JPS63310276A - Power source circuit for horizontal deflection output circuit - Google Patents

Abstract

PURPOSE:To always obtain an image of prescribed width against various horizontal deflection frequencies by keeping time length of a half cycle of a switching period constant, and lowering an output of a regulator as a horizontal deflection period increases. CONSTITUTION:An output pulse Vd2 of a monostable multivibrator 13 is triggered at the time point of a rise of an oscillation waveform VOSC and becomes that which has pulse width of a prescribed time Td2. Subsequently, a switch TR 18 is allowed to conduct by time length of Ton being a little longer by a storage time portion than the pulse width Td2 by the pulse Vd2 through a base resistance 15 being an exciting stage, an exciting transistor TR 16, and an exciting transformer 17. This pulse width Td2 is a prescribed value which is determined by a constant of the multivibrator 13, therefore, the time length Ton also becomes constant. As a result, a value of a DC power supply voltage E'b being an average value of a square wave VSW ascends, when a horizontal deflection frequency fh becomes high. On the other hand, the voltage E'b is E'b=Eb.(Ton/Th). When a deflecting coil current Iy' is derived from these relations, a virtual peak-to-peak value becomes constant, when the time Ton is constant. Therefore, the dimension of an image display part always becomes constant.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a switching regulator power supply circuit for supplying power to a horizontal deflection output circuit in a display device using a picture tube, and particularly relates to a switching regulator power supply circuit for supplying power to a horizontal deflection output circuit in a display device using a picture tube. This is applied to cases where there are various direct correspondences.

(Prior Art) FIG. 6 is a diagram showing one of the conventional examples of a part of a circuit for a separate display tomb to which the present invention relates.

Here, 1 is the same 1 from the previous stage not shown! l'l signal pulse P1. 2 is a horizontal deflection output circuit that oscillates a waveform synchronized with P2, etc., and 2 receives this oscillation waveform and outputs synchronizing signal pulses P1. This is a horizontal deflection output circuit for the purpose of passing a horizontal deflection wave current (deflection coil current) 1y synchronized with P2ff to a horizontal deflection coil 3 attached to the jaw of a picture tube (not shown here).

The DC power supply voltage Eb' of the horizontal deflection output circuit 2 is supplied from the DC type m<voltage) Eb through the switching regulator 4.

In addition, the horizontal deflection current detection circuit 3G and the direction current detection circuit 5
is inserted to obtain a voltage Ey proportional to the peak-to-peak value of the deflection coil current y, which is applied to the comparison circuit 6 and compared with the reference voltage ES.

Historically, the output DC voltage EO of the comparison circuit 6 is applied to the next pulse width modulation circuit 7.

To this pulse width modulation circuit 7, a waveform Vst, which is generated by passing the waveform from the horizontal deflection oscillation circuit 1 to a sawtooth wave generation circuit 8, is separately applied. The output of the pulse width modulation circuit 7 is an h-shaped wave Vd1 whose duty cycle changes according to the value of the voltage Ey, and this square wave Vdl
The switching regulator 4 is excited by the switching regulator 4, and the DC power supply voltage Eb is changed to E by the action of the switching regulator 4.
b' to the horizontal deflection circuit 2.

The operation of the pulse width modulation circuit 7 can also be realized by a type of comparison circuit, for example, as shown in FIG. As the level of the voltage EO increases as shown by the broken line, the pulse width Td1 of the square wave Vd1 becomes narrower.

In this circuit, if the deflection coil current 1y increases and the voltage [Ey proportional to this deflection coil current 1y also increases and attempts to exceed the quasi-voltage ES, then the comparator circuit 6. The operation of the pulse width modulation circuit 7 is to generate a square wave ■d in the direction of decreasing the output DC power supply '1 voltage Eb' of the switching regulator 4.
Assume that the sensor is configured to move a pulse width Td1 of 1.

Th is the horizontal deflection period.

In this way, when the peak-to-peak value of the deflection current 1y tries to increase, Fb' as the DC power supply voltage of the horizontal deflection output circuit 2 tends to decrease.
In the end, feedback moves so that the deflection coil current 1y becomes a constant value.

At this time, the voltage Ey proportional to the deflection coil current 1y always matches the reference voltage ES, so if the value of this reference voltage ES is set, the value of the deflection coil current Iy can also be set freely. Horizontal deflection amplitude can be adjusted.

