CN110974536B - Control circuit of automatic light-changing welding mask - Google Patents
Control circuit of automatic light-changing welding mask Download PDFInfo
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- CN110974536B CN110974536B CN201911394976.0A CN201911394976A CN110974536B CN 110974536 B CN110974536 B CN 110974536B CN 201911394976 A CN201911394976 A CN 201911394976A CN 110974536 B CN110974536 B CN 110974536B
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F9/00—Methods or devices for treatment of the eyes; Devices for putting-in contact lenses; Devices to correct squinting; Apparatus to guide the blind; Protective devices for the eyes, carried on the body or in the hand
- A61F9/04—Eye-masks ; Devices to be worn on the face, not intended for looking through; Eye-pads for sunbathing
- A61F9/06—Masks, shields or hoods for welders
- A61F9/065—Masks, shields or hoods for welders use of particular optical filters
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
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Abstract
The invention discloses a control circuit of an automatic dimming welding mask, which comprises a control circuit for providing the automatic dimming welding mask, wherein the control circuit comprises: the device comprises a power supply circuit, a photoelectric conversion circuit, a signal conditioning circuit, an LCD driving frequency and driving time sequence circuit, an LCD driving voltage adjusting circuit, an LCD driving circuit, a positive and negative voltage conversion circuit and a negative voltage multiplying circuit. The invention adopts the matching of the power supply circuit, the photoelectric conversion circuit, the signal conditioning circuit, the LCD driving frequency and driving time sequence circuit, the LCD driving voltage regulating circuit, the LCD driving circuit, the positive and negative voltage conversion circuit and the negative voltage doubling circuit, so that the driving voltage is higher and the darkness is darker, and simultaneously, the pulse voltage which has very high time and is very short is generated, so that the LCD can respond quickly, thereby avoiding the damage of strong welding light to eyes when an electric welder operates, avoiding the occurrence of electro-optic ophthalmia, being convenient to adjust and set and further improving the production efficiency.
Description
Technical Field
The invention relates to the technical field of welding masks, in particular to a control circuit of an automatic light-changing welding mask.
Background
An auto-dimming mask has a very important parameter, response time, specifically defined as the time from when the mask photoreceptor captures the welding light to when the LCD screen is driven to dim. The time parameter directly determines the comfort of eyes of the electric welder during operation and the damage degree of harmful light to the face and eyes of people. The products produced by domestic manufacturers at present have uneven quality, long response time, poor sensitivity, poor brightness adjustment and other aspects, so that domestic electric welding masks can enter high-end professional markets when users who need to be further improved to jump out of low grades, the electric welders are free from damage of strong welding light to eyes during operation, and electro-optic ophthalmia is avoided.
Disclosure of Invention
The present invention addresses one or more of the above-identified problems by providing a control circuit for an automatic darkening welding helmet.
According to one aspect of the present invention, there is provided a control circuit for an automated darkening welding helmet, the control circuit comprising: the device comprises a power supply circuit, a photoelectric conversion circuit, a signal conditioning circuit, an LCD driving frequency and driving time sequence circuit, an LCD driving voltage adjusting circuit, an LCD driving circuit, a positive and negative voltage conversion circuit and a negative voltage multiplying circuit;
the power supply circuit is electrically connected with other circuits in the circuit to provide electric energy;
the photoelectric conversion circuit consists of an infrared photodiode and is used for detecting an optical signal generated by electric welding and converting the optical signal into an electric signal;
the signal conditioning circuit is electrically connected with the output end of the photoelectric conversion circuit, amplifies the electric signal in the photoelectric conversion circuit, and adjusts the electric signal to enable the voltage of the optical signal to reach a threshold value to drive the post-stage circuit;
the LCD driving frequency and driving time sequence circuit is electrically connected with the output end of the signal conditioning circuit and is used for changing the LCD working frequency and outputting the LCD working frequency to the LCD driving circuit according to time sequence;
the output end of the LCD driving voltage regulating circuit is electrically connected with the LCD driving circuit and is used for setting the LCD driving voltage between the two poles of the LCD;
the positive and negative voltage conversion circuit is used for converting positive voltage in the circuit into negative voltage required by the circuit and outputting the negative voltage to the LCD driving voltage regulation circuit, and square wave voltage signals are output to the negative voltage doubling circuit;
the negative voltage doubling circuit is used for generating pulse voltage by multiplying the signals received from the positive and negative voltage conversion circuit for multiple times and outputting the pulse voltage to the LCD driving circuit;
and the LCD driving circuit is used for matching with other circuits and outputting the received pulse voltage, the LCD driving voltage and the LCD working frequency to the LCD according to a time sequence.
In some embodiments, the signal conditioning circuit includes a filter circuit and an integrated circuit U1, the filter circuit is configured to filter an electrical signal waveform converted from light without strobing or extremely low strobing and output the filtered electrical signal waveform, the integrated circuit U1 includes an operational amplifier U1A and an operational amplifier U1B, an output terminal of the operational amplifier U1A is connected to a negative input terminal of the operational amplifier U1B, the operational amplifier U1A is configured to amplify a voltage signal passing through the filter circuit, and the operational amplifier U1B is configured to serve as a comparator configured to compare a voltage of the input negative input terminal with a voltage of the input positive input terminal and output the voltage;
the positive input end of U1B is connected with resistor R6 and one end of potentiometer W3 respectively, the other end of resistor R6 is connected with circuit supply voltage VCC, the other end of potentiometer W3 is connected with R14 and R17 and then grounded, and the threshold value is set by adjusting potentiometer W3.
