JPS6012866A - Rc network circuit - Google Patents

Abstract

PURPOSE:To improve the life of a resistor without lossing a ringing preventing effect by connecting a diode between both the ends of a resistor in an RC network circuit constituting a parallel side courses between both the ends of a deflecting coil in an image receiving tube to form the side courses. CONSTITUTION:Collector peak voltage 8 is applied to the deflection coil 1 in the image receiving tube. Consequently, current 9 flows into an RC network circuit 6a and the current is divided into current 10 flowing into a diode 7 and current 11 flowing into a resistor 5 at a point (a). Thus, the heat value generated in a resistance 5 is reduced down to almost a half of the case disconnecting a diode 7, so that the capacity of the resistance 5 can be reduced. Current 9 flows in positive and negative direction during a flyback time; the diode 7 is connected when the current flows in the positive arrow 12 direction and the current flows into the resistance 5 in case of the negative direction to act as damping. Since ringing is generated after the negative current has started to flow, the same ringing preventing effect as disconnection of the diode 7 is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a highly reliable, low-cost RC network circuit suitable for preventing ringing in a television receiver.

[Background of the invention]

A deflection yoke used in color television receivers and the like is composed of a horizontal deflection coil and a vertical deflection coil, and a deflection current is passed through each deflection coil to deflect an electron beam in the horizontal and vertical directions. Currently, as a deflection yoke, a semi-toroidal deflection yoke is used in most color television receivers. Therefore, when deflection is performed horizontally or vertically, ringing appears on the screen due to magnetic coupling between the horizontal deflection coil and the vertical deflection coil. In addition, the horizontal deflection coil itself causes vibration, ringing is superimposed on the horizontal deflection current itself, and ringing appears on the screen. As a countermeasure against this problem, an RC network circuit is often used in which a resistor and a capacitor are connected in series between both ends of a horizontal deflection coil or a vertical deflection coil to form a side path.

FIG. 1 shows an example of a conventional RC network circuit, in which an RC network circuit 6 having a capacitor 4 and a resistor 5 connected in series is attached to both ends 2.3 of a deflection coil 1 to prevent ringing.

However, in order to prevent ringing, 8
When attempting to dampen by connecting the RC network circuit 6 to both ends 2.3 of the deflection coil 1 to which a collector peak voltage with a high peak voltage and high frequency is applied, as shown in FIG. is the third
A current shown as 9 in WJ(b) flows during the retrace period TrO. The resistor 5 generates heat due to this current 9, and although ringing is reduced, the temperature of the resistor 5 becomes considerably high. For this reason, there is a drawback that a resistor with a large capacity (heat-resistant power amount) must be attached.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an RC network circuit that does not have the above-mentioned drawbacks and has improved resistance life and reliability without impairing the ringing prevention effect.

(Summary of the Invention) In order to achieve the above object, in the present invention, a diode is connected between both ends of the resistor forming the RC network to form a bypass, and when a high voltage is generated in the television receiver, the diode is connected and the resistor is connected when a high voltage is generated in the television receiver. Almost no current flows through the resistor, and current flows through the resistor only during damping for about half the time compared to conventional methods, reducing heat generation.Of course, the cost of the diode and the amount of time required to connect it tend to push up the cost. However, the effects of improved reliability and overall cost reduction are greater.

[Embodiments of the invention]

FIG. 2 shows an RC network circuit 6a in which the present invention is implemented, and 7 is a diode for reducing heat generation of the resistor according to the present invention. A collector peak voltage 8 shown in FIG. 3<a> is applied to the terminal 3 of the deflection coil 1. This results in
A current as indicated by 9 in FIG. 3(b) flows through the RC network circuit 6a shown in FIG. 2, and a current flows through the diode 7 and a current flows through the resistor 5 at point a shown in FIG. Divided into. The current shown as 10 in FIG. 3 (C) is the electric current flowing through the diode 7, and the current shown in FIG.
The current shown as is the current flowing through the resistor 5. As a result, compared to the amount of heat generated in the resistor 5 in the conventional RC network circuit 6, the amount of heat generated in the resistor 5 in the RC network circuit 6a implementing the present invention is smaller than the amount of heat generated in the resistor 5 in the conventional RC network circuit 6. (in terms of time) is reduced by about half, so it is also reduced by about half, and the capacitance of the resistor used can be reduced. As shown in FIG. 3(b), a current 9 flows in the positive and negative directions during the retrace period Tr, but when a positive current flows in the direction shown as 12 in FIG. is conductive and no current flows through resistor 5, and when a negative current flows in the opposite direction to 12, diode 7 is not conductive and no current flows through resistor 5.
A current flows through it and acts as a damper. Since ringing occurs after negative current begins to flow, the present invention provides the same ringing prevention effect as a conventional RC network circuit that does not connect a diode, extending the life of the resistor 5 and improving reliability. RC network circuits can be created.

〔Effect of the invention〕

As explained above, according to the present invention, the reliability of the RC network circuit for preventing ringing is improved by using an extremely rim measure of connecting diodes to both ends of the resistor to provide a bypass, and moreover, the ringing prevention effect is higher than that of the conventional one. An RC network circuit which is equivalent to the above and also advantageous in terms of cost can be obtained.

[Brief explanation of the drawing]

Figure 1 shows a conventional RC network circuit, Figure 2 shows an embodiment of the present invention, Figure 3 (a) shows the collector peak voltage applied to the RC network circuit, Figure 1 (b) shows the RC
A diagram showing the current flowing in the positive and negative directions in the network circuit, (C) a diagram showing the current flowing in the diode, and (d) a diagram showing the current flowing through the resistor and contributing to damping. l-- Deflection coil, 4-- Capacitor, 5--
Resistor, 6a--RC network circuit implementing the present invention, 7--Diode forming a bypass of the resistor according to the present invention, 8--Collector peak voltage, 9--- Positive and negative directions for the RC network circuit 1 (L- Current flowing in the positive direction through the diode, 11... Current flowing in the negative direction through the resistor contributing to damping, 12...
・Forward direction current flowing through the RC network circuit of the present invention No. 1
Figure ffi'i Figure 2 Figure 3

Claims (1)

[Claims] To prevent ringing, in an RC network circuit consisting of a resistor and a capacitor connected in series to form a parallel circuit between both ends of the picture tube's deflection coil, a diode is connected between both ends of this resistor to form a circuit. An RC network circuit characterized by: