US3702414A - Circuit arrangement for supplying eht to the accelerator anode of a picture display tube - Google Patents

Circuit arrangement for supplying eht to the accelerator anode of a picture display tube Download PDF

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US3702414A
US3702414A US163013A US3702414DA US3702414A US 3702414 A US3702414 A US 3702414A US 163013 A US163013 A US 163013A US 3702414D A US3702414D A US 3702414DA US 3702414 A US3702414 A US 3702414A
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winding
circuit
voltage
anode
eht
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US163013A
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Peter Johannes Hubertu Janssen
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US Philips Corp
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US Philips Corp
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/06—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes without control electrode or semiconductor devices without control electrode
    • H02M7/062—Avoiding or suppressing excessive transient voltages or currents
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N3/00—Scanning details of television systems; Combination thereof with generation of supply voltages
    • H04N3/10—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical
    • H04N3/16—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical by deflecting electron beam in cathode-ray tube, e.g. scanning corrections
    • H04N3/18—Generation of supply voltages, in combination with electron beam deflecting

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  • a diode has its cathode con- [5 6] References cued nected to the junction of the multiplier and the wind- UNTTED STATES PATENTS ing and its anode grounded.
  • the invention relates to a circuit arrangement for supplying EI-lT to the acceleration anode of a picture display tube in a picture display apparatus, comprising a line output transformer, an El-IT winding wound on the core of the transformer, a multiplier circuit constituted by capacitors and rectifiers, which multiplier circuit is connected to a terminal of the EI-IT winding, a diode and a parallel arrangement of a resistor and a capacitor being connected to terminals of the EHT winding.
  • FIG. 1 Such a circuit arrangement is known from US. Pat. application, Ser. No. 231,764 and is shown in FIG. 1.
  • a load circuit consisting of the parallel circuit 1 in series with a diode 2 is arranged between the terminals of the EHT winding 3 in order that a small internal resistance of the EHT source is obtained.
  • a positive voltage is produced at the junction of the parallel arrangement and the diode, which positive voltage is smoothed by a smoothing network 4, 5 so as to be applied to an acceleration anode A, of the picture display tube.
  • a further step described in the said application is the use in the parallel circuit 1 of a capacitor having a much larger capacitance than that of the first capacitor 6 in the multiplier circuit 7. As a result the line output stage is safeguarded in case of flashover.
  • a drawback of this known circuit arrangement is the following. Since it must be possible to adjust the supply voltage at the mentioned acceleration anode A a potentiometer, or three potentiometers when the picture tube is a color picture tube, must be arranged in parallel with the capacitor 5 of the smoothing network with the wipers of said potentiometers being connected to the anodes. This means that a current flows through the resistor 4 of the smoothing network, which causes a considerable and needless loss of power.
  • a further drawback is the mentioned large capacitance of the capacitor in network I. Since this capacitor is to stand a high voltage, it must have large dimensions and it is expensive.
  • An object of the present invention is to obviate these drawbacks and to render the safeguard in case of flash-over more effective and to this end the circuit arrangement according to the invention is characterized in that the cathode of the diode is connected to the junction of the EHT winding and the multiplier circuit, while its anode is connected to earth.
  • FIG. 2 An embodiment of the circuit arrangement according to the invention is shown in FIG. 2 and will be described in greater detail hereinafter.
  • the cathode of the diode 2 is connected to the junction of the EHT winding 3 of the line output transformer and the multiplier circuit 7, while its anode is connected to earth.
  • a capacitor 8 and three potentiometers 9, 10 and 11 are interconnected in parallel and in series with the winding 3.
  • a resistor 12 having a relatively small resistance is arranged between the mary colors red, reen and blue reapectively.
  • the potentiometers may be given high resistances so that the capacitance of capacitor 8 need not be large in order that the voltage at the anodes is satisfactorily smoothed, while the smoothing network 4,5 is not necessary, which may be considered as advantages of the circuit arrangement'according to the invention.
  • a beam current-dependent voltage which may be applied in known manner to a beam current limiter circuit is produced across the resistor 12.
  • the EHT lead that is to say, the capacitor 13 in FIG. 2
  • the capacitor 13 in FIG. 2 is short-circuited to earth.
  • the charge of the capacitors in the multiplier circuit 7 is depleted through the diodes and a negatively directed current pulse is produced at the input of the circuit 7.
  • the diode 2 then becomes conducting so that the said current pulse directly flows to earth without damaging the winding 3 or other non-shown parts of the line output stage present on the primary side of the transformer in which the winding 3 constitutes a secondary winding.
  • a circuit comprising a line output transformer having a high voltage winding, a voltage multiplier means coupled to a first end of said winding, means for supplying a voltage comprising a parallel circuit com prising a resistor and a capacitor coupled to an end of said winding, and means for preventing damage due to arcing comprising a diode having a cathode coupled to said first end of said winding and an anode coupled to ground for at least alternating currents.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Details Of Television Scanning (AREA)

