KR910004658Y1 - Analog/ttl signal automatic transfer circuit for monitor - Google Patents

Abstract

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Description

Analog / TIEL signal automatic switching circuit of monitor

1 is a circuit diagram of an embodiment of the present invention.

2 is a voltage waveform diagram of FIG.

* Explanation of symbols for main parts of the drawings

1: Inverter 2: Buffer

3: amplifying section 4: integrating circuit section

5: Output Q ₁ -Q ₄ : Transistor

R ₁ -R ₉ : Resistor C ₁ , C ₂ : Capacitor

OP ₁ : Operational Amplifier RY: Relay

The present invention relates to an analog / tiel signal automatic switching circuit of a monitor for automatically switching the driving circuit of the monitor by determining whether the signal output from the computer and input to the monitor is an analog signal or a TTL signal.

Conventionally, whenever a signal from a computer is converted from an analog signal to a TI signal or from a TI signal to an analog signal, there is inconvenience of having to switch the circuit of the monitor by manually operating the mechanical switch. There is a problem that the image of the screen collapses, the life of the mechanical switch is short, the failure rate is high.

In order to solve this problem, the ground signal is input when the signal output from the computer is an analog signal and the horizontal synchronous signal is input when the signal is output from the computer to the connection terminal of the computer and the monitor (pin 8 of the IBM compatible computer). This input signal is amplified and integrated to determine whether the signal input to the connection terminal is a horizontal synchronous signal or a ground signal, and the analog drive circuit and the TTI drive circuit are automatically selected and switched by this discrimination signal. As one, the configuration and effect of the present invention in detail as follows.

The horizontal synchronous signal or the ground signal input to the monitor terminal CN ₁ of the monitor is inverted and amplified by the inverting unit 1, and the output of the inverting unit 1 is inverted and amplified through the buffer unit 2. Applied to the unit 3, the output of the amplifier 3 is applied to the integrated circuit unit 4 for integration, and the output of the integrated circuit unit 4 is applied to the output unit 5 so that the analog drive circuit of the monitor It is configured by connecting (ADC) and TTI driving circuit (TDC) to be selectively switched.

In the present invention configured as described above, when an analog signal is output from the computer, the ground signal is input to the connection terminal CN ₁ of the monitor, and the transistor Q ₁ is provided through the bias resistor R ₁ in the inversion unit 1. ), And accordingly transistor Q ₁ is 'off' so that B ⁺ power is applied to buffer portion 2 via resistor R ₂ . When B ⁺ power input to the buffer section 2 is applied to the base of the transistor Q ₂ through the resistor R ₃ , the transistor Q ₂ is turned on so that the output of the buffer section 2 is B ⁺ power supply. The divided voltage divided by the resistors R ₄ and R ₅ is applied to the amplifier 3, but the direct current component is blocked by the coupling capacitor C ₁ of the amplifier _3. ) Is 'off'.

Therefore, B ⁺ power is input to the integrating circuit portion 4 through the resistor (R ₇ ), the output voltage of the integrating circuit portion 4,

Becomes a negative voltage, which is applied to the base of the transistor Q _{4 in the} output section 5, and as the transistor Q ₄ is 'off', the B ⁺ power supply becomes a resistor R _9. The relay RY is operated by being applied to the relay RY coil through. Accordingly, an analog signal which is switched from the contact a of the driving contact c of the relay RY to the contact b and output from the computer and input to the connection terminal CN ₂ is the relay RY contact b ( It is input to the analog drive circuit ADC through c).

On the other hand, when the TTI signal is output from the computer, a horizontal synchronous signal such as 2a is input to the connection terminal CN ₁ of the monitor and the transistor Q _{1 is} provided through the bias resistor R _{1 in the} inverting section ₁ . When applied to the base of the output of the horizontal synchronization signal inverted and amplified by the transistor (Q ₁ ) is applied to the buffer unit (2). The buffer unit 2 is for impedance matching without amplification degree and is inverted and amplified by the inverting unit 1 as the output of the inverting unit 1 is output from the buffer unit 2 and applied to the amplifying unit 3 as it is. When the horizontal synchronizing signal is applied to the base of the transistor Q ₃ through the coupling capacitor C ₁ and the bias resistor R ₃ in the amplifier ₃ , the horizontal synchronizing signal is inverted by the transistor Q ₃ . The amplified waveform is output from the amplifier 3 by amplifying the second waveform. When the second amplified horizontal synchronizing signal is applied to the integrating circuit section 4 by the amplifying section 3 and integrated, a waveform similar to the second c diagram is output, and the integrated signal is applied to the transistor Q ₄ in the output section 5. When applied to the base, the transistor Q ₄ is turned on so that the transistor Q ₄ remains in the turned-on state while the horizontal synchronization signal is input to the connection terminal CN ₁ . Accordingly, as the collector voltage of the transistor Q ₄ becomes the ground potential, the relay RY does not operate and is switched from the contact b of the driving contact c of the relay RY to the contact a. The TTI signal output from the TNC is input to the normal TDL driving circuit TDC through the contact terminals CN ₂ and the contacts a and c of the relay RY.

As described above, the present invention has a simple circuit configuration to determine whether the signal output from the computer is an analog signal or a TTI signal, and the analog drive circuit and the TTI driver circuit are automatically selected and switched by the discrimination signal. It is a useful design that has the advantage of improving the quality of the product because it is not necessary to manually select the TTIEL driving circuit using a mechanical switch and also eliminates the failure rate by the mechanical switch.

Claims (1)

An inverter 1 for inverting and amplifying a horizontal synchronous signal or a ground signal inputted to the monitor terminal CN ₁ , a buffer unit 2 for transmitting an output of the inverter 1 by matching an impedance, and a buffer unit An integrating circuit section 4 for integrating the amplified signal of the amplifying section 3 of the amplifying section 3 which inverts and amplifies the output of (2), and an output of the ordinary analog drive circuit (4) An analog / tiel signal automatic switching circuit of a monitor, characterized in that it is composed of an output unit (5) for selecting and switching an ADC) and a TTI driving circuit (TDC).