CN1037816A - E-w raster correction circuit - Google Patents
E-w raster correction circuit Download PDFInfo
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- CN1037816A CN1037816A CN88103052A CN88103052A CN1037816A CN 1037816 A CN1037816 A CN 1037816A CN 88103052 A CN88103052 A CN 88103052A CN 88103052 A CN88103052 A CN 88103052A CN 1037816 A CN1037816 A CN 1037816A
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Abstract
The E-W modulated current that is produced by an E-W control circuit passes through a class A amplifier (Q
2) be added to deflection circuit output stage (100), be used as a current source at retrace interval with high output impedance.This current source has prevented that retrace interval is at kickback transformer (T
1) high-tension coil (W
1) and comprise deflecting coil (L
H) flyback resonant circuit (27) between the signal coupling that occurs with the flyback frequency.The mean value that described high output impedance has been kept modulated current is not subjected to the influence of the flyback voltage amplitude that produced by flyback resonant circuit (27) at retrace interval.Prevented from thus to change the mouse tooth distortion that causes because of the second plate voltage loads.
Description
The present invention relates to a kind of deflection circuit, in this deflection circuit, the variable-magnitude of deflection current, or the modulated current that can be provided by the semiconductor element end with high output impedance in wide relatively scope is modulated.(for example), the modulation of deflection current amplitude is needed for proofreading and correct outside and inner East and West direction (E-W) pincushion distortion.
In general, horizontal-deflection circuit comprises an output stage, and this output stage comprises a line deflector coil and a sweep capacitor, and this capacitor provides deflection current to deflecting coil in every period sweep time.A flyback capacitor is connected across on the deflecting coil, forms flyback resonant circuit at retrace interval.Retrace interval, energy is replenished by kickback transformer.
The heavy duty of the high electron beam current in the kickback transformer secondary coil comes across during the demonstration, for example, each the white level striped on the cross-hatch pattern (the cross Ratch Pattern) has promptly been represented in the heavy duty of retrace interval to kickback transformer.
In the circuit of some prior art, flyback resonant circuit is the primary coil that is connected to kickback transformer by one of the E-W control circuit less relatively modulation inductance, and at retrace interval, owing to there is above-mentioned load, flyback capacitor may discharge on a small quantity.As a result, discharging current can enter flyback capacitor by deflecting coil from sweep capacitor, and during the white level striped of cross-hatch pattern, the voltage at sweep capacitor two ends has a small amount of decline.Electric charge on the sweep capacitor is replenished at the retrace interval relevant with scan line, and scan line is the show black image part under the form of the netted striped of white.This can cause a reverse little electric current by deflecting coil.The charging of sweep capacitor and discharging current can produce a little pattern displacement, and the result is with the sweep current in the form modulation deflecting coil of low-frequency oscillation.This low frequency modulations can cause on each vertical stripes of cross-hatch pattern and zigzag occur, rather than straight line.Zigzag directly appears under the intersection point of given vertical stripes and horizontal stripe.This distortion use sometimes " mouse tooth " (mouseteeth) distortion represent.They come across the instantaneous appearance of high electron beam current during and just occurred after because represent the deflection circuit of Low ESR flywheel that the energy demand of instantaneous increase is provided for the second plate circuit.Like this, energy is delivered to the variation that this anode circuit can help to cause deflection yoke scan current from deflection circuit.
Announced July 3 at the application 2150796A(1985 that announces such as Britain), corresponding United States Patent (USP) № 4,634,937, name is called East and West direction E-W correcting circuit and (authorized PEHaferl on January 6th, 1987, promptly be called the Haferl patent here) described in a kind of device, adopting provides a kind of and can reduce " Mouseteeth " distortion by an E-W control circuit by the E-W modulated current that a choke with high impedance produces.This choke causes a downward-sloping electric current (in fact being direct current) to the line frequency components integration, and this electric current flows to the E-W control circuit from deflection circuit.At retrace interval, avoided being referred to as the deflection disturbance of mouse tooth " mouseteeth " owing to the weak coupling between kickback transformer and the deflecting coil.Weak coupling is provided by choke, and this choke provides high-frequency isolation for deflection circuit output stage and E-W control circuit.Because suitable choke may be very expensive, the most not hope of people use such choke to reduce " mouse tooth " distortion.
According to a kind of form of the present invention, the deflection circuit output stage that the frequency input signal relevant with deflection frequency worked comprises a flyback capacitor, and this capacitor is connected to deflecting coil to form a flyback resonant circuit at retrace interval.The feed inductance produces a pulse voltage at retrace interval according to input signal, and this voltage is coupled to load circuit.The E-W control circuit that secondary signal is worked, the modulated current of a second frequency of generation, this modulated current is coupled to flyback resonant circuit by a semiconductor device with high output impedance.The high output impedance of semiconductor device is isolated feed inductance and flyback resonant circuit, to prevent that load variations in the load circuit is to the influence of flyback resonant circuit.
Chromoscope with large-screen such as the 45AX picture tube of Philips, needs a large amount of inside pincushion corrections.Deflection circuit generally comprises a deflection transistor switch in parallel with the damper diode device, and this switch is with deflection frequency work.In scan period, by an inside pincushion correction electric current that is connected to the inside pincushion correction circuit generation of sweep capacitor, can reverse nocuously deflection damper diode device.
When the damper diode device comprises the diode of (for example) pair of series connection, mostly need be connected to ground to the link between the diode that is connected in series by conductive switch, so that first half cycle scan period by one of them diode clamp, the collector voltage that makes the deflection transistor switch is to earth potential.
