KR940002187Y1 - High voltage driving circuit for monitor - Google Patents

Abstract

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Description

Drive circuit for high voltage output of monitor

1 is a driving circuit for a conventional high voltage monitor output.

2 is a drive circuit diagram for a monitor high pressure output according to the present invention.

* Explanation of symbols for main parts of the drawings

IC1, IC1 ': Horizontal sync signal plug-in IC2: Monostable multivibrator

A, A ', D: Complementary emitter plug B: Mono multiprocessor

C: fluorescent film protection circuit R1, R1 'R2, R2', R4-R12: resistance

Q1, Q1 ', Q5, Q6: Transistor Q3: Inverting transistor

Q4, Q8: power transistor T1-T2: transformer

D1-D4: Diode C1-C4: Capacitor

L1-L2: Flyback Transformer FRP: Flyback Pulse Signal

The present invention relates to a drive circuit for high voltage output of a monitor, and more particularly, to a drive circuit for high voltage output of a monitor to supply a high voltage to the monitor bonded to the multi-synchronous method.

Conventional monitor high-voltage output driving circuit is a complementary type of the horizontal synchronization signal processing unit IC1 for processing the horizontal synchronization signal and the monitor driving pulse output from the horizontal synchronization signal unit IC1 as shown in FIG. An MOS FET Q3 for driving the monitor high voltage output driving transistor T1 as an input of an emitter blower circuit A, the output of the complementary emitter blower circuit, and the transformer T1. The secondary side fixed voltage drives the primary side of the flyback transformer L1 by driving the high voltage generation output transistor Q4 of the monitor through the diode D1 and the resistor R6.

In the related art, the monitor driving pulse output from the horizontal synchronous signal processing unit IC1 comprises two transistors Q1 constituting the complementary emitter follower A through the resistor R1. It is pressurized by the base of Q2), respectively.

In this case, the complementary emitter plugper circuit A has a very small characteristic as an impedance and performs sufficient current amplification. Therefore, the gate terminal of the MOS FET Q3 is driven through the resistor R4 connected to the output side of the emitter follower circuit, thereby driving the monitor driving transformer T1, so that the monitor driving voltage is connected to the primary side of the transformer. By the turn of n1 / n2 = v2 / v1 on the secondary side, the secondary side is sufficiently amplified by the turn ratio on the primary side to suitably perform the switching operation of the output power transistor Q4.

At this time, the output of the transistor Q4 drives the primary side of the flyback transformer L1.

Here, the diode D1 and the resistor R6 connected in parallel to the secondary side of the monitor driving transformer T1 are a network for reducing power loss at the time of turning off the output power transistor Q4. IB1 / IB2) is being adjusted.

Conventional monitor high voltage output driving circuit which is configured and operated in this way was used in the horizontal synchronous type monitor having a narrow range of single mode and horizontal synchronous signal width, and has a multi horizontal synchronous signal having a range of horizontal synchronous signal path. In the monitor, the transistor Q4 is thermally runaway due to an over-drive or under-drive phenomenon because the base side of the power transistor Q4 does not sufficiently cover a constant base bias driving condition. The possibility could not be ruled out.

Therefore, the present invention was devised to solve the above problems, and an object of the present invention is to optimize the driving circuit for generating a high voltage output to generate a high voltage output in a multi horizontal synchronous monitor having a wide frequency input range. To provide a driving circuit for the high voltage output of the monitor to protect the state.

As shown in FIG. 1, the high-voltage output driving circuit of the monitor according to the present invention includes a horizontal synchronous signal processing unit IC1 for processing an input horizontal synchronizing signal and a driving pulse of the monitor output from the horizontal synchronous signal unit. In the high-voltage output driving circuit of a monitor having a complementary emitter blower circuit A 'which is buffered, a predetermined pulse having a constant pulse width for driving the monitor is output again with the output of the complementary emitter blower circuit as a pressure. A flyback pulse signal connected to the generated mono multi processor B, an inverting transistor Q3 for inverting the output of the processor B as an input, and a collector terminal of the transistor Q3. A fluorescent film protection circuit (C) for protecting the fluorescent film of the monitor by applying FRP), and a complementary emitter follower (D) for sufficient current amplification by inputting the output signal of the fluorescent film protection circuit. And a MOSFET Q3 for driving the monitor high voltage output drive transformer T2 with the output of the emitter follower circuit D as an input, and the amplified voltage of the secondary transformer of the transformer T2. Therefore, it is characterized in that it is configured with the power transistor Q4 for generating the high-voltage generation output of the monitor to drive the plane back transformer L2 connected to the power transistor.

