JP2644344B2 - High voltage stabilization circuit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-voltage stabilizing circuit for a television receiver, a projection television, a display, etc. using a cathode ray tube.

[Conventional technology]

 FIG. 2 is a circuit diagram showing a conventional high-voltage stabilizing circuit.

In FIG. 2, 1 is a high voltage generating circuit, 2 and 3 are resistors constituting a high voltage detecting resistor, 4 is a high voltage capacitor, 6 is a cathode ray tube, 7 is an error amplifier, 8 is a reference power supply, and 9 is a high voltage generating circuit 1. A high voltage control terminal, 10 is a high voltage output terminal of the high voltage generating circuit 1, and 11 is a variable resistor.

The high voltage generating circuit 1 shown in FIG. 2 generates a high voltage from a high voltage output terminal 10 and supplies it to the anode of the cathode ray tube 6. However, this high pressure is not stabilized. Between the high-voltage output terminal 10 and ground, high voltage measuring resistor is provided constituted by resistors 2 and 3, by detecting the pressure generated, and outputs the detected voltage v _d accordingly.

The error amplifier 7 is input from the inverting input terminal of the detection voltage v _d, and a reference voltage from the reference power source 8 is input from the non-inverting input terminal, compares both amplifies and outputs the error voltage . Then, the high voltage generation circuit 1 receives an error voltage from the error amplifier 7 from the high voltage control terminal 9 and generates a high voltage according to the error voltage.

Therefore, even if the high voltage supplied to the anode of the cathode ray tube 6 fluctuates, the fluctuation is caused by the above closed loop (closed loop including the high voltage generating circuit 1, the high voltage detecting resistor, the reference power supply 8, the error amplifier 7, etc.). Is controlled so as to suppress the pressure, so that the high pressure is stabilized.

Note that the high voltage (that is, the anode voltage) supplied to the anode of the cathode ray tube 6 can be set to an arbitrary value by changing the variable resistor 11.

However, in the above-mentioned high-voltage stabilization circuit, if an attempt is made to increase the loop gain in order to increase the response speed, parasitic oscillation occurs, so that the response speed cannot be increased so much. There is a problem that it cannot respond sufficiently to a high-frequency fluctuation among fluctuations in the supplied high pressure.

Therefore, conventionally, in order to solve this problem, a high-voltage capacitor 4 is added between the high-voltage output terminal 10 of the high-voltage generation circuit 1 and the ground. That is, by adding the high-voltage capacitor 4, of the fluctuation of the high voltage supplied to the anode of the cathode ray tube 6, the fluctuation of the frequency that cannot be responded to only by the control loop alone is smoothed by the high-voltage capacitor 4. By doing so.

Examples of this kind of high-voltage stabilizing circuit include, for example, TV Technology, 1987 January, Issued by Electronic Technology Publishing Co., Ltd.
See page 57.

[Problems to be solved by the invention]

In the above-described prior art, among the fluctuations in the high voltage supplied to the anode of the cathode ray tube 6, the fluctuation in the high frequency is suppressed by smoothing the fluctuation with the high voltage condenser 4.

However, the high-voltage capacitor 4, not only the pressure supplied to the anode of the cathode ray tube 6, because thereby detected voltage v _d smoothness to the output of the high voltage measuring resistor, variation of the frequency which can sufficiently respond in a closed loop (i.e., Despite the fact that the frequency is not so high, there is a problem that the change cannot be sufficiently suppressed by the closed loop.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a high-voltage stabilization circuit that can sufficiently suppress any frequency fluctuation among high-voltage fluctuations supplied to a cathode ray tube. To provide.

[Means for solving the problem]

In order to achieve the above object, according to the present invention, the ends of the high-voltage detection resistor and the high-voltage capacitor that are not connected to the output terminal of the high-voltage generation circuit are grounded to ground via a common resistor. I made it.

[Action]

In the present invention, since the high-voltage detection resistor and the high-voltage capacitor are grounded to the ground via a common resistor, a current flowing through the high-voltage detection resistor and a current flowing through the high-voltage capacitor flow through this common resistor. For this reason, the voltage drop of the common resistance includes a high frequency fluctuation and a low frequency fluctuation among high voltage fluctuations supplied to the anode of the cathode ray tube. Therefore, the detection voltage output from the high-voltage detection resistor also includes the fluctuation of both, and all the fluctuations in the frequency that can respond in the closed loop can be suppressed by the closed loop. Can also stabilize the high pressure.

〔Example〕

 Hereinafter, an embodiment of the present invention will be described with reference to FIG.

In FIG. 1, the same components as those in FIG. 2 are denoted by the same reference numerals. In addition, 5 is a resistor.

In this embodiment, the high-voltage detection resistor composed of the resistors 2 and 3 and the high-voltage capacitor 4 are each grounded to the ground via the common resistor 5.

That is, in this embodiment, since the resistor 5 is added, assuming that the voltage across the resistor 3 is v ₃ and the voltage across the resistor 5 is v ₅ ,
Detected voltage v _d becomes _{v d = v 3 + v 5} . If the resistance value of the resistor 5 is R ₅ , the current flowing through the resistor 3 is i _R , and the current flowing through the high-voltage capacitor 4 is i _C , v
_5, v ₅ = Since the _{(i R + i C) ×} R 5, v d is a _{v d = v 3 + i R} × R 5 + i C × R 5.

Here, since i _C is a current flowing when a high-frequency fluctuation appears among the fluctuations of the high voltage (that is, the anode voltage) supplied to the anode of the cathode ray tube 6, i _C × R ₅ is the frequency Is a voltage generated when a high fluctuation of the voltage appears. That is, by a resistor 5, the detected voltage v _d is, among the high-pressure variation supplied to the anode of the cathode ray tube 6 will include without being higher variation smoothness frequency, therefore, Any variation in frequency that can be responded in the closed loop can be suppressed by the closed loop, and high voltage can be stabilized against any variation in frequency.

Although the high-voltage detection resistor and the high-voltage capacitor 4 composed of the resistors 2 and 3 are usually built in the flyback transformer, the resistor 5 added in this embodiment is also different from the high-voltage detection resistor and the high-voltage capacitor 4. Similarly, it can be built in a flyback transformer.

〔The invention's effect〕

According to the present invention, it is possible to sufficiently suppress any frequency fluctuation among the fluctuations of the high voltage supplied to the cathode ray tube by adding a resistor to the conventional high voltage stabilizing circuit. , Can stabilize high pressure, therefore,
Since it is only necessary to add one resistor, the configuration is simple and the cost is low.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of the present invention, and FIG. 2 is a circuit diagram showing a conventional high-voltage stabilizing circuit. DESCRIPTION OF SYMBOLS 1... High voltage generating circuit, 2, 3, 5... Resistor, 4... High voltage capacitor, 6... Cathode ray tube, 7.

Claims (2)

(57) [Claims] A high voltage stabilizing circuit for stabilizing a high voltage supplied from a high voltage generating circuit (10) to a cathode ray tube (6), comprising a first resistor (2,3) and a high voltage capacitor (4). ), One end of which is connected to a supply path for the high-voltage cathode ray tube, a second resistor (5) grounding the other end of the parallel connection circuit, and the first connection. Amplifying means (7) for comparing a voltage taken from an arbitrary position on the resistor constituting the resistor with the reference voltage as the high-voltage detection voltage, amplifying and outputting the difference voltage, and an output of the amplifying means And control means for performing negative feedback control on the high voltage supplied from the high voltage generation circuit to the cathode ray tube. 2. An apparatus comprising at least the high-voltage stabilizing circuit according to claim 1.