JPS597258B2 - Kouatsuhatsu Seisouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high voltage generator for use in, for example, a television receiver, with improved high voltage regulation.

Various methods have been known to improve high pressure regulation.

For example, using a saturable reactor to vary the pulse width according to high pressure load fluctuations? There are methods such as stabilizing the high voltage by adjusting the voltage, changing the DC power supply voltage according to fluctuations in the high voltage load, and connecting a bleeder resistor after the high voltage rectifier. However, these methods have drawbacks such as unnecessary power consumption and high cost due to the large number of parts. The method for connecting the bleeder resistor will be explained below using an example. Figure 1 shows a general horizontal output circuit, where 1 is a horizontal output transistor, 2 is a damper diode, and 3 is a horizontal output transistor.
is a resonance capacitor, 4 is a deflection yoke, 5 is an S-shaped correction and DC cut capacitor, 6 is a flyback transformer, 7 is a primary winding of the flyback transformer, 8 is a secondary winding, and 9 is a high voltage rectifier diode. show.

This can be expressed as an equivalent circuit as shown in FIG.

Here, SW corresponds to the horizontal transistor 1 and damper diode 2, L1 is the equivalent inductance obtained by connecting the inductance of the deflection yoke 4 and the primary winding 7 of the flyback transformer 6 in parallel, C1 is the resonant capacitor, and L2 is the primary winding. The leakage inductance between C and the secondary winding, C2 is the ground capacitance of the secondary winding. In the equivalent circuit of FIG. 2, the voltage VC2 generated across the ground capacitance C2 when SW is open is expressed by equation (1). However, here, D and β are the resonant angular frequencies of this resonant circuit, d is the fundamental angular frequency, and β is the harmonic angular frequency, and when β/(t is a value that satisfies equation (2) for an odd number of N) , the well-known harmonic tuning theory states that no ringing voltage occurs during the scan period.

In equation (2), N=3 is third-order tuning, N-5 is fifth-order tuning, and V, . This is called VN-order tuning by N.

For each order, β/α changes depending on the ratio of Tr and Ts. For example, when Tr=12μs and 14μs (the horizontal repetition period is 63.5μs), β/d for each order is shown in Table 1.
become that way. As can be seen from the above equation (1), the output V
The ratio of the fundamental wave component to the harmonic component of C2 is α/β.V1 Is it determined by the tuning order as shown in Table 1? It has an almost constant value.

As for the output waveform, as can be seen from equation (1), 3,
In the 7th and 11th order tuning, as shown in Figure 3a (the case of 3rd order tuning is shown), the center of the VC2 waveform becomes a convex waveform, and the 5th and 9th order.
, 13th-order tuning results in a concave waveform as shown in FIG. 3b (the case of 5th-order tuning is shown). Here, a comparison between the two and the relationship between the regulation will be explained using the cases of third-order and fifth-order tuning as examples. Figure 3 a shows the output waveforms in the case of third-order tuning, and b shows the output waveforms in the case of fifth-order tuning.
The third-order tuned waveform has a wider width than the third-order tuned waveform. For this reason, when the load is removed, it is clear that 5th-order tuning is better than 3rd-order tuning, which has a wider diode flow angle and high-pressure regulation. In this way, 5th and 9th order tuning has been increasingly used as a method to improve regulation. However, if this continues as it is, the waveform will become double peaks as shown in Figure 3b, so in the small current region, the voltage fluctuation rate will be large until the double peaks are removed as shown in Figure 4. It was hot. In order to eliminate this effect, a bleeder resistor 10 is inserted after the high-voltage diode as shown in FIG. 5, and a constant current is constantly passed, and unless the double-peaked portion is used in a cut-off state, a sufficient effect cannot be obtained. This pattern is shown in FIG. A is the regulation characteristic when there is no bleeder resistance, and B is the regulation characteristic when there is bleeder resistance. If a bleeder resistor is inserted in this way, a current other than the cathode ray tube current will flow, so the resistance value of the bleeder resistor 10 is set to R, and the high voltage is set to E.
If HT is used, a power loss of EHT2/R will occur. Furthermore, since the resistor is connected to the ground from the high-voltage part, a high-voltage resistor with sufficient withstand voltage must be used, and sufficient consideration must be given to insulation, which naturally increases costs and lacks reliability. It happens. SUMMARY OF THE INVENTION An object of the present invention is to provide a device which eliminates the above-mentioned drawbacks of the prior art and effectively improves high pressure regulation.

The feature of the present invention is that in (4k+1) order tuning such as 5th, 9th, and 13th orders, the phases of the fundamental wave and harmonics are opposite at the center of the output waveform, and the output waveform becomes a bimodal waveform with a dent at the center. Does the degree of denting depend on the size of the harmonic components? Varies depending on

FIG. 7 shows this relationship using the case of fifth-order tuning as an example. Here, P is the ratio of the harmonic component to the fundamental component. As can be seen from Equation (1) and β/d in Table 1, P is approximately 0.22 and a deep depression is created as it is, but if it is possible to reduce the harmonic components in some way. Considering that it is possible to reduce the amount of denting, we specifically inserted an attenuation circuit with frequency characteristics in series with the primary winding of the flyback transformer to effectively attenuate harmonic components and shape the output waveform. The indentation characteristic or sharpness of
The aim is to soften the characteristics and improve high pressure regulation. The present invention will be explained below with reference to the figures.

