KR0123410B1 - Circuit for generating high voltage of a monitor - Google Patents

Abstract

A high voltage generating circuit of monitor is provided to improve a stability of high voltage by preventing over current. The high voltage generating circuit of monitor further comprises a speed control means(50) for applying a high voltage to a high voltage stabilizing circuit(40) in order to control a response speed of the high voltage transformer according to the variation of the frequency. The speed control means(50) includes a bias resistor(R51), a transistor(Q51), and a diode(D51). Thereby, it is possible to improve the stability of the generated high voltage.

Description

High Voltage Generation Circuit of Monitor

1 is a view showing the configuration of a high-voltage generating circuit applied to a general monitor.

2 is a view showing the configuration of a high-voltage generating circuit of the monitor applied to the present invention.

* Explanation of symbols for main parts of the drawings

10: input circuit 20: switching circuit

30: output circuit 40: stabilization circuit

410: error detection unit 420: comparison unit

430: inverter unit 440: switching unit

50: speed control unit FBT: high pressure transformer

OP: Amplifier Com: Comparator

Mos: MOS transistor D11-D13, D15: Diode

R11-R16, R51, R52: Resistor C11-C13: Capacitor

Q11-Q13, Q51: Transistor L11: Coil

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high voltage generating circuit of a monitor, and in particular, a horizontal output transistor having speed control means for applying a high voltage to a high voltage stabilizing circuit in order to control the response speed of the high voltage transformer according to a change in frequency lowered when the mode is switched. The high voltage generating circuit of the monitor to prevent the destruction of.

As shown in FIG. 1, a high voltage generation circuit applied to a general monitor is composed of a coil L1, a diode D1, and a capacitor C2. The input circuit 1 rectifies and filters the input power B1. ), A switching circuit (2) composed of a transistor (Q1), a diode (D2), and a capacitor (C2) and switched by an input horizontal synchronization signal, and a primary coil according to the switching state of the switching circuit (2). It consists of a high voltage transformer (FBT) that energizes the energy stored in the circuit to generate a high voltage, a diode (D3), a coil (L2), and a resistor (R1) (R2) to rectify the output voltage of the high voltage transformer (FBT) and filter The output circuit 3 to be applied to the horizontal deflection portion not shown in the drawing, the output circuit 3, and the magnitude of the voltage output from the output circuit 3, and then detect the magnitude of the detected voltage. To control the magnitude of the voltage output from the input circuit 1 by Consists of a purification circuit (4).

Here, the high voltage stabilization circuit 4 is composed of a resistor (R2) (R3) and an amplifier (OP), the error detection unit 41 for detecting an error in the voltage of the output circuit (3) compared to the reference voltage (Vref) ), A resistor R5 (R6), a capacitor C3, and a comparator Com to compare the voltage output from the error detector 41 with the inverted output voltage and the transistor Q2. An inverter section 43 composed of Q3 and a resistor R4, for generating a signal output from the comparing section 42, and applying the inverted output signal to a terminal of the comparing section 42; Mos), which is switched by the output signal of the inverter unit 43, and the voltage determining unit 44 determines the magnitude of the output voltage of the input circuit 1 by the switched state.

On the other hand, the operation of the high-voltage generating circuit of the general monitor configured as described above is as follows.

First, the input power B1 is rectified and filtered by the coil L1, the diode D1, and the capacitor C1 of the input circuit 1, and the output voltage of the filtered input circuit 1 is a high voltage transformer. Is applied to (FBT).

On the other hand, the input horizontal synchronization signal is applied to the base side of the transistor Q1 of the switching circuit 2 and the transistor Q1 is switched. When the transistor Q1 is turned on, the energy input to the high voltage transformer FBT is Accumulate in the primary coil.

After that, the transistor Q1 is turned off by the horizontal synchronizing signal, and the energy accumulated in the primary coil of the high voltage transformer FBT is excited by the secondary coil of the high voltage transformer FBT and then the diode of the output circuit 3 ( D3), coils L2 and resistors R1 and R2 are applied, rectified, filtered and divided.

The high voltage output from the output circuit 3 is applied to the horizontal deflection coil and the vertical deflection coil connected to the cathode ray tube not shown in the drawing so that the input video signal is accurately scanned on the front surface of the cathode ray tube.

The high voltage output from the output circuit 3 is applied to the amplifier OP of the error detection unit 41 of the high voltage stabilization circuit 4 and compared with the reference voltage Vref to detect an error of the high voltage transformer FBT. The error signal is applied to the comparator Com of the comparator 42 and compared with the pulse input through the inverting terminal of the comparator Com. Then, the result of the comparison is compared with the transistor Q2 of the inverter part 43 ( Is reversed by Q3).

