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US3337767A - Circuit arrangement for controlling very rapid deflections of an electron beam in a vacuum tube - Google Patents

Circuit arrangement for controlling very rapid deflections of an electron beam in a vacuum tube Download PDF

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Publication number
US3337767A
US3337767A US367010A US36701064A US3337767A US 3337767 A US3337767 A US 3337767A US 367010 A US367010 A US 367010A US 36701064 A US36701064 A US 36701064A US 3337767 A US3337767 A US 3337767A
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United States
Prior art keywords
current
transistor
coil
voltage
supply
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Expired - Lifetime
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US367010A
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English (en)
Inventor
Charles Jacques Marcel Mari De
Locatelli Jacques Georges
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INDUSTRIELLE DES NOUVELLES TECHNIQUES RADIOELECTRIQUES ET DE L'ELECTRONIQUE FRANCAISE Ste
NOUVELLES TECH RADIOELECTRIQUE
Original Assignee
NOUVELLES TECH RADIOELECTRIQUE
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K4/00—Generating pulses having essentially a finite slope or stepped portions
    • H03K4/06—Generating pulses having essentially a finite slope or stepped portions having triangular shape
    • H03K4/08—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape
    • H03K4/48—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape using as active elements semiconductor devices
    • H03K4/60—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape using as active elements semiconductor devices in which a sawtooth current is produced through an inductor
    • H03K4/69—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape using as active elements semiconductor devices in which a sawtooth current is produced through an inductor using a semiconductor device operating as an amplifier
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/04—Modifications for accelerating switching
    • H03K17/041—Modifications for accelerating switching without feedback from the output circuit to the control circuit
    • H03K17/04113—Modifications for accelerating switching without feedback from the output circuit to the control circuit in bipolar transistor switches
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K4/00—Generating pulses having essentially a finite slope or stepped portions
    • H03K4/06—Generating pulses having essentially a finite slope or stepped portions having triangular shape
    • H03K4/08—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape
    • H03K4/48—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape using as active elements semiconductor devices
    • H03K4/60—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape using as active elements semiconductor devices in which a sawtooth current is produced through an inductor
    • H03K4/62—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape using as active elements semiconductor devices in which a sawtooth current is produced through an inductor using a semiconductor device operating as a switching device
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K4/00—Generating pulses having essentially a finite slope or stepped portions
    • H03K4/06—Generating pulses having essentially a finite slope or stepped portions having triangular shape
    • H03K4/08—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape
    • H03K4/48—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape using as active elements semiconductor devices
    • H03K4/60—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape using as active elements semiconductor devices in which a sawtooth current is produced through an inductor
    • H03K4/69—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape using as active elements semiconductor devices in which a sawtooth current is produced through an inductor using a semiconductor device operating as an amplifier
    • H03K4/696—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape using as active elements semiconductor devices in which a sawtooth current is produced through an inductor using a semiconductor device operating as an amplifier using means for reducing power dissipation or for shortening the flyback time, e.g. applying a higher voltage during flyback time