According to another kind of form of the present invention, the front was narrated, and had high output impedance and provided the transistor of modulated current to be connected on the link between the diode at retrace interval to outside E-W distortion correction circuit.Thisly provide the transistor of modulated current, play a on-off action in the scan period conducting at retrace interval.So just help the transistorized collector voltage of deflection switch is clamped at and approach on earthy current potential.
In the accompanying drawings:
Fig. 1 shows a deflection circuit that embodies a kind of form of the present invention, and this circuit has comprised inner pincushion correction device;
Fig. 2 a-2f shows the waveform that helps key diagram 1 circuit;
Fig. 3 a-3e shows additional waveform useful when key diagram 1 circuit;
Fig. 4 a-4b shows the waveform that occurs at retrace interval, and these waveforms are useful when the circuit of key diagram 1;
Fig. 5 shows second embodiment of the present invention;
Fig. 6 a-6e shows the waveform relevant with the circuit of Fig. 5;
Fig. 7 shows the not cross-hatch pattern of timing of " mouse tooth " distortion;
Fig. 8 shows the part deflection circuit that constitutes third embodiment of the invention.
The deflection circuit 100 of Fig. 1 has embodied a kind of form of the present invention, and it can provide the horizontal deflection of electron beam for 110 ° of 45AX FS of (for example) Philips chromoscope (model A66-EAK00 * 01).In Fig. 1, the direct voltage of voltage regulation B+ that is added between terminal 22 and the ground passes through low resistance R
1Be connected to the terminal 22a of the primary coil W1 of horizontal equilibrium flyback transformer T1.The other end of coil W1 is connected to link 23.Filtering capacitor C1 is connected to ground from terminal 22a.Voltage of voltage regulation B+ is produced by (for example) Switching Power Supply 90.The secondary coil W3 of transformer T1 provides a second plate voltage U by rectifier diode D40.
Line output transistor Q1 is with deflection frequency f
HWork, its base stage are connected to conventional driving and oscillating circuit 50, and transistorized collector electrode to emitter path is connected between link 23 and the ground.Circuit 50 comes synchronously by synchronizing signal Hs with the flyback pulse that signal Hr represents in a well-known manner.In parallel with transistor Q1 is the tandem arrangement of two rectifying tube D1 and D2, and diode D1 and D2 work as the damper diode device.That be connected in parallel with the anode of diode D1 and negative electrode is line deflector coil L
HDevice, this coil is connected to a S shape or sweep capacitor Cs.Deflection flyback capacitor C
RDAnode and negative electrode same and diode D1 are connected in parallel, with deflecting coil L
HForm a flyback resonant circuit 27 in parallel together.The second flyback capacitor C
RTBe connected between link 28 and the ground.A low value capacitor Cp is connected between terminal 23 and the ground.Capacitor Cp is used for the resonance frequency of fine tuning flyback resonant circuit 27.The end points 28(that is connected deflecting coil LH is at capacitor C
RTWith capacitor C
RDBetween tie point) and ground between be the tandem arrangement that diode D3 and controllable E-W current source 25 formed, this current source comprises a downward-sloping transistor Q2 of electric current that has high output impedance at the retrace interval collector electrode.The collector electrode of transistor Q2 is connected to terminal 28 by diode D3, so that a downward-sloping current i through ovennodulation to be provided
3, this electric current is with the vertical-parabola variation.Diode D3 makes transistor Q
2Collector electrode in that to enter scanning terminal, as diode D
2Isolate with ground during conducting, thereby prevent the preceding transistor Q of flyback
2Collector current is saturated.
An inner pincushion correction circuit 60 comprises that is connected a capacitor C
sAnd inductance L
HThe inductance L of the end points 60a of contact place
1The capacitor C of circuit 60
6Be connected between end points 60b and the ground.
Between first half period of scanning, deflection current i
1With the direction opposite with arrow at deflecting coil L
HWith diode D
1Middle circulation.Between second half period of scanning, deflection current i
1With the arrow direction at deflecting coil L
H, diode D
2Circulate among the transistor Q1 of conducting.During the end of scan, transistor Q1 ends, and produces flyback voltage V between end points 23 and ground
1
At retrace interval, flyback capacitor C
RTIn the electric charge diode D that flowed through
3E-W modulation inclination current i
3Take away.At whole retrace period integrated value ∫ i
3Dt is high more, then capacitor C for example
RDThe flyback voltage V at two ends
41Just become big more, and capacitor C
RTThe own modulation voltage V at two ends
3It is more little to become.In the scan period, by deflecting coil L
HDeflection current i
1Peak value directly and in the middle of the retrace period, capacitor C
RDThe flyback voltage V at two ends
41Peak value relevant.By with frame frequency frequency modulation(FM) transistor Q
2Current i
3, switched current source 25 is to the line scanning current i
1Outside pincushion correction is provided.As will illustrating below, the modulated current i in each retrace period
3Mean value control with a kind of like this method: its keeps not being subjected to flyback voltage V
3Influence.Like this, with respect to current i
3Mean value, transistor Q
2Formed a high output impedance.
According to a kind of form of the present invention, the above-mentioned transistor Q that is inserted between coil W1 and the flyback resonant circuit 27
2High output impedance, prevented the retrace interval of being expert at, undesirable high fdrequency component produces coupling by current source 25 between the coil W1 of kickback transformer T1 and flyback resonant circuit 27, that is, in other words, this coupling will cause " mouse tooth " distortion.In addition, transistor Q
2High output impedance prevented that any flyback voltage is to providing the transistor Q of E-W modulation
2Collector current exerts an influence.On the contrary, in the circuit of some prior arts, " mouse tooth " distortion is (the present invention replaces with transistorized high output impedance) that provides the E-W modulated current to prevent by a choke with high impedance.Yet not enough is that choke may be very expensive.Narrated in the Haferl patent that the example of this prior art has been mentioned in the above.
