GB1595105A - Circuit arrangement for controlling the deflecting coil of a picture tube - Google Patents

Circuit arrangement for controlling the deflecting coil of a picture tube Download PDF

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Publication number
GB1595105A
GB1595105A GB4510477A GB4510477A GB1595105A GB 1595105 A GB1595105 A GB 1595105A GB 4510477 A GB4510477 A GB 4510477A GB 4510477 A GB4510477 A GB 4510477A GB 1595105 A GB1595105 A GB 1595105A
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GB
United Kingdom
Prior art keywords
current
resistor
circuit
currents
urv
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
Application number
GB4510477A
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.)
Licentia Patent Verwaltungs GmbH
Licentia Oy
Original Assignee
Licentia Patent Verwaltungs GmbH
Licentia Oy
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 Licentia Patent Verwaltungs GmbH, Licentia Oy filed Critical Licentia Patent Verwaltungs GmbH
Publication of GB1595105A publication Critical patent/GB1595105A/en
Expired legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G1/00—Control arrangements or circuits, of interest only in connection with cathode-ray tube indicators; General aspects or details, e.g. selection emphasis on particular characters, dashed line or dotted line generation; Preprocessing of data
    • G09G1/04—Deflection circuits ; Constructional details not otherwise provided for
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/30—Single-ended push-pull [SEPP] amplifiers; Phase-splitters therefor
    • H03F3/3083—Single-ended push-pull [SEPP] amplifiers; Phase-splitters therefor the power transistors being of the same type
    • H03F3/3086—Single-ended push-pull [SEPP] amplifiers; Phase-splitters therefor the power transistors being of the same type two power transistors being controlled by the input signal
    • H03F3/3091—Single-ended push-pull [SEPP] amplifiers; Phase-splitters therefor the power transistors being of the same type two power transistors being controlled by the input signal comprising two complementary transistors for phase-splitting
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K6/00—Manipulating pulses having a finite slope and not covered by one of the other main groups of this subclass
    • H03K6/02—Amplifying pulses
    • 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

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  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Power Engineering (AREA)
  • Amplifiers (AREA)
  • Details Of Television Scanning (AREA)