In some embodiments, the filter circuit includes a capacitor C1, a capacitor C2, a resistor R2, and a resistor R3, the capacitor C1 and the resistor R2 are connected in series and then connected to one end of R3 and one end of C2, the other end of R3 is grounded, and the other end of C2 is connected to the negative input terminal of the operational amplifier U1A and the negative input terminal of the operational amplifier U1B, respectively.
In some embodiments, the LCD driving frequency and driving timing circuit includes U4, U4 is composed of three 2-input schmitt trigger circuits, each of which is a 2-input nand gate with schmitt trigger function, respectively nand gate U4B, nand gate U4A, and nand gate U4C;
the nand gate U4B is used for signal inversion, and when the input signal is at high level, the output is at low level, whereas when the input is at low level, the output is at high level;
the NAND gate U4A is used as a self-oscillation circuit, the U4A, the R8 and the C7 form an oscillation circuit, square wave signals are generated, and the frequency of the square wave is determined by the capacitance value of the capacitor C7 and the resistance value of the resistor R8;
the nand gate U4C is used for signal inversion, and the output of the nand gate U4C is controlled by the output of U4A and is inverted from the output of U4A.
In some embodiments, the LCD driving voltage adjusting circuit 5 includes a low power consumption operational amplifier U2, an output terminal and a negative input terminal of the low power consumption operational amplifier U2 are connected to an input terminal of the LCD driving circuit 6;
the positive input end of the low-power-consumption operational amplifier U2 is connected with one end of a potentiometer W1B, the other end of the potentiometer W1B is connected with a circuit power supply voltage VCC through a pull-up resistor R15, and the output end of the low-power-consumption operational amplifier U2 is connected with the input end of the LCD driving circuit 6 to provide driving voltage for the LCD driving circuit 6.
In some embodiments, the positive-negative voltage converting circuit 7 includes an integrated voltage converting chip U6, the U6 is an ICL7660AIBAZ chip, the 5 pins corresponding to VOUT of U6 are connected to the GND terminal of the low power operational amplifier U2 through two serially connected diodes, the anode of the diode is connected to the GND terminal of the low power operational amplifier U2, the cathode of the diode is connected to the 5 pins corresponding to VOUT of U6, the pin 2 corresponding to CAP + of U6 is connected to the input terminal of the negative voltage doubling circuit 8, and the pin 4 corresponding to CAP of U6 is connected to the input terminal of the negative voltage doubling circuit 8 through a capacitor E1.
In some embodiments, the negative voltage doubling circuit 8 is used for providing a negative level for an output chip of the LCD driving circuit 6, and comprises U4D and a voltage doubling rectifying unit, U4D is a 2-input nand gate with 2 inputs having a schmitt trigger function, and an output of U4D is connected to an input of the voltage doubling rectifying unit;
the voltage-doubling rectifying unit comprises a bootstrap booster circuit consisting of 8 diodes and 7 capacitors, and the output of the voltage-doubling rectifying circuit is connected to the negative level VEE end of an output chip U3 of the LCD driving circuit 6.
In some embodiments, the LCD driver circuit 6 employs an output chip U3, the U3 employs a dual 4-channel digitally controlled analog switch MC14052BG, and the output terminals Za, Zb of the output chip U3 are connected to the LCD.
In some embodiments, the power circuit 1 includes a power regulator circuit, the power regulator circuit includes a power regulator chip U5, a transistor J6, a collector of the transistor J6 is connected to an anode of the battery BAT, a cathode of the battery BAT is grounded, a base of the transistor J6 is connected to an anode of the solar battery, a cathode of the solar battery is grounded, a collector of the transistor J6 is connected to an input of the power regulator chip U5, the power regulator chip U5 employs a low dropout linear regulator HT7130-1, an output of the power regulator chip U5 is connected to one end of a capacitor E5 and a switch W1B, the other end of the capacitor E5 is grounded, and the other end of the switch W1B is connected to a supply voltage VCC of the circuit.
In some embodiments, the power supply circuit 1 further includes a battery under-voltage reminding circuit, the battery under-voltage reminding circuit includes a low-voltage detection chip U7, a resistor R9, and a light emitting diode LED1, the low-voltage detection chip U7 adopts a chip XC61CC2502MR, a pin 1 of the chip XC61CC2502MR is connected to one end of the resistor R9, a pin 3 of the chip XC61CC2502MR is connected to the battery voltage VBAT and the anode of the light emitting diode LED1, the cathode of the light emitting diode LED1 is connected to the other end of the resistor R9, and a pin 2 of the chip XC61CC2502MR is grounded.
The invention has the advantages that: the control circuit of the automatic light-changing welding mask adopts a power supply circuit, a photoelectric conversion circuit, a signal conditioning circuit, an LCD driving frequency and driving time sequence circuit, an LCD driving voltage adjusting circuit, an LCD driving circuit, a positive and negative voltage conversion circuit and a negative voltage doubling circuit, so that the driving voltage is higher and the darkness is darker, and a very high pulse voltage with short time is generated to ensure that the LCD responds quickly.
Drawings
FIG. 1 is a block diagram of control circuitry for an autodarkening welding helmet;
FIG. 2 is a circuit diagram of a control circuit for an autodarkening welding helmet;
FIG. 3 is a circuit diagram of a power circuit for the control circuit of the automatic darkening welding helmet;
FIG. 4 is a circuit diagram of a photoelectric conversion circuit of the control circuit of the automatic darkening welding helmet;
FIG. 5 is a circuit diagram of a signal conditioning circuit of the control circuit of the autodarkening welding helmet;
FIG. 6 is a circuit diagram of the LCD drive frequency and drive timing circuit of the control circuit of the autodarkening welding helmet;
FIG. 7 is a circuit diagram of an LCD drive voltage adjustment circuit for the control circuit of the automatic darkening welding helmet;
FIG. 8 is a circuit diagram of an LCD drive circuit for the control circuit of the automatic darkening welding helmet;
FIG. 9 is a circuit diagram of the positive and negative voltage switching circuitry of the control circuitry of the automatic darkening welding helmet;
fig. 10 is a circuit diagram of a negative voltage doubler circuit of a control circuit of an autodimming welding helmet.
