KR100647821B1 - Control circuit for automatic shading welding helmet - Google Patents

Abstract

The present invention is a control unit for generating a control signal by converting a welding light detection signal into a digital signal, a temperature compensation and LCD brightness control unit for maintaining a constant light-shielding degree by generating an LCD brightness control signal corresponding to the ambient temperature, the temperature compensation and An LCD driver which generates a drive signal corresponding to the LCD brightness control signal of the LCD brightness controller, an LCD unit which blocks the welding light by a liquid crystal array corresponding to the drive signal of the LCD driver, and an instantaneous high voltage A control circuit for an automatic light shielding welding helmet comprising: a boosting unit for applying a light blocking speed to improve a light blocking speed; and a high voltage control unit for blocking a high voltage applied to the LCD unit from being applied to the LCD driving unit. The temperature compensation is connected between the LCD brightness control unit and the ground and the temperature according to the control signal of the controller A first switch to short-circuit or open the compensation and LCD brightness control unit and the ground, and controlled by the control unit and turned on / off in conjunction with the first switching unit, wherein the LCD driving unit is the LCD of the temperature compensation and LCD brightness control unit. And a second switch for controlling to generate a driving signal corresponding to the brightness control signal.

Welding, helmet, auto, shading, glass, control, circuit.

Description

Control Circuit For Automatic Darkening Welding Helmet

1 is a circuit diagram showing a control circuit for a conventional light shielding welding helmet.

FIG. 2 is a detailed circuit diagram of the LCD driver, the high voltage controller, and the LCD of FIG. 1.

3 is a block diagram illustrating a control circuit for an automatic light shielding welding helmet according to the present invention.

FIG. 4 is a detailed circuit diagram of the LCD driver, the high voltage controller, and the LCD of FIG. 3.

5 is a detailed circuit diagram of the low battery unit of FIG. 3.

<Description of Major Reference Symbols>

10: power supply unit 15: low battery unit

20: control unit 25: amplifying unit

30: filter processing unit 35: sensitivity control unit

40: temperature compensation and LCD brightness control unit

45: LCD drive unit 50: LCD

55: high pressure control unit 60: boosting unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control circuit for an automatic shading welding helmet, and more particularly, to a control circuit for an automatic shading welding helmet capable of improving a reaction speed with respect to welding light, reducing power consumption, and controlling shading regardless of temperature change.

Welding, a technique of joining metal materials by applying heat, pressure, or heat and pressure simultaneously, produces strong light during the welding process, which can cause damage to eyesight when the worker's eyes are exposed to such light.

Therefore, a worker wears a welding helmet during a welding operation. In recent years, an automatic shading welding helmet for detecting light when an arc occurs in a welding operation is used to block light by operating a light blocking filter lens provided with an LCD.

1 is a circuit diagram showing a light shielding control circuit of such a conventional automatic light shielding welding helmet.

As shown in FIG. 1, the shading control circuit of the conventional automatic shading welding helmet includes a power supply unit 100, a control unit 110, an amplifier 120, a filter processing unit 130, a sensitivity control unit 140, and a switch unit ( 150, a temperature compensation and LCD brightness adjusting unit 160, an LCD driving unit 170, a high pressure control unit 180, an LCD 190, and a boosting unit 195.

The power supply unit 100 is for supplying power to each circuit unit, and is turned on before welding starts, and then, after the welding ends, the power supply unit 100 is turned on after being maintained for about 1 minute.

When the sensing current is input from the photodiode in proportion to the intensity of the welding light, the amplifier 120 amplifies the signal of the sensing current and outputs a stable signal.

The filter processing unit 130 may filter light by sunlight or ambient light other than the welding light to perform more precise shading control, and the sensitivity adjusting unit 140 may adjust the sensing sensitivity according to the intensity of the welding light to adjust the ambient light. To prevent interference.

When the control unit 110 receives a detection signal proportional to the welding light through the amplifying unit 120 and the filter processing unit 130, the control unit 110 converts the detection signal into a digital signal to generate necessary control signals.