By the way, such a picture tube display device can be used as a combination.
- When used as an image receiving device for output video images, the horizontal deflection frequency fh tends to be increased in order to make the image more precise. Up until now, the horizontal deflection frequency fh of signals that comply with the normal television signal standard has been around 15.7 kHz, but this poses a problem in terms of image roughness, and in order to solve this problem, the horizontal deflection frequency fh has been increased. , for example 21.8k
llz and 31.5ktlz are becoming more common. Moreover, this frequency standard varies depending on computer manufacturers and is not constant.

Therefore, it would be more convenient for a single display device to display these image signals to be able to handle various types of image signals.

The circuit shown in FIG. 6 can also be used for such purposes.

That is, if the horizontal deflection frequency fh changes, the horizontal deflection scanning time TS will naturally change accordingly.

The relationship between the horizontal deflection scanning time Ts, the DC power supply voltage Eb' of the horizontal deflection output circuit 2, and the deflection coil current 1y is as follows: ly = Ts - Eb' /L -
It is expressed as (1). (However, shi is the inductance value of the deflection coil 3.) Therefore, when the horizontal deflection scanning time Ts changes, the value of the deflection coil current Iy, that is, the horizontal amplitude of the image, should change in proportion to it. It will end up being put away. However, the 6th
In the circuit shown in the figure, as mentioned above, for example, the deflection current 1
When v tries to increase, the DC power supply voltage Eb' decreases, causing a feedback that tries to suppress the deflection coil current IV.In the end, the value of the deflection coil current 1y remains unchanged even if the horizontal deflection frequency t'h changes. It is always a constant value, and when image signals with different horizontal deflection frequency standards come in, the six images can always maintain the same horizontal amplitude.

(Problems to be Solved by the Invention) As described above, the circuit of FIG. 6 uses various different synchronizing signal pulses P1. Even if an image signal with P2 of 1 kf is input, it can be handled satisfactorily, but of course there is a problem in that the circuit becomes significantly more complex than one that supports a single frequency.

The circuit shown in FIG. 6 is not limited to a 4t switching regulator. For example, as shown in FIG. 8, a transistor series regulator 4' is used instead of the switching regulator, and the output DC voltage EO of the comparator circuit 6 is directly added to this transistor series regulator 4'. The pulse width modulation circuit 7 and sawtooth wave generation circuit 8 shown in FIG. 6 can be omitted, and even if the horizontal deflection frequency fh changes, a constant deflection coil current 1y can still be obtained.

In the transistor series regulator 4' shown in FIG. 8 taken as an example, 9 is an excitation transistor, 31 is its base input resistance, 10 is a main control transistor, 11.12
is the base bias resistance of the main control transistor 10, 32
is a smoothing capacitor.

In this way, the circuit t can be made quite simple. but,
When trying to cover a wide frequency range, the DC power supply voltage Eb
The variation range of ' must also be wide, and as a result, the loss of the main control transistor 10 of the transistor series regulator 4' increases significantly, which is a practical problem.

Furthermore, even if any type of regulator is used, the circuit of FIG. 6 ends up relying on negative feedback from the output.

In such a case, there is a problem that the response of the circuit inevitably deteriorates due to the shadow R of the time constant in the loop. That is, when switching from one horizontal deflection frequency to another horizontal deflection frequency, a transient occurs in the amplitude of the image for a while, which tends to cause an unsightly image.

(Means for Solving the Problems) The present invention has been made to solve the above problems, and uses a switching regulator as a means for supplying power to a horizontal deflection output circuit. The switching regulator is made to match the horizontal deflection period, and the time length of a half cycle of the switching period of the switching regulator is constant regardless of the horizontal deflection period, so that the switching regulator is adjusted as the horizontal deflection period increases. By lowering the output voltage of the circuit, a horizontal deflection with a constant amplitude can always be obtained for various horizontal deflection frequencies. A power supply circuit for a deflection output circuit is provided.

(Embodiment) FIG. 1 shows an embodiment of a power supply circuit for a horizontal deflection output circuit according to the present invention.

Here, the part numbered 01, 1, 2, 3.4 is the 6th part of the conventional example.
It moves in the same way as the parts with the same numbers in the figure.

13 is a monostable multivibrator (hereinafter abbreviated as MM), 14 is a variable resistor λ:S, which is a rectangular type that is triggered by the oscillation waveform V osc from the horizontal deflection generating circuit 1 and waits for a constant pulse width Td2. A wave (pulse) Vd2 is output, and the switching regulator 4 is driven by this. Although various types of switching regulators can be used as the switching regulator 4, FIG. 2 shows a simple example of a step-down type chopper regulator.