Detailed Description
The technical scheme of the application is further explained in detail with reference to the attached drawings.
In order to make the technical solutions better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only partial embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It should be understood that the data so used may be interchanged under appropriate circumstances such that embodiments of the application described herein may be used. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
The terms "mounted," "disposed," "provided," "connected," and "sleeved" are to be construed broadly. For example, it may be a fixed connection, a removable connection, or a unitary construction; can be a mechanical connection, or an electrical connection; may be directly connected, or indirectly connected through intervening media, or may be in internal communication between two devices, elements or components. The specific meanings of the above terms in the present invention can be understood by those of ordinary skill in the art according to specific situations.
In accordance with one aspect of the present invention, as illustrated in fig. 1-10, the present invention provides a control circuit for an autodimming welding helmet, and in accordance with one aspect of the present invention, as illustrated in fig. 1-10, the present invention provides a sensitivity adjustment circuit for an autodimming welding helmet, for use with an autodimming welding helmet control circuit, the control circuit comprising: the device comprises a power supply circuit 1, a photoelectric conversion circuit 2, a signal conditioning circuit 3, an LCD driving frequency and driving time sequence circuit 4, an LCD driving voltage adjusting circuit 5, an LCD driving circuit 6, a positive and negative voltage conversion circuit 7 and a negative voltage doubling circuit 8;
the power supply circuit 1 is electrically connected with other circuits in the circuit and provides electric energy;
the photoelectric conversion circuit 2 consists of an infrared photodiode and is used for detecting optical signals generated by electric welding and converting the optical signals into electric signals;
the signal conditioning circuit 3 is electrically connected with the output end of the photoelectric conversion circuit 2, amplifies the electric signal in the photoelectric conversion circuit 2, and adjusts the electric signal to enable the voltage of the optical signal to reach a threshold value to drive a post-stage circuit;
the LCD driving frequency and driving time sequence circuit 4 is electrically connected with the output end of the signal conditioning circuit 3 and is used for changing the LCD working frequency and outputting the LCD working frequency to the LCD driving circuit according to time sequence;
the output end of the LCD driving voltage regulating circuit 5 is electrically connected with the LCD driving circuit and is used for setting the LCD driving voltage between two poles of the LCD;
the positive and negative voltage conversion circuit 7 is used for converting positive voltage in the circuit into negative voltage required by the circuit and outputting the negative voltage to the LCD driving voltage regulating circuit 5, and square wave voltage signals are output to the negative voltage doubling circuit 8;
the negative voltage doubling circuit 8 is used for generating pulse voltage by multiplying the signal received from the positive and negative voltage conversion circuit 7 for multiple times and outputting the pulse voltage to the LCD driving circuit 6;
and the LCD driving circuit 6 is used for matching with other circuits and outputting the received pulse voltage, the LCD driving voltage and the LCD working frequency to the LCD according to a time sequence.
In this embodiment, the signal conditioning circuit 3 includes a filter circuit and an integrated circuit U1, the filter circuit is configured to filter an electrical signal waveform converted from light without stroboflash or extremely low stroboflash and output the filtered electrical signal waveform, the integrated circuit U1 includes an operational amplifier U1A and an operational amplifier U1B, an output terminal of the operational amplifier U1A is connected to a negative input terminal of the operational amplifier U1B, the operational amplifier U1A is configured to amplify a voltage signal passing through the filter circuit, and the operational amplifier U1B is used as a comparator configured to compare an input voltage at the negative input terminal with an input voltage at the positive input terminal and output the amplified voltage;
the positive input end of U1B is connected with resistor R6 and one end of potentiometer W3 respectively, the other end of resistor R6 is connected with circuit supply voltage VCC, the other end of potentiometer W3 is connected with R14 and R17 and then grounded, and the threshold value is set by adjusting potentiometer W3.
In this embodiment, the filter circuit includes a capacitor C1, a capacitor C2, a resistor R2, and a resistor R3, the capacitor C1 and the resistor R2 are connected in series and then connected to one end of R3 and one end of C2, the other end of R3 is grounded, and the other end of C2 is connected to the negative input terminal of the operational amplifier U1A and the negative input terminal of the operational amplifier U1B, respectively. The negative input end of the U1A is connected with the output end of the U1A through a connecting resistor R4 to form negative feedback. The positive input end of U1A is connected with one end of a capacitor C3, one end of a resistor R13 and one end of a resistor R5, the other end of C3 is grounded, the other end of a resistor R13 is grounded, and the other end of the resistor R5 is connected with a circuit supply voltage VCC.
A diode group D6 formed by two diodes connected in series is connected in parallel to the resistor R4, the anode of the diode group D6 is connected with the negative input end of the U1A and the capacitor C2, the cathode of the diode group D6 is connected with the negative input end of the U1B, and the middle of the two diodes is connected with the capacitor C2. The positive input end of the U1B is also connected with a capacitor C4, and the other end of the capacitor C4 is grounded.