FIG. 8 shows a horizontal output circuit according to an embodiment of the present invention. Components that are the same as those in FIG. The difference between the embodiment of the present invention and the example shown in FIG. This is because they are connected and inserted in series. Here, the inductance of the coil 11 is L.

, the capacitance of capacitor 12 is C. , the value of resistance is R. Then, the resonance angular frequency of LOCO is approximately the harmonic angular frequency β
is chosen to be equal to FIG. 9 shows the impedance characteristics in this case, where curve a shows the impedance curve of the LC resonant circuit, and curve b shows the impedance curve of the resistor. The operating principle of the present invention will be explained with reference to FIG. Most of the fundamental angular frequency current flows through the low impedance LC circuit (mostly the coil 11), and a small proportion flows through the resistor, so there is little resistance loss, but on the other hand, most of the harmonic lightning current is supplied through the low impedance resistor 13. This causes large resistance loss. Due to this resistance loss, the harmonic components of the output voltage VC2 are attenuated to a greater extent than the fundamental wave components. For this reason, the amount of depression in the output waveform is small as shown in FIG. 7, and voltage fluctuations can be suppressed in the small current region. FIG. 10 shows a horizontal output circuit according to another embodiment of the present invention, which includes an LC parallel resonant circuit whose resonance frequency is selected approximately equal to the harmonic frequency, and an LCR circuit in which a resistor 13 is further connected in series with a capacitor 12. It is inserted in series with the primary winding of a flyback transformer.

In this case, since the resonant frequency of the LCR circuit is almost equal to the harmonic frequency, the harmonic current component resonates in the LCR circuit and becomes a high impedance and is greatly attenuated by the resistor 13. Because it flows through it, it receives almost no attenuation. For this reason, FB
The harmonic components of the high-voltage output waveform of T are greatly attenuated compared to the fundamental wave components, and the output waveform is flat and voltage fluctuations in the small current region are reduced. FIG. 11 shows still another embodiment of the present invention, 14! -j mechanical filter one,
The attenuation band of the filter constituted by a crystal filter is selected to be approximately equal to the harmonic frequency.

In this case, the regulation can be improved by attenuating harmonic components as in the embodiment shown in FIG. Is the harmonic component attenuated using a resistor element? However, if the Q of the resonant element itself is low and the loss is large, there is no need to add a separate resistance element, and it is possible to fly a resonant element with a low Q that has a parallel resonant frequency almost equal to the harmonic frequency. It is clear from the above explanation that the same effect can be obtained by inserting the back transformer in series with the primary winding.
FIG. 12 shows one embodiment of the present invention, and FIG. 12 shows an equivalent circuit of an LC circuit including a coil 11 and a capacitor 12 in which a horizontal deflection output circuit is additionally inserted in FIGS. In this case, the Q of capacitor 12 is chosen low;
Equivalently, a parallel resistor 17 or a series resistor 18 is connected, which has the same effect as the embodiments shown in FIGS. 8 and 9, and improves regulation by attenuating harmonic components to a greater extent than fundamental components. have an effect. As described above, the main feature of the present invention is that the V1 flyback transformer is constructed by inserting a resonant circuit such as an LCR in series with the primary winding of the flyback transformer to effectively attenuate the harmonic components of the high voltage output waveform. The aim is to flatten the output waveform and improve high pressure regulation.

The amount of attenuation of harmonic components is determined by the resonant frequency of the resonant circuit and the Q of the circuit.
This can be achieved by appropriately selecting the resistance value of the additional resistor, the value of L in the LC circuit, etc., and adjusting the impedance characteristics shown in FIG. In the embodiment shown in Fig. 8, the LCR parallel circuit is inserted on the low voltage side of the primary winding of the flyback transformer, but the same effect can be obtained by inserting it in the middle of the primary winding as shown in Fig. 16. Needless to say.

Although not shown, it may also be inserted into the high voltage side of the primary winding. The effects of the present invention have been explained above, focusing on the case where the output waveform is a bimodal waveform, such as the 5th and 9th order tuning ((4k-1) order tuning). 1
Even in the case of a tuning order in which the output waveform has a sharp point, such as () order tuning), the present invention is effective because it can reduce the degree of v.

Furthermore, FIG. 13 shows another embodiment in which the secondary windings are 81...8. -1,8. and is divided into n by a high-voltage rectifier diode 9. In this case, the order in which the n secondary windings are tuned is arbitrary,
In the case of multiple tuning like this, the LCR circuit to be inserted is
One set may be inserted for one order, or multiple sets of LCR circuits corresponding to each order may be inserted in series. As described above, the present invention does not require a large number of expensive parts as in the prior art, and only requires an inexpensive coil, capacitor, and resistor, which makes it possible to significantly reduce costs and improve reliability.