Definitions

  • the respective first ends of two push-pull field coils are connected to a main D.C. supply through two diodes and to an auxiliary D.C. supply of high voltage through two switching transistors, the control electrodes of which are cross-connected to the respective second ends of the field coils. Only the field coil having an increasing current therethrough is connected to the auxiliary supply through the corresponding transistor, the other field coil being connected to the main supply through the corresponding diode.
  • the present invention relates to a circuit arrangement for electromagnetically controlling very rapid deflections of an electron beam in a vacuum tube, comprising two identical field coils mounted in push-pull and each in series with an electronic control member, preferably a transistor. Circuit arrangements of this type are already known for electromagnetically controlling the deflections of the cathode beam of an electronic tube. It is known that the speed of variation of the current passing through an inductance circuit is limited by the self-inductance of this circuit.
  • the electromotive forces of self-induction induced by certain rapid variations of the controlled current are capable of reversing the voltage applied to the electronic control member; if this latter is an electronic tube which is not very sensitive to the reverse voltages, this arrangement has very few disadvantages.
  • the current control member is a transistor and more generally a semiconductor device comprising at least one junction capable of undergoing irreversible changes when it is subjected to a reverse voltage at least equal to a certain characteristic value; known as the "Zener voltage.
  • This arrangement has the disadvantage of limiting to a certain value the overvoltages which can appear on these coils and consequently, as regards specified self-inductance coils, of limiting the speed at which the currents in the said coils can be modified; in the case of the electromagnetic control of deflections of a beam of electrons, it is understood that the arrangement referred to, if it is concerned with protecting the electronic control members against the reverse voltages, has the serious disadvantage of limiting to relatively low values the speed with which the cathode beam can be deviated.
  • the arrangement according to the invention is of the type hereinbefore indicated and it permits of obtaining speeds of variation in the currents flowing through the field coils which are very much higher than those which can be obtained with the known arrangements previously referred to, while nevertheless ensuring the protection of the electronic current control members, particularly transistors, against the reverse voltages which are liable to destroy them; the arrangement according to the invention makes it possible to obtain a very high speed of deflection of a cathode beam.
  • the circuit arrangement according to the invention is characterised in that two diodes are each interposed between a first end of one of the two field coils and a permanent source of supply voltage, and that two switching transistors each have their emitter-collector path interposed between the said first end of one of the field coils and an auxiliary supply voltage source which is of higher value than the permanent supply voltage, while during the period of each increase in current in one of the two coils, the base of the switching transistor connected to the first end of this coil receives an unblocking current from the second end of the other coil.
  • each current control member is almost permanently traversed by an electric power appreciably smaller than in the case of the prior known arrangements, this providing important advantages when the said control members are semiconductor devices and particularly transistors.
  • the cathode beam With the start and end of each increase in the current flowing through one of the two field coils, the cathode beam is thus subjected to very rapid displacements which respectively move it away from and then bring it back to the positions which are imposed on it by the two field coils under constant operation when they are traversed by perfectly symmetrical currents, while during the period of the said increase in current, the cathode beam is subjected to a displacement which is relatively much slower and substantially rectilinear.
  • the above arrangement thus only permits of causing a cathode beam to pass fro-m a first to a second permanent position only along a broken line path, i.e.
  • One particularly advantageous embodiment of the arrangement according to the invention for electromagnetically controlling very rapid deflections of the cathode beam or ray of an electronic tube has the important advantage of being able to control rectilinear deflections of the cathode ray so as to be able to cause the appearance, for example on the fluorescent screen of a cathode ray tube, a straight luminous segment joining two successive permanent positions of the spot of the said ray or beam.
  • This advantageous embodiment of the arrangement according to the invention is characterised in that the emitter-base interval of at least one supplementary transistor is interposed, on the one hand, between the base of each switching transistor connected to the first end of one of the two fiield coils and, on the other hand, to the second end of the other coil, so as to increase the amplification of the unblocking current of the corresponding switching transistor, which is set up in the said other coil, and thus to reduce the transient dissymmetry between the currents in the two coils.
  • FIGURE 1 is the electric circuit of a first embodiment.
  • FIGURE 2 is a diagram representing the wave forms at different points of the circuits of FIGURE 1.
  • FIGURE 3 represents a part of the electric circuit of a second embodiment.
  • the embodiment of the circuit arrangement according to the invention which is illustrated in FIGURE 1 is designed to control electromagnetically the deflections of the cathode ray or beam of an electronic tube; it comprises essentially two field coils 1' and l" and two transistors 2', 2", which are respectively adapted to control the currents passing through these coils 1', 1 and mounted in push-pull.
