EP0471625B1 - Vorrichtung zur Erzeugung einer regelbaren Gleichspannung - Google Patents

Vorrichtung zur Erzeugung einer regelbaren Gleichspannung Download PDF

Info

Publication number
EP0471625B1
EP0471625B1 EP91402248A EP91402248A EP0471625B1 EP 0471625 B1 EP0471625 B1 EP 0471625B1 EP 91402248 A EP91402248 A EP 91402248A EP 91402248 A EP91402248 A EP 91402248A EP 0471625 B1 EP0471625 B1 EP 0471625B1
Authority
EP
European Patent Office
Prior art keywords
circuit
voltage
frequency
pulses
output
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP91402248A
Other languages
English (en)
French (fr)
Other versions
EP0471625A1 (de
Inventor
Jacques Laeuffer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
General Electric CGR SA
Original Assignee
General Electric CGR SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by General Electric CGR SA filed Critical General Electric CGR SA
Publication of EP0471625A1 publication Critical patent/EP0471625A1/de
Application granted granted Critical
Publication of EP0471625B1 publication Critical patent/EP0471625B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05G—X-RAY TECHNIQUE
    • H05G1/00—X-ray apparatus involving X-ray tubes; Circuits therefor
    • H05G1/08—Electrical details
    • H05G1/26—Measuring, controlling or protecting
    • H05G1/30—Controlling
    • H05G1/32—Supply voltage of the X-ray apparatus or tube
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05G—X-RAY TECHNIQUE
    • H05G1/00—X-ray apparatus involving X-ray tubes; Circuits therefor
    • H05G1/08—Electrical details
    • H05G1/10—Power supply arrangements for feeding the X-ray tube
    • H05G1/20—Power supply arrangements for feeding the X-ray tube with high-frequency ac; with pulse trains