In this embodiment, the LCD driving frequency and driving timing circuit includes U4, U4 is composed of three schmitt trigger circuits with 2 inputs, each of which is a 2-input nand gate with schmitt trigger function, and is respectively a nand gate U4B, a nand gate U4A, and a nand gate U4C;
the nand gate U4B is used for signal inversion, and when the input signal is at high level, the output is at low level, whereas when the input is at low level, the output is at high level;
the NAND gate U4A is used as a self-oscillation circuit, the U4A, the R8 and the C7 form an oscillation circuit, square wave signals are generated, and the frequency of the square wave is determined by the capacitance value of the capacitor C7 and the resistance value of the resistor R8;
the nand gate U4C is used for signal inversion, and the output of the nand gate U4C is controlled by the output of U4A and is inverted from the output of U4A.
The output end of the NAND gate U4B is connected with the resistor R11 and the cathode of the diode D7, the anode of the diode D7 is connected with the other end of the resistor R11, the resistor R11 and the diode D7 are connected in parallel and then connected with the gating signal A0 end of the MC14052BG and the capacitor C6, and the other end of the capacitor C6 is grounded.
The input end of the nand gate U4B is connected with the anode of the diode D1 and one end of the potentiometer W2, the other end of the potentiometer W2 is connected with the resistor R7, the other end of the potentiometer W2 is grounded, the input end of the nand gate U4B is also connected with the filter capacitor C5, the output end of the nand gate U4B is connected with one input end of the nand gate U4A, the other end of the resistor R7 is connected with the output end of the U1B, and the anode of the diode D1 is connected with the output end of the U1B.
The anode of the diode D1 is further connected to VCC through capacitors C8 and R12 in sequence, and the other end of R12 is connected to the pin 8 of the input end of the NAND gate U4C.
The pin 9 of the input end of the not gate U4C is connected with the output end of the not gate U4A, the other input end of the not gate U4A is connected with one end of a capacitor C7 and one end of a resistor R8, the other end of the capacitor C7 is grounded, the other end of the resistor R8 is connected with the pin 9 of the input end of the not gate U4C, and the output end of the not gate U4C is connected with the gating signal A1 end of the MC14052 BG.
In the present embodiment, the LCD driving voltage adjusting circuit 5 includes a low power consumption operational amplifier U2, and the output terminal and the negative input terminal of the low power consumption operational amplifier U2 are connected to the input terminal of the LCD driving circuit 6;
the positive input end of the low-power-consumption operational amplifier U2 is connected with one end of a potentiometer W1B, the other end of the potentiometer W1B is connected with a circuit power supply voltage VCC through a pull-up resistor R15, and the output end of the low-power-consumption operational amplifier U2 is connected with the input end of the LCD driving circuit 6 to provide driving voltage for the LCD driving circuit 6. The LCD driving circuit 6 adopts an output chip U3, the U3 adopts a two-way 4-channel digital control analog switch MC14052BG, and the output ends Za and Zb of the output chip U3 are connected with the LCD.
The low power consumption operational amplifier U2 is of model SGM 8521. The output end of the low-power consumption operational amplifier U2 is connected with the Y3A pin and the Y2B pin of the output chip U3. The input end of the low-power consumption operational amplifier U2 is also connected with a grounded capacitor C9 and a grounded resistor VR 1. The input terminal of the low power consumption operational amplifier U2 is also connected to the Y3B pin of the output chip U3 through a resistor R10. The output terminal of the positive-negative voltage conversion circuit 7 is connected to one terminal of the resistor R10 and the Y3B pin of the output chip U3.
In this embodiment, the positive-negative voltage conversion circuit 7 includes an integrated voltage conversion chip U6, the U6 is an ICL7660AIBAZ chip, the 5 pins corresponding to VOUT of U6 are connected to the GND terminal of the low power consumption operational amplifier U2 through two serially connected diodes, the anode of the diode is connected to the GND terminal of the low power consumption operational amplifier U2, the cathode of the diode is connected to the 5 pins corresponding to VOUT of U6, the pin 2 corresponding to CAP + of U6 is connected to the input terminal of the negative voltage doubling circuit 8, and the pin 4 corresponding to CAP of U6 is connected to the input terminal of the negative voltage doubling circuit 8 through a capacitor E1.
In this embodiment, the negative voltage doubling circuit is configured to generate a pulse voltage by multiple voltage doubling, the negative voltage doubling circuit 8 includes U4D and a voltage doubling rectifying unit, U4D is a 2-input nand gate having a schmitt trigger function, 2 inputs of U4D are connected, and both an output and an input of U4D are connected to a control input of the voltage doubling rectifying unit; the positive and negative voltage conversion circuit 7 is used for converting a positive voltage in the circuit into a negative voltage required by the circuit and outputting the negative voltage square wave voltage signal to the negative voltage doubling circuit 8.
The voltage-doubling rectifying unit comprises a bootstrap booster circuit consisting of 8 diodes and 7 capacitors, and the output of the voltage-doubling rectifying circuit is connected to the negative level VEE end of an output chip U3 of the LCD driving circuit 6. 8 diodes are formed with A, B, C, D, E, F, G crossing points, B, D, F are connected to the output end of U4D through a corresponding capacitor, A, C, E, G are connected to the input end of U4D through a corresponding capacitor, crossing points A, C, E, G are connected with a capacitor E1 through a corresponding capacitor, the cathode of the diode is connected with the output end and the input end of U4D, and the anode of the last diode is connected with the VEE pin of the LCD driving circuit U3 as the output end of the voltage-doubling rectifying unit.
The positive and negative voltage conversion circuit 7 comprises an integrated voltage conversion chip U6, a U6 adopts a chip ICL7660AIBAZ, a pin 2 corresponding to CAP + of the U6 is connected with the input end of the negative voltage doubling circuit 8, and a pin 4 corresponding to CAP-of the U6 is connected with the input end of the negative voltage doubling circuit 8 through a capacitor E1.
