Driver circuit for a measuring transducer as well as measuring system formed therewith

A measuring system, comprising:

• a transmitter electronics including a two-conductor connection circuit for connecting the transmitter electronics to a measuring and supply unit remote therefrom, a driver circuit, and a measuring and operating circuit;
• and,
• electrically connected both with said driver circuit of the transmitter electronics and with said measuring and operating circuit of the transmitter electronics, a physical-to-electrical measuring transducer for producing at least one measurement signal dependent on or corresponding to a physical measured variable of a fluid conveyed in a pipeline;
• said physical measured variable being selected from:
• mass flow rate, density and viscosity and said measuring transducer including at least measuring tube adapted to execute mechanical oscillations and said measuring transducer including an inductive actuator adapted to execute said mechanical oscillations;
• said two-conductor connection circuit being adapted to draw electrical power required for operation of said driver circuit from said measuring and supply unit via a (4 mA to 20 mA) current loop;
• and said driver circuit including:
• a voltage controller for delivering to a controller output a first direct voltage, a direct voltage converter for converting the first direct voltage, applied on a primary side, into a second direct voltage available on a secondary side, and an end stage operated by means of the second direct voltage for converting a control signal lying on a signal input into a driver signal for the measuring transducer;
• wherein:
• the second direct voltage exhibits a magnitude, which is always smaller than a magnitude of the first direct voltage, and the driver signal exhibits an electrical power, which is higher than an electrical power of the control signal.