Abstract

A circuit has a horizontal output transformer with an output winding. A voltage multiplier is connected to the winding to provide the voltage to a CRT ultor electrode. In addition, a diode has its cathode connected to the junction of the multiplier and the winding and its anode grounded. This supplies the voltages for the acceleration anodes without using a large capacitor in the multiplier and reduces the current drain from the winding.

Description

O United States Patent [151 3,702,414
Janssen 1 Nov. 7, 1972 [54] CIRCUIT ARRANGEMENT FOR 3,143,686 8/1964 Vonderschmitt et SUPPLYING EHT TO THE al. ..315/27 XY ACCELERATOR ANODE OF A 3,417,347 12/1968 Claverie ..315/29 X PICTURE DISPLAY TUBE 3,020,484 2/1962 Janssen et al. ..315/29 X [72] Inventor: Peter Johannes Hubert Janssen, 3,609,446 9/1971 Hursh et al. ..315/29 X iimnasingel, Eindhoven, Nether- FOREIGN PATENTS 0R APPLICATIONS an S 1,026,932 4/1966 Great Britain ..315/29 [7 3] Assignee: U.S. Philips Corporation, New
York Primary Examiner-Carl D. 'Quarforth [22] Filed: July 15, 1971 Assistant Examiner-P. A. Nelson Attorney-Frank R. Trifari [21] Appl. No.: 163,013
[57] ABSTRACT C(i1. ..315/29, A circuit has a horizontal output transformer with an [.1 p A voltage multiplier is connected to [58] Fleld of Search ..315/14, 27 R, 27 XY, 28, 29 the winding to provide the voltage to a CRT ultor electrode. In addition, a diode has its cathode con- [5 6] References cued nected to the junction of the multiplier and the wind- UNTTED STATES PATENTS ing and its anode grounded. This supplies the voltages for the acceleration anodes without using a large 2,801,364 7/1957 Janssen ..315/29 X capacitor in the multiplier and reduces the Current 2,801,366 7/1957 Janssen et al. ..315/29 X drain from the winding 2,879,447 3/1959 Preisig ..315/29 X 3,139,538 6/1964 Geller ..315/29 X 5 Claims, 2 Drawing Figures AIR A16 A18 PATENTEDnnv 1 m2 3.702.414
l L 13": if m 10 18 12 F|g.2
IXVEXTOR.
PETER JOIIANNES H. JAYFSYX CIRCUIT ARRANGEMENT FOR SUPPLYING EIIT TO THE ACCELERATOR ANODE OF A PICTURE DISPLAY TUBE The invention relates to a circuit arrangement for supplying EI-lT to the acceleration anode of a picture display tube in a picture display apparatus, comprising a line output transformer, an El-IT winding wound on the core of the transformer, a multiplier circuit constituted by capacitors and rectifiers, which multiplier circuit is connected to a terminal of the EI-IT winding, a diode and a parallel arrangement of a resistor and a capacitor being connected to terminals of the EHT winding.
Such a circuit arrangement is known from US. Pat. application, Ser. No. 231,764 and is shown in FIG. 1. In thisFIG. a load circuit consisting of the parallel circuit 1 in series with a diode 2 is arranged between the terminals of the EHT winding 3 in order that a small internal resistance of the EHT source is obtained. A positive voltage is produced at the junction of the parallel arrangement and the diode, which positive voltage is smoothed by a smoothing network 4, 5 so as to be applied to an acceleration anode A, of the picture display tube. A further step described in the said application is the use in the parallel circuit 1 of a capacitor having a much larger capacitance than that of the first capacitor 6 in the multiplier circuit 7. As a result the line output stage is safeguarded in case of flashover. v
