Transformer device

• US 5,579,202 A
• Filed: 01/24/1995
• Issued: 11/26/1996
• Est. Priority Date: 02/07/1994
• Status: Expired due to Term

• Current Assignee: Labyrint Marketing As
• Original Assignee: Labyrint Development AS (Scanfil Oyj)
• Inventors: Horsrud, Johan, Tolfsen, Ulf, Syvertsen, Nils S.
• Primary Examiner(s): FLEMING, FRITZ M
• Application Number:
  US08/377,437
• Time in Patent Office: 672 Days
• Field of Search: 361/232, 361/235, 361/270, 361/264, 327/304, 336/84 C, 336/84 R, 336/180-182, 363/24, 363/134, 323/911, 307/108
• US Class Current: 361/232
• CPC Class Codes: H01F 19/08 Transformers having magnetic bias, e.g. for handling pulses
• CPC Class Codes: H01F 30/08 without magnetic core

Abstract

An air-core transformer device for supplying a high-frequency, pulsating DC voltage on the secondary side of the transformer. The primary side of the transformer has two windings which are bifilar-wound having a mutual phase relationship of 180°, where the end of the first winding is connected in series with the beginning of the second winding at a common junction point. The voltage supply on the primary side is controlled by a time-set or time-variable power control signal at the beginning of the first winding and at the end of the second winding. A DC voltage is supplied to the common junction point. Two oscillatory circuits are formed on the primary side by a frequency control signal supplied over a field effect transistor, and are maintained by two capacitors C1 and C2, C1 being connected in parallel with the first winding and C2 being connected in parallel with the second primary winding. A first insulating layer is placed on the primary side, and around the first insulating layer there is provided an electrostatic screen which can be connected to an earth connection. A second insulating layer is positioned around the electrostatic screen. The secondary side of the transformer consists of a multi-layered secondary coil which is wound around the second insulating layer, each layer of the secondary coil being enveloped by an insulating material.

Claims

1. A transformer device, said transformer device having a primary side and a secondary side and being capable of supplying a high-frequency, pulsating DC voltage on said secondary side, said transformer device being an air core type having no core of ferromagnetic material, said transformer device comprising:

a first winding and a second winding, said windings being bifilar-wound in a reciprocal phase relationship of 180°

, said first winding and said second winding each having a beginning portion and an end portion,

a coupling of said first and second windings, said coupling being in series and including a common junction point of said end portion of said first winding and said beginning portion of said second winding,

a voltage supply on said primary side, said voltage supply being controlled by a time-set or time-variable power control signal at said beginning portion of said first winding and at said end portion of said second winding, said voltage supply providing a DC voltage to said common junction point;

two capacitors positioned on said primary side, one of said capacitors being coupled in parallel to said first winding and the other of said capacitors being coupled in parallel to said second winding so as to form two oscillatory circuits;

a first insulating layer positioned around said primary side;

an electrostatic screen positioned around said first insulating layer, said electrostatic screen being capable of being connected to a ground connection;

a second insulating layer positioned around said electrostatic screen;

a multi-layered secondary coil on said secondary side, said secondary coil comprising layers wound around said second insulating layer, each wound layer of said secondary coil being enveloped by an insulating material; and

wherein said pulsating DC voltage on said secondary side has a frequency which is twice the frequency of said power control signal.

2. A transformer device as disclosed in claim 1, wherein said secondary coil has terminals connected to treatment electrodes capable of being used on a patient, said transformer device further comprising a capacitor connected in series between one of said terminals and one of said electrodes, which, together with said patient positioned between said electrodes, forms a secondary side oscillating circuit.

3. A transformer device as disclosed in claim 2, wherein said wound layers of said secondary coil are arranged as adjacent, intercrossing layers.

4. A transformer device as disclosed in claim 3, wherein said secondary coil comprises eight of said wound layers, and each of said wound layers comprises 36 turns.

5. A transformer device as disclosed in claim 1, wherein said wound layers of said secondary coil are arranged as adjacent, intercrossing layers.

6. A transformer device as disclosed in claim 5, wherein said secondary coil comprises eight of said wound layers, and each of said wound layers comprises 36 turns.

7. A transformer device as disclosed in claim 1, further comprising noise suppressing ferrite cores, a first conductor leading from said first winding on said primary side, a second conductor leading from said second winding on said primary side, and a third conductor leading from said common junction point, each of said conductors extending through at least one of said noise suppressing ferrite cores.

8. A transformer device as disclosed in claim 1, wherein said frequency of said pulsating DC voltage on said secondary side is in the range of 500 kHz-4 MHz.

9. A transformer device as disclosed in claim 1, wherein said pulsating DC voltage on said secondary side is in the range of 0-2600 V.

10. A transformer device as disclosed in claim 1, wherein said frequency of said pulsating DC voltage on said secondary side is approximately 1 MHz.