CN1155183A - Low-power transconductance drive amplifier - Google Patents
Low-power transconductance drive amplifier Download PDFInfo
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- CN1155183A CN1155183A CN 96118546 CN96118546A CN1155183A CN 1155183 A CN1155183 A CN 1155183A CN 96118546 CN96118546 CN 96118546 CN 96118546 A CN96118546 A CN 96118546A CN 1155183 A CN1155183 A CN 1155183A
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Abstract
A convergence correction voltage waveform is applied to a power amplifier circuit. An output stage of the power amplifier drives a deflection coil of a cathode ray tube with a convergence correction current, which is proportional to the convergence correction voltage waveform. A differential voltage potential across an output device of the output stage is compared against a predetermined reference voltage. As the differential voltage potential begins to drop below the predetermined reference voltage, a buck-topology voltage regulator, which is coupled to the output device, turns on. The differential voltage potential is thereby maintained at a level greater than the predetermined reference voltage.
Description
Present invention relates in general to the amplifier circuit field, specifically, relate to the power amplifier that is used to drive such as the deflecting coil of CRT convergence coil.
Used CRT has the distortion of video image in the television receiver on the cathode ray tube screen grating of CRT.These distortions can comprise pincushion distortion, barrel-shaped distortion, trapezoidal distortion, horizontal nonlinearity and vertical nonlinearity.
Projection receiver comprises 3 CRT, can settle in the mode from axle each other, and among three CRT two can settle from axle with respect to projection screen.CRT each other and to be presented on respect to the aligning of projection screen on the projection screen just will be the video image distortion that is present in already on the CRT screen grating.In addition, this aligning also is incorporated into throwing among the video image on the projection screen itself with other distortion, and these distortions comprise the vertical trapezium distortion of level, oblique distortions and arc distortion.Because the orientation of each CRT is inequality with respect to projection screen, therefore the distortion on each of three kinds of colors is also different.
In order to proofread and correct these distortions, projection receiver all has auxiliary deflection coil usually on each of CRT.The so-called convergence coil of these auxiliary deflection coils.Each of three CRT needs a horizontal deflection coil and a frame deflector coil in its convergence coil, need 6 deflecting coils in the convergence coil system altogether.
The deflecting coil of convergence coil need be added with the electric current that its waveform is suitable for proofreading and correct the video image on projection screen.These waveforms are the combination of parabola, slope and the DC level of horizontal rate and vertical speed rate normally, and as the product of these parabolas, slope and DC level.
Because the amplitude and the shape of the current waveform of six deflecting coils of excitation differ from one another, therefore, each of six convergence coils all is to be driven by independent power amplifier.Each of power amplifier will be assembled the low pressure waveform that waveform generator produces and be used as input voltage, and the generation electric current corresponding with deflecting coil be as output, and this electric current voltage therewith is directly proportional, and is enough to drive coil.
The convergence coil that the United States Patent (USP) that is presented to E.Rodriguez-Cavazos 4961032 shown in Figure 5 has been described a kind of CRT of being used for drives a kind of possible scheme of the power amplifier of deflecting coil.State kind of power amplifier and during the different piece of yoke current waveform, adopt two different power supplys.For example, in the forward stroke interval of the input voltage waveform that provides by waveform generator 8, when the required driving voltage of deflecting coil is low, partly use low voltage level+V at the scan line of yoke current waveform
LOWWhen the rapid variation in the electric current that flows through deflecting coil makes high driving voltage add to deflecting coil, during the flyback part of current waveform, then use high voltage level+V in response to sensing circuit 22
HIGHDuring the negative journey of convergence correction waveform, usefulness-V
LOWVoltage level and-V
HIGHVoltage level.By each of two different pieces of the current waveform of deflecting coil used different power supplys, then the power dissipation in assembling amplifier will reduce.This can make the used radiating area of the output device of assembling amplifier less, and is content with very little and assembles the requirement of amplifier power supply.
Need further to reduce the power dissipation in assembling amplifier.Particularly, make the power dissipation of the output device of assembling amplifier reduce to minimum.
In the power amplifier of circuit, when changing output device conducting electric current, make the differential voltage current potential at output device two ends keep minimum regardless of output voltage according to the present invention.
This amplifier circuit comprises: the output stage that is used to produce the output current that drives the high frequency load; And the first terminal of following the tracks of the output stage of the voltage on second terminal of output stage, like this, between first and second terminals, keep the potential difference current potential.This potential difference current potential can be greater than predetermined voltage potential on amplitude.
According to feature of the present invention, amplifier circuit also comprises: the semiconductor output device, be used to produce the output current that drives the high frequency load, and this output device has first and second electrodes, and second electrode is coupled in the load; And no matter the change of output device second electrode voltage is used to maintain on the amplitude device greater than the first and second interelectrode potential difference current potentials of predetermined voltage potential.