Hereinafter, the date and time according to the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 2, when the horizontally synchronized driving pulse is output from the horizontal synchronous signal processor IC1 ', the input signal is sufficiently input to the base of the complementary emitter follower transistors Q1' and Q2 through the resistor R1 '. Amplified and then mono multiprocessor (B) is a mono stable multivariator designed to have a predetermined pulse width at rising age, the pulse width being determined by the set values of resistor (R3), variable resistor (VR1) and capacitor (C1). Is determined.

Herein, it is assumed that the horizontal frequency range input therein is considerably wide. In turn on / off during the switching operation of the horizontal output power transistor Q8, in order to minimize the driving bias loss of the transistor base, the frequency range depends on the frequency range. Different driving current values are required because the driving conditions of the power transistor Q8 are different.

Therefore, it is necessary to vary the amount of current for each frequency to amplify the power transistor Q8 through the monitor output voltage drive transformer T2 so that the switching operation is optimally performed over a wide frequency range.

Thus, the current flowing through the secondary transformer with respect to the current flowing in the primary transformer of the transformer T2 is turned on in proportion to the duty cycle ratio of the turn-on time for each corresponding frequency. It will convert the duty ratio with respect to time.

Next, since the mono multi-processor B outputs an output value having a constant pulse width, the duty ratio is changed when the frequency is changed.

In the fluorescent film protection circuit B, the power supply VCC1 input to the collector side of the high voltage output transistor Q3 is a flyback pulse signal generated at the horizontal synchronization signal input terminal. Since the FRP) is inputted to the rectified power supply, when the operation of the horizontal synchronization signal input terminal stops, the power supply of the high voltage output transistor Q4 is stopped and at the same time, the high voltage output is also stopped.

Therefore, the high voltage output is stopped when the horizontal synchronizing signal input terminal does not operate, thereby preventing the whole line from appearing on the monitor screen.

In addition, the output of the fluorescent film protection furnace (C) is input to the complementary emitter follower circuit (D), and the output of the emitter blower circuit (D) drives the high voltage output by driving the bosspet (Q7). The output voltage of the secondary transformer of the transformer T2 is supplied to the power transistor collector side by driving the power transistor Q8 through a network for reducing the power loss current in which the diode D1 and the resistor R6 are configured in parallel. The connected flyback transformer L1 is driven.

Therefore, the driving voltage of the monitor is input to the amplified high voltage of the back transformer L1.

The present invention constructed and operated as described above reduces power consumption and thermal runaway of the power transistor by switching the power transistor driving circuit for generating a high voltage output to an optimal state in a multi-horizontal synchronous monitor having a wide frequency input range. Can improve the reliability.

In addition, by stopping the high voltage output operation when the horizontal synchronization signal input terminal is stopped, there is an excellent effect of preventing the occurrence of all-day lines on the monitor screen to protect the fluorescent film of the monitor.

Claims (2)

A mono multi processor which generates a predetermined pulse having a constant pulse width for driving the monitor by inputting the output of the complementary emitter follower A 'buffering the driving pulse of the monitor output from the horizontal synchronizing signal processor IC1 ( B) and; An inverting transistor (Q3) which inverts the output of the processor (B) as an input; A fluorescent film protection circuit (C) connected to the collector terminal of the transistor (Q3) for protecting the fluorescent film of the monitor by applying a fly back pulse signal (FRP); A complementary emitter follower circuit (D) for performing sufficient current amplification by inputting the output signal of the fluorescent film protection circuit; MOSFET A3 for driving the high voltage output drive transformer T2 of the monitor by inputting the output of the emitter follower circuit D; And a power transistor Q4 for generating a high voltage output of the monitor according to the amplified voltage of the secondary transformer of the transformer T2, and a flyback transformer connected to a collector of the power transistor Q4. L2) to drive the high-voltage output drive circuit of the monitor characterized in that. 2. The fluorescent film protection circuit (C) according to claim 1, wherein a base of the power transistor (Q4) and a collector terminal are connected between the inverting transistor (Q3) and the complementary emitter follower (D) circuit, and the transistor ( And a diode (D1, D2), a capacitor (C3) and a resistor (R8) connected in parallel to the collector terminal of Q4).