Capacitor C
RTBy ground and capacitor C
1Be connected to coil W1 to form second flyback resonant circuit, this resonant circuit is connected with flyback resonant circuit 27, comprises coil W1 thereby form one, capacitor C
RTCombination flyback resonant circuit with flyback resonant circuit 27.This combination flyback resonant circuit is tuned to (for example) flyback frequency.For the combination resonant circuit be tuned to the flyback frequency, flyback resonant circuit 27 and comprise coil W1 and capacitor C
RTSecond flyback resonant circuit by respectively be tuned to may be lower than on the frequency of flyback frequency.
Capacitor C
RTProduce flyback voltage at coil W1 two ends, this voltage side by side appears at deflecting coil L
HTwo ends.Therefore, the flyback voltage H at the coil W4 two ends of synchronizing information is provided to driver and oscillator 50
rAdvantageously include and resemble deflecting coil L
HOn flyback voltage or resemble capacitor C
RDThe same synchronizing information of last voltage V41.Capacitor C
RTAct on and done detailed description in the Haferl patent.
Select capacitor Cp, C
RDAnd C
RTValue obtaining correct flyback time, and avoid in the flyback time voltage V
1Modulation.Capacitor C
RTDecision minimum deflection current amplitude, this electric current is equivalent to current i
3(being zero).
Except when flyback begins, as transistor Q
2The transistor Q of E-W control circuit 25 among Fig. 1 can appear when still being in saturation condition outside the cycle of a weak point immediately
2Be expert at all the other times of retrace period, all as the work of Class A inclination current amplifier.Transistor Q
2In the inclination current i
3In resistance R
4Proportional feedback voltage V of last generation
R4, this resistance is connected transistor Q
2Emitter and ground between.Voltage V
R4Feed back to transistor Q by resistance R 5
3Base stage.Transistor Q
3Collector electrode be connected to transistor Q at end points 25a place
2Base stage.At retrace interval, the inclination current i
3Mean value because (for example) resistance R
4And R
5Negative feedback arrangement make it not be subjected to voltage V
3The shape and the influence of changes in amplitude and keep independent.Therefore, at transistor Q
2Collector electrode on, for the flyback frequency be higher than the current i of flyback frequency
3Mean value set up high output impedance, the inclination current i
3Mean value be resistance R by wide region control
11Regulate, this resistance is according to frame parabolic voltage V
10(narration below) decides transistor Q
3Emitter voltage.Like this, current i
3Mean value under frame frequency speed, press voltage V
10Modulated with the parabolic shape form.
Fig. 2 a-2f, 3a-3e and 4a-4b show the waveform that helps key diagram 1 device work.At Fig. 1, identical label and symbolic representation components identical or function among the 2a-2f, 3a-3h and 4a-4b.
The parabolic voltage V of Fig. 1
10Be (for example) capacitor C by the frame deflection circuit 300 of routine
cLast generation, the parabolic voltage V of Fig. 3 d
10By blocking capacitor C
4, resistance R
14With an adjustable E-W controlling resistance R
12Be ac-coupled to the transistor Q among Fig. 1
3Emitter.
Flyback voltage V
3Be by diode D
3With integrating circuit or resistance R
2With capacitor C
2The low pass filter of forming (this filter output frequency is higher than frame frequency) connects.Voltage through low pass filter passes through resistance R
3Be added to transistor Q
3Emitter.At capacitor C
2The low frequency negative feedback voltage of last generation causes voltage V
3Mean value press frame frequency parabolic voltage V in the vertical-parabola mode
10Change.Since degenerative cause, (for example) voltage V
3The frame frequency envelope peak with from voltage V
10What obtain is added in transistor Q
3Penetrate-frame parabolic voltage that Ji ties has inverse relationship.This by resistance R
2And R
3The low frequency feedback device that constitutes has played the DC stabilization effect, has improved linearity simultaneously.
Be added to transistor Q simultaneously
3Base stage be frame sawtooth voltage V as keystone
11Adjustable part (shown in Fig. 3 e), this voltage is that the resistance R s from Fig. 1 obtains.The capacitor Cc of resistance R s and frame deflector coil Lv and circuit 300 is connected in series.
At retrace interval, current i
3downward-slopingly have a waveform that is included among Fig. 1) be by by resistance R
6With capacitor C
3The low pass filter that composes in parallel obtains, and described resistance and capacitor all are connected transistor Q
2Base stage and ground between.Resistance R
4On negative feedback voltage V
R4Make capacitor C
3On voltage become higher, and the current i when flyback is begun
3Bigger when finishing than flyback.Like this, since degenerative effect, voltage V
R4Trend descends, current i
3By capacitor C
3Discharge gradually.This advantage is transistor Q
2Power consumption can maintain low magnitude (as 2 watts), this is owing to when flyback begins, work as current i
3When bigger, corresponding to the voltage V of waveform among Fig. 1 than the flyback end
3Still be low.Such benefit is, the modulation dynamic range of control circuit 25 is (for example by the current i of retrace interval
3Mean value decision) increased.
At second half cycle of flyback, the high electron beam load electric current of the transformer T1 coil W3 that flows through causes voltage V
3Downward-sloping, and shown in Fig. 2 f, can be to voltage V
3Additional harmonic oscillation.Flyback pulse voltage V
3Width placed restrictions on modulation dynamic range equally, this pulse duration is by as voltage V
3By the diode D among Fig. 1
2Clampedly determine to earth potential moment.In second flyback half cycle, because the current i of Fig. 2 e
3Be downward-sloping, and at second flyback half cycle, voltage V
3Downward-sloping steepness compares current i
3It is little when retrace interval arrives (for example) fixed value.Thereby further increased dynamic range.
