US2944206A

US2944206A - Firing circuit for voltage regulator tube

Info

Publication number: US2944206A
Application number: US496108A
Authority: US
Inventors: Charles B Brahm
Original assignee: United Aircraft Corp
Current assignee: Raytheon Technologies Corp
Priority date: 1955-03-23
Filing date: 1955-03-23
Publication date: 1960-07-05
Anticipated expiration: 1977-07-05

Description

July 5, 1960 Q 5 BRAHM 2,944,206

FIRING CIRCUIT FOR VOLTAGE REGULATOR TUBE Filed March 23, 1955 INVENTOR.

CHARLES B. BRAHM LM 1M5 ATTORNEY FIRING emourr FOR VOLTAGE REGULATOR TUBE United Aircraft Corporation, East Hartford, Conn,

5 a corporation of Delaware Filed ar. 23, 1195's, Ser. No. 496,108

4 Claims. c1. 323-16) This invention relatesto voltage regulator circuits and 'par't'icula rly to circuits" utilizing gaseous discharge tubes 7 including the firing-circuits for the tubes. Anfobject ofthis invention is 'a'circuit for firing a gaseous discharge tube and also limiting the loss in the line."

A'further objectis 'a circuit utilizing the availableline Charles uranium, Windsor Lo'cks, Conn, assignor to voltage for firing the tubeand limitingthe tube running" load to a --minimum.

A further object is a circuit utilizing a single. power source and separate lines for firing the tube and for supplying the load so that; the power loss will be maintained at a minimum. I

Other objects and advantages will be apparent from the following specification and attached drawings: in

which:

Fig. l is a circuit diagram incorporating a voltage regulator including the'firing circuit of the invention.

Fig.'2 is a circuit diagram incorporating the invention utilizing the line voltage for firing the voltage regulator tube.

In voltage regulator tube circuits having a material voltage source variation in which the minimum source voltage is above the firing voltage, it becomes important to maintain the dropping resistance between the source and the voltage regulator tube at a maximum to keep the total current through the dropping resistor at a minimum and only slightly above the load current. Normally where the linevoltage is used to fire the tube the optimum dropping resistance cannot be used because the dropping resistance and the load resistance forms a voltage divider circuit which will determine the voltage supply available at the junction of the two resistors, where the volt age regulator tube is normally connected. In order to obtain the necessary comparatively high voltage supply to fire the tube, especially where the line voltage is only slightly above the voltage necessary for firing, the dropping resistor must be made small in order to still have available at the junction of the dropping and load resistors, where the voltage regulator tube is connected, a voltage supply high enough to fire the tube. With such a small dropping resistor, the current through the dropping resistor and the tube becomes excessive when the tube starts to conduct, resulting in a high 1 R loss through the resistor or an overloading of the tube or both. If the resistance is made large enough to prevent the tube from overloading, it will then drop the line voltage so much that at the minimumline voltage there will not be voltage supply enough left at the junction of the dropping and load resistances to fire the tube.

lnorder to permit the use of an optimum dropping resistance in the operating circuit, I have provided a separate circuit for firing the tube, thus allowing the dropping resistor to be the optimum resistance for limiting the current through the voltage regulator tube to a minimum while providing sufiicient current to provide the necessary regulation.

In Fig. 1 the direct current source voltage is indicated lator tube.

is 2,944,206. Pa ent- 4 4 1 6! 2 p at E the dropping resistor R the voltage regulator tube VR, the load resistant R and the load or regulated voltage supply E The voltage-regulator tube is connected at 10 between the dropping resistance R and the load resistance R;, and a rectifier CR is inserted in the line between the connection 10 and the voltage regu- A second source of voltage Episconnected through a dropping resistor R to the voltage regulator tube at point 12 so that the rectifier CR isolates this second source of voltage E from the load resistance.

' Before the voltage regulator tube'starts to conduct, it

-acts as an open circuit to both 'the source voltage E 'and the auxiliary voltage E There will be-some-current flow through R and R from the source E5 which will make the voltage supply at 10 somewhat less" than the E voltage source. new will'be no current flow through R because the rectifier will block current flow through R and the voltage regulator tube is not conducting;

therefore, the full voltage of E will be applied across the rectifier tube to fire it and the resistance R, can be made high to limit the current flow through the voltage i regulator tube'to the desired amount. R isjnot utilized in firingthe tube, it can' be made at the optimum value to supply the desiredrun'nin'g voltage As the resistance orvoltage supply at po'i'nt- 10' with theoptimunr amount additional current over the load current 'to'provide satisi factory operation of the voltageregulator tube.