Definitions

  • the present invention relates to devices for obtaining a DC voltage whose value is adjustable over a wide range, said devices being more particularly adapted to polarize a focus of an X-ray tube to a value chosen by the practitioner implementing a radiological installation.
  • Such devices are known from documents US-A-4, 541, 041 and GB-A-2,045,019.
  • a radiological tube is generally constituted as a diode, that is to say by two electrodes, one of which, called cathode, emits electrons while the other, called anode, receives these electrons on a small surface which constitutes the X-ray source.
  • the cathode has a filament heated by an electric current which constitutes the source of electrons.
  • an electric current which constitutes the source of electrons.
  • a metal part, called a concentration part, supporting the filament is isolated from the latter and brought to a negative potential, called polarization, with respect to said filament.
  • polarization a negative potential
  • to modify the shape and therefore the concentration of the electron beam it is usual to modify this polarization potential over a wide range, for example between 300 and 3000 volts.
  • the cathode is itself brought to a voltage of the order of -20 to -75 kilovolts relative to the mass, which poses insulation problems to apply this potential or bias voltage.
  • the invention relates more particularly to a device for obtaining a bias voltage of a concentrating part of an X-ray tube cathode which is variable over a wide range of values.
  • Figure 1 gives the block diagram of a device of the prior art. It includes a supply circuit 10 which supplies a DC voltage E regulated and adjustable from an AC voltage supplied by the sector. The voltage E is applied to the terminals of an inverter circuit 11 which comprises a chopping circuit 12 and a control circuit 14.
  • the alternating signal supplied by the inverter circuit 11 is applied to a voltage step-up transformer 15, the secondary winding of which is connected to a rectification and filtering circuit 16.
  • This circuit 16 provides a direct voltage V s which is applied between the piece of concentration and filament of the x-ray tube.
  • the voltage V s being difficult to measure due to the high common mode potential (20 to 75 kilovolts), it is preferable to measure the voltage E which is substantially proportional to it and to regulate it.
  • the voltage E is measured by a resistive divider comprising the resistors R1 and R2 and the divided signal is applied to a voltage / frequency converter circuit 20 which receives, moreover, a signal V ref corresponding to the voltage that the it is desired to obtain between the concentration piece and the filament of the x-ray tube.
  • the chopper circuit 12 comprises, for example, two transistors 21 and 22, the openings and closings of which are controlled by the control circuit 14.
  • the control circuit 14 is also a voltage / frequency converter circuit similar to the circuit 20 but whose frequency is fixed.
  • the object of the present invention is therefore to provide a device for obtaining an adjustable direct voltage which does not have the above-mentioned drawbacks.
  • the means for undulating said voltage E comprise an oscillating circuit whose resonant frequency is greater than the frequency F.
  • the power circuit 33 comprises, in addition to the inverter circuit 35, a first rectification and filtering circuit 34 which, from an alternating voltage e, supplies a regulated direct voltage E supplying the switches T1 and T2.
  • the pulses supplied by the inverter circuit 35 are applied to the primary winding 36p of an isolation transformer 36 of the pulse type, the secondary winding 36s of which is connected to a rectification and filtering circuit 37 which supplies the required DC voltage V p .
  • the inverter circuit 35 comprises, as indicated above, at least two switches T1 and T2 produced by field effect transistors according to the metal-oxide technology more known by the English abbreviation of MOSFET transistors.
  • these transistors T1 and T2 each include in parallel a diode D1 for the transistor T1 and a diode D2 for the transistor T2, diodes including the anode is connected to the source S and the cathode connected to the drain D of the associated transistor.
  • the gate G of the transistor T1 is connected to the output 32-a of the control circuit 32 while the gate G of the transistor T2 is connected to the output 32-b of the control circuit 32.
  • the inverter circuit also includes a resonant circuit consisting of capacitors C1 and C2 and a coil L.
  • the capacitors C1 and C2 are connected in series between the drain D of the transistor T1 and the source S of the transistor T2 while the coil L is disposed in the primary circuit 36p of the transformer 36 and is connected on one side directly to the source of the transistor T1 and on the other side to the common point C of the capacitors C1 and C2 via the primary winding 36p of the transformer 36.
  • the inverter circuit may comprise only one capacitor, instead of the two capacitors C1 and C2, which would be connected for example to the negative terminal of the supply circuit 34.
  • the rectification and filtering circuit 37 is of the conventional type and has an output resistance R at the terminals of which the bias voltage V p is taken .
  • the control circuit 32 comprises a first logic AND circuit 40 which has two inputs on one of which are applied the variable frequency pulses F supplied by the circuit 31 while the other input is connected to a first delay circuit 41 whose delay is ⁇ 1.
