KR960006094Y1 - Power converting apparatus for multi-scan deflection - Google Patents

Abstract

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Description

Power Inverter for Multiscan Deflection

1 is a circuit diagram showing a power converter of the present invention.

2 is a circuit diagram showing a conventional power converter.

* Explanation of symbols for main parts of the drawings

1 pulse width modulator 2 switching circuit

5: power supply for screen size conversion 6: power stabilizer

7: power variable control unit 8: power variable unit

The present invention is a multi-scan deflection power supply for varying the power supply of the flyback transformer to selectively convert the aspect ratio of the screen displayed on the CRT to 16: 9 and 4: 3 with Multiscan Deflection. In particular, the present invention relates to a multi-scan deflection power converter that can vary the power supplied to a flyback transformer by using an output voltage of a conventional switching transformer used to supply operating power to each part of the device. It is about.

Conventional multi-scan deflection power converter has a pulse width modulator 31 for outputting a pulse signal having a predetermined width in accordance with the input signal as shown in Figure 2, and is output from the pulse width modulator 31 A switching transistor Q11 for performing a switching operation by a pulse signal, a switching transformer T11 for inducing a DC power source applied to the primary side to an AC power source on the secondary side by the switching operation of the switching transistor Q11, Half-wave rectified and flattened AC power induced to the secondary side of the switching transformer T11 and supplied to the flyback transformer FBT as an operating power source by a diode D11, a condenser C11, and a coil L11. The rectification and smoothing unit 33, and the pulse width modulator driver 32 for controlling the width of the output pulse signal of the pulse width modulator 31 in accordance with the screen conversion signal input by the user's operation.

In the conventional power converter configured as described above, the pulse width is determined by the output signal of the pulse width modulator driver 32 based on the screen conversion signal input according to a user's operation while the power is applied to the primary side of the switching transformer T11. When the modulator 31 outputs a pulse signal of a predetermined width, the switching transistor Q11 is repeatedly turned on and off by the output pulse signal of the predetermined width, and the DC power supply is turned on in response to the transistor Q11 being turned on and off. The power source induced from the primary side to the secondary side of the switching transformer T11 is rectified and smoothed through the half-wave rectification and smoothing unit 33 to be applied to the flyback transformer (FBT) and the pulse width modulator driver 32. do.

At this time, when the screen conversion signal supplied according to the user's operation is applied at a high potential, the pulse width modulator driver 32 drives the pulse width modulator 31 according to the applied high potential so that the high potential period is longer than the low potential period. Since the signal is output, the on time of the transistor Q11 is longer than the off time.

Therefore, the power level induced from the primary side to the secondary side of the switching transformer T11 is increased, so that the output power of the half-wave rectification and smoothing unit 33 is high, and the power applied to the flyback transformer FBT is high, so that the screen size is long. As a result, the aspect ratio of the screen becomes 16: 9.

When the screen conversion signal is applied at the low potential, the pulse width modulator 31 outputs the high potential period of the pulse signal shorter than the above, so that the power level induced to the secondary side of the switching transformer T11 is lowered, thereby reducing the half-wave rectification and smoothing ( In 33), the power level applied to the flyback transformer (FBT) is lowered, which causes the screen to be shorter in size, resulting in a 4: 3 aspect ratio.

However, the above-described conventional power converter uses a switching transformer and a switching transistor of a conventional switching circuit used to supply operating power to each part of the device. The operating power supplied to each part of the device is changed together during the conversion of the product. Therefore, separate switching transformer and switching transistor must be used. The switching transformer and switching transistor are expensive, which increases the production cost of the device and also increases the size of the switching transformer. There is a problem that has a lot of influence on the miniaturization of the, and the use efficiency of the switching transformer is low.

The present invention has been made to solve the above-mentioned conventional problems, the second side of the switching transformer by using the switching transformer and the switching transistor of the existing switching circuit to supply the operating power to each part of the device. After rectifying and smoothing the power, it is changed according to the screen conversion signal and applied to the flyback transformer so that only the power level supplied to the flyback transformer is changed while the operating power supplied to each part of the device is not changed by the switching circuit. It is an object of the present invention to provide a power converter capable of accurately converting the aspect ratio of a screen to 16: 9 and 4: 3, which will be described in detail with reference to the accompanying drawings of FIG.