This holdout device can comprise: the device that the differential voltage current potential is compared with predetermined voltage potential; Capacitor, and be used for device to electric capacity charging in response to comparison means.
When the voltage potential amplitude of being on duty was hanged down predetermined voltage potential, comparison means made charging device charge to electric capacity.On the voltage potential amplitude of being on duty during greater than predetermined voltage potential, comparison means will be ignored the variation of voltage on output device second electrode and the conducting constant current.
Voltage on the electric capacity can be in the voltage and the potential difference current potential sum that approximate on the amplitude in load.The potential difference current potential can comprise predetermined voltage potential and overshoot voltage and, its amplitude depends on the switching speed of switching device.Even after the voltage in the load changed polarity, the potential difference current potential still existed.
Charging device can comprise: the switching device with first electrode that is coupled to the first voltage potential source; Its first end is coupled to second electrode of switching device, the inductance that second end is coupled to electric capacity first end; And, be coupling in first end of inductance and the diode between the second voltage potential source, like this, when switching device was tending towards non-conduction, diode became forward bias.
Switching device can comprise first and second dual-polar triodes that Darlington connects, and these two triodes voltage potential amplitude of being on duty can almost be turn-offed during greater than predetermined voltage potential simultaneously.A Schottky diode can be coupled to second triode from first triode (Q53 or Q54).
According to further feature of the present invention, amplifier circuit comprises: the semiconductor output device that is used to produce the output current that drives load; Be used for device that the first and second interelectrode potential difference current potentials of output device are compared with predetermined voltage potential; And, be coupled to output device and in response to the switching mode voltage rectifier of comparison means.
The switching mode voltage rectifier can be ignored the change of the voltage on second electrode of output device, and the potential difference current potential is maintained on the amplitude on the level greater than predetermined voltage potential.The potential difference current potential can comprise predetermined voltage potential and overshoot voltage and, its amplitude depends on the speed of switching mode voltage rectifier in response to comparison means.
The switching device of switching mode voltage rectifier can be operated in by on the determined frequency of load.
When the voltage potential amplitude of being on duty is equal to or greater than predetermined voltage potential, comparison means will make the switching voltage rectifier disconnect.
Fig. 1 illustrates according to amplifier circuit of the present invention with block diagram and circuit diagram form;
Fig. 2 is the schematic diagram of an embodiment of amplifier circuit shown in Figure 1;
Fig. 3 is the schematic diagram of another embodiment of amplifier circuit shown in Figure 1;
Fig. 4 is the specific voltage waveform relevant with the embodiment of Fig. 2 and Fig. 3;
Fig. 5 illustrates the circuit of the amplifier of prior art with block diagram and schematic diagram.
See Fig. 1, waveform generator 10 provides a convergence correction voltage waveform 15 to input stage 25.Waveform generator 10 can be a traditional design, and does not repeat them here.Input stage 25 drives the triode Q5 and the Q7 of driver-level 30.Then, Q5 and Q7 drive output device Q8, Q24, Q10 and the Q26 of output stage 40 respectively.Output device Q8, Q24, Q10 and Q26 drive deflecting coil L to greatest extent with the convergence correction electric current I CORR that is proportional to convergence correction voltage waveform 15
1The convergence correction electric current I
CORRFlow through the current sense resistance R
11And formation sensing voltage V
SENSEVoltage V
SENSEThrough resistance R
6Feed back to input stage 25.Resistance R
20Control deflecting coil L by the high-frequency gain of limiting power amplifier 100
1Circulation.
Fig. 2 illustrates the detailed circuit diagram of amplifier 100.Amplifier 100 have be respectively+10V and-the first and second voltage potential sources of 10V; Be respectively+45V and-the third and fourth voltage potential source of 45V; And source of reference potential, for example, those of ordinary skill in the art can change the level in these voltage potential sources according to circuit, signal and load request.
Driver-level 30 can comprise first and second current amplifier circuits substantially.First current amplifier circuit roughly comprises triode Q5, resistance R 5 and R129 and diode D81.First current amplifier can be respectively has input and output side at base stage and the collector electrode of Q5.Second current amplifier circuit can roughly comprise triode Q7, resistance R 7 and R130 and diode D82.Second current amplifier circuit can have the input and output side at Q7 base stage and collector electrode respectively.Q5 and Q7 can be respectively MPSA92 and MPSA42.Diode D81 and D82 can comprise Schottky diode as shown in Figure 2, and can be IN5817.