  • the output of the AND circuit 40 is connected, on the one hand, to a bistable circuit 43 and, on the other hand, to the first delay circuit 41 as well as to a second delay circuit 42 whose delay is ⁇ 2.
  • the output corresponding to state 1 of the bistable circuit 43 is connected to one of the two inputs of a second logic AND circuit 44 while the output corresponding to state 0 is connected to one of the two inputs of a third AND circuit logic 45.
  • the second input of AND circuits 44 and 45 is connected to the output of the second delay circuit 42.
  • the purpose of these pulses of frequency F is to alternately control the transistors T1 and T2 by means of circuit 32 so as to create current pulses whose rectification and filtering in circuit 37 leads to the desired voltage V p between terminals 33-a and 33-b.
  • This curve 81 takes account of the linearity faults of the system while the curve 80 is a theoretical curve.
  • a bias voltage V p desired by the practitioner or by the device for controlling the radiological device corresponds to a numerical code N p which, applied to counter 31, leads the latter to supply pulses 70 and 70 '(figure 4-a) at frequency F according to the correspondence given by curve 81 of figure 3-a.
  • the pulse 70 controls the delay circuit 41 to end the opening signal 71 (figure 4-c) so that the AND circuit 40 closes for a time ⁇ 1.
  • the pulse 70 also controls the delay circuit 42 so that it provides a signal T'1 of duration ⁇ 2 (figure 4-b) which makes passing the circuits AND 44 and 45. Only the circuit AND 44, which receives the signal state 1 of the bistable circuit 43, provides a signal T'1 making the transistor T1 conductive at time t o (FIG. 4-d).
  • This signal T'1 makes and keeps the transistor T1 conductive and a current i1 (figure 4-d) says positive, flows in the transistor T1, the coil L, the primary winding 36p of the transformer 36, the capacitors C1 and C2 and the supply circuit 34 (in fact i1 / 2 in each capacitor).
  • This current i1 gives rise to a voltage V (figure 4-e) of rectangular shape at the terminals of the primary winding 36p and this results in a current I (t) (figure 4-f) in the secondary winding 36s of the transformer 36, current of identical appearance to the current i1 flowing in the primary winding.
  • the current i1 charges the capacitor C2 and discharges the capacitor C1 and their charging voltage is opposed to the circulation of the current i1 so that the latter is canceled at time t1, that is to say before the end of signal T'1.
  • the capacitor C2 then discharges while the capacitor C1 charges and a current i2 (figure 4-d), said to be negative, flows in the capacitors C1 and C2, the primary winding 36p, the coil L, the diode D1 and the supply circuit 34 (in fact i2 / 2 in each capacitor).
  • the signal T'1 ends by the effect of the delay circuit 42 introducing a delay ⁇ 2 so that the AND circuits 44 and 45 are blocked.
  • the delay circuit 41 After the time t2 and more precisely after a delay ⁇ 1 from the end of the signal 71 (figure 4-c), the delay circuit 41 provides a signal 71 'which turns the AND circuit 40 on.
  • a pulse 70 ' is supplied by the circuit 31 and its front edge controls the change of state of the bistable circuit 43, which goes to state 0 , as well as the resetting of the delay circuits 41 and 42.
  • This reset has the effect of terminating the signal 71 'and of supplying the signal T'2 which opens the AND circuits 44 and 45.
  • the bistable circuit 43 is at state 0 , only the AND circuit 45 provides a signal output on terminal 32-b and a pulse is applied to the control electrode of transistor T2 at time t ' o to make it conductive.
  • a current i'1 said to be negative, then flows in the transistor T2, the circuit 34, the capacitors C1 and C2 (in fact i'1 / 2 in each condenser), the primary winding 36p of the transformer 36 and the coil L.
  • This negative current gives rise to a negative voltage V (figure 4-e) of rectangular shape across the terminals of the primary winding 36p and it results in a current I (t) negative (figure 4-f) in the secondary winding 36s of the transformer 36, current of identical appearance to the current i'1 circulating in the primary winding.
  • the negative current i'1 charges the capacitor C1 and discharges the capacitor C2 and their charging voltage is opposed to the circulation of the current i'1 so that the latter is canceled out at time t'1.
  • the capacitor C1 then discharges while the capacitor C2 charges and a positive current i'2 flows in the capacitors C1 and C2 (in fact i'2 / 2 in each capacitor), the primary winding 36p, the coil L, the diode D2 and the supply circuit 34.
  • This positive current gives rise to a positive rectangular voltage (FIG. 4-e) at the terminals of the primary winding 36p and, consequently, to a positive current I (t) (figure 4-f) in the secondary winding 36s.
  • the pulses which are thus created by the inverter circuit 35 are applied to the transformer 36 and are rectified and filtered in the circuit 37 and it appears at the terminals of the load resistor R a voltage V p corresponding to the frequency F determined by calibration.
  • the curves 80 'and 81' of the figure 4-b show the variations of the ratio V p / F according to the frequency F in correspondence with the curves 80 and 81 respectively of the figure 4-a. These curves and in particular the real curve 81 ′ resulting from the calibration are linear throughout the range.
  • the rectangular shape of the signals of the figure 4-e is due to the fact of the presence of the rectifying and filtering circuit 37 including / understanding diodes which, while becoming conducting, realize short-circuits.