Description

(54) A CIRCUIT ARRANGEMENT FOR CONTROLLING THE DEFLECTING COIL OF A PICTURE TUBE (71) We, LICENTIA PATENT-VERWALTUNGS G.m.b.H., of I Theodor-Stern-Kai, 6 Frankfurt/Main 70 Federal Republic of Germany, a German body corporate, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and.by the following statement:- The invention relates to a circuit arrangement for controlling the deflection coil of a cathode ray picture tube, for providing a current which is proportional to any desired voltage shape which has been predetermined.
Control circuits for deflection coils of a picture tube are generally known. One type of circuit is described for example on pages 368 and 369 of the book by Tietze, Schenk "Halbleiter-Schaltungstechnik" ("Semiconductor Circuit Technology"), Springer-Verlag, 1974 (Illustration 12.13). Furthermore, it is known to switch an operational amplifier disposed in front of this type of control circuit and to include negative feedback in the control circuit in order to obtain a precision amplifier (page 377 of the said item of literature). In this way it is desired to obtain an amplifier which has good input data for the operational amplifier used. However it is disadvantageous that the operational amplifier limits the bandwidth of the arrangement to relatively low values. Furthermore, two operational amplifiers connected in inverting manner are required for the example first mentioned (Illustration 12. 13) in order to achieve an oppositely oriented feedback as a result of a phase shift of 1800 between their input and output.
The above-mentioned disadvantages may be avoided by bypassing the operational amplifier or amplifiers at high frequencies and passing the input signal direct to the final stage. However the drive circuit of the final stage must then have a sufficiently large voltage amplification in this frequency range so that even at high frequencies there is still sufficient overall amplification.
A general arrangement and a precision amplifier are shown in Illustrations 12.23 and 12.24 of the item of literature mentioned. However, it has been proved that the precision amplifier shown is relatively susceptible to interference.
A broadband amplifier has also already been proposed (German Patent Application P 26 23 379.4) in which control transistors have their collectors coupled with the bases of final transistors in order to produce a voltage-controlled current, the collectors being connected together and driving their current into a deflection coil. A part of the voltage present at the connecting point of the collectors of the final transistors in thus fed back into the driver stage and a differentiating stage is connected in parallel with the signal branch such that addition of the output signal of the differentiating stage to the input signal takes place whereby setting of the amplitude for the purpose of compensating the increase in response time of the amplifiers is undertaken. It has been proved that this arrangement has only a relatively small bandwidth.
The invention seeks to provide a circuit arrangement which is not susceptible to interference, has a good zero point stability and a high bandwidth.
According to the invention there is provided a circuit arrangement for controlling the deflection coil of a cathode ray tube with a current proportional to a desired predetermined voltage shape, the circuit arrangement comprising a broadband amplifier as preamplifier, a constant current source having a respective circuit for pro producing positive or negative currents connected via respective resistors symmetrical to the signal input, to the output of the broadband amplifier, whereby signal currents from the amplifier are combined with the respective positive or negative current, a power amplifier connected by its output to the deflection coil, the power amplifier comprising two complementary end stages, each having two transistors in cascade, each stage being connected by its input to one of the positive or negative current producing circuits to receive the combined currents therefrom and both being connected by their outputs jointly to the deflection coil and a negative feed back circuit between input and output of the circuit arrangement, the arrangement being such that the deflection coil current is inversely proportional to the value of the said resistors.
Voltage feedback from the deflection coil may take place via an RC network and current feed may take place via resistors.
A substantial advantage is the use of a simple resistor for controlling the current source.
An embodiment is shown in the drawings in accordance with the invention, by way of example only:- Fig. 1 shows a block diagram of the arrangement of the invention, Fig. 2 shows a circuit diagram illustrating in greater detail an arrangement in accordance with the invention, and Fig. 3 shows a general example of calculation for the purpose of explaining the mode of operation of the circuit of Figure 2.
In Figure 1 an input voltage U5 is supplied to an operational amplifier 1 which controls a current source 2 via a resistor not shown. The current source 2 supplies an amplifier 3 which contains for example two Darlington final stages or one Darlington final stage and one complementary Darlington final stage. The amplifier 3 is connected to the deflection coil 4 of a picture tube not shown in the drawing and to a load resistor 5. A voltage feedback line 6 coupled with the circuit input is connected to the connecting line between the amplifier 3 and the deflection coil 4. A current feedback takes place by means of an electrical line 7 to the circuit input, the line 7 being connected to the connecting line between the deflection coil 4 and the load resistor 5.
