JPH04105763U - Horizontal amplitude correction circuit - Google Patents

Abstract

(57) [Summary] [Purpose] The purpose of the present invention is to provide a horizontal amplitude correction circuit that can correct pincushion distortion and also cope with the case of a screen with a window pattern (partial brightness change). [Configuration] One end of the control circuit 3 for sensing the load current and controlling horizontal amplitude changes is connected to the low potential part of the horizontal output circuit 7, the other end is grounded, and the horizontal output circuit 7 is connected to pincushion distortion correction. Further, an amplitude correction signal generation circuit 4 is connected to the low potential side of the control circuit 3, and a pincushion distortion correction circuit 2 is connected to the amplitude correction signal generation circuit 4. Amplitude correction is performed by changing the voltage of the pincushion distortion correction circuit 2 in accordance with changes in the control signal.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention is a horizontal amplitude correction circuit that corrects horizontal amplitude in television receivers. related to the road.

0002

[Conventional technology]

In recent years, there has been a noticeable trend toward higher image quality and larger screens in television receivers. There is. In particular, as the screen gets larger, regular TV programs will need to be adjusted to maintain screen brightness. This requires a higher voltage than that required for conventional television receivers.

0003 However, as the high voltage increases, the voltage applied to the cathode ray tube may become abnormal. The risk of becoming too high is greater. Therefore, abnormalities in the deflection circuit and high voltage output circuit There is usually an overcurrent protection circuit that turns off the power when the power is turned off.

0004 By the way, the above-mentioned protection circuit includes a circuit for detecting an abnormal state. This detection method was developed by the present applicant in Utility Application No. 2-400888. There are some things that are proposed in the report. Figure 4 shows the proposed circuit.

[0005] Figure 4 shows the horizontal deflection circuit of a television receiver, and 1 is a flyback transducer. (FBT), n1 is the primary winding and n2 is the secondary winding. 3 is the control circuit , consists of a parallel circuit of a capacitor C5 and a resistor R0. 8 is a horizontal output circuit, T R1 is horizontal output transistor, D3 is diode, C9 is capacitor, DY is water Flat deflection coil, C10 is a capacitor, +B is a DC power supply, C6 is a capacitor .

[0006] Next, the operation will be explained. In FIG. 4, the control circuit 3 includes a resistor R0 and a capacitor C It consists of 5 parallel circuits, and the E side terminal is connected to the low potential side of the horizontal output circuit 8. At the same time, a load current information signal is output to an overcurrent protection circuit (not shown).

[0007] That is, DC voltage +B is applied to the DC power supply capacitor C6, and the DC voltage +B is applied to the DC power supply capacitor C6. A voltage drop corresponding to the load current is charged across the capacitor C5. This voltage drop The voltage is proportional to the load current, so it will definitely rise in the event of an abnormality (overload). It works just like that.

[0008] As described above, since one end of the control circuit 3 is grounded, the potential of the control circuit 3 is also It can be directly connected to the overcurrent protection circuit without the need for low insulation, and this control circuit 3 It has the advantage that it can perform correction and also function as a load current detection circuit.

[0009] On the other hand, as the screen becomes larger, raster distortion becomes more influential. In particular, the left and right threads The influence of winding distortion is significant. Therefore, in order to correct this on the circuit, A circuit as shown in Publication No. 9102 (H04N3/16) has been proposed.

0010 Therefore, as the screen size becomes larger, various effects will occur, so the above-mentioned correction is necessary. circuits and protection circuits will be required.

[0011] Therefore, in order to carry out all the above-mentioned amendments and protections, FIG. 5 shows a case where the control circuit 3 shown in FIG. 4 is added to the circuit proposed in the publication. Note that the description of the same drawing numbers as those in FIG. 4 will be omitted, and only FIG. 5 will be described.

0012 In FIG. 5, 7 is a horizontal output circuit, which includes diodes D1, D2, and a capacitor. It consists of C1, C2, C3, C4, horizontal coil DY, and coil L1. 2 is thread In the winding distortion correction circuit, resistors R1, R2, R3, R9, R10, transistor TR3, It consists of TR4.

[0013] Next, to simplify the explanation of the operation, the pincushion distortion correction circuit 2 has a parameter corresponding to the pincushion distortion. The volley wave is amplified by transistor TR4 via R9 and controls transistor TR3. control Then, the voltage across capacitor C4 is modulated in a parabolic manner, and the water The current flowing through the flat coil DY changes, and the pincushion distortion is corrected.

[0014] In addition, this pincushion distortion correction circuit is designed to correct horizontal amplitude due to changes in brightness. A DC component voltage is applied to the ABL information via R10, and horizontal amplitude correction is performed. Ru.