Inner pillow distortion equalizing is according to an inner pincushion correction modulated current i
2(the capacitor C in the inner pincushion correction circuit 60 of flowing through
6And inductance L
1) and make deflection current i
1Become serpentine to finish.In scan period, current i
2(comprise deflecting coil L to be higher than the scanning resonant circuit
HWith sweep capacitor C
s) certain frequency of scanning resonance frequency flow through and comprise sweep capacitor C
sCurrent path the time, changed sweep capacitor C
sOn voltage Vcs.Current i
2The terminal 28 of amplitude in Fig. 1 on by the voltage V among Fig. 2 f
3Modulate, to provide inner pincushion correction, current i
2Amplitude big more, thereby the peak-to-peak amplitude of the scanning voltage Vcs of the generation high more deflection current i that is provided that makes just
1The amount of serpentine also big more, vice versa.With RCA Corp.'s name application, the name of announcing on September 9th, 1987 is called among the European publication application № 0236064 of " pincushion correction in the deflection circuit " has made more detailed description to the work of circuit 60.
The capacitor C of circuit 60
6And inductance L
1With sweep capacitor C
sWith deflecting coil L
HFormed the resonant circuit part of correcting circuit 60 in scan period.The resonant circuit of circuit 60 is partly by inductance L
1Be tuned to be lower than frequency f
HFrequency on so that current i
2The end of scan of being expert at can not reach null value before; And it is tuned to than deflecting coil L
HWith sweep capacitor C
sOn the much higher frequency of the scanning resonant circuit frequency of forming.When but correcting value needs timing, inner ditty system inductance L
1It can be changeable type.For all reference values of the circuit shown in Fig. 1, inductance L
1Can make the resonant circuit of circuit 60 partially-tuned to (for example) 14KHz.
By deflection current i
1The voltage Vcs part that causes is the parabolical waveform normally, and in each line period H, it comprises scanning and the sinusoidal wave part of flyback respectively.In scan period, the sinusoidal wave part of corresponding voltage Vcs is to approximate coil L
HWith capacitor C
sThe frequency of scanning resonance frequency on.This resonance frequency (for example) approximates 7KH
zAt retrace interval, corresponding sinusoidal wave part is about 44KH
z
Inductance L
1With capacitor C
6Be included in the branch circuit, in scan period, this branch and sweep capacitor C
sIn parallel.Between first half period of scanning, resonance current i
2With the direction opposite with arrow from ground, by capacitor C
6, inductance L
1, capacitor C
s, diode D
1, the deflection transistor Q1 of conducting returns ground.Between second half period of scanning, current i
2Direction circulation with arrow: pass through diode D from ground
2, capacitor C
s, inductance L
1With capacitor C
6And get back to ground.
At retrace interval, deflection current i
1Comprising flyback capacitor C
RD, deflecting coil L
HWith sweep capacitor C
sCirculate in the current path of forming.Sweep capacitor C
sProvide Low ESR at retrace interval, to prevent current i
1Comprising capacitor C at whole retrace interval
6And inductance L
1The branch road of circuit 60 in circulate.Because in the retrace interval inductance L
1By capacitor C
s, the bypass of deflection inductance, and flyback voltage V
1In fact be not subjected to inductance L
1Influence, therefore, when the deflection circuit among Fig. 1 100 is operated in higher deflection frequency (for example 2XfH), can help adopting lower voltage level B+.
Be expert at scan period the voltage V among Fig. 1
3Shown in Fig. 2 f, remain on zero.In the middle of frame scan, work as current i
3When reaching maximum, line flyback voltage V
3Be in the such minimum value of (for example) zero volt.Therefore, in this case, be exactly capacitor C
sOn scanning voltage Vcs, produced resonance current i
2Work as current i
3When maximum, capacitor C flows through among Fig. 2 C
sCurrent i
2With with Fig. 2 a in current i
1Identical phase place is at capacitor C
sIn with current i
1Addition is so that voltage Vcs is maximum serpentine.During frame scan, work as current i
3Become hour, then corresponding as shown in fig. 1 waveform is such, line flyback voltage V
3Become increasing.Because the positive peak of voltage Vcs or the V among Fig. 2 d
2Appear in the middle of the line scanning voltage V
3Phase place and the phase place of voltage Vcs moved 180 ° approximately, simultaneously, the retrace interval of being expert at, the modulation voltage V among Fig. 2 f
3Peak value appears.Therefore, the voltage Vcs addition with on the capacitor Cs among Fig. 1 forms voltage V
2Voltage V
3Have with scanning voltage Vcs to current i
2The adverse effect that is risen.As flyback voltage V
3During increase, current i
2Reduce, make scanning voltage Vcs or V
2Modulation degree reduces, thereby reduces serpentine.Flyback voltage V
3Further increase can cause current i
2Amplitude to zero.As flyback voltage V
3When continuing to increase, can cause current i
2Along flowing in the other direction.
Like this, modulate voltage V among Fig. 2 d among Fig. 2 C
2Current i
2By the voltage V among Fig. 2 f
3Modulate.Because voltage V
3Be by the current i among Fig. 2 e
3Modulate, so voltage V among Fig. 2 d
2The parabolic shape waveform by the current i among Fig. 2 e
3Modulated with frame rate, thereby inner pillow distortion equalizing is provided.
