipated power of the switch element (100-106). The device also has an integrator (60) that responds to the sum signal (pv.sub.sum) and outputs an output signal (th) corresponding to the chip temperature of the switch element (100-106). Such a device is suitable for temperature monitoring in realtime at switch output stages having variable switching frequency.

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Nürnberg, Germany

Walter Burger