In this embodiment, the LCD driving circuit 6 uses an output chip U3, the U3 uses a dual 4-channel digital control analog switch MC14052BG, and the output terminals Za and Zb of the output chip U3 are connected to the LCD.
In this embodiment, the power circuit 1 includes a power voltage stabilizing circuit, the power voltage stabilizing circuit includes a power voltage stabilizing chip U5, a transistor J6, a collector of the transistor J6 is connected to an anode of the battery BAT, a cathode of the battery BAT is grounded, a base of the transistor J6 is connected to an anode of the solar battery, a cathode of the solar battery is grounded, a collector of the transistor J6 is connected to an input terminal of the power voltage stabilizing chip U5, the power voltage stabilizing chip U5 employs a low dropout linear regulator HT7130-1, an output terminal of the power voltage stabilizing chip U5 is connected to one end of a capacitor E5 and a switch W1B, the other end of the capacitor E5 is grounded, and the other end of the switch W1B is connected to a power supply voltage VCC of the circuit.
In this embodiment, the power supply circuit 1 further includes a battery under-voltage reminding circuit, the battery under-voltage reminding circuit includes a low-voltage detection chip U7, a resistor R9, a light emitting diode LED1, the low-voltage detection chip U7 adopts a chip XC61CC2502MR, a pin 1 of the chip XC61CC2502MR is connected to one end of the resistor R9, a pin 3 of the chip XC61CC2502MR is connected to the battery voltage VBAT and the anode of the light emitting diode LED1, the cathode of the light emitting diode LED1 is connected to the other end of the resistor R9, and a pin 2 of the chip XC61CC2502MR is grounded.
In embodiment 1, a linear voltage stabilizing chip U5 with low power consumption is adopted in a power supply voltage stabilizing circuit, so as to reduce power consumption caused by voltage stabilization; as shown in the figure, T + and T-are respectively connected with the anode and the cathode of the solar cell, and the whole machine enters a working state only when light exists, so that the useless loss of the electric quantity of the cell is further reduced; the switch W1B adopts a resistance switch two-in-one potentiometer, and the switch of W1B can manually cut off the output of the voltage stabilizing chip.
In embodiment 3, the photoelectric conversion circuit is composed of an infrared photodiode, and converts an infrared light signal in the electric welding light into an electric signal, so that the following circuit can drive the LCD black screen in time accordingly, thereby protecting the naked eyes of the welder from being irradiated by strong light.
In embodiment 4, the signal conditioning circuit includes a filter circuit composed of C1, C2, R2, and R3, and filters out electrical signal waveforms converted from lights without stroboflash or extremely low stroboflash, such as sunlight and fluorescent light, the post-stage circuit does not respond, does not drive the LCD black screen, and only responds to stroboflash light signals of about 50HZ to hundreds of HZ, and the voltage of the stroboflash light signals of 50HZ to hundreds of HZ needs to reach a certain threshold value to drive the post-stage, which is set by the user adjusting potentiometer W3.
The response time is typically several milliseconds to tens of milliseconds due to the technical bottleneck of the LCD. After the electric welding light is generated, the circuit drives the LCD with the voltage set by the user, when the LCD is stabilized to the set darkness level, the driving voltage of the LCD is higher, the darkness level is darker, and the electric welding light penetrates through the LCD to stab eyes of the user within the time of several milliseconds to tens of milliseconds. It is necessary to apply a very high, short duration pulsed voltage before driving the LCD with the user-set LCD driving voltage for fast response of the LCD. This circuit thus cooperates with the following U3 chip to achieve this function
In the embodiment 7, in the positive and negative voltage conversion circuit, part of the circuit needs negative voltage, and only one 3V button battery is needed for the power supply of the whole machine, and a negative voltage charge pump chip is needed to realize positive and negative conversion. Compared with other types of negative voltage circuits, the negative voltage circuit of the charge pump has the advantages of extremely high efficiency and extremely low static power consumption.
In embodiment 9, the LCD driving circuit, in cooperation with other modules, outputs the pulse voltage, the LCD driving voltage for setting the darkness by the user, the LCD operating frequency, and the like to the LCD according to the time sequence.
The working principle is as follows:
1) in the static state:
static means no stroboscopic light or dark environment, where the LCD is not driven. The reason is as follows:
the light without strobing is converted by the photodiode in the photoelectric conversion circuit 2 to form a dc voltage, but the isolation of C1 prevents the processing of the subsequent circuits.
In dark light, the photodiode in the photoelectric conversion circuit 2 does not generate voltage, and no voltage signal is sent to a subsequent circuit.
In both cases, the voltage obtained at the inverting input of the operational amplifier U1A in the signal conditioning circuit 3 approaches zero.
Different from the traditional inverse operational amplifier circuit, in order to solve the problem of offset voltage inherent to the operational amplifier when the operational amplifier is powered by a single power supply, the forward input end of the operational amplifier is raised, namely R13/R13+ R5 VCC, and the value of the input voltage is about 328mv, so that the static output voltage of the inverse operational amplifier circuit is also changed into R13/R13+ R5 VCC which is about 328 mv. In terms of gain, the gain of the inverting operational amplifier circuit still follows the rule of a basic inverting operational amplifier, namely:
Vo＝-R4/Xc2＝-R4*2πfc；
since the voltage obtained at the inverting input of the current operational amplifier U1A is close to zero, the output will not change after U1A, and the static voltage output, i.e., R13/R13+ R5 VCC, is still maintained at about 328 mv. U1B is also an operational amplifier, but is used as a comparator here, and the reference voltage is introduced to the positive input terminal, and the range can be adjusted by W3. The variation range of the reference voltage is W3min + R14+ R17/R6+ W3min + R14+ R17 VCC to W3max + R14+ R17/R6+ W3max + R14+ R17 VCC by calculation, and the variation range is about 380mv-600mv by substituting the component values in the figure.