Outside pillow distortion equalizing requires deflection current i among Fig. 2 a
1Amplitude littler in the top and the bottom of grating than the center.During inner pillow distortion equalizing, require the amount of top and bottom serpentine littler than the center.In top and bottom, the inclination current i
3Less, make flyback voltage V
3Amplitude higher.Voltage V
3Amplitude higher, make current i
2Amplitude less.In the centre of frame scan, the inclination current i
3Be in maximum, thereby make flyback voltage V
3Amplitude be in minimum value.Therefore, in the centre of frame scan, deflection current i
1With inner pincushion correction current i
2Amplitude all be in maximum, the result makes the more apparent serpentine of voltage Vcs.This advantage is by selecting the value of circuit element in the circuit 60, to can be given outside pincushion correction amount and obtain needed inner pincushion correction amount.
In retrace period, circuit 60 and capacitor C
RTIn parallel.Therefore, capacitor C
RTValue must be big than without circuit 60 time, to take into account the influence of 60 pairs of total required flyback capacitor amounts of circuit.If do not consider to increase unfriendly " mouse tooth " distortion, increase capacitor C
RTValue the coupling between kickback transformer T1 and the resonant circuit 27 is strengthened.
Resistance R 18 is connected end points 22a and inductance L
1Middle end points (or tap) 112 between.Resistance R 18 provides one around deflecting coil L
HDirect current i with coil W1
4Current i
4Flow through resistance R 18 and inductance L
1, because at supply power voltage V
6And capacitor C
sBetween an additional DC current path is provided, just help stabilising condenser C
sIn direct voltage.
Coil L
HAnd capacitor C
sVoltage V on the link 60a
2Direct current mean value equal capacitor C
1And the voltage V on the tie point 22a between the resistance R 18
6Like this, except that the part that is provided by coil W1, also be provided as the constant required part direct current of mean value that keeps average voltage Vcs via resistance R 18, this helps reducing capacitor Cs and second plate load variations and produces instantaneous discharge, thereby has also reduced " mouse tooth " distortion.
Inductance L
1(Fig. 2 d's) voltage V on the end points
2(Fig. 3 c's) voltage V
5The phase place of AC portion opposite.The position of tap 112 is to select like this among Fig. 1: promptly in scan period, help the inductance coil L in Fig. 1
1Tap 112 on produce one and have minimum alternating current component, approximate voltage V greatly
2And V
5The voltage V of mean value
4The 18 pairs of deflection circuits 100 of resistance R and the inner pincushion correction circuit 60 that are connected in the tap 112 among the abundant of all do not constitute very heavy load, and therefore, benefit is the A.C. losses that can't increase circuit 100 and 60.
Because voltage V
6Be pulsating voltage, the current i of resistance R 18 among the Fig. 1 that flows through among Fig. 3 a
4Be zigzag.Current i
4Can help proofreading and correct some asymmetric line linearity error.Scan period is because power supply is at coil L
HAnd inductance L
1On loss (voltage V in tap 112
4Can descend slightly) can cause linearity error.Voltage V
4Decline, may cause current i near line scanning when terminal
1And i
2Amplitude diminish.Current i
4Toothing helps reducing the voltage V that is produced
4The quantity that descends, thereby some so asymmetric linear error of recoverable at least.
Between first half period of scanning, current i
2With the direction opposite, from ground, by capacitor C with the arrow indication
6, inductance L
1With capacitor C
sFlow to diode D
1And D
2Between link 28.Energy regeneration current i W1 flows through the coil W1 of kickback transformer T1 by the arrow direction, as long as current i
2Less than energy regeneration current i W1, diode D
2Just keep conducting, and be current i
2The ground path is provided back.Yet, work as current i
2Amplitude when being increased to the amplitude that equals the energy regeneration circuit iW1 that reducing among the coil W1, diode D
2Just become and end.This situation is undesirable, because this situation may make the scanning voltage of transistor Q1 end points 23 rise to substantially exceeds " " current potential.
According to another kind of form of the present invention, inclination current transistor Q
2Conversion enters saturation condition in the incipient stage of line-scanning period.This advantageously is inner pincushion modulated current i
2First half cycle in the scan period provides current path.In scan period, current i
2Make voltage V
3Increase, so that forward bias diode D
3Because transistor Q
2Be saturated, help diode D
3Be current i
2By saturated transistor Q
2The loop, earthing is provided, and makes voltage V
3Clamped to approximately zero lying prostrate.
When realizing another form of the present invention, transistor Q
2Be converted to saturatedly by the flyback pulse Hr on the coil W4, this flyback pulse is by capacitor C
5Be added to transistor Q
3Base stage.One comprises capacitor C
5And resistance R
15And R
16Shaping network produce one at the voltage V that raises up shown in the waveform of Fig. 1 correspondence in scan period from pulse Hr
7(upramping Voltage).Voltage V
7Negative-going portion by diode D
4And resistance R
17Be added to transistor Q
3Base stage, make transistor Q to form one
3And Q
2Saturated voltage V
9Be included in the voltage V among Fig. 1
9, represented transistor Q
3The waveform of base voltage.At Fig. 1 voltage V
9Waveform in, time ta(comes across the flyback end), transistor Q
3And Q
2By negative voltage V
9Drive and enter saturated.Two transistor Q
3And Q
2Keep saturated up to diode D
4Voltage V is raised up
7Till time tb during reverse bias.In tb-ta ' cycle, transistor Q
2Be provided biasing, so that the time t of the retrace interval of being expert at
a' realize Class A work afterwards, thus high output impedance is provided.
Fig. 2 b shows the flyback voltage V on the end points 23 in Fig. 1
1Waveform.The flyback voltage V of Fig. 2 b
1Advantage be not to be subjected to E-W modulated current i
3The influence of modulation degree.