  • This means that the control signals applied respectively to the control electrodes 3, 3 of the transistors 2', 2 are always in phase opposition, for example synchronous rectangular pulses, and therefore of the same duration but of opposite polarity, and the same amplitude (positive for the electrode 3 and negative for the electrode 3 in the example illustrated in FIGURE 1).
  • These two symmetrical control signals are derived from a single asymmetrical control signal applied to the input terminal 6 of the circuit; this asymmetrical input signal acts on the input of a preamplifier 7, the output of which is connected to the input of an intermediate amplifier stage which is formed in the example illustrated by a transistor 8', of which the base is the control electrode and the collector is connected to a polarization source, while the emitter transmits the output signal to the control electrode 3' of the transistor 2'; a negative feed-back is set up by means of an impedance 9 between the emitter of the transistor 2' and the input of the preamplifier 7'; in this negative feed-back circuit, a signal in phase opposition with the asymmetrical signal applied to the input terminal 6 is extracted; this signal in phase opposition is applied by means of an impedance 10 to the input of a second preamplifier 7", the output of which is likewise connected to the input of an intermediate amplifier stage, likewise formed by a transistor 8" mounted in the same manner as the transistor 8', and the
  • Each of the upper ends a, a" of the coils 1', 1" is connected to a permanent supply voltage source U and to an auxiliary supply voltage source U chosen in such a way as to satisfy the relation lU j lU l, by the intervention of respectively independent electronic switches 4, 4"; each of these electronic switches 4', 4" is formed by a transistor 11, 11", of the n-p-n type in the example illustrated, the emitter of which is connected to the upper end a or a" of the corresponding coil 1' or 1", and the collector is connected to the auxiliary supply voltage source U while its base serves as control input for the corresponding switch; this latter comprises in addition a diode 12', 12", preferably of a semiconductor type, the anode of which is connected to the permanent supply voltage source U while its cathode is connected jointly to the upper end a or a" of the coil 1' or 1".
  • control input of the switch 4' that is to say, the base electrode of the transistor 11'
  • control input of the switch 4" that is to say, the base electrode of the transistor 11
  • FIGURE 1 The operation of the circuit shown in FIGURE 1 will now be described by means of wave form diagrams shown in FIGURE 2; when constant voltages are applied to the bases 12, b" of the two transistors 2, 2", the two transistors 11', 11" are blocked for the reasons which will hereinafter be indicated, while the two diodes 12', 12" are conductive, so that if they are neglected the voltage drops at their terminals, and also the ohmic resistances of the coils 1, 1", the collectors c, c" of the transistors 2, 2" receive voltages which are practically equal to +U it is thus seen that the two transmitters 11', 11 have substantially the same voltage at their bases and at their emitters, this explaining that they are blocked.
  • the transistor 11" does not cease to be blocked and the diode 12" to be conductive, so that the upper end a" of the coil 1" is kept at the voltage +U
  • the current 1 ceasing to vary, no further pulse is applied to the base of the transistor 11', so that the latter is again blocked, and the diode 12', the cathode of which is no longer brought to a voltage higher than the voltage U,, applied to its anode, again becomes conductive; as a consequence, the voltage U is again applied to the upper end a of the coil 1, and also in first approximation to the collector c of the transistor 2.
  • v represents the voltage applied to the upper end a of the coil 1' or 1" and v is the potential of the collector c of the transistor 2' or 2", or given self-inductance coils L.
  • the amplitude of the speed of increase of t' has for example the value and v is close to U while the i then has the since v is close to v t amplitude of the speed of decrease of value t /8 e i designating the emitter current of the transistor 2 or 2" and its current gain, which is generally very much higher than 1; on the other hand, by representing by R, v and u the resistance, the potential and the polarisation voltage, respectively, of the emitter of the transistor 2' or 2", it is obvious that:
  • the field coil 1" sends, by way of its lower end, an unblocking current I' into the base-emitter path of the transistor 11'; as the value of this base current I' of the transistor 11' is connected to that of its emitter current i by the relation I b B in which 5 designates the current amplification of the transistor 11' which, under transient conditions, corresponding to a spectrum extending towards the high frequencies, has a value appreciably smaller than under constant running conditions, and the value i is on the other hand determined by that of v (Formula 4) the fraction of the current i, flowing through the field coil 1", which is shunted in the direction of the base of the said transistor 11', is relatively large; as the voltage pulse which then appears at the lower end of the field coil 1' is negative, and as a consequence it does not unblock the transistor 11', the value of the current i flowing through the said field coil 1' is always given by the above Formula 4', while the Formula 4" is replaced by:
  • T B VN OWQ which shows that, to the extent that their arithmetic mean is no longer constant, the currents i,, and i flowing through two field coils 1 and 1" are no longer symmetrical during the transient running period under consideration, in which v varies.