Furthermore, since the method is used to attenuate high-Q resonance, power consumption can be reduced significantly.

Furthermore, it is possible to suppress harmful vibrations (ringing) that occur during the running period, thereby preventing an increase in loss due to ringing, induction interference to other circuits, and an increase in current of the horizontal hydraulic transistor. This will be explained with reference to FIGS. 14 and 15. Figure 14 shows the secondary side output voltage waveform of the flyback transformer 6 for one horizontal period, Figure 2 shows the case without the LCR circuit of the present invention, and Figure E shows the case with the LCR circuit of the present invention inserted. Represent each. LCR
Without the circuit, the harmful ringing voltage 20 that occurs during the scan period continues with little attenuation during the scan period. If the angular frequency of this ringing voltage is r, there is a relationship of r + β, so by inserting an LCR circuit, not only the output waveform during the retrace period becomes flat as shown in figure E, but also the ringing voltage 20 during the scanning period becomes flat. Attenuate. FIG. 15 shows the harmful effects of ringing during the scanning period and the effects of the present invention, taking the collector current of a horizontal output transistor as an example.
Figure 1 shows the collector current waveform when there is no LCR circuit, and Figure 1 shows the collector current waveform when the LCR circuit is inserted. When a ringing current is superimposed on the scanning period, depending on the phase, the maximum collector current Icp increases to ICP2 as shown in the diagram. Since the ringing phase is extremely unstable and changes due to fluctuations in the high voltage load and variations in circuit constants, it is necessary to reduce the ringing current. According to the present invention, at the end of the scanning period v, the ringing current can be attenuated to almost zero as shown in Figure 1, making it possible to prevent an increase in Icp.

[Brief explanation of drawings]

Figure 1 is a general horizontal deflection output circuit diagram, Figure 2 is its equivalent circuit, Figures 3 and 4 are waveform diagrams for explaining the circuit,
Figure 5 is a horizontal deflection output circuit diagram using a bleeder resistor, Figure 6 is a characteristic diagram for explaining the same horizontal deflection output circuit, and Figure 7 is a diagram of the horizontal deflection output circuit using a bleeder resistor.
The figure is a waveform diagram for explaining the present invention, Figure 8 is a horizontal deflection output circuit diagram showing an embodiment of the present invention, Figure 9 is an impedance characteristic curve for explaining the present invention, Figures 10 and 11 are figure,
FIGS. 12, 13, and 16 are circuit diagrams of other embodiments of the present invention, and FIGS. 14 and 15 are waveform diagrams for explaining other effects of the present invention. 6... Flyback transformer, 7... Primary winding, 8
...Secondary winding, 11...Coil, 12...Capacitor 13...Resistor, 14...Filter.

Claims (1)

[Claims] 1. At least a flyback transformer, a horizontal output transistor connected to the primary winding of the flyback transformer, a deflection yoke and a resonant capacitor connected in parallel to the horizontal output transistor, and a flyback transformer. A high-voltage rectifier diode is connected to the secondary winding of the transformer, and the fundamental wave component and its harmonic components of the retrace output voltage generated in the secondary winding of the flyback transformer are rectified by the rectifier diode. In a high voltage generator that generates high voltage, a resonant circuit that resonates at the frequency of harmonic components is connected in series with the primary winding, and
A high voltage generator characterized in that a resistor is connected to this resonant circuit, and the tip of the retrace output voltage is flattened. 2 At least a flyback transformer, a horizontal output transistor connected to the primary winding of this flyback transformer, a deflection yoke and a resonant capacitor connected in parallel to this horizontal output transistor, and a secondary winding of the flyback transformer. A high-voltage transformer is equipped with a high-voltage rectifier diode connected to the flyback transformer, and generates a high voltage by rectifying the fundamental wave component and its harmonic components of the retrace output voltage generated in the secondary winding of the flyback transformer. In the generator, resonance occurs at the frequency of the harmonic component. The parallel resonant circuit consisting of a capacitor and a coil is the above 1.
A high voltage generator characterized in that a resistor is connected in series with the next winding and in parallel with this parallel resonant circuit, and the tip of the return output voltage is flattened.
3 At least a flyback transformer, a horizontal output transistor connected to the primary winding of this flyback transformer, a deflection yoke and a resonant capacitor connected in parallel to this horizontal output transistor, and a secondary winding of the flyback transformer. A high-voltage transformer is equipped with a high-voltage rectifier diode connected to the flyback transformer, and generates a high voltage by rectifying the fundamental wave component and its harmonic components of the retrace output voltage generated in the secondary winding of the flyback transformer. In the generator, a parallel resonant circuit consisting of a capacitor and a coil that resonates at the frequency of the harmonic component is connected in series with the above primary winding, and a resistor is connected in series with this capacitor. A high voltage generator characterized by a flattened tip of the line output voltage.