For conducting, each of output device Q8, Q24 and Q10, Q26 all needs to be about the bias voltage of 1V usually.Specifically, the voltage of Q8 base stage must be higher than the about 1V of emitter of Q24, and the base voltage of Q10 must be lower than the about 1V of the emitter of Q26.Because the emitter-base bandgap grading of Q24 and Q26 is coupled, and is biased to conducting in order to make two Darlington output devices, the pressure drop of the 2V that must have an appointment between Q8 base stage and Q10 base stage.In the present embodiment, by diode D1, D2 and D3 realize the pressure drop a little less than 2V.
When preventing undesirable common mode current, biasing output device Q8, Q24 and Q10, Q26 are in the threshold value of conducting.When " dead band " that make the output device switching point is minimum, can make output device Q8, Q24 and Q26 quickly respond to quick variation in convergence correction voltage waveform 15.
The comparison circuit 50 of working with output device Q8, Q24 can roughly comprise voltage rectifier D69, triode Q49, resistance R 83 and diode D41 and D70.D69 can comprise the Zener diode of specified 5.1V, and model is IN5231.The model of Q49 can be MPSA42.
The comparator circuit 51 of working with output device Q10, Q26 roughly comprises voltage rectifier D68, triode Q50, resistance R 73 and diode D42 and D72.D68 can comprise the Zener diode of specified 5.1V, and its model is IN5231.The model of Q50 can be MPSA92.
The switched rectifier circuit 60 of working with output device Q8, Q24 can comprise the buck topology rectification circuit with triode Q57 and Q80; Darlington pair switching device Q53, Q31; Diode D62 and D66; Inductance L 8; Capacitor C 43; And the buffer circuit that comprises resistance R 90 and capacitor C 34.The model of Q53 can be MPSA92.The model of Q57 and Q80 can be BC556B.The model of Q31 can be MJE5195.D62 and D66 can be MUR160.
The switched rectifier circuit 61 of working with output device Q10, Q26 and comparator circuit 51 can roughly comprise the step-down topology rectifier circuit with triode Q58 and Q81; Switching device Q54, Q36; Diode D63 and D67; Inductance L 6; Capacitor C27; And the buffer circuit that comprises resistor R 88 and capacitor C33.The model of Q36 and Q54 can be TIP41C and MPSA42.The model of Q58 and Q81 can be BC546B.The model of D63 and D67 can be MUR160.
At work, convergence correction voltage waveform 15 is coupled on the input stage 25 of Q63 base stage by resistance R 52.Triode Q63 and Q64 resistance Q117, R112 and R123 form an anti-phase differential amplifier, make input offset voltage minimum so that a voltage gain to be provided.Obtain the output of differential amplifier at the collector electrode of Q63 and Q64.Q63 and Q64 collector voltage are respectively at the voltage less than Q63 and Q64 base stage.Thereby this collector electrode that allows Q63 and Q64 by resistance R 122 and R123 respectively ground connection make electric current minimum in the anti-phase differential amplifier.
Inverting amplifier drives two devices that are coupling in the Current Control between Q63 and the Q64 collector electrode.First current control device is made up of triode Q69 and Q70 and resistance R 3, and second current control device is made up of triode Q66 and Q67 and resistance R 114.
Under the state of balance, convergence correction voltage waveform 15 has the amplitude of zero volt, and the constant current of flowing through resistance R 117 is divided equally by resistance R 122 and R123.Similarly, the electric current that flows through resistance R 114 is by triode Q66 and Q77 conducting in the same manner, and the electric current that flows through resistance R 3 is by triode Q69 and Q70 conducting in the same manner.
The input utmost point 25 is specially designed, like this, is enough to make respectively the triode Q5 and the just in time conducting of Q7 of driving stage 40 by the electric current of triode Q77 and Q70 conducting under poised state.Like this, under poised state, through Q5, D1, D2, D3 and Q7 flow to the common mode current between 1mA and 2mA from the tertiary voltage potential source of+45V-the 4th voltage potential source of 45V.The sort circuit structure can make triode Q5 and Q7 can quickly respond to change in convergence correction voltage waveform 15.
During the negative polarity component of convergence correction voltage waveform 15, Q63 is tending towards not conducting, and like this, the electric current that flows through resistance R 122 reduces.Keep constant owing to flow through the electric current of resistance R 117, the electric current that then flows through resistance R 123 need increase by one with flow through resistance R 122 in the identical and opposite polarity amount of amount of electric current minimizing.
Equally, Q66 and Q70 are tending towards not conducting.Flowing through electric current after the increase of resistance R 123, that the voltage of Q66 and Q69 base stage is become is more negative, thereby makes Q66 be tending towards not conducting.Similarly, in resistance R 122, flow through reduce after electric current make the base voltage corrigendum of Q70 and Q77, thereby make Q70 be tending towards not conducting.