The voltage of the reverse input end of the U1B of the comparator is R13/R13+ R5 VCC, which is less than the minimum reference voltage W3min + R14+ R17/R6+ W3min + R14+ R17 VCC of the forward input end, and is about 380 mv. Therefore, the output of the comparator U1B is high, approaching VCC.
Since the U1B outputs high level, it is transmitted to the LCD driving frequency and driving sequence circuit 4, and after charging the C5 through R7 and W2, the voltage that C5 will get to VCC is sent to the nand gate U4B, and the U4B is equivalent to an inverter because two input pins are short-circuited, and the output is low level, and is divided into two paths to control the back stage circuit.
Wherein the first path: after the output end of the nand gate U4B passes through R11, D7 and C6, the voltage across the capacitor C6 is zero, and then the U3 in the LCD driving circuit adopts MC14052BG as a two-way 4-to-1 analog switch, and the gating signal a1 of the two-way 4-to-1 analog switch is 0.
And a second path: the output of the nand gate U4B is fed into one of the inputs of the nand gate U4A, as shown in the nand gate truth table: there are 0 out of 1 and all 1 out of 0, so the output of U4A must be high.
The high level of the output of U4A is fed into one of the inputs of NAND gate U4C, and the other end is connected to the junction of R12 and C8. From the previous analysis, it is known that the potential on the right side of the capacitor C8 is VCC, so that both ends of the series connection of R12 and C8 are substantially connected to VCC, and it is found that the potential on the left side of C8 is almost equal to the potential on the right side of C8, and then VCC is equal to high level.
Then, at this time, both input terminals of the nand gate U4C are at high level, the output thereof must be at low level 0, and the low level is transmitted to the gate pin a0 of the two-way 1-out-of-4 analog switch U3, so that a0 is 0
The analysis shows that: the two-way 4-to-1 analog switch U3 gates signals: a0 ═ a1 ═ 0, and the logical control relationship of MC14052BG shows that: Y0A and Za are turned on to GND, Y0B and Zb are turned on to GND, and Za and Zb are connected to two electrodes of LCD respectively, so the difference of voltage between two electrodes of LCD is 0, so it will not become dark.
2) In the state of stroboscopic light irradiation
Under the flash light irradiation state, the negative voltage doubling circuit 8 can generate a pulse high voltage to the LCD driving circuit, a short-time strong voltage is applied to enable the LCD to be quickly blackened, a voltage corresponding to the required LCD darkness is applied through the LCD driving voltage adjusting circuit 5, and the polarity of two pins of the LCD is switched at a certain frequency by matching with the LCD driving frequency and the driving time sequence circuit 4, so that the LCD cannot return to the original position after the direct-current voltage is applied for a long time. The principle is as follows:
at the moment of strong light irradiation, voltages are generated across the light emitting diodes D10 and D11 in the photoelectric conversion circuit 2, but since the voltages across the capacitors cannot change abruptly, the voltage signals generated by the diodes D11 and D12 can be quickly coupled to D6 through the capacitors C1 and C2 and injected into the reverse input end of the comparator U1B. When the voltage at the reverse input end of the comparator U1B is greater than that at the positive input end of the comparator, the output of U1B is low.
The low level output by U1B changes the right side of the capacitor C8 to low level through D1, and at this time VCC charges the capacitor C8 through the resistor R12, but it takes a certain time t equal to RC, so that the potential on the left side of the current C8 still approaches to 0V on the right side, and one input terminal of the nand gate U4C is 0. According to the truth table of the NAND gate, 0 goes out of 1, all 1 goes out of 0, and the output of the NAND gate U4C is definitely high, so that the gating signal A0 of the two-way 4-to-1 analog switch in the LCD driving circuit 6 is 1.
At this time, both input ends of the nand gate U4B are 0, the output is high, VCC charges the capacitor C6 through the resistor R11, but this requires a certain time t equal to RC, so the voltage across the current C6 still approaches to 0, that is, the gate signal a1 of the two-way 4-to-1 analog switch in the LCD driving circuit 6 is 0.
In summary, the two-way 1-by-4 analog switch U3 gates the signal a0 equal to 1 and a1 equal to 0, and then obtains the following results according to the logic control relationship of the MC14052 BG: Y1A and Za turn on being VCC, Y1B and Zb turn on being VEE, Za and Zb connect two electrodes of LCD respectively, and the LCD two-pole voltage difference is VCC in MC14052BG minus the voltage of VEE, VEE is the negative high voltage that negative voltage doubling circuit exported VEE in U3, from this, LCD obtains this voltage and darkens fast.
3) After the instant of strong light irradiation
After the moment of strong light irradiation, if the light is stroboscopic, the ac voltage generated at the two ends of the leds D10 and D11 is coupled to the input end of the inverting operational amplifier U1A through C1 and C2, and after proportional amplification, the static voltage at the positive input end of the inverting operational amplifier U1A is output to the inverting input end of the comparator U1B. At this time, the voltage of the reverse input end of the comparator U1B is greater than that of the forward input end, the voltage range of the forward input end is W3min + R14+ R17/R6+ W3min + R14+ R17 VCC to W3max + R14+ R17/R6+ W3max + R14+ R17 VCC, and the range is known to be about 380mv to 600mv by substituting the component values in the figure, the output of the comparator U1B continues to maintain the previous low level output, and the nand gate U4B of the LCD driving frequency and driving timing circuit 4 outputs high level.
