JPH0467772A - High voltage stabilizing circuit - Google Patents

Abstract

PURPOSE:To improve dynamic regulation together with static regulation by constituting it of a differentiating amplifier for the high frequency range ingredients of output voltage and a unidirectional conductive element, which passes only the trailing ingredients. CONSTITUTION:This is the one provided with a means, which emphatically takes out the trailing ingredients of the dynamic regulation having great influence upon the curvature of a screen and adds it to the feedback signal from an amplifier 15, and herein a differentiating amplifier 16, which amplifies the high frequency range ingredients of the high voltage on the secondary side by differentiation, and a diode 17 as a unidirectional conductive element, which passes only the trailing ingredients of the differentiating amplifier 16, are provided on the rear stage of a differential amplifier 13 so that they may be parallel with the amplifier 15, and the output of this diode 17, that is, the output of only the trailing ingredients of the differentiating amplifier 16 is added to the output from the amplifier 15 by an adder 18, and is supplied to a control circuit 9.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high stabilization circuit that stabilizes a high voltage supplied to the anode side of a picture tube of a television receiver, for example.

Conventional technology Conventionally, for example, a high-voltage stabilizing circuit in a television receiver has a configuration as shown in Figure 5, and is periodically turned on and off.
The output of the horizontal output transistor (1), which repeats When it is OFF, the pulse voltage generated in the primary coil (6a) of the fly hack transformer (6) is stepped up and taken out to the output side of the secondary coil (6b), and the high voltage output is sent to the high voltage rectifier diode (7).
Smoothing (DC conversion) by the anode power supply capacity of the picture tube
and is supplied to the picture tube as an anode voltage. In addition, (6c) is a tertiary side coil, (8) is a DC power supply, and the DC power supply (8) is connected to one end of the primary side coil (6a) via a control circuit (9) as shown in the figure. , when the voltage value is varied depending on the conductivity of the power supply transistor of the control circuit (9), a fly hack transformer (
6) The peak value of the pulse voltage generated on the primary side changes. Then, in order to correct the regulation of the high output voltage generated on the secondary side, the high output voltage is detected as divided by resistors (10) and (11), and the divided voltage at point P is used for impedance conversion. Buffer (1
2) in addition to the non-inverting terminal of the differential amplifier (13),
The inverting terminal of the differential amplifier (13) is compared with the reference voltage applied from the direct type a (14), the difference is taken out from the differential amplifier (13) as an error voltage, and the difference is taken out from the differential amplifier (13).
), after which the control circuit (9) is controlled. Needless to say, this control system is a negative retrace control. As a result, the voltage value of the direct type a (8) is controlled by the control circuit (9), the peak value of the pulse voltage generated on the primary side of the flyback transformer (6) is changed, and the high voltage on the secondary side is changed. Regulation correction, ie, stabilization, of the output voltage will be performed.

Problem to be Solved by the Invention However, when stabilizing high pressure using conventional negative feedback control, the time constant of the entire system is relatively large and its phase characteristics deteriorate, so it is necessary to increase the correction speed. That is, if the amplifier is set to high speed and low gain in order to improve responsiveness, there is a risk that the entire system will become unstable. Therefore, in practice, amplifiers are used at low speeds (low-frequency biased type), and as a result, they are hardly able to cope with high-frequency regulation changes, that is, dynamic regulation. Almost no improvements have been made to the falling portion. i.e., low frequency regulation changes that affect the overall size of the television screen;
That is, although it is effective in improving static regulation, it is hardly effective in improving dynamic regulation, which causes vertical image blurring on a television screen, and the effect on image quality is large.

The present invention has been made in view of these points, and an object of the present invention is to provide a high voltage stabilizing circuit that can sufficiently improve not only static regulation but also dynamic regulation.

In order to achieve the above-mentioned purpose of reducing the amount of power, the present invention boosts and extracts the pulse voltage on the primary side to the secondary side, converts it to direct current on the secondary side, and detects the output voltage on the secondary side. In a high voltage stabilizing circuit that performs negative feedback control of the peak value of the pulse voltage on the primary side based on the detection, a means is provided to emphasize the falling component of the dynamic regulation and extract it and add it to the negative feedback signal. is composed of a differential amplifier that differentially amplifies the high-frequency component of the output voltage, and a unidirectional conductive element that passes only the falling component of the differential amplifier.

Effect: With this configuration, dynamic regulation can be improved in addition to static regulation without impairing the stability of the entire system.

叉”L plexus An embodiment of the present invention will be described below with reference to the drawings.