The circuit diagram shown in Figure 2 shows construction of the blocks 1 to 3 shown in Figure 1 in greater detail these being indicated by broken lines in this Figure. Furthermore, in Figure 2 the rest of the electrical components 4 to 7 shown in Figure 1 are drawn in, as well as extensive circuit connections. Resistors R, and R4 and the capacitors C1 to C3, serve to connect the operational amplifier 1. The RC network provided for the voltage feedback is made up of resistors R7 and R9 and the capacitor C5 whilst the resistors R2 and R3 are used for current feedback.
The constant-current source 2 has circuits for producing either positive or negative currents. The first circuit comprises a Zener diode CRX connected to the positive pole of a direct voltage source UB1 the Zener diode being connected in series with a resistor R14. The connecting line between the Zener diode CRR and the resistor R14 is connected to the base of a transistor Q1, the emitter of which is coupled to the positive pole of the direct voltage source UB1 B via a resistor R,6 having a parallel connected capacitor C13 and its collector is coupled to the base of a transistor Q3. The transistor Q3 is the input transistor of a Darlington circuit Q3 Q5 which forms a first half of the power amplifier 3, the complementary half circuit being constituted by Q5, Q6.
The second circuit of the current source for producing negative currents has similar components to the first circuit for producing positive currents. The construction elements of the second circuit are designated CR4, R1S. R18, C14, and Q2. Thus it should be noted that the Zener diode CR4 and the resistor R,8 are connected to the negative pole of the direct voltage source U82. The collector of the transistor Q2 is routed to the base of an input transistor Q4 of the complementary half circuit.
The base of a further transistor Q5 is connected to the emitter of the input transistor Q3 to form therewith the Darlington circuit. A capacitor C7 and resistor R20 connect this base to the emitter of Q5. To this emitter are connected the voltage feedback line 6, the emitter of Q4 and the collector of Q6.
The collector of the input transistor Q4 is coupled via a capacitor Ca and a resistor R2, to the negative pole of the direct voltage source UB2 and furthermore is electrically connected to the base of the related output transistor Q6.
The deflection coil 4 of the picture tube which is not shown graphically is connected to the connecting line between the emitter of the input transistor Q4 and the resistor R20 as well as to the connecting line between the emitter of the transistor Q6 and the collector of the transistor Q6. The other end of the deflection coil 4 is routed to the current feedback line 7 and an earthed measuring resistor 5.
Control of the current source 2 by the operational amplifier 1 takes place via resistors R10 and R,2. The resistor R10 is electrically connected at one end to the connecting line between the resistor R,6 and the emitter of the transistor Q, of the circuit for producing the positive currents. The resistor R,2 is electrically connected to the connecting line between the resistor R18 and the emitter of the transistor Q2 of the circuit for producing the negative currents.
In Figure 3 the portion of the circuit arrangement which is of interest for the purpose of explaining the invention is shown with its currents and its voltages.
Thus: RV=Operational amplifier IK1, IK2=Constant currents of the two sources URV=Output voltage of the operational amplifier U61, UB2=Battery voltages UR16; URl8=Constant voltage sources l,=Load current (input current for the next stage) If the two outer mesh rotations a and b are considered then the following equations ensue: a) UB1-URV-I1 . R10-U516=0 (1) b) UB2+URV-I2 . R12-UR18=0 (2) The following equations can be written for the three junctions c, d and e: c) |K1 I, I =0 (3) d) 1K2+12+I"=0 (4) e) I'-I"-IL=0 (5) From these equations the following is determined as load current I,: UB2+URV-UR18 UB1-URV-UR16 I,= (6) R12 R10 If a symmetrical construction is a precondition, then it is: UB1|=|Ub2|; |IK1|=IK2|; |UR16|=|UR18 R,o=R12 So equation (6) is simplified to the expression: 2. URV 2. URV I,= = (73 R10 R.2 As a result it is established that the load current I, is proportional to twice the amplifier output voltage URV and is inversely proportional to the resistors Rlo or R,2 respectively. Thus a simple relationship for designing symmetrical circuits has been stated.
WHAT WE CLAIM IS: 1. A circuit arrangement for controlling the deflection coil of a cathode ray tube with a current proportional to a desired predetermined voltage shape, the circuit arrangement comprising a broadband amplifier as preamplifier, a constant current source having a respective circuit for producing positive or negative currents connected via respective resistors symmetrical to the signal input, to the output of the broadband amplifier, whereby -signal currents from the amplifier are combined with the respective positive or negative currents, a power amplifier connected by its output to the deflection coil, the power amplifier comprising two complementary end stages, each having two transistors in cascade, each stage being connected by its input to one of the positive or negative current producing circuits to receive combined current therefrom and both being connected by their
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