At this time, the capacitor C6 connected to the gate pin a1 of the U3 of the LCD driver circuit 6 is charged by the high level output from the nand gate U4B and the resistor R11, and becomes high, that is, a1 is 1.
When VCC charges through the resistor R12, the pin 8 of the input terminal of the nand gate U4C goes high in the capacitor C8, and the pin 1 of the input terminal of the not gate U4A is connected to the output of the U4B, so the pin 1 input of the not gate U4A is also high. And U4A, R8 and C7 form an oscillating circuit. I.e., the square wave signal oscillated by the output of U4A, when pin 8 of U4C is already at a high level, the output of U4C is inverted with respect to the output of nand gate U4A, i.e., the level of gate signal a0 in LCD driver circuit 6 is controlled by the output of U4A and is in opposite phase.
In summary, it is found that the gate signal a1 of the two-way 4-to-1 analog switch in the LCD driving circuit 6 is 1, and a0 is constantly changing. Thus, the resulting voltages for the LCD are: the output voltage of U2 in the LCD driving voltage adjusting circuit 5 is subtracted by the output voltage of U6 in the positive-negative voltage converting circuit 7, but the polarity is changed continuously.
4) After the stroboscopic light is cancelled
After the strobe light is removed, the circuit state is restored to the static state after a delay, and the LCD becomes transparent.
The delay is generated because: when the output of the nand gate U4B changes from low to high, the capacitor C5 needs to be fully charged through R7 and W2 before the latter circuit becomes the same as in the quiescent state, so that the LCD does not become transparent immediately after the strobe light is deactivated, but becomes transparent after the capacitor C5 is fully charged.
The foregoing are only some embodiments of the invention. It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the inventive concept thereof, and these changes and modifications can be made without departing from the spirit and scope of the invention.
Claims (9)
1. Control circuit of automatic optically variable welding face guard, its characterized in that, control circuit includes: the device comprises a power supply circuit (1), a photoelectric conversion circuit (2), a signal conditioning circuit (3), an LCD driving frequency and driving sequence circuit (4), an LCD driving voltage adjusting circuit (5), an LCD driving circuit (6), a positive and negative voltage conversion circuit (7) and a negative voltage doubling circuit (8);
the power supply circuit (1) is electrically connected with other circuits in the circuit to provide electric energy;
the photoelectric conversion circuit (2) consists of an infrared photodiode and is used for detecting optical signals generated by electric welding and converting the optical signals into electric signals;
the signal conditioning circuit (3) is electrically connected with the output end of the photoelectric conversion circuit (2), amplifies an electric signal in the photoelectric conversion circuit (2), and adjusts the electric signal to enable the voltage of the optical signal to reach a threshold value to drive a post-stage circuit;
the LCD driving frequency and driving time sequence circuit (4) is electrically connected with the output end of the signal conditioning circuit (3) and is used for changing the LCD working frequency and outputting the LCD working frequency to the LCD driving circuit according to time sequence;
the output end of the LCD driving voltage regulating circuit (5) is electrically connected with the LCD driving circuit and is used for setting the LCD driving voltage between two poles of the LCD;
the positive and negative voltage conversion circuit (7) is used for converting positive voltage in the circuit into negative voltage required by the circuit and outputting the negative voltage to the LCD driving voltage regulating circuit (5), and outputting a square wave voltage signal to the negative voltage doubling circuit (8);
the negative voltage doubling circuit (8) is used for generating pulse voltage by multiplying the voltage of the signals received from the positive and negative voltage conversion circuit (7) for multiple times and outputting the pulse voltage to the LCD driving circuit (6);
the LCD driving circuit (6) is used for matching with other circuits and outputting the received pulse voltage, the LCD driving voltage and the LCD working frequency to the LCD according to a time sequence;
the signal conditioning circuit (3) comprises a filter circuit and an integrated circuit U1, wherein the filter circuit is used for filtering and outputting an electric signal waveform converted from light without stroboflash or extremely low stroboflash, the integrated circuit U1 comprises an operational amplifier U1A and an operational amplifier U1B, the output end of the operational amplifier U1A is connected with the negative input end of the operational amplifier U1B, the operational amplifier U1A is used for amplifying a voltage signal passing through the filter circuit, and the operational amplifier U1B is used as a comparator and used for comparing the voltage of the input negative input end with the voltage of the input positive input end and then outputting the voltage;
the positive input end of U1B is connected with resistor R6 and one end of potentiometer W3 respectively, the other end of resistor R6 is connected with circuit supply voltage VCC, the other end of potentiometer W3 is connected with R14 and R17 and then grounded, and the threshold value is set by adjusting potentiometer W3.
2. The control circuit of the automatic dimming welding mask of claim 1, wherein the filter circuit comprises a capacitor C1, a capacitor C2, a resistor R2 and a resistor R3, the capacitor C1 and the resistor R2 are connected in series and then connected with one end of R3 and one end of C2, the other end of R3 is grounded, and the other end of C2 is connected with the negative input ends of an operational amplifier U1A and an operational amplifier U1B respectively.
3. The control circuit for an automatic darkening welding helmet of claim 1, wherein the LCD drive frequency and drive timing circuit comprises U4, U4 is comprised of three 2-input schmitt trigger circuits, each of which is a 2-input nand gate with schmitt trigger function, nand gate U4B, nand gate U4A, nand gate U4C;
the nand gate U4B is used for signal inversion, and when the input signal is at high level, the output is at low level, whereas when the input is at low level, the output is at high level;
the NAND gate U4A is used as a self-oscillation circuit, the U4A, the R8 and the C7 form an oscillation circuit, square wave signals are generated, and the frequency of the square wave is determined by the capacitance value of the capacitor C7 and the resistance value of the resistor R8;
the nand gate U4C is used for signal inversion, and the output of the nand gate U4C is controlled by the output of U4A and is inverted from the output of U4A.