Fig. 5 shows the second embodiment of the present invention, be referred to as deflection circuit 100 ' circuit can provide the deflection current i that proofreaies and correct through E-W to video color 110PIL-FS10 picture tube (model A66EAS00 * 01)
1'.Substitute as a kind of, after being used as some and changing as shown in phantom in FIG., it can be used in combination with the picture tube of 110COTY SP type too.Fig. 6 a-6e shows the waveform relevant with the circuit of Fig. 5.Fig. 1,5 with 6a-6e in identical label and symbolic representation same element or function.Be noted that the inside pincushion correction circuit 60 among Fig. 1 is not embodied in the circuit of Fig. 5.In scan period, the transistor Q among Fig. 5
2' not as switch work; And the transistor Q among Fig. 1
2Scan period as a switch job.In many others, 100 among the deflection circuit 100 among Fig. 1 and Fig. 5 ' is similar, and works in a similar manner.
Fig. 6 a shows the voltage V on the transistor Q1 ' among Fig. 5
1'.Be noted that the voltage V of Fig. 6 a
1' amplitude and the width influence that is not subjected to the modulation of the E-W control circuit 25 ' cause among Fig. 5.Fig. 6 b shows the voltage V for the E-W control circuit 25 by Fig. 5 that obtains outside pincushion raster correction ' modulation
3'.Capacitor C
RD' on the peak value flyback voltage by the voltage V of the same value of Fig. 6 b
3' amplitude modulation.Flyback resonant circuit 27 ' resonance among Fig. 5 is stared at rare in the base of flyback frequency
Pulse voltage V among Fig. 6 b
3' trailing edge by the inclination current i among Fig. 5
3' modulation.Like this, the pulse voltage V among Fig. 6 b
3' as time t
2And t
3Between shown in like that, narrower in the centre of frame scan than top and bottom.Be expert at scan period, because damper diode D
2' conducting makes the voltage V among Fig. 5
3' be zero.As a result, in this cycle, diode D
3' be reverse biased.
Deflection current i among Fig. 6 d
1' modulation be 7%.Transistor Q among Fig. 5
2' power consumption be about 2 watts.
In the television set of using aspheric surface phosphor screen picture tube (for example RCA110COTYSP pipe), may need the frame parabolic shape building mortion that adds, so that the gradient on parabolic shape both sides is more smooth.A kind of like this parabolic shape building mortion 70 dots in Fig. 5.Device 70 act on the PEHaferl name, the United States Patent (USP) № 4687972 that name is called " raster distortion correction circuit that is used for video display devices " has done detailed explanation.Link voltage V in the device 70
11' capacitor C
500' by flowing through resistance R
155' current charges, voltage V
11' one-tenth sawtooth waveforms when scanning with frame frequency.During the low-pressure section of frame parabolic voltage, capacitor C
500' pass through resistance R
166', diode D
8' and resistance R
14' discharge.Resistance R
14' on voltage drop to form parabolic wavy.The amount that parabolic shape is shaped is subjected to passing through resistance R
155The control of ' charging current.Capacitor C
500' work as a desirable voltage source, and help suppressing sawtooth voltage.
Fig. 8 shows one and can be used in Fig. 5 device the E-W control circuit 25 of (for example replace control circuit 25 ') ".Similar label element or the function similar among Fig. 5 and Fig. 8 with symbolic representation.Transistor Q among Fig. 8
2" and the transistor Q among Fig. 5 of having illustrated of front
2', all do not play on-off action in scan period.
Retrace interval, the control circuit 25 among Fig. 8 " frame frequency scanning parabolic shape signal V
10" pass through resistance R
77The transistor Q that " is connected to temperature-compensating differential amplifier 77 "
4" base stage.Transistor Q
4" base stage also pass through resistance R
78" and diode D
78" be connected to an end (for example coil W4 ' among Fig. 5) of kickback transformer coil.So in whole scan period, the transistor Q among Fig. 8
4" base voltage by clamped to about 2.5 volts.
Amplifier 77 " transistor Q
5" collector electrode be connected to transistor Q
2" base stage so that a pulse V is provided in each retrace period
Q5".Pulse V
Q5" crest voltage with the vertical-parabola form, according to signal V
10" and change.Transistor Q
2" emitter pass through resistance R
4" connect resistance R
4" and resistance R
44" and capacitor C
44" the shunt circuit be connected in series.Transistor Q
2" emitter voltage V
Q2Represented and flow through transistor Q
2" the current i of collector electrode
3".Voltage V
Q2By determining the amplifier 77 " resistance R of closed loop gain
45" feed back to transistor Q
5" base stage.Current i
3" by diode D
3" deliver to the end points 28 of flyback resonant circuit " (not pointing out among Fig. 8), so that E-W to be provided modulated current.Transistor Q
2" and diode D
3" work respectively with Fig. 5 in transistor Q
2' and diode D
3' similar.By the resistance R among Fig. 8
45" negative feedback, in each retrace period according to parabolic shape signal V
10" set up current i
3" mean value.Current i like this
3Flyback voltage V on " mean value just can advantageously keep not being subjected to end points 28 "
3" the influence of amplitude.Thereby help having reduced the distortion of mouse tooth.
