Siemens Aktiengesellschaft

Holger Heil

Josef-Matthias Gantioler

Jenoe Tihanyi

Rainald Sander

Norbert Krischke

An integrated comparator includes an inverter with a first depletion FET and a first enhancement FET, and a series circuit with a second depletion FET and a second enhancement FET. The second depletion and enhancement FETs are connected in series between a first supply voltage terminal and a first input terminal. A node between the second enhancement and depletion FETs is connected to the gate terminal of the first enhancement FET. The transfer characteristic curve of the second enhancement FET is steeper than the transfer characteristic curve of the first enhancement FET. All of the MOSFETs are of the same channel type. The voltage to be compared is connected between the second enhancement FET and ground. The switching point is determined by the transfer characteristics of the two enhancement FETs.

Integrated comparator circuit with four MOSFETS of defined transfer

A temperature sensor contains a bipolar transistor adjacent a cell array of a power MOSFET or IGBT. In order to detect temperature independently of a voltage drop across the power semiconductor component, a zone of the same conduction type is disposed between the cell array and a base zone. That zone is connected to a fixed bias voltage.

Field effect-controllable power semiconductor component with temperature

A comparator circuit includes a series circuit having a first MOSFET and a second MOSFET. An inverter has a third MOSFET and a fourth MOSFET. A node between the first and second MOSFETs is connected to a gate terminal of the fourth MOSFET. An input voltage is applied between ground and the second MOSFET. A series circuit of a fifth MOSFET and a Zener diode polarized in the blocking direction is connected parallel to the fourth MOSFET. A response threshold of the comparator circuit is defined by adjusting a resistance of the Zener diode occurring in the reverse direction. The resistance is adjusted through the use of a voltage pulse that can be applied to a terminal connected to a cathode of the Zener diode.

Integratable comparator circuit with adjustable response threshold

The temperature of a power semiconductor component is monitored by feeding the block current of a bipolar transistor which is in thermal contact with the component to an amplifying current mirror. The output signal of the current mirror is compared with a reference current. If the mirrored current is greater than the reference current, then the system produces a corresponding output. Temperatures of the power semiconductor component below 140.degree. C. can be reliably detected.

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Holger Heil