  • the spot of the cathode ray is not subjected to a uniform displacement throughout the period of the increase in current in the field coil 1; in the usual case, where two pairs of field coils such as 1 or 1" are provided, arranged in such a way as to exert actions perpendicular to one another on the cathode ray of the vacuum tube, for example, along the directions of two orthogonal coordinate axes, it is along the directions of these two axes that the spot of the cathode ray is subject to very rapid displacements at the start and end of each increase in the current i' since there is no linear relationship between these very rapid displacements along the two axes under consideration, it is understood that the resultant very rapid displacements of the spot on the screen do not take place in the direction of the straight line passing through the two permanent positions, respectively the initial and final positions, of the said spot; the latter traces, on the contrary, on the fluorescent screen, a broken line which joins the initial point to the final point.
  • the improvement of the arrangement according to the present invention as illustrated in FIGURE 3 consists in introducing the emitter-base path of a supplementary transistor 13' or 13" between, on the one hand, the base of each transistor 11', 11" connected to the upper end of one of the two field coils 1' or 1" and, on the other hand, the lower end of the other coil 1" or 1'.
  • the collector of each supplementary transistor 13' or 13" is in addition directly connected, like those of the transistors 11', 11", to the auxiliary supply voltage source U
  • a current-limiting resilstance 14 or 14" is interposed between the emitter of each of the supplementary transistors 13, 13 and the base of the corresponding transistors 11 or 11".
  • the comparison of the above Formulae 7 and 13 shows that, by virtue of the improvement under consideration, the current 1' derived at the bottom end of the field coil 1" has a value which is clearly smaller than in the case of the arrangement shown in FIGURE 1, in the case where the current amplification B of the supplementary transistor 13' has a value greater than one.
  • a circuit arrangement for electromagnetically controlling very rapid defiections of an electron beam in a vacuum tube comprising two identical field coils, disposed for push-pull actions on said electron beam, a main D-C voltage supply, two diodes connected to said main supply and to respective first ends of said field coils for passing currents therethrough, two electronic control devices with control electrodes, on which respectively two balanced control signals are impressed, said electronic control devices being respectively connected to said field coils for simultaneously increasing the current through one and decreasing the current through the other of said field coils, an auxiliary D-C supply having a voltage superior in absolute value to that of said main supply, two switching transistors with their respective emitter-collector paths being inserted between said auxiliary supply and said respective first ends of the field coils, and low resistance D-C connection means inserted between the second end of each one field coil and the base of the switching transistor connected to the first end of the other field coil, whereby only the transistor connected to the one field coil having an increasing current therethrough and the diode connected to the other field coil are transiently
  • the low resistance D-C connection means inserted between the second end of each one field coil and the base of the switching transistor connected to the first end of the other field coil comprises the emitter-base path of at least one further transistor, the collector of which is conductively connected to the auxiliary supply.
  • a circuit arrangement for electromagnetically controlling very rapid deflections of an electron beam in a vacuum tube comprising a right and a left identical field coils, disposed for push-pull actions on said electron beam, a main D-C voltage supply, two diodes respectively inserted between said main supply and first ends of said field coils for passing currents therethrough, two semiconductor control devices respectively connected to the second ends of said field coils, said two semi-conductor devices having control electrodes, on which respectively two balanced control signals are impressed for simultaneously increasing the current through one and decreasing the current through the other of said field coils, an auxiliary D-C supply having a voltage superior in absolute value to that of said main supply, a right and a left switching transistors with their respective emitter-collecor paths inserted between said auxiliary supply and said respective first ends of the right and left field coils, the respective bases of said right and left transistors being conductively connected to the respective second ends of said left and right field coils, whereby only the transistor connected to said one field coil having an increasing current therethrough is made
  • a circuit arrangement for electromagnetically controlling very rapid deflections of an electron beam in a vacuum tube comprising two identical field coils, disposed for push puli actions on said electron beam, a main D-C voltage supply, an auxiliary D-C supply having a voltage superior in absolute value to that of said main supply, two controllable, electronic switches, each of said switches having a control input, means for connecting one terminal of said switch to the first end of one of said field coils for switching said first coil end from said main supply to said auxiliary supply only during the time a current pulse of predetermined polarity is applied on its control input, means for connecting a second terminal of said switch to said main supply, means for connecting a third terminal of said switch to said auxiliary D-C supply, two electronic control devices with control electrodes, on which respectively two balanced control signals are impressed, means for connecting said electronic control devices to said field coils for simultaneously decreasing the current through one and increasing the current through the other of said field coils, and means for transmitting a current pulse having said predetermined polarity from the second end of

