Wide band domino effect high voltage regulator

• US 5,070,538 A
• Filed: 01/02/1990
• Issued: 12/03/1991
• Est. Priority Date: 01/02/1990
• Status: Expired due to Fees

• Current Assignee: United States Of America As Represented By The Secretary Of The Air Force
• Original Assignee: United States Of America As Represented By The Secretary Of The Air Force
• Inventors: Jones, Franklin B., Kerfoot, Charles S., Milberger, Walter E.
• Primary Examiner(s): Kuntz, Curtis
• Assistant Examiner(s): Faile, Andrew
• Application Number:
  US07/459,870
• Time in Patent Office: 700 Days
• Field of Search: 455/126, 323/265, 323/270, 323/350, 323/351, 330/297
• US Class Current: 455/126
• CPC Class Codes: G05F 1/44 semiconductor devices only
• CPC Class Codes: G05F 1/595 semiconductor devices connected in series
• CPC Class Codes: H03F 1/0283 Reducing the number of DC-current paths
• CPC Class Codes: H03F 3/211 using a combination of several amplifiers H03F3/60 takes precedence
• CPC Class Codes: H03F 3/2171 with field-effect devices H03F3/2173 - H03F3/2178 take precedence
• CPC Class Codes: H03F 3/245 with semiconductor devices only
• CPC Class Codes: H03F 3/426 with junction-FET's

Abstract

The high voltage regulator employs a field effect transistor (FET) amplifier and a wide band frequency compensated RC voltage divider. The device comprises a FET amplifier used as a current source in a 20 KV power supply. The negative output of the supply is sensed by a voltage divider consisting of two resistors in parallel with two capacitors. The voltage divider output is applied to the non-inverting input of an operational amplifier whose reference is set to affect the linear operation of an inverting operational amplifier. A no load to full load and line regulation of 0.1% is provided to a microwave tube. For a 16-KV regulated output the inverting amplifier must have a dc operation point of 4 KV to accommodate a 20% storage capacitor voltage droop and a ±5% line change. At this level the inverting amplifier provides a swing of ±4 KV. This range allows for a large line voltage variation and storage capacitor voltage droop. The dynamic range and bandwidth of the regulator not only provides regulation for long term line voltage regulation but also negates the effects of line voltage transitions over a wide frequency and amplitude range.

Claims

1. A wide band high voltage regulator used with a high voltage power supply feeding a load, the high voltage power supply having first and second terminals for supplying direct current, with the load coupled between the first terminal and ground;

wherein said wide band high voltage regulator comprises a domino effect amplifier, a voltage divider, and an operational amplifier;

wherein said domino effect amplifier comprises N stages in tandem from a first stage to an Nth stage, each stage being a three-terminal unit having an input terminal, an output terminal and a common terminal, input means coupled between the input and common terminals of the first stage, the input means being coupled to an external signal source to provide an input signal to the first stage, the output terminal of the Nth stage being coupled via current-limiting means to the second terminal of said high-voltage power supply;

each stage after the first having its input terminal coupled to the common terminal of the preceding stage, and its common terminal coupled to the output terminal of the preceding stage;

each stage comprising an amplifying device having an inverting input, a non-inverting input and an output, a reference resistor connected between the input terminal of each stage and the non-inverting input of each amplifying device, a feedback resistor connected between the inverting input and the output of the amplifying device, the non-inverting input of each amplifying device being the common terminal of the stage, and the output of each amplifying device being the output terminal of each stage;

wherein said voltage divider is connected from the first terminal of the high voltage power supply to ground and has a tap near the ground end;

said operational amplifier has a non-inverting input, an inverting input, and an output, with its non-inverting input coupled to the tap of the voltage divider, its inverting input coupled to ground, and its output coupled to said input means of the domino effect amplifier.

2. A wide band high voltage regulator according to claim 1, wherein said load is a microwave transmitting tube, and a storage capacitor is connected between the first terminal of the high voltage power supply and ground;

and wherein said voltage divider comprises a high voltage resistor in parallel with a high voltage capacitor connected between the first terminal of the high voltage power supply and said tap, and a low voltage resistor in parallel with a low voltage capacitor connected between the tap and ground, the resistance-capacitance product of the high level arm being set equal to that of the low level arm.

3. A wide band high voltage regulator according to claim 1, wherein said voltage divider comprises a high voltage resistor in parallel with a high voltage capacitor connected between the first terminal of the high voltage power supply and said tap, and a low voltage resistor in parallel with a low voltage capacitor connected between the tap and ground, so that the resistors are frequency compensated by the parallel capacitors, wherein the high voltage capacitor is a variable high voltage piston capacitor used to set the resistance-capacitance product of the high level arm equal to that of the low level arm.

