US3735238A - Process and apparatus for providing image brightness over a wide range of discharge repetition rates - Google Patents

Process and apparatus for providing image brightness over a wide range of discharge repetition rates Download PDF

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US3735238A
US3735238A US00181547A US3735238DA US3735238A US 3735238 A US3735238 A US 3735238A US 00181547 A US00181547 A US 00181547A US 3735238D A US3735238D A US 3735238DA US 3735238 A US3735238 A US 3735238A
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voltage
load
multiplying
capacitors
repetition rate
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US00181547A
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English (en)
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C Miller
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General Radio Co
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Gen Radio Co
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/30—Circuit arrangements in which the lamp is fed by pulses, e.g. flash lamp

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  • the present invention relates to processes and apparatus for supplying energy discharges to a load, such as a flashtube and the like, that is to be repetitively energized by voltage supplied by a voltage-multiplying power supply.
  • the invention will be particularly described in connection with its preferred application to repetitively discharged loads, such as flashtubes, discharge gaps and similar devices, as for such applications as stroboscopy and the like, though it is to be understood that the basic features thereof are equally applicable to the supplying of voltage to loads from voltage-multiplying power supplies of this character in other applications, as well.
  • Voltage multiplier power supplies are particularly well suited for use in small portable equipments, having the advantages that, in practice, they are typically smaller, lighter weight and less expensive than equivalent transformer-operated supplies.
  • systerns are those described in, for example, US. letters Pat. Nos. 2,342,257; 2,478,901; 2,965,807; 3,115,594; 3,267,328; 3,286,128; 3,340,426; 3,354,379; 3,463,992; 3,513,376; and RE 24,823.
  • none of these techniques sufficiently accommodates for the desirable variation in energy from the power supply discharged into the flash lamp or similar load when the rate of repetition of the charging and discharging or flashing varies over wide limits. While attempts have been made to try to render more uniform the energy per flash over a wide range of repetition rates, these efforts have not proven adequately satisfactory and they have been accompanied by several disadvantages hereinafter explained.
  • the subjective image brightness to an observer using the stroboscope is proportional to flash lamp power, with the power in the lamp being also proportional to the energy per flash times the flash repetition rate.
  • a flash lamp has a maximum power limit, however, that cannot be exceeded without damage. It is thus common practice to design a stroboscope circuit to produce the greatest possible light output commensurate with the limitations dictated by the components, allowable heat rise, etc.
  • the charging resistor or resistance in the flash lamp anode circuit is of such value that the storage or discharge capacitor normally recharges completely between flashes, producing a constant illumination each flash.
  • Maximum power to the lamp and maximum subjective image brightness thus occurs at or near the maximum flash repetition rate, and the subjective image brightness decreases approximately in proportion to the decrease in flash repetition rate.
  • the discharge capacitor is recharged to the power supply output voltage by current flowing through the charging resistor, with a consequent dissipation of power by the resistor in the form of heat equal to the power in the lamp at the particular flash repetition rate.
  • the value of the charging resistor may be adjusted with relation to the discharge capacitor to increase the time required to charge the capacitor with respect to the shortest interflash period.
  • the capacitor does not recharge completely at higher flash repetition rates. This can compensate somewhat for the loss of light at lower flash rates by providing an increasing anode voltage at decreasing frequencies; but this is subject to the principal disadvantage that such resistive compensation causes heat to be lost in the resistor in excess of the power dissipated in the lamp at high repetition rates. This is especially disadvantageous in small instruments or in instruments employing plastic enclosures the integrity of which might be jeopardized at elevated temperatures.
  • An object of the present invention accordingly, is to provide a new and improved process and apparatus for supplying voltage to a load, such as a repetitively discharged flash lamp and the like, that shall not be subject to the above-described disadvantages, but that, to the contrary, enables substantially constant power automatically to be produced in the load irrespective of variation in the discharge repetition rate over wide ranges thereof and without excess heat losses or complex range-changing circuits.
  • a load such as a repetitively discharged flash lamp and the like
  • this result is attained by providing a substantially pure reactive voltage drop within the power supply circuit itself that enables a substantially linear variation of stored voltage with current produced thereby through the load as the result of discharge, thus enabling substantially constant power to be produced in the load for a wide variation in the discharge repetition rate.
  • a further object of the invention is to provide a novel voltage-multiplier power supply apparatus and process of more general applicability, as well.
  • FIG. 1 of which is a schematic circuit diagram illustrating a preferred form of the invention, operating in accordance with the process thereof, and illustratively shown adapted to the triggering of flashtubes or other lamps, as in the stroboscope and similar applications:
  • FIG. 2 (a) is an equivalent circuit diagram of the circuit of FIG. 1, designed in accordance with the invention.
  • FIG. 2 (b) is a graph illustrating the phenomenon underlying the operation of the invention and plotting load current along the abscissa.
  • FIG. 3 is a graph illustrating the performance of the circuits of FIG. 1 and hereinafter described FIG. 4, plotting the lamp and charging resistor power for the preferred form of the invention of FIG. 1, and the resistor power in the conventional prior art stroboscope circuit of FIG. 4;
  • FIG. 4 is an equivalent circuit diagram of such a typical prior art conventional stroboscope circuit.
  • a quadrupler power supply (at first blush of conventional configuration) is shown comprising a source 1 of, for example, alternatingcurrent input voltage, (or any similar input voltage source), connected to enable the storing or charging of direct-current voltage in capacitors C1, C2, C3 and C4, with the aid of rectifiers R,, R R and R, In this circuit, the rectifiers are connected in series and in closed charging loops containing capacitors C and C, also connected in series.
  • the rectifier R is disposed in a first closed charging and storing loop circuit with the capacitor C, and rectifiers R and R are similarly connected in a loop containing capacitor C Capacitors C, and C are connected in series with rectifiers R, R and R and the input from the source 1, with the point of series connection 6 between the capacitors C, and C being connected between the rectifiers R, and R
  • the point P of series connection of the capacitors C and C is similarly connected between the rectifiers R 2 and R
  • V represents the no-load supply voltage
  • R represents the Thevenin resistance
  • R represents a variable resistance load.
  • the load voltage of such a circuit varies in the linear manner shown by the regulation curve 8 of FIG. 2 (b), with the slope determined by the value of R
  • the advantage of this circuit is that the magnitudes of the V and R may be set over wide ranges by varying the number of stages of voltage multiplication and the values of the storage capacitors, respectively.
  • Image brightness compensation of the flashes produced by the lamp 2 with variation in discharge repetition rate over wide ranges is effected by the resulting reactive dropping of the supply voltage, substantially eliminating any resistive excess heat dissipation in the charging resistor 11, as shown in the flat curve 9 of FIG. 3, and, in view of the linear characteristics of FIG. 2 (b), resulting in a substantially constant power supplied to the lamp and image brightness over a wide flash lamp rate or repetition range.
  • a process for supplying voltage to a load such as a flashtube and the like that is to be repetitively discharged by voltage periodically charged and stored in a voltage-multiplying power supply that comprises, applying alternating-current voltage to a plurality of interconnected capacitor storage circuits each comprising closed charging and storing loops containing separate voltage-multiplying capacitors and rectifier elements with certain of the loops sharing common rectifier elements to enable voltage multiplication, triggering the discharge of the stored voltage developed across the storage circuits to discharge the same through the load, controlling said triggering to effect the same repetitively, each time following the substantially complete voltage charging and storing in the plurality of storage circuits, varying the repetition rate of said charging and storing, and adjusting the value of at least one of the voltage-multiplying capacitors to a value very small compared with the large voltage-regulating capacitance value of other of the voltage-multiplying capacitors to eliminate substantial resistive dissipation with variation of repetition rate and to provide a substantially linear variation of stored voltage across the storage circuit
  • Apparatus for supplying voltage to a load such as a flashtube and the like that is to be repetitively discharged having, in combination, voltage-multiplying circuit means containing a plurality of voltagemultiplying storage capacitors connected with a plurality of rectifiers in closed loops sharing certain of the rectifiers and having an output circuit, means for connecting a load to be repetitively energized from the voltage periodically stored in the output circuit, means for varying the rate of repetition of such storing and energizing of the load, and means comprising a voltage multiplying capacitor adjusted to a value very small compared with the value of said storage capacitors and connected in the voltage-multiplying circuit therewith to provide substantially constant power in the load irrespective of variation in said repetition rate.