In addition, Q69 and Q77 become more conducting.Q77 becomes more conducting, and it will be from the base stage venting of Q5 multiple current more, thereby makes Q5 conducting more completely.Simultaneously, the more conducting because Q69 becomes, Q70 and Q7 base stage provide less electric current, thereby Q7 is turn-offed.
Select resistance R 5 and R129, make the electric current of Q5 conducting equal 12 times of Q77 conducting electric current.Diode D81 makes the Q5 conducting than low forward voltage drop when input stage 25 is in poised state.D81 provides temperature-compensating by the temperature of emitter-base bandgap grading-base stage pressure drop of tracking Q5, so that Q5 avoids the influence of thermal drift.
The output device Q8 of the current drives output stage 40 of Q5 conducting, Q24.Because output device Q8, Q24 begin conducting, the convergence correction electric current I CORR that is provided by capacitor C 43 flows through Q24, and enters deflecting coil L1.
Because capacitor C 43 will be assembled correcting current I
CORRBe added to deflecting coil L1, node J
1Voltage begin to descend.In case voltage drop gets enough, potential difference current potential V
DIFF, Q24Drop to reference voltage V
RFEUnder, diode D41, D69 and D70 are by reverse bias, and Q49 and Q57 disconnection.Switched rectifier circuit 60 is to capacitor C 43 positive charge, thereby with potential difference current potential V
IFFF, Q24Return to and equal reference voltage V at least
REFLevel.
Because convergence correction electric current I
CORRFlow through deflecting coil L1, to reference voltage V
REFWhat will be concerned about in the selection of value is speed issue, and switched rectifier circuit 60 and 61 is just with this speed responsive node J
1And J
4Upward required voltage.In typical convergence correction circuit, switched rectifier circuit 60 and 61 may be on capacitor C 43 and C27 the electric current 5 of several order of amps of conducting or 6 seconds.At this point, need make reference voltage V
REFHigh as far as possible.At this moment, reference voltage V
REFShould keep minimum, the power that is dissipated by output device Q8, Q24 and Q10, Q26 is with minimum like this.Exchange agreement between the power dissipation of switched rectifier circuit 60 and 61 bandwidth and output device Q8, Q24 and Q10, Q26 has been set up a kind of working frame, reference voltage V
REFIn this framework, select just.The those of ordinary skill in field of the present invention can be weighed this two factors, thereby determines reference voltage V
REFAcceptable value.In this preferred embodiment, V
REFSatisfactory value be defined as 8V from experience.
When Q57 is in off-state, but switching device Q53, Q31 conducting.Inductance L 8 is coupled to the tertiary voltage potential source by triode Q31.So positive charging current begins to flow through triode Q31.After the intrinsic current hysteresis, this charging current begins to flow through the buffer circuit that comprises resistance R 90 and capacitor C 34, till it is directly by 43 chargings of 8 pairs of capacitor C of inductance L in the inductance L 8.
In case at node J
1Voltage arrive potential difference current potential V
DIFF, Q24Equal reference voltage V
REFPoint, diode D41 and D70 begin forward bias, and voltage rectifier D69 keeps being about the substantially invariable voltage drop of 7.5V from its negative electrode to anode.As a result, Q49 conducting.
The electric current that flows through triode Q49 is limited by diode D41 and D70.Voltage on the resistance R 83 equals the pressure drop on diode D41 and the D70, and is lower than the base stage of Q49 and the pressure drop between emitter junction.Like this, in this preferred embodiment, the voltage on the resistance R 83 will approximate 0.6V, current flowing resistance R83 and triode Q49, thus keep constant approximately at 6mA.Electric current is limited by this mode, and like this, the drive current of Q57 is in output voltage V
OutGamut in all keep constant.
The major part of this electric current releases from the base stage of Q57 and Q80, therefore makes its conducting, when Q57 and Q80 conducting, makes switching device Q53, Q31 be biased to shutoff by the base stage that the tertiary voltage current source is added to Q53 and Q31.When conducting, the pressure drop on Q57 and the Q80 is lower than the required conducting voltage of base-emitter knot of Q53 and Q31.Triode Q57 and Q80 make triode Q53 and Q31 be in off-state respectively, and a low impedance path that the electric charge in the base-collector junction that is stored in Q53 and Q31 is bled off meanwhile is provided.Resistance R 66 is guaranteed electric current five equilibrium roughly on Q57 and Q80.Sort circuit disconnects Q53 and Q31 simultaneously, thereby switching device Q53, Q31 are switched fast enough, and potential difference current potential V
DIFF, Q24On amplitude, keep greater than reference voltage current potential V
REF
In another embodiment of the power amplifier 100 of Fig. 3, available Schottky diode D71 replaces Q81.When the Q57 conducting,, make Q31 be biased to off-state by the tertiary voltage potential source being added to the base stage of Q53 and making D71 positively biased.When its conducting, the low forward voltage drop of diode D71 and the pressure drop sum on the Q57 are lower than the required conducting voltage of base-emitter knot of Q31.The tertiary voltage potential source is being added to the base stage of Q53 and when diode D71 is added to the Q31 base stage, Q57 provides a low impedance path from the base stage of Q53 and Q31 to the tertiary voltage potential source, by path, stored charge can emit in the base-collector junction of Q53 and Q31.