Claims (26)
1, have the arrangement for deflecting that pattern distortion is proofreaied and correct, comprising:
Input signal source (the H that frequency is relevant with first deflection frequency
s);
Deflecting coil (LH);
Be connected to the switching device (Q1) of described deflecting coil, this switching device works in described first deflection frequency according to described input signal, with in the scan period of given deflection cycle, produces sweep current (i in described deflecting coil
1);
Supply voltage source (90);
Be connected the feed inductance (W1) between described supply voltage source (90) and the described switching device (Q1), to produce the second flyback pulse voltage, described feed inductance is connected to described flyback resonant circuit (27), in described retrace period, from the upper and lower teeth not meeting properly ┑ of institute ribbon Miao well-behaved 90) provide supply current to replenish the energy loss the described flyback resonant circuit (27);
Load circuit (at the U end) by the described second flyback pulse voltage drive in the described feed inductance (W1); With
Modulating signal source (300);
It is characterized in that: (Q2's may command semiconductor device Q3) reacts to described modulation signal, produces modulated current (i
3), this modulated current is delivered to described flyback resonant circuit (27) and is modulated described sweep current (i
1), proofread and correct described semiconductor device (Q2, Q so that carry out pattern distortion
3) in described retrace period, form high output impedance, so that described feed inductance (W1) is isolated with described flyback resonant circuit (27) in described retrace period basically.
2, according to the device of claim 1, be characterised in that wherein said first deflection frequency is the horizontal deflection frequency, wherein said output impedance value is more much bigger than the resistance value of one of described deflecting coil and described feed inductance at least on described horizontal deflection frequency.
3,, be characterised in that wherein said semiconductor device (Q2, Q according to the device of claim 1
3) comprising an amplifier, this amplifier keeps described modulated current (i in described retrace period
3) mean value be not subjected to the influence of the described first flyback pulse voltage.
4,, be characterised in that wherein said amplifier (Q2, Q according to the device of claim 3
3) as class A amplifier.
5,, be characterised in that wherein said semiconductor device (Q2, Q according to the device of claim 1
3) output impedance that forms, on the collector electrode of transistor (Q2), be high impedance, to prevent because of described modulated current (i
3) influence and the load current in the described load circuit is changed.
6,, be characterised in that wherein said feed inductance comprises the coil of kickback transformer (T1) (W1) according to the device of claim 1.
7,, be characterised in that wherein said load circuit is connected to the secondary coil of described kickback transformer (T1) (W3) to produce a second plate voltage (U) according to the device of claim 6.
8,, be characterised in that the second flyback capacitor (C according to the device of claim 1
RT) described feed inductance (W1) is connected to described flyback resonant circuit (27), comprise and the same synchronizing information of the described first flyback pulse voltage to cause the described second flyback pulse voltage.
9,, be characterised in that the second flyback capacitor (C according to the device of claim 1
RT) described feed inductance (W1) is connected to described flyback resonant circuit (27), be tuned in second flyback resonant circuit of described flyback frequency with formation, this flyback resonant circuit comprises described first flyback resonant circuit (27), described feed inductance (W1) and the described second flyback capacitor (C
RT).
10,, be characterised in that device (C according to the device of claim 1
4) described modulation signal is reacted and is connected to described semiconductor device (Q2, Q
3), so that in described retrace period, produce the described downward-sloping modulated current that has.
11, according to the device of claim 1, be characterised in that wherein said feed inductance comprises a kickback transformer (T1), this transformer has the high-tension coil (W3) that first coil (W1) that is connected to described power supply (90) and produce described second pulse voltage on it, and wherein said load circuit comprises a high-tension circuit (U).Derive a second plate voltage, wherein said semiconductor device (Q2, Q on the second plate end, to go up described second pulse voltage that produces by described high-tension coil (W3)
3) comprise that one has prevented to influence the transistor Q2 that the load electron beam current is changed because of described flyback resonant circuit (27) basically on described second plate end.
12, according to the device of claim 1, be characterised in that wherein said modulating signal source (300) is the frame frequency frequency, described first deflection frequency is the line frequency frequency.
13,, be characterised in that wherein said semiconductor device (Q2, Q according to the device of claim 1
3) comprising the transistor (Q2) that the line frequency signal is reacted, described transistor was worked as conductive switch in the described scan period, and had low output impedance.
14, according to the device of claim 13, be characterised in that described transistor (Q2) in described retrace period as having the class A amplifier of described high output impedance and working, cause by its collector electrode described modulated current be provided.
15,, be characterised in that sweep capacitor (C according to the device of claim 1
s) be connected to described deflecting coil (L
H), in the described scan period, to form the first scanning resonant circuit, cause the described sweep current that in described sweep capacitor, flows through, in the described scan period, at described sweep capacitor (C with described deflecting coil
s) and parabolic voltage of the middle generation of branch circuit (60), thereby in described branch circuit, produce second a modulated current (i who modulates its amplitude according to described modulated current
2), the described second modulated current (i
2) deliver to described sweep capacitor (C
s) changing the described parabolic voltage on this capacitor, thus inner pincushion distortion reduced to a certain extent.
16,, be characterised in that wherein said sweep capacitor (C according to the device of claim 15
s) play a Low ESR shunt capacitance, so that in fact described sweep current flows through in described branch circuit (60) at whole described retrace period.
17,, be characterised in that described branch circuit (60) comprises the second capacitor (C according to the device of claim 15
6) and modulation inductance (L
1), this electric capacity and inductance and the described first sweep capacitor (C
s) and described deflecting coil (L
H) form the second scanning resonant circuit, so that the described second scanning resonant circuit is tuned on the frequency of the resonance frequency that is higher than the described first scanning resonant circuit.
18,, be characterised in that wherein said semiconductor device (Q2, Q according to the device of claim 15
3) comprise the transistor (Q2) that the line frequency signal is reacted, in the described scan period, the line frequency signal makes described transistor work as the switch of a conduction.
19, according to the device of claim 1, be characterised in that described switching device (Q1) is conducting at least during the first of described scan period, so that the voltage on the described switching device end points remains essentially in the described scan period on the predetermined constant level, wherein said semiconductor device (Q2, Q
3) comprise transistor (Q2) as switch work, transistor (Q2) is when not conducting of described switching device (Q1), at least the second portion in the described scan period is conducting, so that the described voltage on the described end points of described switching device remained essentially on the described predetermined constant level in the whole described scan period.
