The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 04, 1984
Filed:
Mar. 29, 1982
Gerhard Donig, Erlangen, DE;
Siemens Aktiengesellschaft, Munich, DE;
Abstract
An embodiment of the present invention provides an excitation arrangement suitable for use in producing a pulse-shaped field of substantially constant intensity. To start-up the current at the beginning of a pulse, a coil (1) is fed with a high voltage (line 3) via an ignitable and blockable power semiconductor (7). For the duration of the pulse, switch-over is then effected to the supply of a lower voltage (line 4) by means of a power transistor (31) controllable to a constant current. Free-running diodes are used to decay the current. One coil end (2) is preferably connected via an FET (7) which is controllable to a constant voltage, to the high voltage; via an FET (30), which is likewise controllable to a constant voltage, to the lower-voltage (4); and via a controllable FET (52) to a reference line (6). Corresponding FET's (50, 51, 31) are provided at the other coil end (5). The controllable FET's (51, 52) require no potential-isolated control, and moreover, the power-FET's do not require their own additional free-running diodes (mentioned above) due to their inherent diode characteristic for currents flowing in the blocking direction.