KR890007508Y1 - Rgb bias variable circuits crt - Google Patents

Abstract

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Description

RGB bias variable circuit of CRT

1 is a conventional RGB bias variable circuit diagram.

2 is an RGB bias variable circuit diagram according to the present invention.

* Explanation of symbols for main parts of the drawings

Q ₁ , Q ₂ , Q ₃ : Image Output Transistor

Q ₄ , Q ₅ , Q ₆ : Voltage control transistor

D ₁ , D ₂ , D ₃ : Protective diode

R ₁₆ , R ₁₇ , R ₁₈ : Power voltage safety resistor

R ₁ , R ₂ , R ₃ , VR ₁ , VR ₂ , VR ₃ : Variable resistor

The present invention relates to an RGB bias variable circuit applied to the cathode of a CRT in a high resolution color display monitor.

In the conventional RGB bias variable circuit, as shown in FIG. 1, the red, green, and blue (RGB) image signal inputs have different image output characteristics according to the bias variation by the variable resistors VR ₁ , VR ₂ , and VR _3, respectively. It is changing.

Here, the RGB bias means that the cathode of the color CRT preserves the circuit because the bias response characteristics of the red, green, and blue signals are different.

For example, in the red (R) image output circuit, the impedance Z seen from the emitter of the transistor Q ₁ is changed according to the variation of the variable resistor VR ₁ , and thus the image output characteristic is changed.

this is The value of ZR changes according to the change of VR ₁ , so Z changes.

However, such a conventional RGB bias variable circuit requires a separate bias adjustment voltage (Vdc ') for adjusting the bias voltage, and the RGB image characteristics are slightly different from each other, and the transistors Q ₁ , Q ₂ , Q ₃ ) It is not enough to adjust the balance of the overall image characteristics only by adjusting the variable resistors (VR ₁ , VR ₂ , VR ₃ ) connected to the emitter of Q ₃ ). Had a floating problem.

The present invention prevents the deterioration of the image quality generated by varying the image characteristics of RGB in the conventional RGB bias variable circuit slightly different from each other, so that the image characteristics are variable while the RGB balance is variable. The objective was to obtain an RGB bias variable circuit that would not be affected by this.

Hereinafter, a description will be given with reference to the accompanying drawings.

As shown in FIG. 2, a bias control circuit A _{1 is} formed by connecting a variable resistor R ₁ , a resistor R ₁₀ , a capacitor C ₄ , and a diode D ₁ transistor Q ₄ at a power supply terminal dc _. And the output power supply V ₁ of the bias control circuit A ₁ adjusted by the adjustment of the variable resistor R ₁ to the transistor Q ₁ through the resistor R ₄ and the coil L ₄ . Connect to the collector. The transistor Q _{1 is} supplied with the red signal input to the base and connects the capacitor C ₁ and the resistor R ₇ in parallel to the emitter to supply the red cathode signal of the CRT. In other words, the enemy bias control circuit A ₁ is connected to the collector side of the image output transistor Q1 that controls the enemy cathode of the CRT.

In this way, a transistor (Q ₅ ), a variable resistor (R ₂ ) resistor (R ₁₁ ), and a capacitor (C ₅ ) diode (D ₂ ) are connected to the collector side of the image output transistor (Q ₂ ) that controls the green cathode of the CRT. Connect the green bias control circuit (A ₂ ).

In addition, the collector side of the image output transistor Q ₃ controlling the blue cathode of the CRT is connected to a transistor Q ₆ , a variable resistor R ₃ , a resistor R ₁₂ , and a capacitor C ₆ diode D ₃ . This is by connecting the bias control circuit (A ₃ ).

Looking at the operation and effect of the present invention configured as such a circuit is as follows.

On the power supply (Vcd) supply side of each RGB image output circuit, a bias control circuit (A ₁ , A ₂ , A ₃ ) including a transistor and its peripheral circuits is installed to control only the supply voltage of the image output circuit (decrease or increase). By doing so, an appropriate bias is obtained while not affecting image output characteristics.

In other words, in one example, red (R) image supply voltage (Vcd) that is advanced in the output circuit is a power supply voltage control transistor (Q ₄₎ and a variable resistance (R ₁₎ and a resistor (R ₁₀₎ a through image output transistor (Q ₁ Voltage V ₁ supplied to the image output transistor Q ₁ according to the variation of the variable resistor R ₁ . To the power supply Vcd can be changed.

Here, the diode D ₁ is for protecting the transistor Q ₄ , and the resistor R ₁₆ is for supply voltage stabilization.

In the same manner, the supply voltages V ₂ and V _{3 of} the green (G) image output circuit and the blue (B) image output circuit may be appropriately added or subtracted according to the variation of the variable resistors R ₂ and R ₃ , respectively.

Therefore, according to the circuit of the present invention, since a separate bias adjustment voltage (Vcd) is not required and the RGB bias of the CRT is also possible by varying the supply power supply voltage of the image output circuit, it affects the emitter side impedance of each image output transistor. There is a practically advantageous advantage that can vary the RGB bias of the CRT without giving.

Claims (1)

In a bias variable circuit in which an image input signal of red cyan (RGB) is corrected by a cathode (Q ₁ , Q ₂ , Q ₃ ) of the cathode red cyan signal of the CRT, an image of correcting the cathode red cyan signal of the CRT. An enemy bias in which a transistor (Q ₄ ), a variable resistor (R ₁ ) resistor (R ₁₀ ), and a capacitor (C ₄ ) diode (D ₁ ) are connected to each collector side of the output transistors (Q ₁ , Q ₂ , Q ₃ ). The rust bias control circuit A ₂ and the transistor Q connected to the control circuit A ₁ , the transistor Q ₅ , the variable resistor R ₂ , the resistor R ₁₁ , and the capacitor C ₅ diode D ₂ . ₆ ), a blue bias control circuit A ₃ connected with a variable resistor R ₄ , a resistor R ₁₂ , and a capacitor diode D ₂ , and the red green blue bias control circuit A ₁ (A ₂ ) ( output voltage (V ₁ of _{a 3), V 2, V} 3) is a RGB bias of the CRT, it characterized in that the connection hayeoseo to be applied to the collector side of the transistor _{(Q 1, Q 2, Q} 3) Circuit.