Endress+hauser Gmbh+co.

Endress + Hauser Gmbh + Co. Kg

Jurgen Meier

Armin Wernet

Bernd Strutt

Gustav Wetzel

Christoph Schleith

Hans-Jorg Florenz

A circuit arrangement for the protection of at least one component of a two wire electrical current loop, which is connected in series with a burden to an AC/DC electrical current source. The two wire electrical current loop has a rectifier a clock signal producer and a switch. The rectifier forms a DC circuit, wherein the component is connected in the DC circuit and wherein the clock signal producer outputs a clock signal to the switch for clocking the DC circuit. The circuit arrangement has a diode, wherein the conduction direction of the diode points from the anode of the diode to the cathode of the diode. The cathode of the diode is connected to the DC circuit, and the anode of the diode is supplied with a periodic or constant voltage from a first voltage source, and the voltage is at least periodically greater than a predetermined threshold value.

Circuit arrangement for the protection of at least one component of a two wire electrical current loop

A voltage regulator circuit for generating a regulated output DC voltage from a non-regulated DC or AC voltage, comprises an input rectifier circuit for rectifying the non-regulated AC voltage and a series regulator, containing a gate-controllable transistor, which regulates the output voltage supplied to it by the rectifier to a first voltage value. The transistor of the series regulator is a field-effect transistor (20) which in the ON condition charges a charging capacitor (46), the charging voltage of which forms the regulated output voltage. Connected to the gate terminal (21) of the field-effect transistor is a first threshold circuit (26, 28, 30, 32) receiving the non-regulated DC voltage which applies to this gate terminal (21) a voltage turning OFF the field-effect transistor (20) as soon as the non-regulated DC voltage exceeds a predetermined threshold value. Furthermore, connected to the gate terminal (21) of the field-effect transistor (20) is a second threshold circuit (36, 38, 40, 42) receiving the regulated output DC voltage which applies to this gate terminal (21) a voltage turning OFF the field-effect transistor (20) as soon as the regulated output DC voltage exceeds a predetermined design value.

Voltage regulator circuit

A transmitting station is connected to a receiving station by a two-wire line via which the supply current required for operating the transmitting station is transferred from the receiving station to the transmitting station. The transmitting station comprises a supply circuit including a voltage regulator for maintaining the operating voltage of the transmitting station constant and an energy store for compensating current and/or voltage fluctuations. Via the two-wire line a signal current, variable between two limit values, is further transferred from the transmitting station to the receiving station. This signal current consists of the supply current for the transmitting station and a supplementary current determined by the transmitting station. For transfer of the communication information between the transmitting station and the receiving station, a symmetrical communication current is superimposed on the signal current. The communication current is superimposed on the current flowing from the two-wire line into the supply circuit of the transmitting station.

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Maulburg, Germany

Jurgen Meier