Referring to Fig. 2,, promptly interrupt again through the charging current of inductance L 8 in case switching device Q53, Q31 disconnect.As a result, at node J
2The polarity of voltage rapidly by just becoming negative.The buffer circuit that comprises resistance R 90 and capacitor C 34 will be owing to disconnect the voltage peak that the electric current flow through cause in inductance L 8.Diode D66 when attempting at the voltage of node to surpass the tertiary voltage power source voltage with node J
2Be clamped to the tertiary voltage potential source and prevent at node J
2Last generation circulation.
Node J
2The change of polarity makes diode D62 become positively biased, thereby derives an electric current from the second voltage potential source.This electric current flows into capacitor C 43 through inductance L 8, and like this, capacitor C 43 is charged to amplitude to greatest extent and is about output voltage V
Out, reference voltage V
REFOn overshoot voltage and voltage voltage of the switching speed that depends on switching device Q53, Q31.Fig. 4 is illustrated in node J
1With output voltage V
OutThe exemplary voltage waveforms VJ of relevant capacitor C 43
1Voltage waveform VJ
1Serrated portion representative as output device Q8, Q24 conducting convergence correction electric current I
CORRThe charging and the discharge of capacitor C 43.
Again referring to Fig. 2, as node J
3Voltage when having negative polarity, can allow capacitor C 43 will assemble correcting current I by triode Q24
CORRBe added to deflecting coil L1.The appearance of this situation is because the voltage on inductance and the phase relation of current waveform that is to say that voltage is ahead of 90 ° in electric current on inductance.
In Q24 conducting convergence correction electric current I
CORRThe time node J
3Polarity of voltage become negative, node J
1Voltage will become more negative so that potential difference current potential V
DIFF, Q24Keep equaling reference voltage V
REF
The voltage level of the anode by being chosen in diode D62, those skilled in the art can be controlled at node J
1Voltage to the tracking degree of the negative drift of node J3.In this preferred embodiment, the anode of diode D62 is coupled to the second voltage potential source, like this, and at node J
1Voltage because the output voltage V of following node J3
OutAnd drop to-10V.In case determine present embodiment node J on the experience
1Voltage on amplitude, surpass-10V, at node J
1Follow output voltage V
OutVoltage obviously reduce.Equally, technical staff's in the art conclusion is, be suitable for anode with diode D62 be coupled to be different from-voltage level of 10V on.
The response of the positive polarity component of 100 pairs of convergence correction voltage waveforms 15 of power amplifier is similar to the response of having described that is directed to the negative polarity component.During the positive polarity component, Q63 becomes conducting more, and like this, the electric current that flows through resistance R 122 increases.Because the electric current that flows through resistance R 117 is still constant, the electric current that flows through resistance R 123 need reduce with flow through resistance R 122 in the identical and opposite polarity amount of electric current increase.
Meanwhile, Q69 and Q77 begin to be tending towards not conducting.The electric current that flows through the increase of resistance R 122 makes the voltage of the base stage of Q70 and Q77 become more negative, thereby makes Q77 be tending towards not conducting.Similarly, the electric current that reduces in the resistance R 123 makes the corrigendum that becomes of the voltage of Q66 and Q69 base stage, thereby makes Q69 be tending towards not conducting.
In addition, triode Q66 and the Q70 conducting more that becomes.Because Q70 conducting more, then it imports the base stage of Q7 with more electric current, thereby makes Q7 conducting more completely.Simultaneously, because the Q66 conducting more that becomes, Q77 is less from the electric current that the base stage of Q5 releases, thereby turn-offs Q5.
Selecting resistance R 7 and R130 to make the electric current of triode Q7 conducting is 12 times of electric current of Q70 conducting.The low forward voltage drop of diode D82 is in the flat triode Q7 conducting that makes when claiming the weighing apparatus state in input stage 25.The diode D82 also voltage drop of the emitter-base stage by following the tracks of Q7 avoids the influence of thermal drift so that temperature-compensating to be provided with protection Q7.
