Current-regulator circuit of an electromagnetic flowmeter

A current-regulator circuit of an electromagnetic flowmeter for generating a supply current for an excitation circuit comprising at least one excitation coil which in operation is traversed by an excitation current, said current-regulator circuit comprising:

• control electronics
• to the input end of which an excitation current signal representative of the excitation current and a reference current signal representative of a reference value for the excitation current are applied, and
• which provides at the output end a pulse-width-modulated first clock signal;
• and
• setting electronics with
• a storage choke,
• a smoothing capacitor,
• a first switch, and
• a second switch,
• the setting electronics being powered from a two-wire interface and being controlled by the first clock signal, and
• the setting electronics setting a choke current flowing through the storage choke by means of the first switch and the second switch in such a way that
• the smoothing capacitor is traversed by an alternating-current component of the choke current, and
• the excitation circuit is traversed by a direct-current component of the choke current representing the supply current.