Patent ID: 8036007

Claim:
A bus connection ( 1 ) for connecting a field device ( 2 ) to a field bus ( 3 ) whereby the bus connection ( 1 ) has a circuit ( 5 ) for sending and receiving databus signals (RxD, TxD, TRS) and for generating at least one regulated operating voltage (U A1 ), and the regulated operating voltage (U A1 ) generated from a bus voltage (U Bus ) supplying the field bus ( 3 ), comprising: a controllable resistor (T 1 ) configured to generate an additional operating voltage (U A2 ); circuitry (OP, R 1 , R 2 , R 3 , R 5 , Z 1 , Z 2 ) configured to control the controllable resistor (T 1 ) as a function of the bus voltage (U Bus ) such that: the input voltage (U B ) of the circuit ( 5 ) is regulated at its minimum required power supply voltage, circuit ( 5 ) and the controllable resistor (T 1 ) are connected to the bus voltage (U Bus ) in series, and the sum of the regulated operating voltage (U A1 ) and the additional operating voltage (U A2 ) is supplied to the field device ( 2 ) as the power supply voltage (U A ).