20,, be characterised in that the diode (D that the pair of series of wherein said switching device on comprising transistor seconds (Q1) and being connected across described transistor seconds (Q1) is connected according to the device of claim 19
1, D
2) device, the described the first transistor (Q2) of wherein conducting in the second portion of described scan period is connected described diode (D
1, D
2) between tie point (28) on, with one of described in the described diode of box lunch during not conducting, another diode (D
2) the maintenance Low ESR.
21, power supply and modulated arrangement for deflecting, it comprises:
The input signal that frequency is relevant with first deflection frequency;
Deflecting coil (L
H);
Be connected to described deflecting coil (L
H) switching device (Q1), be that the described input signal of described first deflection frequency is worked according to frequency so that the sweep time of deflection cycle inherent described deflecting coil (L
H) the middle sweep current (i that produces
1);
Be connected to described deflecting coil (L
H) to form the deflection flyback capacitor (C of deflection flyback resonant circuit (27)
RD), this resonant circuit produces the first flyback pulse voltage with the flyback frequency in the flyback time of described deflection cycle;
┑ ribbon Miao is well-behaved stand tall and upright 0);
Be connected the feed inductance (W1) between described power supply (90) and the described flyback resonant circuit (27), in described feed inductance (W1), to produce the second flyback pulse voltage;
Load circuit (on U) by the described second flyback pulse voltage energize in the described feed inductance (W1); With
Modulating signal source (300);
It is characterized in that: transistor (Q2) reacts to described modulation signal, and is connected to described flyback resonant circuit (27) so that modulated current (i to be provided
3), this modulated current is to described sweep current (i
1) modulation that produces, cause described modulated current to replenish the energy that loses in the described flyback resonant circuit (27), described transistor (Q2) has high output impedance, so that in described retrace period, described load circuit (at U) and described flyback resonant circuit (27) are isolated, thereby prevent to cause because of the influence of described flyback resonant circuit the variation of described load current at described retrace interval.
22, power supply and modulated arrangement for deflecting, it comprises:
The input signal that frequency is relevant with first deflection frequency;
Deflecting coil (L
H);
Be connected to described deflecting coil (L
H) switching device (Q1, D
1, D
2) this switching device is that the described input signal of described first deflection frequency is worked according to frequency so that the sweep time of deflection cycle inherent described deflecting coil (L
H) the middle sweep current that produces;
Be connected to described deflecting coil (L
H) to form the deflection flyback capacitor (C of deflection flyback resonant circuit (27)
RD), this resonant circuit produces the first flyback pulse voltage with the flyback frequency in the flyback time of described deflection cycle;
Supply voltage source (90);
Be connected to the feed inductance (W1) between described power supply (90) and the described flyback resonant circuit (27), to produce second flyback voltage, and current path from described power supply (90) to described flyback resonant circuit (27) is provided, transmit input supplying electric current to replenish the energy loss in the described flyback resonant circuit (27) by this path;
Load circuit (at the U end) by the described second flyback pulse voltage drive in the described feed inductance (W1); With
Modulating signal source (300);
It is characterized in that: transistor (Q2) reacts to described modulation signal, to produce described modulated current (i according to described modulation signal
3), this modulated current is modulated described sweep current (i
1), described transistor (Q2) has high output impedance at described retrace interval, to prevent that one of described at least first and second flyback pulse voltages are to described modulated current (i
3) exert an influence.
23,, be characterised in that device (Q according to the device of claim 22
3) described modulated current is reacted and is connected to the control utmost point of described transistor (Q2), so that the feedback signal of the described modulated current of representative to be provided by the negative-feedback signal path, described feedback signal is connected to described control electrode, so that described modulated current and described modulation signal are adapted.
24, according to the device of claim 22, be characterised in that wherein said first deflection frequency is a line-scanning frequency, described modulation signal is the vertical-parabola signal.
25,, be characterised in that low pass filter (R according to the device of claim 24
2, C
2) cut-off frequency be significantly less than described line-scanning frequency, described low pass filter is connected to the principal current conductive electrode of described transistor (Q2), described low pass filter (R
2, C
2) second feedback signal path of described frame frequency frequency is provided, this signal has been represented the frame frequency component of voltage of flyback voltage on the described principal current conductive electrode.
26,, be characterised in that wherein said switching device (Q1, D according to the device of claim 22
1, D
2) comprise the rectifying tube (D that pair of series connects
1, D
2), the collector electrode of wherein said transistor (Q2) is connected to described rectifying tube (D
1, D
2) between link (28), described device also comprises the first (C that all is connected to described link (28)
RD) and the second (C
RT) flyback capacitor, in order to set up on link: part goes up described second flyback voltage that produces at described feed inductance (W1), thereby make described modulated current with the vertical-parabola form, according to described modulation signal changes in amplitude of described part generation to the described flyback voltage on the described link (28).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN88103052A CN1037816A (en) | 1988-05-16 | 1988-05-16 | E-w raster correction circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN88103052A CN1037816A (en) | 1988-05-16 | 1988-05-16 | E-w raster correction circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1037816A true CN1037816A (en) | 1989-12-06 |
Family
ID=4832421
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN88103052A Pending CN1037816A (en) | 1988-05-16 | 1988-05-16 | E-w raster correction circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1037816A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1309242C (en) * | 2001-05-08 | 2007-04-04 | 汤姆森许可公司 | Raster distortion correction circuit |
-
1988
- 1988-05-16 CN CN88103052A patent/CN1037816A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1309242C (en) * | 2001-05-08 | 2007-04-04 | 汤姆森许可公司 | Raster distortion correction circuit |
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