4. Control circuit for automatic darkening welding helmets according to claim 1, characterized in that the LCD drive voltage regulating circuit (5) comprises a low power operational amplifier U2, the output and negative input of which are connected to the output of the low power operational amplifier U2 and to the input of the LCD drive circuit (6);
the positive input end of the low-power-consumption operational amplifier U2 is connected with one end of a potentiometer W1B, the other end of the potentiometer W1B is connected with a circuit power supply voltage VCC through a pull-up resistor R15, and the output end of the low-power-consumption operational amplifier U2 is connected with the input end of an LCD driving circuit (6) and provides a driving voltage for the LCD driving circuit (6).
5. The control circuit of the automatic dimming welding mask according to claim 4, wherein the positive and negative voltage conversion circuit (7) comprises an integrated voltage conversion chip U6, U6 adopts a chip ICL7660AIBAZ, 5 pins corresponding to VOUT of U6 are connected with GND end of a low power consumption operational amplifier U2 through two serially connected diodes, anode of the diode is connected with GND end of the low power consumption operational amplifier U2, cathode of the diode is connected with 5 pins corresponding to VOUT of U6, 2 pin corresponding to CAP + of U6 is connected with input end of a negative voltage doubling circuit (8), 4 pin corresponding to CAP of U6 is connected with input end of the negative voltage doubling circuit (8) through a capacitor E1.
6. The control circuit of the automatic darkening welding helmet according to claim 4, wherein the negative voltage doubler circuit (8) is used to provide a negative level for the output chip of the LCD driver circuit (6), and comprises U4D and a doubler rectifier unit, U4D is a 2-input nand gate with a schmitt trigger function at 2 inputs, and the output of U4D is connected to the input of the doubler rectifier unit;
the voltage-multiplying rectifying unit comprises a bootstrap booster circuit consisting of 8 diodes and 7 capacitors, and the output of the voltage-multiplying rectifying circuit is connected to the negative level VEE end of an output chip U3 of the LCD driving circuit (6).
7. The control circuit of the automatic darkening welding helmet of claim 4, wherein the LCD driving circuit (6) uses an output chip U3, the U3 uses a two-way 4-channel digital control analog switch MC14052BG, and the output terminals Za, Zb of the output chip U3 are connected to the LCD.
8. The control circuit of the automatic light-changing welding mask according to claim 4, wherein the power circuit (1) comprises a power voltage stabilizing circuit, the power voltage stabilizing circuit comprises a power voltage stabilizing chip U5 and a triode J6, a collector of the triode J6 is connected with an anode of a battery BAT, a cathode of the battery BAT is grounded, a base of the triode J6 is connected with an anode of a solar battery, a cathode of the solar battery is grounded, a collector of the triode J6 is connected with an input end of a power voltage stabilizing chip U5, the power voltage stabilizing chip U5 adopts a low dropout linear regulator HT7130-1, an output end of the power voltage stabilizing chip U5 is connected with one end of a capacitor E5 and a switch W1B, the other end of the capacitor E5 is grounded, and the other end of the switch W1B is connected with a power supply voltage VCC of the circuit.
9. The control circuit of the automatic dimming welding mask as claimed in claim 4, wherein the power circuit (1) further comprises a battery under-voltage reminding circuit, the battery under-voltage reminding circuit comprises a low-voltage detection chip U7, a resistor R9 and a light-emitting diode LED1, the low-voltage detection chip U7 adopts a chip XC61CC2502MR, a pin 1 of the chip XC61CC2502MR is connected with one end of a resistor R9, a pin 3 of the chip XC61CC2502MR is connected with the battery voltage VBAT and the anode of the light-emitting diode LED1, the cathode of the light-emitting diode LED1 is connected with the other end of the resistor R9, and a pin 2 of the chip XC61CC2502MR is grounded.
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| CN117155186B (en) * | 2023-07-31 | 2024-07-05 | 荣耀终端有限公司 | Motor system, voltage doubling circuit, motor control method and electronic equipment |
| CN118162723A (en) * | 2024-04-16 | 2024-06-11 | 苏州绿恺动力电子科技有限公司 | Welding machine control circuit |
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| US6815652B1 (en) * | 2000-09-11 | 2004-11-09 | Jackson Products, Inc. | Low power phototransistor-based welding helmet providing reduced sensitivity to low intensity light and sharp phototransistor response to high intensity light |
| US6841772B1 (en) * | 2001-05-05 | 2005-01-11 | Jackson Products, Inc. | Eye-protection device having dual high voltage switching |
| KR100635071B1 (en) * | 2004-12-30 | 2006-10-16 | 서운수 | A Control Circuit For Automatic Darkening Welding Helmet |
| CN2787186Y (en) * | 2005-04-15 | 2006-06-14 | 王修建 | Automatic light-changing electric welding protective mask |
| CN201058071Y (en) * | 2006-11-08 | 2008-05-14 | 江西亨泰科技有限公司 | Control circuit for full digital type automatic light-changing welding face mask |
| CN201139682Y (en) * | 2007-11-09 | 2008-10-29 | 中原工学院 | Microcontroller controlled eye protector for welder automatically changing light |
| CN203042627U (en) * | 2012-12-12 | 2013-07-10 | 北京工业大学 | Automatic darkening weld cap device with double protection functions |
| CN204050007U (en) * | 2014-07-14 | 2014-12-31 | 宁波吉欧光电科技有限公司 | Intelligent digitalized automatic beam change welding filter |
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