The switch unit 150 is turned on when a drive control signal of the controller 110 is input to operate the temperature compensation and LCD brightness adjusting unit 160. The temperature compensation and LCD brightness adjusting unit 160 shields the light regardless of temperature change. The figure remains constant and generates an LCD brightness control signal corresponding to the DIN number selected by the user. The welding helmet of the present invention is to adjust the LCD brightness up to DIN 9 ~ 13 in accordance with the molten light intensity and is set to DIN 11 when not set.

When the LCD driver 170 receives the temperature control signal and the brightness control signal of the LCD brightness controller 160, the LCD driver 170 generates a square wave to drive the LCD 190, and the booster 195 boosts the power voltage by 6 times (36V). By applying instantaneous high voltage to both terminals of the LCD 190 to improve the shading speed, the high voltage controller 180 prevents the high voltage applied to the LCD 190 from entering the LCD driver 170 and the LCD driver 170. ) Is prevented from being damaged, and the instantaneous high voltage is applied to the LCD 190 to improve the shading speed.

The switch unit 150 is composed of transistors, which have a characteristic sensitive to a change in temperature. Therefore, when the temperature change is severe, the characteristic change of the switch unit 150 according to the temperature change has a problem that the temperature compensation is not performed properly in the temperature compensation and the LCD brightness adjusting unit 160, so that the brightness is not adjusted well.

2 is a detailed circuit diagram of the LCD driver 170, the high voltage controller 180, and the LCD 190 of FIG. 1. Referring to FIG. 2, the driving and high pressure control operation of the LCD 190 will be described.

The 36V instantaneous high voltage boosted by the booster 195 is applied to one end of the LCD 190 through the transistor Q130 so that the LCD 190 is quickly driven, and the driving voltage of the LCD driver 170 is driven by the LCD 190. It is applied to one end or the other end to drive the LCD 190.

When the driving voltage is output from the 11th terminal of the LCD driver 170, the driving current flows to the ground via the diode D100, the LCD 190, and the transistor Q110, and the driving voltage is applied to the 10th terminal of the LCD driver 170. When output, the drive current flows to ground via diode D110, LCD 190 and transistor Q100.

Diodes D100 and D110 prevent high current from flowing into the LCD driver 170 by the high voltage. The LCD driver 170 uses 4047 chips, which have a rated voltage of ± 18V. Therefore, when a high voltage of 36V is introduced, the chip may be destroyed, thereby preventing the high voltage from flowing into the LCD driver 170 using diodes D100 and D110.

However, in the conventional high voltage control unit 180, diodes D100 and D110 are employed to prevent high voltage from being applied to the LCD driver 170. However, when the diode is used, a voltage drop of about 0.7V occurs across the diode. Since the LCD driver 170 needs to generate a driving voltage higher than the voltage drop value, the LCD driver 170 increases power consumption and shortens the life of the chip.

In addition, since the transistors Q100 and Q110 are located in each discharge path of the driving current, power consumption by the transistors Q100 and Q110 increases.

Therefore, the need for the shading control circuit of the automatic shading welding helmet to overcome the unreasonable points of the shading control circuit of the conventional automatic shading welding helmet to smoothly adjust the LCD brightness regardless of the temperature change and to reduce the power consumption There is a situation.

The present invention has been made to solve the above problems, an object of the present invention is to insert a switch into the ground terminal of the temperature compensation and LCD brightness control unit to improve the reaction speed and temperature compensation and LCD brightness control regardless of temperature change It is to provide a shading control circuit of the automatic shading welding helmet can be made.

Another object of the present invention is to provide a shading control circuit of an automatic shading welding helmet that can reduce power consumption by using one transistor as the discharge route of the current passing through the LCD.

Still another object of the present invention is to provide a light shielding control circuit of an automatic light shielding welding helmet that can reduce power consumption due to voltage drop by eliminating a diode for preventing high voltage inflow.