Here, the square waveform (pulse) V
d2 is applied to the base electrode of the excitation transistor 16 through the base resistor 15. In addition, the excitation transistor 16
The collector electrode is the primary winding 1317a of the excitation transformer 17.
The other end of this secondary winding 17a is connected to a DC power source E. (This DC type rAE can of course be shared with the main DC power supply (voltage) Eb depending on the design method.) Secondary winding 17 of the excitation transformer 17
b is connected between the base and emitter of the switch transistor 18.

The polarity of the winding of this excitation transformer 17 is the pulse V
It is assumed that the polarity is set so that the switch transistor 18 becomes conductive during a period of pulse width Td2 of d2.

Further, 19 is a flywheel diode, 20 is a block coil, and 21 is a smoothing capacitor. Although the 18 14PH1-transistor is used as an example as the main switching element here, it is of course possible to use other switching elements, such as field effect transistors, in which case there is no accumulation effect. It may make the design easier.

In this way, the pulse width Td2111 of the pulse Vd2
], the excitation transistor 16 and, in turn, the switch transistor 18 become conductive, and the switch transistor 18 becomes conductive.
A square wave Vsw is generated at the emitter terminal of. The period Ton during which the h-shaped wave Vsw is at a high level is the period (time length) during which the switch transistor 18 is conductive, and is slightly wider than the previous pulse width Td2 by the accumulation time of the transistor. There is.

This square wave Vsw is smoothed by a choke coil 20 and a smoothing capacitor +J21 to obtain a DC power supply voltage Eb/fi corresponding to the average value of the square wave Vsw.

FIG. 3 shows how the output DC power supply voltage Eb' changes when the horizontal deflection frequency fh changes. Fig. 3(a) shows when the horizontal deflection frequency h is low, Fig. 3(b) shows the case when the deflection frequency th is high.Th and Th' are the horizontal deflection periods.

Here, the output pulse Vd2 of MM13 has a propagation waveform yo
It is triggered at the rising edge of sc (it may also be at the falling edge) and has a pulse width of a certain time Td2.

Next, the base resistor 15° excitation transistor 16. which is the excitation stage. Through the excitation transformer 17, this pulse Vd2
causes the switch transistor 18 to change to the previous pulse width Td.
2, it is made conductive only for a period of time Ton, which is slightly longer than 2 by an amount corresponding to the accumulation time. Since this pulse width Td2 is a constant value determined by the constant of MM13, the conduction period (time length) TOn
is constant regardless of the horizontal deflection frequency fh. Then, the DC'1 source voltage Eb which is the average value of this square wave Vsw
The value of ' increases as the horizontal deflection frequency fh increases as shown in FIG. 3(b).

By the way, as can be seen from Figure 3, the value of the DC power supply voltage Eb' is Eb' = Eb - (Ton/Th)
・Q:). These two equations can be expressed as the deflection coil current 1y
Substituting into equation (1) to find, Iy = Eo −Ts −Ton/ (Th −L)
-(3), which means that t increases in proportion to the horizontal deflection period Th, and is never constant. (However, the inductance of the deflection coil 3 is direct.) Here, the horizontal deflection retrace time Tr is the horizontal deflection frequency "h
Since it is determined by the circuit constant of the horizontal deflection output circuit 2 regardless of the diameter of the core 1, the retrace time Tr is constant unless this constant is changed.

Here, as shown in Fig. 4, if the virtual deflection coil current is defined as IV' when the deflection coil current is made to flow at the same slope for the entire horizontal deflection period [h], then (3)
From the equation, 1y'=Iy ・(Th /TS')=Eb - (T
on/L) ・C4), and in the end, if the conduction tlJ and Ton are constant, the virtual deflection coil current IV'
The peak-to-peak value of is constant regardless of the horizontal deflection period number fh.

If we consider that the virtual deflection coil current value Iy' is constant in relation to the image plane of the picture tube, we get the result as shown in FIG.

That is, when the horizontal deflection frequency fh changes, the time for loading actual image information with respect to the total horizontal deflection period Th (the ratio of image signal m>Tsig is approximately constant. Then, here, up to the retrace time Tr) Total horizontal deflection circumference II including
1] The fact that the virtual deflection coil current Iv' corresponding to T h is constant means that the deflection coil current (1 DC) lsig corresponding to the image signal period Tsig is also constant.