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  • Discharge-Lamp Control Circuits And Pulse- Feed Circuits (AREA)
US00181547A 1971-09-17 1971-09-17 Process and apparatus for providing image brightness over a wide range of discharge repetition rates Expired - Lifetime US3735238A (en)

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US18154771A 1971-09-17 1971-09-17

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4045708A (en) * 1975-08-28 1977-08-30 General Electric Company Discharge lamp ballast circuit
US4562526A (en) * 1982-07-01 1985-12-31 Honeywell Inc. Voltage control circuit
US4687971A (en) * 1984-11-08 1987-08-18 Fuji Xerox Company, Limited Power supply for discharge lamp
US6314008B1 (en) * 2000-10-16 2001-11-06 Jianwen Bao Adjustable low spurious signal DC-DC converter
US20050163190A1 (en) * 2001-04-11 2005-07-28 Omron Corporation Electronic clinical thermometer

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB367785A (en) * 1930-11-19 1932-02-19 John Douglas Cockcroft Improvements in high voltage direct current systems
US3329247A (en) * 1965-10-06 1967-07-04 Eaton Yale & Towne Electromagnetic coupling apparatus
US3412311A (en) * 1966-03-28 1968-11-19 Westinghouse Electric Corp Battery-operated power supply circuitry for providing long battery lifetime and close regulation of the output voltages

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB367785A (en) * 1930-11-19 1932-02-19 John Douglas Cockcroft Improvements in high voltage direct current systems
US3329247A (en) * 1965-10-06 1967-07-04 Eaton Yale & Towne Electromagnetic coupling apparatus
US3412311A (en) * 1966-03-28 1968-11-19 Westinghouse Electric Corp Battery-operated power supply circuitry for providing long battery lifetime and close regulation of the output voltages

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Electronics, Multiplier Phototube, July 8, 1960 Vol. 33 No. 28 P. 51 *
IBM Technical Disclosure Bulletin, Self Regulated Pulse Power Supply, Vol. 9, No. 11, April, 196, p. 1,666 *

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4045708A (en) * 1975-08-28 1977-08-30 General Electric Company Discharge lamp ballast circuit
US4562526A (en) * 1982-07-01 1985-12-31 Honeywell Inc. Voltage control circuit
US4687971A (en) * 1984-11-08 1987-08-18 Fuji Xerox Company, Limited Power supply for discharge lamp
US6314008B1 (en) * 2000-10-16 2001-11-06 Jianwen Bao Adjustable low spurious signal DC-DC converter
US20050163190A1 (en) * 2001-04-11 2005-07-28 Omron Corporation Electronic clinical thermometer
US20050220170A1 (en) * 2001-04-11 2005-10-06 Omron Corporation Electronic clinical thermometer
US7059767B2 (en) * 2001-04-11 2006-06-13 Omron Corporation Electronic clinical thermometer
US7284904B2 (en) 2001-04-11 2007-10-23 Omron Corporation Electronic clinical thermometer

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Publication number Publication date
FR2153099A1 (cs) 1973-04-27

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