Still another object of the present invention is to provide a light shielding control circuit of an automatic light shielding welding helmet that has a low battery unit so that the light emitting diode is turned on when the battery life is exhausted, thereby indicating and indicating a low battery level.                         

According to an aspect of the present invention for achieving the above object, a control unit for generating a control signal by converting the welding light detection signal into a digital signal, by generating an LCD brightness control signal corresponding to the ambient temperature to maintain a constant light shielding degree A temperature compensation and LCD brightness adjusting unit, an LCD driving unit generating a driving signal corresponding to the LCD brightness control signal of the temperature compensation and LCD brightness adjusting unit, and the welding light by a liquid crystal array corresponding to the driving signal of the LCD driving unit. Automatic shading including a LCD unit for blocking, a boosting unit for applying an instantaneous high voltage to the LCD unit to improve the shading speed, and a high voltage control unit for blocking the high voltage applied to the LCD unit from being applied to the LCD driving unit. A control circuit for a welding helmet, which is controlled by the control unit and connected between the temperature compensation and the LCD brightness adjusting unit and the ground. And a first switch for shorting or opening the temperature compensation and LCD brightness controller and ground according to a control signal of the controller, and controlled by the controller and turned on / off in conjunction with the first switch, wherein the LCD driver And a second switch for controlling to generate a driving signal corresponding to the LCD brightness control signal of the temperature compensation and the LCD brightness adjusting unit.

Here, a power supply unit for supplying power, a low battery unit for displaying the voltage when the voltage of the power supply unit is less than a predetermined value, an amplifier for amplifying the detected welding light, a filter processing unit for filtering the ambient light other than the welding light and the welding light It is preferable that a sensitivity control unit for adjusting the detection sensitivity and prevent the interference of the ambient light is further included.

In addition, it is preferable that the amplification section includes three stages of amplification means.

In addition, the low battery unit generates a voltage drop of a predetermined value when the battery voltage falls below a predetermined value, the voltage drop means one end is connected to the input terminal of the controller, ON / OFF by the output terminal of the controller It is preferred that a third switch and anode at which is controlled are connected to the battery and a cathode is connected to the third switch.

In addition, the high-pressure control unit is driven by the control unit, one end is connected to the boosting unit and one end of the LCD, the other end is driven by the control unit, the fourth switch is connected to the first drive voltage output terminal of the LCD driver; And a fifth switch having one end connected to the other end of the LCD and the other end connected to the ground, and a first resistor connected to one end of the LCD and the other end connected to the second driving voltage output terminal of the LCD driver. More preferred.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

3 is a block diagram illustrating a control circuit for an automatic light shielding welding helmet according to the present invention.

Control circuit for automatic light-shielding welding helmet according to the invention the power supply unit 10, the low battery unit 15, the control unit 20, the amplifier 25, filter processing unit 30, sensitivity control unit 35, temperature compensation And an LCD brightness controller 40, a transistor Q15, a switch S / W, an LCD driver 45, an LCD 50, a high pressure controller 55, and a booster 60.

In the above configuration, the power supply unit 10, the control unit 20, the filter processing unit 30, the sensitivity control unit 35, the temperature compensation and LCD brightness control unit 40, S / W, LCD driver 45, LCD 50 And the configuration of the booster 60 is the same as the conventional, the functional aspects of the high-pressure control unit 55 is the same as the conventional description thereof will be omitted (the detailed circuit of the high-pressure control unit 55 will be described in FIG. ).

The amplifier 25 is not shown in the detailed circuit, but consists of a three-stage OP AMP. Conventional amplification unit 35 is composed of two stage OP AMP to detect the weak initial welding light in consideration of the slow reaction speed of the LCD 50 due to insufficient amplification of the weak initial welding light when welding is started. Even when amplified by a large signal to improve the driving speed of the LCD (50).