Landscapes

  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • X-Ray Techniques (AREA)
  • Dc-Dc Converters (AREA)

Claims (3)

  1. Einrichtung zur Erzeugung einer einstellbaren Gleichspannung Vp eines Fokussierungsteils einer Röntgenröhrenkathode, mit:
    - Versorgungsmitteln (33) zum Bilden einer konstanten Gleichspannung E,
    - Mitteln (35) zum Wechselrichten der Gleichspannung E, um Wechselspannungsimpulse mit der Frequenz F zu erzeugen, die jeweils einer von einem Impuls zum folgenden konstanten Elektrizitätsmenge entsprechen, wobei die Mittel (35) aus einem Schwingkreis bestehen, dessen Resonanzfrequenz größer als die Frequenz F ist,
    - einem Transformator (36) zum Erhöhen der Spannung der Wechselspannungsimpulse,
    - Mitteln (37) zum Gleichrichten und Filtern der erhöhten Wechselspannungsimpulse, um die genannte Gleichspannung Vp zu erzeugen,
    - Mitteln zum Abwandeln der Frequenz F der Wechselspannungsimpulse in Abhängigkeit von der gewünschten Gleichspannung Vp, wobei diese Mittel umfassen:
    - Mittel (31), um durch Eichung die Frequenz F der Impulse in Abhängigkeit von der zur erzeugenden Spannung Vp zu bestimmen,
    - Mittel (32) zum Bilden von Steuerimpulsen mit der Frequenz F aus der Information des Wertes der genannten Frequenz F, wobei die Impulse in die Mittel zum Wechselrichten der Gleichspannung E eingegeben werden.
  2. Einrichtung gemäß Anspruch 1, dadurch gekennzeichnet, daß die Mittel zum Bilden von Steuerimpulsen mit der Frequenz F umfassen:
    - eine Zählschaltung (31), die Impulse mit der Frequenz F ausgibt, und
    - eine Logikschaltung (32), die Signale zum Steuern der Mittel zum Wechselrichten der Spannung E ausgibt, deren Dauer größer ist als die Halbperiode, jedoch kleiner als die genannte Resonanzperiode, und deren Wiederholperiode höchstens gleich der genannten Resonanzperiode ist.
  3. Einrichtung gemäß Anspruch 2, dadurch gekennzeichnet, daß die Logikschaltung (32) umfaßt:
    - eine erste UND-Schaltung (40), wovon einer der beiden Eingänge mit dem Ausgang der Zählschaltung (31) verbunden ist,
    - eine bistabile Schaltung (43), deren Steuereingang mit dem Ausgang der ersten UND-Schaltung (40) so verbunden ist, daß sie ihren Zustand bei jedem Signal ändert, das von dieser letzteren ausgegeben wird,
    - eine zweite UND-Schaltung (44), wovon einer der beiden Eingänge mit demjenigen Ausgang der bistabilen Schaltung (43), der dem Zustand 1 entspricht, verbunden ist,
    - eine dritte UND-Schaltung (45), wovon einer der beiden Eingänge mit demjenigen Ausgang der bistabilen Schaltung (43), der dem Zustand 0 entspricht, verbunden ist,
    - eine erste Verzögerungsschaltung (41), deren Eingang mit dem Ausgang der ersten UND-Schaltung (40) verbunden ist und deren Ausgang mit dem zweiten Eingang der ersten UND-Schaltung (40) verbunden ist, und
    - eine zweite Verzögerungsschaltung (42), deren Eingang mit dem Ausgang der ersten UND-Schaltung (40) verbunden ist und deren Ausgang mit dem anderen Eingang der zweiten und der dritten UND-Schaltungen (44, 45) verbunden ist.
EP91402248A 1990-08-14 1991-08-14 Vorrichtung zur Erzeugung einer regelbaren Gleichspannung Expired - Lifetime EP0471625B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9010348 1990-08-14
FR9010348A FR2665999B1 (fr) 1990-08-14 1990-08-14 Dispositif d'obtention d'une tension continue reglable.

Publications (2)

Publication Number Publication Date
EP0471625A1 EP0471625A1 (de) 1992-02-19
EP0471625B1 true EP0471625B1 (de) 1994-03-23

Family

ID=9399670

Family Applications (1)

Application Number Title Priority Date Filing Date
EP91402248A Expired - Lifetime EP0471625B1 (de) 1990-08-14 1991-08-14 Vorrichtung zur Erzeugung einer regelbaren Gleichspannung

Country Status (4)

Country Link
US (1) US5243509A (de)
EP (1) EP0471625B1 (de)
DE (1) DE69101476T2 (de)
FR (1) FR2665999B1 (de)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5638260A (en) * 1995-05-19 1997-06-10 Electronic Measurements, Inc. Parallel resonant capacitor charging power supply operating above the resonant frequency
US5715155A (en) * 1996-10-28 1998-02-03 Norax Canada Inc. Resonant switching power supply circuit
FR2768241B1 (fr) * 1997-09-10 1999-12-03 Ge Medical Syst Sa Dispositif et procede de regulation a commande optimale d'un convertisseur a transistors
JP3673075B2 (ja) * 1998-03-09 2005-07-20 新電元工業株式会社 スイッチング電源装置
JP3322217B2 (ja) * 1998-07-21 2002-09-09 株式会社豊田自動織機 インバータ
DE50009885D1 (de) * 1999-12-17 2005-04-28 Fleck Carl M Steuerbare zündschaltung
US20120256571A1 (en) * 2009-12-28 2012-10-11 Toyota Jidosha Kabushiki Kaisha Power supply device
DE102020212085A1 (de) * 2020-09-25 2022-03-31 Siemens Healthcare Gmbh System zur Regelung einer Hochspannung für Röntgenanwendungen, ein Röntgenerzeugungssystem und ein Verfahren zur Regelung einer Hochspannung