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US367010A 1963-05-17 1964-05-13 Circuit arrangement for controlling very rapid deflections of an electron beam in a vacuum tube Expired - Lifetime US3337767A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR935224A FR1369395A (fr) 1963-05-17 1963-05-17 Montage pour commander des variations très rapides du courant d'un circuit selfique
FR968094A FR1398810A (fr) 1963-05-17 1964-03-20 Dispositif pour commander des déflexions très rapides du faisceau cathodique d'un tube électronique

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US3337767A true US3337767A (en) 1967-08-22

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US367010A Expired - Lifetime US3337767A (en) 1963-05-17 1964-05-13 Circuit arrangement for controlling very rapid deflections of an electron beam in a vacuum tube

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US (1) US3337767A (nl)
DE (1) DE1229653B (nl)
FR (2) FR1369395A (nl)
GB (1) GB1043376A (nl)
NL (1) NL147595B (nl)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3440485A (en) * 1967-02-24 1969-04-22 Westinghouse Electric Corp Ppi deflection amplifier utilizing energy recovery
US3453555A (en) * 1967-04-19 1969-07-01 Burroughs Corp High speed deflection amplifier
US3470484A (en) * 1967-12-14 1969-09-30 Tektronix Inc Amplifier having push-pull output with current sharing operation
US3628066A (en) * 1969-11-10 1971-12-14 Okonite Co Adjustable frequency bipolar square wave generating circuit
US3628083A (en) * 1969-08-06 1971-12-14 Systems Res Labor Magnetic deflection amplifier utilizing both positive and negative voltage supplies for high-speed deflection
US4054816A (en) * 1976-07-02 1977-10-18 International Business Machines Corporation Sweep circuit for cathode-ray tube display

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3983452A (en) * 1975-03-31 1976-09-28 Rca Corporation High efficiency deflection circuit

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US315573A (en) * 1885-04-14 Miecm geaham tousley
US2912618A (en) * 1957-12-19 1959-11-10 Philips Corp Circuit arrangement in radar receivers for controlling the deflection of the cathode-rays in cathode-ray tube indicators
US3092753A (en) * 1962-01-15 1963-06-04 Hughes Aircraft Co Magnetic deflection apparatus for cathode ray type tube

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US315573A (en) * 1885-04-14 Miecm geaham tousley
US2912618A (en) * 1957-12-19 1959-11-10 Philips Corp Circuit arrangement in radar receivers for controlling the deflection of the cathode-rays in cathode-ray tube indicators
US3092753A (en) * 1962-01-15 1963-06-04 Hughes Aircraft Co Magnetic deflection apparatus for cathode ray type tube

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3440485A (en) * 1967-02-24 1969-04-22 Westinghouse Electric Corp Ppi deflection amplifier utilizing energy recovery
US3453555A (en) * 1967-04-19 1969-07-01 Burroughs Corp High speed deflection amplifier
US3470484A (en) * 1967-12-14 1969-09-30 Tektronix Inc Amplifier having push-pull output with current sharing operation
US3628083A (en) * 1969-08-06 1971-12-14 Systems Res Labor Magnetic deflection amplifier utilizing both positive and negative voltage supplies for high-speed deflection
US3628066A (en) * 1969-11-10 1971-12-14 Okonite Co Adjustable frequency bipolar square wave generating circuit
US4054816A (en) * 1976-07-02 1977-10-18 International Business Machines Corporation Sweep circuit for cathode-ray tube display

Also Published As

Publication number Publication date
FR1369395A (fr) 1964-08-14
DE1229653B (de) 1966-12-01
FR1398810A (fr) 1965-05-14
GB1043376A (en) 1966-09-21
NL147595B (nl) 1975-10-15
NL6405513A (nl) 1964-11-18

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