Output device Q10, the Q26 of the current drives output stage 40 of Q7 conducting.Because output device Q10, Q26 begin conducting, convergence correction electric current I CORR flows into capacitor C27 from deflecting coil L1 through triode Q26.
Along with the convergence correction electric current I
CORRTo capacitor C 27 chargings, node J
4On voltage begin to raise.In case this voltage rise enough height make potential difference current potential V
DIFF, Q26Be lower than reference voltage V
REF, diode D42, D68 and D72 are promptly by partially anti-, and Q50 and Q58 shutoff.Switched rectifier circuit 61 can not charged to capacitor C 27 negative senses.Thereby with potential difference current potential V
DIFF, Q26Return to and equal reference voltage V at least
REFVoltage.
Along with Q58 is in off state, but switching device Q54, Q36 conducting.Inductance L 6 is coupled to-the 4th voltage potential source of 45V by triode Q36.So negative charge current begins to flow through triode Q36.After the current hysteresis relevant with inductance L 6, the buffer circuit that this electric current begins through comprising resistance R 88 and capacitor C 33 flows out until it and can directly flow out from capacitor C 27 through inductance L 6 from capacitor C 27.
In case node J
4Voltage reach potential difference current potential V
DIFF, Q26Equal reference voltage V
REFSome the time, diode Q42 and D72 begin forward bias and voltage rectifier D68 keep about 7.5V between its negative electrode and anode substantially invariable voltage drop.As a result, triode Q50 conducting.
The electric current that flows through triode Q50 is subjected to the restriction of diode Q42 and D72.The voltage of resistance R 73 equals the pressure drop on diode D42 and the D72, and is lower than the voltage drop that the base-emitter of Q50 is tied.So in this preferred embodiment, the voltage on the resistance R 73 can equal about 0.6V, and current flowing resistance R73 flows through Q50 again, thereby keeps about 6mA.The limited in this way drive current to Q58 of this electric current is being exported piezoelectricity V
OutGamut in keep constant.
The major part of this electric current flows into the base stage of Q58 and Q81, thereby makes its conducting.When Q58 and Q81 conducting, make Q54 and Q36 be biased to off-state by the base stage that the 4th voltage potential source is added to Q54 and Q36.In its conducting, the pressure drop on Q58 and the Q81 is lower than the required conducting voltage of base-emitter knot of Q54 and Q36.Q58 and Q81 make Q54 and Q36 be in off state, the low impedance path that provides the charge stored in the base-collector junction that can make Q54 and Q36 to release simultaneously.Resistance 72 is guaranteed to divide equally electric current on Q58 and Q81.The sort circuit structure is turn-offed Q54 and Q36 simultaneously, thereby switching device Q54 and Q36 are enough promptly switched, and makes potential difference current potential V
DIFF, Q24On amplitude greater than reference voltage current potential V
REF
In another embodiment of power amplifier shown in Figure 3 100, available Schottky diode D73 replaces triode Q81.When the Q58 conducting, by on the base stage that the tertiary voltage potential source is added to Q54 and make diode D73 positively biased make Q54, Q36 be biased to off state.The required conducting voltage of the base-emitter knot low forward drop of diode D73 and the pressure drop on the Q58 and that when its conducting, be lower than Q36.The tertiary voltage current potential is being added to the Q54 base stage and when diode D73 is added to the base stage of Q36, Q58 provides a low impedance path from the base stage of Q54 and Q36 to the tertiary voltage potential source, by path, Q54 and Q36 base stage collector plate are tied the electric charge that is stored and can be released.
Goodbye Fig. 2, in case switching device Q54, Q36 shutoff, through the negative charge current interruption of inductance L 6.As a result, at node J
5The polarity of voltage just becoming from negative rapidly.The buffer circuit that comprises resistance R 88 and capacitor C 33 will be got off by the caused any voltage overshoot amplitude fading of electric current that inductance L 6 is flow through in disconnection.By with node J
5When the voltage of this node attempts to surpass the amplitude in the 4th voltage potential source, be clamped to the 4th voltage potential source and prevent at node J
5Circulation.
At node J
5On reversing make diode D63 positively biased, thereby with current lead-through in the first voltage potential source.This electric current flows out and through inductance L 6 from capacitor C 27, and like this, C27 negative sense to greatest extent is charged to amplitude and approximates output voltage V
Out, reference voltage V
REFOn the voltage of the overshoot voltage sum of the switching speed that depends on switching device Q54, Q36.Fig. 4 is illustrated in node J
4With output voltage V
OutThe exemplary voltage waveforms of relevant C27.Voltage waveform V
J4Serrated portion representative as output device Q10, Q26 conducting convergence correction electric current I
CORRThe charge and discharge of capacitor C 27.