Therefore, the modulus of the image information display portion on the picture tube corresponding to the deflection coil current 1 sig corresponding to the image signal period T sig remains constant even if the horizontal deflection frequency fh changes. In this case, if the retrace time T is constant, if the horizontal deflection period WI Th changes, the scanning time Ts will naturally change.
The ratio of the retrace time T' and
Although Iy also changes, the amplitude of the image on the receiver tube remains the same. In addition, in FIG. 6 of the conventional example, at return II, f
Unless iSlTr is also changed in proportion to the horizontal deflection period Th,
This actual image width will change.

As mentioned above, from the above equation (4), the virtual deflection ``il laminar flow l''
It can be seen that the value of V' is proportional to the conduction period (time length) Ton of the switching regulator 4, and that this virtual deflection coil current 1' is proportional to the size of the image on the actual picture tube. Therefore, by changing the time constant for determining the pulse width of MM13 using the variable resistor 14,
As a result, by changing the pulse width Td and conduction period Ton, the horizontal amplitude of the image can be adjusted freely.

Furthermore, since this circuit does not use feedback like the conventional example, the response is good rather than miserable, and there is little distortion in the image when the horizontal deflection frequency is switched.

(Effects of the Invention) As described in detail above, according to the power supply circuit of the horizontal deflection output circuit of the present invention, with a simple configuration, a stock with a constant width can always be obtained for various horizontal deflection frequencies, and The switching response is also good, and the image width can be easily adjusted. −

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the power supply circuit of the horizontal deflection output circuit according to the present invention, and FIG. 2 specifically shows a part of the embodiment of the power supply circuit of the horizontal deflection output circuit of the present invention. The circuit diagrams, FIG. 3, FIG. 4, and FIG. 5 are explanatory diagrams of the operation of the present invention, FIG. 6 is a block diagram of a conventional one-line circuit, FIG. 7 is an explanatory diagram of its operation, and FIG. 8 is a conventional diagram. It is a figure which shows another example of a circuit. DESCRIPTION OF SYMBOLS 1...Horizontal oscillation circuit, 2...Horizontal deflection output circuit, 3...Horizontal deflection coil, 4...Switching regulator, 4'...Transistor series regulator, 5...
・Deflection coil current detection circuit, 6... Comparison circuit, 7...
・Pulse width modulation circuit, 8...Sawtooth wave generation circuit, 9
．． 16... Auxiliary transistor, 10... Main control transistor, 13... Monostable multivibrator (MM), 14...
...Variable resistor, 15...Base resistance, 11...Auxiliary transformer, 18...Switch transistor, one.
...Flywheel diode, 20...Choke coil, 21...Smoothing capacitor, E...DC power supply,
Eb, Eb'...DC power supply (voltage), EO...Output DC voltage, ES...Equivalent voltage, Ey...Voltage proportional to Iy, h...Horizontal deflection frequency, Iy, Iy', l5iq...deflection coil current, L...inductance value of deflection coil 3, P
l, P2...Synchronization signal pulse, Tdl, Vd2...Pulse width (time length), Th,
Th'...Horizontal deflection period, Ton...1 period (time length), Tr...-horizontal deflection return line ([) interval, Ts...horizontal deflection scanning time, 7 sig... Time (illustration by Tomoma), Vdl, V
d2...Square wave (pulse), VSt...Sawtooth wave. 1, Indication of the case Special revision application No. 146728 No. 146728 of 1982, Name of the invention, Power supply circuit for horizontal deflection output circuit 3, Person making the amendment Case Relationship of patent applicant Address: 3-12 Moriya-cho, Kanayō-ku, Yokohama, Kanagawa Prefecture Voluntary amendment 5, Detailed description of the invention in the specification subject to amendment 6, Contents of amendment: , 62. δ, t"j

Claims (3)

[Claims] (1) There is a horizontal deflection output circuit for supplying a deflection current to the horizontal deflection coil, and a switching regulator that converts voltage from a DC power supply and supplies power to the horizontal deflection output circuit, and the switching regulator The switching period is made to match the horizontal deflection period, and the time length of a half cycle of the switching period of the switching regulator is made constant regardless of the horizontal deflection period, so that the output voltage of the switching regulator is decreased as the horizontal deflection period increases. A power supply circuit for a horizontal deflection output circuit, which is characterized by the following features: (2) The switching regulator obtains a pulse having a constant pulse width regardless of the horizontal deflection frequency by adding a waveform related to horizontal deflection to a monostable multivibrator, and performs a switching action based on this pulse. A power supply circuit for the horizontal deflection output circuit according to scope 1. (3) A power supply circuit for a horizontal deflection output circuit according to claim 2, wherein the monostable multivibrator is configured to have a variable output pulse width.