The pulse signal inverted by the transistors Q2 and Q3 is applied to the MOS transistor Mos of the switching unit 44. When the high potential state signal is input to the MOS transistor Mos, the MOS When the transistor Mos is turned on and the voltage B1 is accumulated in the coil L1 of the input circuit 1, and the low potential signal is input to the MOS transistor Mos, the MOS transistor Mos is turned on. The voltage B1 that is turned off and accumulated in the coil L1 of the input circuit 1 is rectified and filtered through the diode D1 and the capacitor C1.

The output signal of the MOS transistor Mos is distributed by the resistors R5 and R6 of the comparator 42, and the divided voltage is shaped by the capacitor C3 and then inverted by the comparator Com. Is applied to the terminal.

However, in the mode switching in which the accumulated energy of the transformer is high and low, the conventional high voltage generation circuit takes a long time for the output voltage B1 of the input circuit to be lowered, and during this time, the output voltage B1 becomes the switching circuit 2. Since it is applied to the collector side of transistor Q1, there is a problem that transistor Q1 is overloaded and destroyed.

Accordingly, an object of the present invention is to solve such a problem, and an object of the present invention is to apply a high voltage to an error detection unit during mode switching so that the response speed of a high voltage transformer can be quickly controlled to protect a horizontal output transistor. Its purpose is to provide a high voltage generator circuit.

In order to achieve the above object, the present invention generates a voltage output from an input circuit by a high voltage transformer at a high voltage according to a switching state switched by an input horizontal synchronization signal, and detects the high voltage output from the output circuit in a high voltage stabilization circuit. In the monitor for controlling the magnitude of the voltage output from the input circuit, the speed control means for applying the voltage to the high-voltage stabilization circuit to control the response speed of the high-voltage transformer according to the frequency change lowered when the mode is switched Characterized in that it is included.

Hereinafter, an embodiment of a high voltage generation circuit of a monitor according to the present invention will be described in more detail with reference to the accompanying drawings.

2 is a view showing the configuration of a high-voltage generating circuit in the monitor to which the present invention is applied, and as shown therein, a power source B1 composed of a coil L11, a diode D11, and a capacitor C11 and inputted thereto. ), An input circuit 10 for rectifying and filtering), a switching circuit 20 composed of a transistor Q11, a diode D12, and a capacitor C12 and switched by an input horizontal synchronization signal, and the switching circuit ( The high voltage transformer is composed of a high voltage transformer (FBT), a diode (D13), a coil (L12), and a resistor (R11) (RS), which energize the energy stored in the primary coil according to the switching state of the switch 20 to generate a high voltage. Output circuit 30 to rectify and filter the output voltage of FBT and apply it to a horizontal deflection unit not shown in the figure, and detect the magnitude of the voltage output from the output circuit 30, and then Output from input circuit 10 by size In order to control the response speed of the high voltage transformer (FBT) according to the frequency change and the high voltage stabilization circuit 40 which controls the magnitude of the voltage to be changed, the high voltage B2 is applied instead of the output voltage of the output circuit 30 at the time of mode switching. It consists of the speed control part 50 which applies to the stabilization circuit 40. FIG.

Here, the high voltage stabilization circuit 40 is composed of a resistor (R12) (R13) and an amplifier (OP), the error detection unit 410 for detecting an error in the voltage of the output circuit 30 compared to the reference voltage (Vref) ), A resistor R15 (R16), a capacitor C13, a comparator Com, and a comparator 420 for comparing the voltage output from the error detector 410 with an inverted output voltage, and a transistor Q12. Q13 is an inverter unit 430 for inverting the signal output from the comparator 420 and applying the inverted output signal to the inverting terminal of the comparator 420, and the MOS transistor Mos. And a voltage determination unit 440 which is switched by an output signal of the inverter unit 430 and whose magnitude of the output voltage of the input circuit 10 is determined by the switched state.

In addition, the speed controller 50 includes a resistor R51 for biasing a signal output from a microprocessor not shown in the figure at the time of mode switching, and a transistor Q51 in which on / off is controlled according to an output signal of the resistor R51. ) And the reverse bias is applied when the transistor Q51 is turned on, and the output voltage of the output circuit 30 is applied to the error detector 41. When the transistor Q51 is turned off, the positive bias is applied and the high voltage B2 is applied. Is composed of a diode D51 for applying to the error detector 41.

Reference numeral R52 denotes a resistor for operating the transistor Q51.

On the other hand, look at the operation of the high-voltage generating circuit of the monitor applied to the present invention in this configuration as follows.

First, the input voltage R1 is rectified and filtered by the coil L11, the diode D11, and the capacitor C11 of the input circuit 10, and the output voltage of the filtered input circuit 10 is transformer. Is applied to (FBT).

