JPS58184875A - Preventing device of generation of abnormal high voltage - Google Patents

Abstract

PURPOSE:To attain low cost, by constituting the device with two resonance capacitors. CONSTITUTION:The connecting point of the resonance capacitors 30, 31 is connected to the base of a switching transistor (TR)20 via a diode 17, an electrolytic capacitor 18 and a resistor 19. The intermediate tap of a flyback transformer 8 is connected to the emitter of the TR20 via a diode 10 and an electrolytic capacitor 13. A pulse given to the other intermediate tap of the transformer 8 is rectified at a diode 12 and an electrolytic capacitor 14 and smoothed, and a DC voltage is formed, which is divided at resistors 15 and 16. The connecting point of the resistors 15, 16 is connected to the collector of the TR20. When a horizontal deflection circuit is active normally, the TR20 is set off, the emitter voltage and the base voltage are decided, and the dividing ratio of the resonance capacitors 30, 31 is decided to be matched for the conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an abnormal high voltage generation prevention device that is used in television receivers or video equipment and can prevent the generation of X-rays due to abnormally high voltage. The purpose is to provide.

Figure 1 shows the circuit of a conventional abnormal pressure prevention device.

In FIG. 1, 1 is a horizontal oscillation circuit, 2 is a horizontal drive circuit, 3 is a fixed resistor, 4 is a horizontal output transistor, and 6 is a horizontal oscillation circuit.
is damper diode, 6,7,23゜24.25.2
6.27 is a resonant capacitor, 28 is a horizontal deflection coil, 2
9 is an S-shaped supplementary capacitor, 8 is a fly bank transformer, 9 is a rectifier, 22 is a cathode ray tube, 12 is a diode, 14 is an electrolytic capacitor, 16, 11.16 is a fixed resistor, 21 is a horizontal oscillation stop The circuits +B1 and +B2 are DC voltages.

+B1. When 10B2 (181 = 110 volts, 10B2 = 12 volts) is applied to the circuit, horizontal oscillation circuit 1
operates, and its output is applied to the horizontal drive circuit 2 (33).The output of the horizontal drive circuit 2 is applied to the base of the horizontal output transistor 4 via the fixed resistor 3 (7). Horizontal output transistor 4, damper diode 5, and resonant capacitors 6, 7, 23°24.25.26.2
7, horizontal deflection coil 28, and S-shaped supplementary capacitor 29
The horizontal deflection output circuit is operated by the fly-down transformer 8. The operation is well known and will therefore be omitted. The output of the flyback transformer 8 is passed through the high voltage rectifier 9 to the anode (
I am 71 years old. Father, on the other hand, flyback transformer 8
The output of Jl is collected as a DC voltage via the diode 12 and the electrolytic capacitor 14, and this 1f4uc4 voltage is divided by the fixed resistor 16.16 to 71. It is added to the water oscillation stop circuit 210 input terminal. Fixed resistor 16
．． The constant 16 indicates that under normal conditions, the horizontal oscillation stop circuit 21 does not operate, the high voltage rises abnormally, and the wire tube and 2° angle are emitted.

By the way, the capacitors 6, 7, 23-271r, t are originally set to operate horizontal oscillation stop circuit 21 to stop the operation of horizontal oscillation circuit 1.
J capacitor is fine, but if this one capacitor becomes open, then fixed resistor 1
The terminal voltage of 6 and the anode voltage of the cathode ray tube are not proportional.

This occurs because the harmonics of the horizontal deflection circuit and flyback transformer 8 are mixed.

FIG. 2 shows the relationship between the heel current and the anode voltage of the cathode ray tube. If the capacitor is open, the X-ray emission will exceed line A of 6 mH as shown in characteristic B. In this case, the voltage across the resistor 16 is small, the circuit 21 does not operate, and a large amount of X-rays are emitted. Therefore,
In order to prevent such a situation from occurring, that is, to achieve characteristic C, multiple capacitors6,7.23~27 are used.
Divide into. By dividing in this way, all the capacitors will not be open at once, and at most only one will be open, so the number of X-rays will not increase by 1 as described above. However, providing a plurality of capacitors has the drawback of increasing costs.

The present invention aims to eliminate the above-mentioned drawbacks and provide an inexpensive device.One embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 shows a circuit of an abnormally high pressure prevention device according to an embodiment of the present invention. In FIG. 3, the same numerals as those in FIG. 1 are the same circuits, so the same numerals are used to omit the explanation.

The connection point of the resonant capacitors 30 and 31 is connected to the base of the switching transistor 20 (another switching element may be used) via the diode 17, the electrolytic capacitor 18, and the fixed resistor 19. The intermediate tag of the flyback transformer 8 is connected to the emitter of the switching transistor 2o through the tie auto 10 and the electrolytic capacitor 13. The pulse (below the above-mentioned tap) is rectified and smoothed by a diode 12 and an electrolytic capacitor 14 with a DC current of fL. This DC voltage
The voltage is divided by fixed resistors 16 and 16. This fixed resistor 1
The connection point 5.16 is connected to the collector of the Suinonano trans/star 2o. It is also connected to the collector r1 of the suitenge transistor 20 and the input terminal of the horizontal oscillation stop circuit 21. When the horizontal deflection circuit is in normal operation, the emitter voltage of the switching transistor 2o and the base voltage of the switching transistor 20 are determined so that the switching transistor 2o is turned on.
The division ratio of the resonant capacitors 30 and 31 is also determined to meet the above conditions.

Now, if the resonant capacitor 31 is open, the base of the switching transistor 20 becomes 0 volts, the switching transistor 20 is turned on, and a DC voltage is input from the collector to the horizontal oscillation stop 11 and the bow path 21. When the resonant capacitor 30 becomes inoperable, the same operation as described above occurs, and the water oscillation circuit 1 stops.

When the resonance capacitors 30 and 31 are open, the water/r-oscillation circuit 1v1 is stopped, regardless of the proportionality between the anode voltage of the cathode ray tube 22 and the terminal voltage of the fixed resistor 16. Therefore, there is no need to divide and use many resonant capacitors as in the past.

As described above, according to the present invention, it is not necessary to use many contents, and it can be implemented at low cost.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a conventional device for generating abnormal high voltage μb, Fig. 2 is a characteristic diagram for explaining the same device, and Fig. 3 is an embodiment of the present invention for preventing abnormal high voltage from occurring in U. FIG. 3 is a circuit diagram of the device. 1...Water light oscillation circuit, 21...Water 3
1'-oscillation 1=! ? Stop rotation l, s,. 41. Flyback transformer, 10.12! ······diode,
13q14...Smooth 3 intenosa, 15, 16
, , , , Voltage dividing resistor, 30,3100006. Resonant capacitor, 20 , , , ) transistor, 1
7. Diode, 18, Contemp, 19...Resistance 0 1 (Embedded name: Patent attorney 1 Satoshi Nakao, etc. 1 yen.

Claims (1)

[Claims] When the DC voltage obtained by rectifying and smoothing the n pulses obtained from the fly bank transformer exceeds a certain value, the horizontal oscillation stop circuit is activated so as to stop the operation of the horizontal oscillation (b) path. A pulse having a larger amplitude than the above pulse is taken out from the flyback transformer, rectified and smoothed, and this rectified and smoothed DC voltage is applied to the horizontal oscillation stop circuit via a switching element. The resonant capacitor of the water 1Y deflection circuit provided in the front stage of the transformer is constructed with a direct tally circuit of two capacitors, and a voltage t'1. The output of the switching element is rectified and smoothed, and the obtained DC voltage is used to control the on/off of the switching element.