1 is a circuit diagram showing a power converter of the present invention, as shown here, a switching transformer (T1) for converting a direct current power source into an alternating current source according to an output signal of the pulse width modulator 1 to generate an operating power source of the device. And a screen size including a switching circuit 2 of the switching transistor Q1 and a diode D1 and a capacitor C1 for rectifying and smoothing the output power of the switching circuit 2 to output the screen size conversion power. A power supply unit 6 including a conversion power supply unit 5, a transistor Q2, a resistor R1, and a capacitor C2 stabilizing the output power of the screen size conversion power supply unit 5, and a screen; A power variable controller 7 comprising resistors R2-R4, variable resistors VR1 and VR2, and transistors Q3 for varying and outputting the output power level of the power stabilizer 6 according to the converted signal; Power for converting the screen size according to the output power of the power variable control unit 7 Resistors (R5, R6), transistors (Q4), and diodes that variably output the level of the output power of the feeder 5 to a flyback transformer (FBT) to convert the aspect ratio of the screen to 16: 9 and 4: 3. It consisted of the power supply variable part 8 which consists of (D2).

Reference numerals 3 and 4 in the drawing description of FIG. 1 are power supply units for rectifying and smoothing the output power of the switching circuit 2 to supply DC operation power to each part of the apparatus.

In the power conversion device of the present invention configured as described above, the switching transistor Q1 of the switching circuit 1 is repeatedly turned on and off in accordance with a pulse signal output by the pulse width modulator 1 while a DC power is applied. The DC power is induced from the primary side of the switching transformer T1 to the secondary side according to the on and off of Q1, and the AC power induced to the secondary side of the switching transformer T1 is the power supply unit 3 (4). ) Is rectified and smoothed, and supplied to each part of the device as the operating power, rectified by the diode D1 of the power supply unit 5 for screen size conversion, and smoothed by the capacitor C1 to power for screen size conversion. Is output.

As described above, the screen size converting power output from the screen size converting power supply 5 is charged to the capacitor C2 through the resistor R1 of the power stabilizer 6 and applied to the base of the transistor Q2. Since it is turned on, the output power of the screen size conversion power supply 5 is stabilized through the transistor Q2 and then input to the power variable control unit 7.

In this state, when the screen conversion signal is input at a low potential according to the user's operation, the transistor Q3 of the power variable controller 7 is turned off, so that the variable resistor VR2 is not grounded, and thus the power stabilizer 6 Output power is divided by the resistors R2 and R4 and the variable resistor VR1 and output.

Therefore, the power level output from the power variable control unit 7 and applied to the base of the transistor Q4 of the power variable unit 8 becomes high, and is output through the transistor Q4 from the power supply unit 5 for screen size conversion. Since the power level becomes high, the power level supplied to the flyback transformer (FBT) becomes high, and the aspect ratio of the screen becomes 16: 9.

When the screen conversion signal is input at a high potential, the transistor Q3 is turned on in contrast to the above, and the resistor R4 and the variable resistor VR2 are grounded because the variable resistor VR2 is equivalently grounded through the transistor Q3. In parallel, the output power of the power supply stabilizer 6 is divided and output by the resistors R2 and R4 and the variable resistors VR1 and VR2.

Therefore, the power level output from the power variable control unit 7 and applied to the base of the transistor Q4 of the power variable unit 8 is lower than the above, and the power supply unit 5 for screen size conversion is provided through the transistor Q4. Since the output power level is low, the power level supplied to the flyback transformer (FBT) is low, and the aspect ratio of the screen is converted to 4: 3.

As described in detail above, the present invention does not use an expensive switching transformer and a switching transistor separately, but uses a switching transformer and a switching transistor of a conventional switching circuit installed in the device to supply operating power to each part, thereby producing the device. Costs are reduced and miniaturization is easy.

Claims (1)

(Correction) rectifies and smoothes the switching circuit 2 for generating the operating power of the device by converting the DC power into AC power according to the output signal of the pulse width modulator 1, and the output power of the switching circuit 2 A power supply unit 5 for outputting the screen size conversion power, a power stabilizer 6 for stabilizing the output power of the power supply unit 5 for converting the screen size, and the power according to the screen conversion signal The output power level of the screen size conversion power supply unit 5 in accordance with the power variable control unit 7 for varying the output power level of the stabilizer (6) and outputs the output power of the power variable variable control unit (7). A power conversion device for multi-scan deflection, characterized by comprising a power variable unit (8) for converting a flyback transformer (FBT) to a variable aspect ratio of the screen to 16: 9 and 4: 3.