On the other hand, the input horizontal synchronization signal is applied to the base side of the transistor Q11 of the switching circuit 20 and the transistor Q11 is switched. When the transistor Q11 is turned on, the voltage input to the high voltage transformer FBT is Accumulate in the primary coil.

After that, the transistor Q11 is turned off by the horizontal synchronizing signal, and the voltage accumulated in the primary coil of the high voltage transformer FBT is excited by the secondary coil of the high voltage transformer FBT and then the diode of the output circuit 30. D13, coil L12, and resistor R1, RS are applied, rectified, filtered and then distributed.

On the other hand, the control signal in the high potential state output from the microprocessor not shown in the drawing is applied to the transistor Q51 through the resistor R51 of the speed controller 50, the transistor Q1 is turned on, the transistor Q51 As is turned on, the diode D51 is reverse biased so that the high voltage B2 connected to the collector side of the transistor Q51 is applied to ground.

Accordingly, when the high voltage transformer FBT is excited, the excited output voltage of the high voltage transformer FBT is applied to the horizontal deflection coil and the vertical deflection coil connected to the cathode ray tube not shown in the drawing through the output circuit 30 and is input. The video signal is on the front of the cathode ray tube

It is injected correctly.

The high voltage output from the output circuit 30 is applied to the amplifier OP of the error detection unit 410 of the high voltage stabilization circuit 40, and the error of the high voltage output from the high voltage transformer FDT compared to the reference voltage Vref. The signal is detected, and the error signal is applied to the comparator Com of the comparator 420 and compared with the pulse input through the inverting terminal of the comparator Com. Inverted by transistors Q12 and Q13.

The pulse signal inverted by the transistors Q12 and Q13 is applied to the MOS transistor Mos of the switching unit 440. At this time, when a signal having a high potential state is input to the MOS transistor Mos, the MOS transistor When Mos is turned on to charge a voltage in coil L11 of input circuit 10 and a low-potential signal is input to MOS transistor Mos, MOS transistor Mos is turned off to input circuit 1. The voltage accumulated in the coil L11 is rectified and filtered through the diode D11 and the capacitor C11.

The output signal of the MOS transistor Mos is distributed by the resistors R15 and R16 of the comparator 420, and the divided voltage is shaped by the capacitor C13 and then the inverting terminal of the comparator Com. Is applied to.

However, when the mode is switched, the low-potential signal output from the microprocessor (not shown) is applied to the base side of the transistor Q51 through the resistor R51 of the speed controller 50 so that the transistor Q51 is turned on. The high voltage B2 applied to the collector side of the transistor Q51 is applied to the error detection unit 41 of the high voltage stabilization circuit 40 by turning off the diode D51.

After that, the high voltage B2 of the speed controller 50 is applied to the error detector 41 so that the MOS transistor Mos is turned off and the MOS transistor Mos is turned off. And the magnitude of the voltage applied to the transistor Q21 of the switching unit 20 is controlled so that the transistor is protected.

As described above, since the transistor Q51 of the speed controller 50 is turned off and the high voltage B2 is applied to the error detector 41 when the mode is switched, the frequency of the high voltage transformer FBT is increased. It is rapidly lowered to protect the transistor Q21 of the switching unit 20.

As described above, the high voltage generating circuit of the monitor according to the present invention can control the horizontal output transistor by controlling the speed at which the frequency of the high voltage transformer is lowered when the mode is switched, thereby increasing the reliability of the product. There is an effect that can prevent malfunction.

Claims (2)

The voltage output from the input circuit 10 is generated at high voltage according to the switching state switched by the input horizontal synchronizing signal, and the high voltage output from the output circuit 30 is detected by the high voltage stabilization circuit 40 to detect the input circuit ( In the monitor for controlling the magnitude of the voltage output from 10), connected between the output circuit 30 and the high voltage stabilization circuit 40 to control the response speed of the high voltage transformer according to the change in the frequency lowered when the mode is switched In order to apply a high voltage to the high-pressure stabilization circuit 40 to the speed control means 50 further comprises a high-voltage generating circuit of the monitor. According to claim 1, wherein the speed control means 50 is a resistor (R51) for biasing the control signal output from the microprocessor during mode switching, and the transistor on / off in accordance with the signal input through the resistor (R51) When Q51 and the transistor Q51 are turned on, reverse bias is applied, and the output voltage of the output circuit 30 is applied to the high voltage stabilization circuit 40. When the transistor Q51 is turned off, positive bias is applied. High voltage generating circuit of the monitor, characterized in that consisting of a diode (D51) for applying a high voltage (B2) to the high-voltage stabilization circuit 40 via the resistor (R52).