Goodbye Fig. 2 is as node J
3Voltage when having positive polarity, capacitor C 27 can absorb the convergence correction electric current I from deflecting coil L1 through Q26
CORR, this is owing to the relation between voltage on the inductance and electric current, promptly voltage takes the lead 90 ° in electric current on inductance.
In Q26 conducting convergence correction electric current I
CORRThe time, if node J
3Polarity of voltage just become, at node J
4On voltage more just become so that potential difference current potential V
DIFF, Q26Equal reference voltage V
REF
By being chosen in the voltage level of diode D63 negative electrode, those skilled in the art can be controlled at node J
4To node J
3The tracking degree of just drifting about.In this preferred embodiment, the negative electrode of diode D63 is coupled to the first voltage potential source, like this, and at node J
4Voltage owing to follow node J
3Output voltage V
OutAnd be elevated to+10V.In case determine present embodiment node J on the experience
4Voltage on amplitude, surpass+10V, at node J
4Follow output voltage V
OutVoltage obviously reduce.Equally, technical staff's in the art conclusion is, be suitable for negative electrode with diode D63 be coupled to be different from+voltage level of 10V on.
Claims (21)
1. amplifier circuit comprises:
Output stage (40) is used for producing driving high frequency load (L
1) output current (I
CORR), described output stage has the first (J
1Or J
4) and the second (J
3) terminal;
It is characterized in that:
Described the first terminal (the J of described output stage
1Or J
4) follow the tracks of the described second terminal (J of described output stage
3) on voltage (V
Out), like this, between described first and second terminals, keep potential difference current potential (V
DIFF, Q24Or VD
IFF, Q26).
2. amplifier circuit as claimed in claim 1, wherein said output stage (40) are characterised in that semiconductor output device (Q8 and Q24 or Q10 and Q26).
3. amplifier circuit as claimed in claim 2 is characterized in that described first and second ends are electrodes of described output device (Q8 and Q24 or Q10 and Q26).
4. amplifier as claimed in claim 1 is characterized in that the described potential difference current potential (V between described first and second terminals
DIFF, Q24Or V
DIFF, Q26) on amplitude greater than predetermined voltage potential (V
REF).
5. amplifier circuit comprises:
Semiconductor output device (Q8 and Q24 or Q10 and Q26) is used for producing driving high frequency load (L
1) output current (I
CORR), described output device has first and second electrodes, and described second electrode is coupled to described load;
It is characterized in that:
Be used at the described first and second interelectrode maintenance potential difference current potential (V
DIFF, Q24Or V
DIFF, Q26) device, this potential difference current potential is no matter voltage (V on described second electrode of described output device
Out) change, on amplitude greater than predetermined voltage potential (V
REF).
6. amplifier circuit as claimed in claim 5, wherein said holding device is characterised in that:
Be used for described potential difference current potential (V
DIFF, Q24Or V
DIFF, Q26) and described predetermined voltage potential (V
REF) device (50 or 51) of comparing;
Capacitor (C43 or C27); And
Be used in response to the device (60 or 61) of described comparison means (50 or 51) described electric capacity (C43 or C27) charging.
7. amplifier as claimed in claim 6 is characterized in that as described potential difference current potential (V
DIFF, Q24Or V
DIFF, Q26) amplitude drops to described predetermined voltage potential (V
REF) under the time, comparison means (50 or 51) makes described charging device (60 or 61) charge to described electric capacity (C43 or C27).
8. amplifier as claimed in claim 7 is characterized in that as described potential difference current potential (V
DIFF, Q24Or V
DIFF, Q26) amplitude is greater than described predetermined voltage potential (V
REF) time, described comparison means (50 or 51) is no matter the described voltage (V on described second electrode of described output device (Q8 and Q24 or Q10 and Q26)
Out) variation and constant current of conducting.
9. amplifier as claimed in claim 6 is characterized in that being about described load (L on the voltage amplitude on the described electric capacity (C43 or C27)
1) described voltage (V
Out) and described potential difference current potential (V
DIFF, Q24Or V
DIFF, Q26) and.
10. amplifier as claimed in claim 6, wherein said potential difference current potential (V
DIFF, Q24Or V
DIFF, Q26) be characterised in that and be described predetermined voltage potential (V
REF) and the overshoot voltage sum, its amplitude is determined mutually in the switching speed of described switching device (Q53 and Q31 or Q54 and Q36).
11. amplifier as claimed in claim 5 is characterized in that even at described load (L
1) voltage (V
Out) still keep described potential difference current potential (V during the pole reversal
DIFF, Q24Or V
DIFF, Q26).