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2908767A1 (de) * 1979-03-06 1980-09-18 Siemens Ag Roentgendiagnostikgenerator mit einem dem hochspannungstransformator vorgeschalteten wechselrichter
JPS5753100A (en) * 1980-09-13 1982-03-29 Toshiba Corp X-ray equipment
FR2507842A1 (fr) * 1981-06-12 1982-12-17 Gen Equip Med Sa Regulateur de tension a semi-conducteur et generateur de radiologie comportant un tel regulateur
NL8103265A (nl) * 1981-07-08 1983-02-01 Hollandse Signaalapparaten Bv Energieomzetter.
US4541041A (en) * 1983-08-22 1985-09-10 General Electric Company Full load to no-load control for a voltage fed resonant inverter
JPS61161698A (ja) * 1985-01-09 1986-07-22 Hitachi Medical Corp インバ−タ式ｘ線装置
FR2577373B1 (fr) * 1985-02-12 1995-02-17 Thomson Cgr Alimentation haute tension continue, notamment pour emetteur de rayons x
DE3621803A1 (de) * 1986-06-28 1988-01-07 Philips Patentverwaltung Roentgengenerator
FR2629959B1 (fr) * 1988-04-08 1994-02-11 Thomson Cgr Procede de regulation de la tension d'un signal de tension, notamment pour tube a rayons x
FR2646972B1 (fr) * 1989-05-12 1992-01-03 Gen Electric Cgr Generateur haute tension a grande dynamique de puissance
JP2707465B2 (ja) * 1989-06-29 1998-01-28 スタンレー電気株式会社 インバータ装置

Also Published As

Publication number Publication date
FR2665999A1 (fr) 1992-02-21
EP0471625A1 (de) 1992-02-19
DE69101476T2 (de) 1994-08-11
FR2665999B1 (fr) 1994-01-28
US5243509A (en) 1993-09-07
DE69101476D1 (de) 1994-04-28

Similar Documents

Publication Publication Date Title
FR2562284A1 (fr) Regulateur predictif de retour a modulation d'impulsions en duree
FR2745446A1 (fr) Circuit integre de correction de facteur de puissance
EP0471625B1 (de) Vorrichtung zur Erzeugung einer regelbaren Gleichspannung
EP0499589A1 (de) Vorrichtung zum Messen von Strömen
EP0471626B1 (de) Vorrichtung zur Speisung und Regelung des Stromes für den Kathodenglühfaden einer Röntgenröhre
FR2702044A1 (fr) Circuit de traitement pour signal de sortie de capteur analogique résistif, notamment pour jauge de carburant sur véhicule automobile et systèmes équipés.
EP0278193B1 (de) Schaltung zum Messen des die Primärwicklung des Ausgangstransformators eines Wechselrichters durch fliessenden Gleichstromanteiles
EP0612141B1 (de) Leistungsregelungsverfahren und -vorrichtung für eine Schaltung mit einem Resonanzumrichter
EP0011534B1 (de) Verfahren und Vorrichtung zur Verarbeitung von analogischen, insbesondere pseudoperiodischen Signalen
EP0401067A1 (de) Ansteuervorrichtung für einen elektromagnetischen Schalter
FR2685474A1 (fr) Circuit d'exploitation pour capteur inductif dont l'inductance depend de la grandeur a mesurer.
EP0480796B1 (de) Vorrichtung zur Erzeugung und Umschaltung von hohen Spannungen an Röntgenröhren-Elektroden
US4648702A (en) Toner density detector and toner supplier
EP0241373A1 (de) Stromversorgungsvorrichtung für den Glühfaden einer Röntgenröhre
CA1074862A (fr) Generateur de tres haute tension commutable
FR2472879A1 (fr) Circuit et procede d'isolement de signaux electriques
EP0038240B1 (de) Gleichstromversorgung und ihre Verwendung zum Speisen einer kathodischen Röhre
EP0109871B1 (de) Vorrichtung zur Messung ionisierender Strahlung
FR2538632A1 (fr) Procede et circuit de commande de transistor de puissance
US3988611A (en) Direct voltage power supply apparatus
EP0051007B1 (de) Horizontal- und/oder Vertikalablenkungsvorrichtung mit Korrektur auf einem Bildteil und diese Vorrichtung umfassender Fernsehempfänger
FR2684501A1 (fr) Dispositif d'alimentation en tension continue reguliere a convertisseur hyporesonant commande en dephasage retard.
FR2680297A1 (fr) Dispositif d'alimentation d'une charge non lineaire.
FR2672166A1 (fr) Dispositif pour obtenir une tension continue a faible ondulation residuelle.
BE481572A (de)

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE NL

17P Request for examination filed

Effective date: 19920320

17Q First examination report despatched

Effective date: 19930714

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE NL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Effective date: 19940323

REF Corresponds to:

Ref document number: 69101476

Country of ref document: DE

Date of ref document: 19940428

NLV1 Nl: lapsed or annulled due to failure to fulfill the requirements of art. 29p and 29m of the patents act
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20050930

Year of fee payment: 15

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20070301