' The'voltage regulator tubehas'a range of currents at which it will satisfactorily operate in regulating-"By utilizing the above system-in which a portion ofthe currentis' supplied from E through R 'and the remainder ';'"of the current is supplied fro'inE through R ,]it is sible to design the resistors R and R so that an optimum current flow through the regulator'tubewill besufiicieiit to supply the necessary voltage drop from the source E to the voltage supply point 10 to provide the desired regulation even where the source E has a material variation, from from to volts. The rectifier CR will of course transmit current from the source E through the regulator tube when the voltage regulator tube is conducting as both the rectifier CR and the regulator tube VR are connected to conduct in the same direction.

Where the voltage of the power source is equal to or above the firing voltage, it is possible to use this source instead of an auxiliary source for firing the tube and still have the resistance R an optimum resistance.

Fig. 2 shows the source voltage connected in a separate firing circuit to fire the voltage regulatortube with this second circuit incorporating the resistance R and isolated from the load resistance by the rectifier CR so that before the voltage regulator tube starts to conduct, the full voltage of the source may be applied as a voltage supply across the voltage regulator tube to fire the tube and after the tube starts to conduct then the source E through the resistor R can supply the operating circuit the voltage to be regulated with the resistor R chosen to provide the minimum power loss while maintaining an efficient operation of the voltage regulator tube. As before the resistance R, can be chosen to provide a minimum power loss while assisting in the etficient operation of the voltage regulator tube. The rectifier CR, as before, will act to isolate the circuit including the resistance 3 rectifier thus providing one circuit for firing the tube, which circuit can be designed with an optimum resistance for low loss and efilcient tube operation and a second circuit for providing the voltage to be regulated with a dropping resistor which can also be designed for a minimum power loss with efiicient voltage regulation within the operating limits of the tube current.

It is to be understood that the invention is not limited to the specific embodiment herein illustrated and described, and may be used in other ways without departure from its spirit as defined by the following claims.

I claim:

1. In combination a direct current power source, a load connected across said source, a voltage regulator tube and a rectifier in series connected across said source in parallelwith said load, means modifying the potential of said source in accordance with current flow through said load and rectifier, a connection, including means modifying the potential of said source in accordance with current fiow, connecting said source directly across said tube to provide a firing circuit for said tube.

I 2. In combination a source of direct current, two parallel connections from said source each having means dropping voltage in accordance with current fiow through the respective connection, a voltage regulator tube connected directly across one said connection and connected in series with a rectifier conducting in the same direction as said tube across the other connection.

, 3. In combination, a gas tube having a relatively stable forward voltage drop and a preferred range of variable current characteristics, a rectifier having a relatively low forward resistance and a relatively high back resistance connected in series so that both the tube and the rectifier have the same forward direction, a load connected across ,said series arranged tube and rectifier, an impedance voltage higher than the tube firing voltage to regulate the voltage applied to said load by controlling the voltage drop between said source and said tube and load, said impedance selected to provide the optimum operating conditions and the preferred range of variable current in said tube, said impedance dropping the voltage of said source to below the firing voltage of said tube due to the current flow through said load when said tube is not operating, a relatively high impedance arranged in a firing circuit receiving its entire voltage from said source and connected directly across said tube andsaid source in parallel with the circuit containing the first mentioned impedance and isolated from said load by the rectifier to supply a voltage from said mum to said tube unaffected by current flow through the load to fire the tube.

4. In combination with a direct current operating circuit comprising, a series arranged direct current voltage source, dropping resistor and load, a voltage regulator tube having a working voltage less than the direct current voltage of said source and arectifier conducting in the same direction connected in series across said load and voltage source supplying all the voltage for said voltage pp y 7 References Cited in the file of tLis patent UNITED STATES PATENTS Higgins Nov. 2, 1954 Medal Oct. 16, 1956 OTHER REFERENCES Vacuum Tube Circuits, L. B. Arguimbau, John Wiley & Sons, 1948, p. 44.