RF high-voltage power supply

• US 4,706,182 A
• Filed: 12/30/1986
• Issued: 11/10/1987
• Est. Priority Date: 01/10/1986
• Status: Expired due to Term

• Current Assignee: Senichi Masuda
• Original Assignee: Senichi Masuda
• Inventors: Masuda, Senichi
• Primary Examiner(s): Salce, Patrick R.
• Assistant Examiner(s): JONES, JUDSON
• Application Number:
  US06/947,814
• Time in Patent Office: 315 Days
• Field of Search: 363/24, 363/28, 363/133, 363/134, 363/139, 422/186.15, 422/186.16, 204/176
• US Class Current: 363/139
• CPC Class Codes: H02M 7/5233 the commutation elements being in a push-pull arrangement

Abstract

There is disclosed a small-sized RF high-voltage power supply capable of stably supplying an RF high voltage to a load at the maximum power efficiency, even if the load has a nonlinear electrostatic capacity that varies with the applied voltage. The power supply has an RF step-up transformer equipped with a primary winding having a tap to which one end of a power capacitor is connected. An oscillating inductor, a thyristor, and the other end of the power capacitor are connected in series with each end of the primary winding in this order. Each thyristor conducts when a voltage is applied to it from the corresponding end of the primary winding. A diode is connected in antiparallel with each thyristor. The thyristors are alternately triggered to conducting state.

Claims

1. An RF high-voltage power supply comprising:

an RF step-up transformer having a primary winding that receives a lower voltage and has a tap, the transformer further having a secondary winding that delivers a higher voltage between its both output terminals;

a power capacitor connected with a charging DC power supply and having one end connected to the tap of the primary winding and the other end connected with both ends of the primary winding;

a first series combination of an oscillating inductor and anti-parallel combination of an externally controlled switching device that conducts when the capacitor discharges and a diode, one end of the primary winding being connected in series with the first combination;

a second series combination of an oscillating inductor and anti-parallel combination of an externally controlled switching device that conducts when the capacitor discharges and a diode, the other end of the primary winding being connected in series with the second combination; and

a control power supply for supplying control signals alternately to the control terminals of the externally controlled switching devices to alternately bring the switching devices into conduction.

2. The RF high-voltage power supply of claim 1, wherein a protective capacitor is connected between the output terminals of the secondary winding.

3. The RF high-voltage power supply of claim 1 or 2, wherein a fuse is inserted between the tap of the primary winding and one end of the power capacitor.

4. The RF high-voltage power supply as claimed in claim 1, wherein each of the externally controlled switching devices is a silicon controlled rectifier or thyristor.

5. The RF high-voltage power supply as claimed in claim 1, wherein each of the externally controlled switching devices is a field-effect transistor.

6. The RF high-voltage power supply as claimed in claim 1, wherein a small amount of inductance is connected in series with the diode of each antiparallel combination.

7. The RF high-voltage power supply as claimed in claim 2, wherein each of the externally controlled switching devices is a silicon controllled rectifier or thyristor.

8. The RF high-voltage power supply as claimed in claim 3, wherein each of the externally controlled switching devices is a silicon controlled rectifier or thyristor.

9. The RF high-voltage power supply as claimed in claim 2, wherein each of the externally controlled switching devices is a field-effect transistor.

10. The RF high-voltage power supply as claimed in claim 3, wherein each of the externally controlled switching devices is a field-effect transistor.

11. The RF high-voltage power supply as claimed in claim 2, wherein a small amount of inductance is connected in series with the diode of each antiparallel combination.

12. The RF high-voltage power supply as claimed in claim 3, wherein a small amount of inductance is connected in series with the diode of each antiparallel combination.

13. The RF high-voltage power supply as claimed in claim 4, wherein a small amount of inductance is connected in series with the diode of each antiparallel combination.

14. The RF high-voltage power supply as claimed in claim 5, wherein a small amount of inductance is connected in series with the diode of each antiparallel combination.