A drawback of this known circuit arrangement is the following. Since it must be possible to adjust the supply voltage at the mentioned acceleration anode A a potentiometer, or three potentiometers when the picture tube is a color picture tube, must be arranged in parallel with the capacitor 5 of the smoothing network with the wipers of said potentiometers being connected to the anodes. This means that a current flows through the resistor 4 of the smoothing network, which causes a considerable and needless loss of power. A further drawback is the mentioned large capacitance of the capacitor in network I. Since this capacitor is to stand a high voltage, it must have large dimensions and it is expensive. An object of the present invention is to obviate these drawbacks and to render the safeguard in case of flash-over more effective and to this end the circuit arrangement according to the invention is characterized in that the cathode of the diode is connected to the junction of the EHT winding and the multiplier circuit, while its anode is connected to earth.
An embodiment of the circuit arrangement according to the invention is shown in FIG. 2 and will be described in greater detail hereinafter.
In FIG. 2 the cathode of the diode 2 is connected to the junction of the EHT winding 3 of the line output transformer and the multiplier circuit 7, while its anode is connected to earth. A capacitor 8 and three potentiometers 9, 10 and 11 are interconnected in parallel and in series with the winding 3. A resistor 12 having a relatively small resistance is arranged between the mary colors red, reen and blue reapectively. Since the voltage across po entrometers 9, l and 11 is high and since the anodes A A and A draw substantially no current, the potentiometers may be given high resistances so that the capacitance of capacitor 8 need not be large in order that the voltage at the anodes is satisfactorily smoothed, while the smoothing network 4,5 is not necessary, which may be considered as advantages of the circuit arrangement'according to the invention.
A beam current-dependent voltage which may be applied in known manner to a beam current limiter circuit is produced across the resistor 12.
When a flashover occurs in the picture display tube, the EHT lead, that is to say, the capacitor 13 in FIG. 2, is short-circuited to earth. As a result the charge of the capacitors in the multiplier circuit 7 is depleted through the diodes and a negatively directed current pulse is produced at the input of the circuit 7. The diode 2 then becomes conducting so that the said current pulse directly flows to earth without damaging the winding 3 or other non-shown parts of the line output stage present on the primary side of the transformer in which the winding 3 constitutes a secondary winding.
It is to be noted that it is advantageous to incorporate the diode 2 with the diodes and the capacitors of the multiplier circuit in one housing. It will be evident that the potentiometers 9, l0 and 11 may be replaced by a resistor of fixed value. The acceleration anodes are then connected directly or through an optionally variable resistor to the junction of the winding 3 and this re sistor of fixed value.
What is claimed is:
l. A circuit comprising a line output transformer having a high voltage winding, a voltage multiplier means coupled to a first end of said winding, means for supplying a voltage comprising a parallel circuit com prising a resistor and a capacitor coupled to an end of said winding, and means for preventing damage due to arcing comprising a diode having a cathode coupled to said first end of said winding and an anode coupled to ground for at least alternating currents.
2. A circuit as claimed in claim I wherein said parallel circuit is coupled to a second winding end.
3. A circuit as claimed in claim 1 wherein said resistor comprises a potentiometer.
4. A circuit as claimed in claim 1 wherein said supplied voltage is derived from said resistor.
5. A circuit as claimed in claim 1 wherein said anode is directly connected to ground.

