High voltage power supply

• US 4,393,441 A
• Filed: 07/17/1981
• Issued: 07/12/1983
• Est. Priority Date: 07/17/1981
• Status: Expired due to Fees

• Current Assignee: Harald Enge
• Original Assignee: Harald Enge
• Inventors: Enge, Harald A.
• Primary Examiner(s): Shoop, William M.
• Assistant Examiner(s): Wong, Peter S.
• Application Number:
  US06/284,483
• Time in Patent Office: 725 Days
• Field of Search: 363/44-48, 363/59-61, 363/67-70, 363/126, 307/110, 320/1
• US Class Current: 363/61
• CPC Class Codes: H02M 7/103 Containing passive elements (capacitively coupled) which are ordered in cascade on one source

Abstract

A modified double Greinacher high voltage power supply wherein the side-string capacitances thereof have an inductance associated in series therewith, the inductance/capacitance circuits being appropriately tuned to the frequency of the R-F input voltage source. Preferably the center-string capacitance may have an inductance associated in series therewith, such circuit being similarly tuned. The input R-F voltage, rather than being supplied as a sine wave is supplied substantially as a square wave to the first stage and is transmitted to each of the subsequent stages substantially as a square wave.

Claims

1. A power supply for producing a DC output voltage comprising

a plurality of serially-connected voltage producing stages including a first stage, a final stage, and intermediate stages therebetween, each of said stages including

bridge rectifier means having first and second side-string terminals and first and second center-string terminals;

a first circuit having series-connected, side-string capacitance and inductance means;

a second circuit having series-connected, side-string capacitance and inductance means; and

center-string capacitance means connected between said center-string terminals;

an AC input voltage source, having a pair of output terminals for supplying an AC voltage having a substantially square wave shape;

the first circuit of said first stage connected between one of the output terminals of said AC input voltage source and the first side-string terminal of the first stage bridge rectifier means;

the second circuit of said first stage connected between the other of the output terminals of said AC input voltage source and the second side-string terminal of the first stage bridge rectifier means;

the first center-string terminal of the bridge rectifier means of said first stage being connected to a first DC output terminal;

the first circuit of each successive stage connected between the first side-string terminal of its bridge rectifier means and the first side-string terminal of the bridge rectifier means of the preceding stage;

the second circuit of each successive stage being connected between the second side-string terminal of its bridge rectifier means and the second side-string terminal of the bridge rectifier means of the preceding stage;

center-string inductance means connected from the first center-string terminal of the bridge rectifier means of each successive stage to the second center-string terminal of the bridge rectifier means of the preceding stage and from the first center-string terminal of said first stage to the first DC output terminal;

the product of the values of the inductance means and the capacitance means of said first and second circuits of each of said stages and the product of the values of the center-string capacitance means and the center-string inductance means of each of said stages being selected to be substantially equal;

the center-string terminal of the bridge rectifier means of the final stage providing a second DC output terminal.

2. A power supply in accordance with claim 1 wherein the frequency of said square wave voltage is selected so that the first harmonic thereof is substantially in resonance with said first and second circuits.

3. A power supply in accordance with claim 1 wherein the values of the center-string capacitances of each stage are substantially greater than the values of the capacitances in the first and second circuits of each stage.

4. A power supply in accordance with claim 1 wherein the values of the center-string capacitances of each stage are substantially equal to the values of the capacitances in the first and second circuits of each stage.

6. A power supply in accordance with claim 1 or 5 and further including a surge resistor connected in series with the second center-string terminal of said final stage for preventing damage to the bridge rectifier means.

7. A power supply in accordance with claim 1 or 5 wherein said AC input voltage source comprises

a square wave voltage source;

transformer means having a primary responsive to the square wave output from said square wave source and means for defining the DC potential of the secondary of said transformer means.

8. A power supply in accordance with claim 1 or 5 wherein said AC input voltage source comprises

a square wave voltage source;

transformer means comprising a pair of transformers the primaries of which are connected in parallel and are responsive to the square wave output of said square wave source and the secondaries of which have commonly connected terminals connected to the first DC output terminal, the other terminals of each of said secondaries forming the output terminals of said AC input voltage source.

9. A power supply in accordance with claim 7 wherein the secondary of said transformer means has a center terminal and further including an additional inductance means connected between said center terminal and the first center-string terminal of said input stage.

10. A power supply in accordance with claim 9 wherein the value of said additional inductance means is substantially equal to the value of the leakage inductance of said transformer means.

11. A power supply in accordance with claim 1 or 5 wherein the first and second circuit of only a selected number of said stages include inductance means, said selected number being less than the total number of said stages, and the values of the inductance means and capacitance means in the side-strings of said stages being selected so that the total impedance of each side-string is substantially in series resonance with the first harmonic of the square wave input AC voltage.

12. A power supply in accordance with claim 11 wherein the first and second circuits of alternating stages include inductance means and the first and second circuits of intervening stages do not include inductance means.

13. A power supply in accordance with claim 8 and further including an additional inductance means connected between said commonly connected terminals and the first center-string terminal of said input stage.

14. A power supply in accordance with claim 13 wherein the value of said additional inductance means is substantially equal to the value of the leakage inductance of said transformer means.

5. A power supply for producing a DC output voltage comprising

a plurality of serially-connected voltage producing stages including a first stage, a final stage, and intermediate stages therebetween, each of said stages including

bridge rectifier means having first and second side-string terminals and first and second center-string terminals;

a first circuit having series-connected, side-string capacitance and inductance means and diode means connected in parallel with said side-string capacitance;

a second circuit having series-connected, side-string capacitance and inductance means and diode means connected in parallel with said side-string capacitance; and

center-string capacitance means connected between said center-string terminals;

an AC input voltage source, having a pair of output terminals for supplying an AC voltage having a substantially square wave shape;

the first circuit of said first stage connected between one of the output terminals of said AC input voltage source and the first side-string terminal of the first stage bridge rectifier means;

the second circuit of said first stage connected between the other of the output terminals of said AC input voltage source and the second side-string terminal of the first stage bridge rectifier means;

the first center-string terminal of the bridge rectifier means of said first stage being connected to a first DC output terminal;

the first circuit of each successive stage connected between the first side-string terminal of its bridge rectifier means and the first side-string terminal of the bridge rectifier means of the preceding stage;

the second circuit of each successive stage being connected between the second side-string terminal of its bridge rectifier means and the second side-string terminal of the bridge rectifier means of the preceding stage;

means for interconnecting the first center-string terminal of the bridge rectifier means of each successive stage to the second center-string terminal of the bridge rectifier means of the preceding stage;

the center-string terminal of the bridge rectifier means of the final stage providing a second DC output terminal.