One of the biggest points of the present invention is the configuration of transistor Q15 and switch S / W. As shown in FIG. 3, in the present invention, there is no switch between the control unit 20 and the temperature compensation and LCD brightness adjusting unit 40. Instead, the transistor Q15 is grounded at the temperature compensation and LCD brightness adjusting unit 40. Connected to the transistor Q15 and switched on / off in conjunction with the transistor Q15 is the output terminal of the control unit 20 (base terminal of the transistor Q15), the LCD driver 45, and the temperature compensation and LCD brightness controller 40 It is connected to the output terminal of. As shown in FIG. 4, the switch S / W Q18 is a MOSFET, with a gate terminal at an output terminal of the controller 20, a drain terminal at an output terminal of the temperature compensation and LCD brightness controller 40, and a source terminal. It is connected to the LCD driver 45.

Therefore, when the control signal of the control unit 20 is applied to the base terminal of the transistor Q15 and the gate terminal of the switch S / W, the transistor Q15 is turned on to complete the temperature compensation and ground path of the LCD brightness controller 40 to compensate for the temperature. The LCD brightness controller 40 is driven, and the switch S / W is turned on, and the LCD brightness control signal generated by the temperature compensation and the LCD brightness controller 40 is input to the LCD driver 45.

Inserting the transistor Q15 into the ground terminal of the temperature compensation and LCD brightness adjusting unit 40, that is, the rear end, eliminates the temperature compensation difficulty due to temperature change, and the temperature compensation and LCD brightness adjusting unit 40 even when the transistor Q15 is OFF. Since a voltage is applied across both ends of the transistor, the response speed is faster than when the transistor Q15 is turned on in this state.

In other words, since the final voltage required for the operation is already applied to both ends of the temperature compensation and LCD brightness controller 40, the temperature compensation and the LCD brightness controller 40 starts to operate simultaneously with the short circuit of transistor Q15. Faster.

Applicant has regarded this phenomenon, when the switch unit is located in front of the temperature compensation and the LCD brightness control unit 40, the drive voltage (power) is the temperature compensation and LCD brightness control unit 40), even if the switch is turned on, a slight charging time is required for the final compensation voltage to be applied to both the temperature compensation and the LCD brightness control part 40 due to the capacitance component inside the LCD brightness control part 40 and the temperature compensation part. As necessary, it was analyzed that the reaction rate was delayed.

As a result of experimenting with a large number of workers, it was confirmed that the present invention shows a significantly faster reaction speed than the case where the switch part is located in the front of the conventional temperature compensation and LCD brightness control unit 40. It seems reasonable.

This slight difference in response rate is very important for auto-shielding welding helmets because the slight difference in response rate can cause fatal consequences of vision damage.

4 is a detailed circuit diagram of the LCD driver 45, the LCD 50, and the high pressure controller 55 of FIG. 3.

Referring to FIG. 4, when the 36V instantaneous high voltage generated by the booster 60 is applied, the MOSFET Q19 is turned off to prevent the high voltage from being applied to the LCD driver 45.

When the drive voltage is output from the 11th terminal of the LCD driver 45, the drive current flows to the ground via the MOSFET Q19, the LCD 50, and the transistor Q20, and the drive voltage is applied to the 10th terminal of the LCD driver 45. When output, the drive current flows to ground via LCD 50, resistor R57 and transistor Q20.

That is, the voltage for driving the LCD 50 is applied to be alternated at regular intervals, and the discharge is made through the transistor Q20 regardless of which of the LCD 50 is applied.

FIG. 5 is a detailed circuit diagram of the low battery unit 15 of FIG. 3. An operation of the low battery unit 15 will be described with reference to FIG. 5.

On the positive side of the battery, resistors R7, R8 and zener diode ZD1 for voltage drop are connected in series, and other elements are connected in parallel across the two. The resistors R7 and R8 and other devices are set to an appropriate value such that a 1.5V drop across resistors R7, R8 and zener diode ZD1 occurs when the battery drops from 6V to 4.5V.