[0015] However, in this pincushion distortion correction circuit, the DC voltage of the input parabolic wave is If there is no change, the voltage at point A will not change. In other words, horizontal amplitude correction is not possible. That is.

[0016] Therefore, as shown in Fig. 3, the central part 6 of the screen is white and the surrounding area 5 is black, so-called In the case of a screen like the Indian pattern (partial brightness change), the resistance R of the control circuit 3 The circuit in Figure 5 cannot change the potential at point A even if the voltage across 0 changes. won.

[0017]

[Problem that the idea aims to solve]

This invention not only corrects pincushion distortion, but also The purpose is to provide a horizontal amplitude correction circuit that can also handle (partial brightness changes). do.

[0018]

[Means to solve the problem]

This invention connects the primary winding of a flyback transformer in series with the horizontal output circuit. a control circuit consisting of a parallel circuit of a resistor and a capacitor connected to the ground; and the control circuit connected to the ground. one end, the other end of the control circuit that outputs load current information, and the horizontal output circuit. a pincushion distortion correction circuit connected to the pincushion distortion correction circuit; and a pincushion distortion correction circuit connected to the other end of the control circuit. and a horizontal amplitude correction signal generation circuit connected to the horizontal amplitude correction signal generating circuit. This is a correction circuit.

[0019]

[Effect] With the above configuration, the present invention not only corrects pincushion distortion but also corrects load voltage. Amplitude correction can be performed using flow information.

[0020]

【Example】

FIG. 1 shows an embodiment of the present invention. In addition, parts in Figure 1 that are the same as those in Figure 5 have the same drawing numbers. I will omit the explanation.

[0021] In FIG. 1, 4 is an amplitude correction signal generation circuit, and resistors R4, R5, R6, R 7, R8, capacitors C7 and C8, and transistor TR5.

[0022] Next, the operation will be explained. First, conventionally, both ends of the capacitor C5 of the control circuit 3 are As mentioned above, the voltage drop corresponding to the load current is charged. This charged Since the voltage is proportional to the load current, it is difficult to detect changes in the displayed brightness information. can be done.

[0023] Then, the voltage across the capacitor C5 is input to the amplitude correction signal generation circuit 4, The resistance is divided by resistors R4 and R5, and the horizontal component is removed by capacitor C7. after that, It is input to the base of transistor TR5, is inverted and amplified by transistor TR5, and is output to the resistor. The DC component is removed by resistor R8 and capacitor C5, and the output of pincushion distortion correction circuit 2 is reduced. The amplitude is corrected by the load current.

[0024] By the way, considering the case of the wind pattern shown in Figure 3, the controller The voltage across the capacitor C5, that is, the voltage across the resistor R0 is as shown in Figure 2a, and the brightness The voltage increases in the area where the temperature increases. (Here V is one vertical period) Then, the voltage obtained by dividing this voltage by resistance and removing the horizontal component is as shown in Figure 2b, This voltage is applied to the base of transistor TR5. Furthermore, transistor TR5 The voltage amplified by is as shown in Figure 2c, and this voltage is connected to capacitor C8 and resistor R. 8, information on only the AC component is supplied to the pincushion distortion correction circuit 2.

[0025] Thereafter, the output of the pincushion distortion correction circuit 2 is controlled by the voltage input to the transistor TR4. The force has an output waveform as shown in Figure 2d.

[0026] In other words, as you can see from this waveform, in areas where the screen brightness is increasing, The winding distortion correction amount is reduced. Apply correction in the direction of decreasing horizontal amplitude. Na Therefore, the brighter areas of the screen are smaller because the high voltage decreases and the horizontal amplitude increases. This is because it is necessary to make corrections so that

[0027]

[Effect of the idea]

According to the present invention, in addition to correcting pincushion distortion, the screen (Partial brightness change) can also correct the horizontal amplitude.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a waveform diagram for explaining an embodiment of the present invention.

[Figure 3] Wind pattern.

FIG. 4 is a diagram showing a conventional example.

FIG. 5 is a diagram showing a conventional example.

[Explanation of symbols]

1 Flyback transformer 2 Pincushion distortion correction circuit 3 Control circuit 4 Amplitude correction signal creation circuit 7 Horizontal output circuit R0 resistance C5 capacitor

Claims (1)

[Scope of utility model registration request] 1. A control circuit comprising a parallel circuit of a resistor and a capacitor connected in series to a primary winding of a flyback transformer and a horizontal output circuit, one end of the control circuit connected to ground, and a control circuit configured to transmit load current information. the other end of the control circuit that outputs;
A horizontal amplitude correction circuit comprising: a pincushion distortion correction circuit connected to the horizontal output circuit; and a horizontal amplitude correction signal generation circuit connected to the other end of the control circuit and connected to the pincushion distortion correction circuit. .