It should be noted that the same parts as those in the prior art will be given the same reference numerals and the explanation thereof will be omitted.

In this example, the falling component of dynamic regulation that has a large effect on screen tilt is emphasized and extracted.
It is provided with means for adding to the negative feedback signal from the amplifier (15) described above, and specifically, as shown in Figure 1, it is placed downstream of the differential amplifier (13) and in parallel with the amplifier (15). , a differential amplifier (16) that differentially amplifies the high-frequency component of the high-voltage output voltage on the secondary side;
A diode (17) is provided as a unidirectional conductive element that passes only the falling component of the diode (17).
), that is, the output of only the falling component of the differential amplifier (16), is added to the output from the amplifier (15) by the adder (1
8) and then supplied to the control circuit (9). Here, an amplifier (15) and a differential amplifier (16)
) is as shown in Figure 2, and the amplifier (15) is a low-frequency biased type (characteristic curve F in Figure 2) that has a large gain for low frequency components. On the other hand, the differential amplifier (16) is a high-frequency biased type that has a large gain for high-frequency components (characteristic curve F'' in Figure 2), and the output of only the falling component is negatively fed back. (In other words, since the correction speed of only the falling component for dynamic regulation is amplified), the stability of the system is not impaired.

Therefore, in such a configuration, in addition to static regulation correction of the high voltage output voltage on the secondary side, dynamic regulation,
In particular, the falling component can be corrected, and static and dynamic regulation can be sufficiently improved.

For example, when displaying a figure like the one shown in Figure 3 on a TV screen, in an ideal state with no regulation changes, a TV screen like the one shown in Figure 3(a) would be obtained, but the secondary side If no regulation correction of the high voltage output voltage is performed at all, that is, if there is no negative feedback control system, the TV screen will have a large screen curve as shown in Figure 3 (b), and the regulation waveform on the secondary side will be Figure 4 (
It looked like a). In addition, the TV screen when using the conventional negative feedback control system is as shown in Fig. 3(c), and although the screen curvature has been improved to some extent compared to Fig. 3(b), it is not sufficient. This is because the correction speed cannot keep up with the high frequency dynamic regulation, and the regulation waveform on the secondary side is shown in Figure 4 (
As shown in b), the improvement was insufficient. For it,
When the negative feedback control system of this embodiment is used, the output waveform from the diode (17) as shown in FIG. 4(c) increases the amount of negative feedback for the falling component of high-frequency dynamic regulation. As a result, the regulation waveform on the secondary side is sufficiently improved with almost no change as shown in Figure 4(d), and the TV screen also appears on the third side.
As shown in Figure (d), it can be made sufficiently improved to have almost no bending.

In this embodiment, the diode (17) is provided to emphasize and extract only the falling component of the dynamic regulation, but this is also important for keeping the system stable. 17), the output of the differential amplifier (16) as shown in Figure 4(e) is directly fed back negative feedback, causing oscillation due to phase delay.
There is a risk that the regulation waveform will become as shown in FIG. 4(f).

Effects of the Invention As described above, according to the high voltage stabilizing circuit of the present invention, only by adding a differential amplifier and a unidirectional conductive element, only the falling component of dynamic regulation can be emphasized and extracted and added to the negative feedback signal. Therefore, static and dynamic regulation can be sufficiently improved without impairing the stability of the entire system, and it is particularly suitable for use in high-definition televisions that require high image quality.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an embodiment of the present invention, Fig. 2 is a diagram showing the frequency-gain characteristics of the width amplifier, Fig. 3 is a diagram for explaining the improved state of regulation, and Fig. 4 is FIG. 3 is a waveform diagram for explanation, and FIG. 5 is a diagram showing a conventional example. (6), --- fly bank transformer, (8) - DC power supply (9) - control circuit, (16) - differential amplifier. (17)--diode, (18)--adder.

Claims (2)

[Claims] (1) The pulse voltage on the primary side is boosted and taken out to the secondary side, converted to DC on the secondary side, and the output voltage on the secondary side is detected. Based on the detection, the peak value of the pulse voltage on the primary side is determined. A high-voltage stabilizing circuit that performs negative feedback control, characterized in that it is provided with means for emphasizing and extracting a falling component of dynamic regulation and adding it to a negative feedback signal. (2) The first aspect of the present invention is characterized in that the means comprises a differential amplifier that differentially amplifies the high frequency component of the output voltage, and a unidirectional conductive element that passes only the falling component of the differential amplifier. High voltage stabilization circuit as described.