Therefore, when the battery is exhausted and the supply voltage drops to 4.5V, a voltage of 3V is applied to the anode side of the zener diode ZD1, and this voltage is applied to terminal 2 which is an input terminal of the control unit 20. Terminal 1 of the controller 20 is an inverter terminal, and when a voltage of 3V or more is applied, it is recognized as HIGH and outputs a LOW output. When a voltage of 3V or less is applied, it is recognized as a LOW and outputs a HIGH output. Therefore, when the 3V voltage is input to the second terminal, a HIGH signal is output at the first terminal, and the HIGH signal is applied to the base terminal of the transistor Q6 to turn on the transistor Q6. When transistor Q6 is on, the LED is turned on, which emits light, indicating that the battery is low.

According to the present invention as described above, by inserting the switch into the ground terminal of the temperature compensation and LCD brightness control unit to improve the reaction speed and the light shielding control circuit of the automatic shading welding helmet that can perform temperature compensation and LCD brightness control irrespective of temperature change There is an effect that can provide.

In addition, by using one transistor as the discharge route of the current passing through the LCD, the power consumption can be reduced.

In addition, by removing the configuration of the diode for preventing the high voltage inflow can also reduce the power consumption according to the voltage drop.

In addition, the low battery unit may provide a light shielding control circuit of an automatic light shielding welding helmet that turns on a light emitting diode when the battery life is expired and displays and informs a low battery level.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, it is possible to make various modifications or variations without departing from the spirit and scope of the invention. Accordingly, the appended claims will cover such modifications and variations as fall within the spirit of the invention.

Claims (5)

A control unit for generating a control signal by converting the welding light detection signal into a digital signal, a temperature compensation and LCD brightness control unit for generating a constant brightness control LCD brightness control signal corresponding to the ambient temperature, the temperature compensation and LCD brightness control LCD driving unit for generating a driving signal corresponding to the LCD brightness control signal of the negative, LCD unit for blocking the welding light by the liquid crystal array corresponding to the driving signal of the LCD driving unit, the instantaneous high voltage is applied to the LCD A control circuit for an automatic light shielding welding helmet comprising a boosting unit for improving speed and a high voltage control unit for blocking a high voltage applied to the LCD unit from being applied to the LCD driving unit. A first switch controlled by the controller and connected between the temperature compensation and LCD brightness controller and the ground to short-circuit or open the temperature compensation and LCD brightness controller and the ground according to a control signal of the controller; And A second switch controlled by the control unit and interlocked with the first switching unit, the second switch controlling the LCD driving unit to generate a driving signal corresponding to the LCD brightness control signal of the temperature compensation unit and the LCD brightness adjusting unit; Control circuit for automatic light-shielding welding helmets characterized in that it comprises a. The method of claim 1, A power supply unit for providing power; A low battery unit displaying the voltage of the power unit below a preset value; An amplifier for amplifying the detected welding light; Filter processing unit for filtering the ambient light other than the welding light; And The control circuit for automatic shielding welding helmets characterized in that it further comprises a sensitivity control unit for adjusting the detection sensitivity of the welding light and to prevent the interference of the ambient light. The method of claim 2, And the amplifying unit includes three stages of amplifying means. The method of claim 2, The low battery unit Voltage drop means for generating a voltage drop of a predetermined value when the battery voltage falls below a predetermined value, and one end of which is connected to an input terminal of the controller; A third switch in which ON / OFF is controlled by an output terminal of the controller; And A control circuit for automatic light shielding welding helmet, characterized in that an anode is connected to the battery and a cathode is connected to the third switch. The method of claim 1, The high pressure control unit A fourth switch driven by the controller, one end of which is connected to one of the boosting unit and one end of the LCD, and the other end of which is connected to the first driving voltage output terminal of the LCD driver; A fifth switch driven by the controller, one end of which is connected to the other end of the LCD and the other end of which is connected to ground; And And a first resistor having one end connected to one end of the LCD and the other end connected to a second drive voltage output terminal of the LCD driver.

Images