12. amplifier as claimed in claim 6, wherein said charging device (60 or 61) is characterised in that:
Switching device (Q53 and Q31 or Q54 and Q36) has first electrode that is coupled to the described first voltage potential source;
Inductance (L8 or L6) has first end of second electrode that is coupled to described switching device and is coupled to second end of first end of described electric capacity (C43 or C27); And
Be coupling in described first end of described inductance (L8 or L6) and the second voltage potential source (10V or+diode (D62 or D63) between 10V), like this, when described switching device (Q53 and Q31 or Q54 and Q36) when being tending towards not conducting, described diode (D62 or D63) beginning positively biased.
13. as the amplifier circuit of claim 12, wherein said switching device (Q53 and Q31 or Q54 and Q36) is characterised in that the first and second bipolar junction triodes that are arranged in Darlington type structure.
14., it is characterized in that as described potential difference current potential (V as the amplifier circuit of claim 13
DIFF, Q24Or V
DIFF, Q26) on amplitude greater than described predetermined voltage potential (V
REF) time, described first (Q53 or Q54) or second (Q31 or Q36) bipolar junction triode almost turn-off simultaneously.
15., it is characterized in that Schottky diode (D1 or D73) is coupled on described second triode (Q31 or Q36) from first triode (Q53 or Q54) as the amplifier circuit of claim 13.
16. an amplifier circuit comprises:
Semiconductor output device (Q8 and Q24 or Q10 and Q26) is used for producing driving load (L
1) output current (I
CORR), described output device has first and second electrodes;
It is characterized in that:
Device (50 or 51) is used for the described first and second interelectrode potential difference current potential (V
DIFF, Q24Or V
DIFF, Q26) and predetermined voltage potential (V
REF) compare; And
Be coupled to described output device and in response to the switching mode voltage rectifier (60 or 61) of described comparison means.
17. as the amplifier circuit of claim 16, it is characterized in that described switching mode voltage rectifier (60 or 61) no matter described second electrode of described output device (Q8 and Q24 or Q10 and Q26) on change in voltage with described potential difference current potential (V
DIFF, Q24Or V
DIFF, Q26) amplitude that maintains is greater than predetermined voltage potential (V
REF) level on.
18. as the amplifier circuit of claim 16, wherein said potential difference current potential (V
DIFF, Q24Or V
DIFF, Q26) be characterised in that and be described predetermined voltage potential (V
REF) with overshoot voltage and, its amplitude depends on the speed of described switching mode voltage rectifier (60 or 61) in response to described comparison means (50 or 51).
19. as the amplifier circuit of claim 16, the feature of wherein said switching mode voltage rectifier (60 or 61) is a step-down topology rectifier circuit.
20. as the amplifier circuit of claim 16, the switching device (Q53 and Q31 or Q54 and Q36) that it is characterized in that described switching mode voltage rectifier (60 or 61) is with by described load (L
1) definite frequency switching.
21., it is characterized in that as described potential difference current potential (V as the amplifier circuit of claim 20
DIFF, Q24Or V
DIFF, Q26) amplitude equal or exceed described predetermined voltage potential (V
REF) time, described comparison means (50 or 51) makes described switching device (Q53 and Q31 or Q54 and Q36) by conducting.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 96118546 CN1155183A (en) | 1995-11-28 | 1996-11-27 | Low-power transconductance drive amplifier |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US563,528 | 1995-11-28 | ||
| CN 96118546 CN1155183A (en) | 1995-11-28 | 1996-11-27 | Low-power transconductance drive amplifier |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1155183A true CN1155183A (en) | 1997-07-23 |
Family
ID=5125171
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 96118546 Pending CN1155183A (en) | 1995-11-28 | 1996-11-27 | Low-power transconductance drive amplifier |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1155183A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101297477A (en) * | 2005-10-20 | 2008-10-29 | 艾利森电话股份有限公司 | Transconductance device |
| CN1707969B (en) * | 2004-06-11 | 2010-07-28 | 瑞昱半导体股份有限公司 | Transmission line driver |
| CN101917165B (en) * | 2006-07-28 | 2014-02-05 | 全焊接技术公司 | Electron beam system, image generator, and amplifier of high-speed driving inductor |
-
1996
- 1996-11-27 CN CN 96118546 patent/CN1155183A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1707969B (en) * | 2004-06-11 | 2010-07-28 | 瑞昱半导体股份有限公司 | Transmission line driver |
| CN101297477A (en) * | 2005-10-20 | 2008-10-29 | 艾利森电话股份有限公司 | Transconductance device |
| CN101297477B (en) * | 2005-10-20 | 2011-02-02 | 艾利森电话股份有限公司 | Transconductance device |
| CN101917165B (en) * | 2006-07-28 | 2014-02-05 | 全焊接技术公司 | Electron beam system, image generator, and amplifier of high-speed driving inductor |
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