Current generator and method for generating current pulses

A current generator for supplying regulated-intensity current pulses to terminals of a load, comprising:

• a plurality of secondary stages, each secondary stage comprising:
• a DC voltage source isolated from DC voltage sources of other secondary stages;
• a switching circuit comprising four switches disposed as two half-bridges, each formed from two switches mounted in series between terminals of the voltage source;
• wherein the switching circuits are interconnected to form a chain, a midpoint of a half-bridge of each secondary stage being connected to a midpoint of a half-bridge of a secondary stage downstream in the chain, each of two secondary stages at ends of the chain comprising the midpoint of a half-bridge configured to connect to a terminal of the load;
• wherein one of said plurality of secondary stages is designated as a regulator stage, comprises, between the DC voltage source and the switching circuit, a regulator circuit comprising a smoothing inductor, a switch disposed between a terminal of the smoothing inductor and the DC voltage source, and a circuit connecting the terminal of the smoothing inductor to the switching circuit when the switch of the regulator circuit is in an OFF state;
• a control circuit, during a generation of a current pulse, configured to:
• control the switches of the switching circuits of the secondary stages to dispose in series the DC voltage sources of a group of secondary stages, including the regulator stage, selected according to a current intensity reference value;
• isolate the DC voltage sources of unselected secondary stages;
• and
• control successive switching of the switch of the regulator circuit to regulate an intensity of a current flowing in the load around the current intensity reference value.

A method for generating current pulses on terminals of a load, comprising the steps of:

• generating a current pulse by a current generator comprising a plurality of secondary stages, each secondary stage comprising:
• a DC voltage source isolated from DC voltage sources of other secondary stages;
• a switching circuit comprising four switches disposed as two half-bridges, each formed from two switches mounted in series between terminals of the voltage source;
• wherein the switching circuits are interconnected to form a chain, a midpoint of a half-bridge of each secondary stage being connected to a midpoint of a half-bridge of a secondary stage downstream in the chain, each of two secondary stages at ends of the chain comprising the midpoint of a half-bridge configured to connect to a terminal of the load;
• and
• wherein one of said plurality of secondary stages is designated as a regulator stage, comprises, between the DC voltage source and the switching circuit, a regulator circuit comprising a smoothing inductor, a switch disposed between a terminal of the smoothing inductor and the DC voltage source, and a circuit connecting the terminal of the smoothing inductor to the switching circuit when the switch of the regulator circuit is in an OFF state;
• controlling the generation of the current pulse by the current generator by:
• selecting a group of secondary stages designated as active stages in accordance with a current intensity reference value, which includes the regulator stage;
• controlling the switches of the switching circuits of the secondary stages to dispose in series the DC voltage sources of the active stages and to isolate the DC voltage sources of unselected secondary stages;
• and
• controlling successive switching of the switch of the regulator circuit to regulate an intensity of a current flowing in the load around the current intensity reference value.