Claims (5)

1. A circuit comprising a line output transformer having a high voltage winding, a voltage multiplier means coupled to a first end of said winding, means for supplying a voltage comprising a parallel circuit comprising a resistor and a capacitor coupled to an end of said winding, and means for preventing damage due to arcing comprising a diode having a cathode coupled to said first end of said winding and an anode coupled to ground for at least alternating currents.
2. A circuit as claimed in claim 1 wherein said parallel circuit is coupled to a second winding end.
3. A circuit as claimed in claim 1 wherein said resistor comprises a potentiometer.
4. A circuit as claimed in claim 1 wherein said supplied voltage is derived from said resistor.
5. A circuit as claimed in claim 1 wherein said anode is directly connected to ground.
US163013A 1971-06-15 1971-07-15 Circuit arrangement for supplying eht to the accelerator anode of a picture display tube Expired - Lifetime US3702414A (en)

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GB2803071A GB1357971A (en) 1968-09-16 1971-06-15 Supply for television display tubes

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5742470A (en) * 1995-07-20 1998-04-21 U. S. Philips Corporation Circuit arrangement including an EHT cascade circuit

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2801364A (en) * 1950-09-20 1957-07-30 Philips Corp Circuit-arrangement in which a signal is supplied to a control-device
US2801366A (en) * 1953-08-13 1957-07-30 Philips Corp Circuit arrangement for producing a sawtooth current
US2879447A (en) * 1954-06-18 1959-03-24 Rca Corp Adjustable voltage supplies
US3020484A (en) * 1958-09-30 1962-02-06 Philips Corp Circuit arrangement for producing a current having a non-linear sawtooth waveform through a coil
US3139538A (en) * 1962-01-11 1964-06-30 Sylvania Electric Prod Sawtooth current generator employing r. c. network and diode effecting low power loss in circuit
US3143686A (en) * 1962-08-14 1964-08-04 Rca Corp Flyback transformer and transistorized deflection circuit
GB1026932A (en) * 1963-01-11 1966-04-20 Philips Electronic Associated Improvements in and relating to line deflection circuits for television receivers
US3417347A (en) * 1966-08-23 1968-12-17 Thomson Houston Comp Francaise Blocking oscillator circuit and sweep system using the same
US3609446A (en) * 1969-06-02 1971-09-28 Rca Corp Power supply utilizing a diode and capacitor voltage multiplier for tracking focusing and ultor voltages

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2801364A (en) * 1950-09-20 1957-07-30 Philips Corp Circuit-arrangement in which a signal is supplied to a control-device
US2801366A (en) * 1953-08-13 1957-07-30 Philips Corp Circuit arrangement for producing a sawtooth current
US2879447A (en) * 1954-06-18 1959-03-24 Rca Corp Adjustable voltage supplies
US3020484A (en) * 1958-09-30 1962-02-06 Philips Corp Circuit arrangement for producing a current having a non-linear sawtooth waveform through a coil
US3139538A (en) * 1962-01-11 1964-06-30 Sylvania Electric Prod Sawtooth current generator employing r. c. network and diode effecting low power loss in circuit
US3143686A (en) * 1962-08-14 1964-08-04 Rca Corp Flyback transformer and transistorized deflection circuit
GB1026932A (en) * 1963-01-11 1966-04-20 Philips Electronic Associated Improvements in and relating to line deflection circuits for television receivers
US3417347A (en) * 1966-08-23 1968-12-17 Thomson Houston Comp Francaise Blocking oscillator circuit and sweep system using the same
US3609446A (en) * 1969-06-02 1971-09-28 Rca Corp Power supply utilizing a diode and capacitor voltage multiplier for tracking focusing and ultor voltages

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5742470A (en) * 1995-07-20 1998-04-21 U. S. Philips Corporation Circuit arrangement including an EHT cascade circuit

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AU466902B2 (en) 1973-01-04

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