4. A wide band high voltage regulator according to claim 1, wherein in said domino effect amplifier there are at least a second stage and a third stage following said first stage, and at least for the third to the Nth stages, the reference and feedback resistors are of equal value to provide a gain of substantially one, with the gain of the amplifier being the sum of the gains of the stages;

wherein the amplifying device of each stage is a FET transistor, having a gate electrode used as the inverting input, a source electrode used as the non-inverting input, and a drain electrode used as the output.

5. A wide band high voltage regulator according to claim 4, wherein said load is a microwave transmitting tube, and a storage capacitor is connected between the first terminal of the high voltage power supply and ground;

and wherein said voltage divider comprises a high voltage resistor in parallel with a high voltage capacitor connected between the first terminal of the high voltage power supply and said tap, and a low voltage resistor in parallel with a low voltage capacitor connected between the tap and ground, the resistance-capacitance product of the high level arm being set equal to that of the low level arm.

6. A wide band high voltage regulator according to claim 4,

wherein said voltage divider is connected from the first terminal of the high voltage power supply to ground and has a tap near the ground end;

wherein said voltage divider comprises a high level arm in series with a low level arm, wherein the high level arm comprises a high-voltage resistor in parallel with a high-voltage capacitor coupled between the first terminal and the tap, and the low level arm comprises a low-voltage resistor in parallel with a low-voltage capacitor coupled between the tap and ground, so that the resistors are frequency compensated by the parallel capacitors;

the high-voltage resistor having a high voltage end for connection via the first terminal to the high voltage power supply and a low voltage end connected to said tap, wherein the high voltage capacitor is a variable high voltage piston capacitor used to set the resistance-capacitance product of the high level arm equal to that of the low level arm.

7. A wide band high voltage regulator according to claim 6, wherein said load is a microwave transmitting tube, and a storage capacitor is connected between the first terminal of the high voltage power supply and ground;

wherein said voltage divider is wholly contained inside an enclosure comprising an insulating tube coated with metal to provide a metal shield and electrical ground;

wherein the high-voltage capacitor comprises a quartz glass tube, a first plate which is a cylindrical copper slug contained within the inner surface of the quartz glass tube and a second plate which is a copper foil wrapper around the outer surface of the quartz glass tube, with the thickness of the quartz glass tube setting the distance between the two plates, the quartz glass tube being designed to be long enough to provide adequate creepage distance to span between low voltage and high voltage connections;

the quartz glass tube having a portion near the low voltage end of said high-voltage resistor which is wrapped with said copper foil and attached to the low voltage end of the high-voltage resistor;

wherein the high-voltage resistor and the high-voltage capacitor are supported within said enclosure between a first supporting disk at the high-voltage end and a second supporting disk at the low-voltage end, and the low-voltage resistor and the low-voltage capacitor are supported within said enclosure between the second supporting disk and a third supporting disk at an end of the enclosure;

wherein said quartz glass tube has an extension at the low voltage end made to allow for creepage between the inner portion slug and the second supporting disk, the metal slug has rounded ends to minimize corona, a small inner conductor is used to minimize capacitance in the rest of the quartz glass tube and attaches the metal slug to the high-voltage end of the high-voltage resistor, the capacitance value being adjusted by positioning the copper slug either more or less inside of the outer shield such that the overlap increases or decreases the surface area of the two concentrical capacitor plates that are separated dielectric formed by the quartz glass tube;

wherein the high-voltage resistor is positioned near the center of the enclosure to minimize its stray capacitance to ground, and the piston capacitor parallels the high-voltage resistor;

wherein the first supporting disk is inserted far enough into the enclosure to provide a required creepage distance for the operational voltage, and wherein the first terminal is formed with silicone insulated wire to exit at the first supporting disk.

8. A wide band high voltage regulator according to claim 5, wherein said microwave transmitting tube generates r-f output which is coupled to an antenna;

further including an amplitude compensation regulator loop comprising an amplitude detector and an amplifier in tandem coupled from the output to said antenna to the input means of the domino effect amplifier.

9. A wide band high voltage regulator according to claim 5, wherein said microwave transmitting tube generates r-f output which is coupled to an antenna;

further including a phase compensation regulator loop comprising an amplitude detector and an amplifier in tandem coupled from the output to said antenna to the input means of the domino effect amplifier.

10. A wide band high voltage regulator according to claim 9,

further including an amplitude compensation regulator loop comprising an amplitude detector and an amplifier in tandem coupled from the output to said antenna to the input means of the domino effect amplifier.