  1. **WARNING** start of CLMS field may overlap end of DESC **.
    transistor Q6 and the collector of the transistor Q6. The other end of the deflection coil 4 is routed to the current feedback line 7 and an earthed measuring resistor 5.
    Control of the current source 2 by the operational amplifier 1 takes place via resistors R10 and R,2. The resistor R10 is electrically connected at one end to the connecting line between the resistor R,6 and the emitter of the transistor Q, of the circuit for producing the positive currents. The resistor R,2 is electrically connected to the connecting line between the resistor R18 and the emitter of the transistor Q2 of the circuit for producing the negative currents.
    In Figure 3 the portion of the circuit arrangement which is of interest for the purpose of explaining the invention is shown with its currents and its voltages.
    Thus: RV=Operational amplifier IK1, IK2=Constant currents of the two sources URV=Output voltage of the operational amplifier U61, UB2=Battery voltages UR16; URl8=Constant voltage sources l,=Load current (input current for the next stage) If the two outer mesh rotations a and b are considered then the following equations ensue: a) UB1-URV-I1 . R10-U516=0 (1) b) UB2+URV-I2 . R12-UR18=0 (2) The following equations can be written for the three junctions c, d and e:
    c) |K1 I, I =0 (3) d) 1K2+12+I"=0 (4) e) I'-I"-IL=0 (5) From these equations the following is determined as load current I,: UB2+URV-UR18 UB1-URV-UR16 I,= (6) R12 R10 If a symmetrical construction is a precondition, then it is: UB1|=|Ub2|; |IK1|=IK2|; |UR16|=|UR18 R,o=R12 So equation (6) is simplified to the expression: 2. URV 2. URV I,= = (73 R10 R.2 As a result it is established that the load current I, is proportional to twice the amplifier output voltage URV and is inversely proportional to the resistors Rlo or R,2 respectively. Thus a simple relationship for designing symmetrical circuits has been stated.
    WHAT WE CLAIM IS: 1. A circuit arrangement for controlling the deflection coil of a cathode ray tube with a current proportional to a desired predetermined voltage shape, the circuit arrangement comprising a broadband amplifier as preamplifier, a constant current source having a respective circuit for producing positive or negative currents connected via respective resistors symmetrical to the signal input, to the output of the broadband amplifier, whereby -signal currents from the amplifier are combined with the respective positive or negative currents, a power amplifier connected by its output to the deflection coil, the power amplifier comprising two complementary end stages, each having two transistors in cascade, each stage being connected by its input to one of the positive or negative current producing circuits to receive combined current therefrom and both being connected by their
    outputs jointly to the deflection coil and a negative feed back circuit between input and output of the circuit arrangement, the arrangement being such that the deflection coil current is inversely proportional to the value of the said resistors.
  2. 2. A circuit arrangement according to Claim 1, wherein each circuit for producing positive currents or negative currents has a Zener diode which lies in series with a resistor and which is applied to the positive or negative pole of a d.c.
    voltage source the connecting line between the Zener diode and the resistor is connected to the base of a transistor the emitter of which is connected via a resistor having a parallel capacitor to the positive or negative pole of the d.c. voltage source; and wherein the collectors of both transistors are electrically conductively connected to each other via diodes and are connected to the base of the input transistors of the related complementary end stage.
  3. 3. A circuit arrangement according to Claim I or 2, wherein voltage feedback from the deflection coil is provided by R-C network and current feedback is effected via resistors.
  4. 4. A circuit arrangement for feeding the deflection coil of a cathode ray tube substantially as described herein with reference to the drawings.
GB4510477A 1976-10-29 1977-10-28 Circuit arrangement for controlling the deflecting coil of a picture tube Expired GB1595105A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19762649718 DE2649718C3 (en) 1976-10-29 1976-10-29 Circuit arrangement for controlling the deflection coil of a picture tube

Publications (1)

Publication Number Publication Date
GB1595105A true GB1595105A (en) 1981-08-05

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ID=5992024

Family Applications (1)

Application Number Title Priority Date Filing Date
GB4510477A Expired GB1595105A (en) 1976-10-29 1977-10-28 Circuit arrangement for controlling the deflecting coil of a picture tube

Country Status (2)

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DE (1) DE2649718C3 (en)
GB (1) GB1595105A (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE420142B (en) * 1980-04-01 1981-09-14 Ericsson Telefon Ab L M CIRCUIT FOR CONTROL OF THE VILO DRUM IN A CLASS AB AMPLIFIER STEP
DE3420312C2 (en) * 1984-05-30 1986-10-09 SGS Halbleiter-Bauelemente GmbH, 8018 Grafing Control circuit for a deflection power transistor
DE19600593C1 (en) * 1996-01-10 1997-04-03 Schwerionenforsch Gmbh Amplifier especially for generating high voltage signals

Also Published As

Publication number Publication date
DE2649718A1 (en) 1978-05-03
DE2649718B2 (en) 1978-11-09
DE2649718C3 (en) 1979-07-05

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PS Patent sealed
PCNP Patent ceased through non-payment of renewal fee