CN215934449U - Overvoltage protection and undervoltage protection circuit of electric welding machine - Google Patents
Overvoltage protection and undervoltage protection circuit of electric welding machine Download PDFInfo
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- CN215934449U CN215934449U CN202121789292.3U CN202121789292U CN215934449U CN 215934449 U CN215934449 U CN 215934449U CN 202121789292 U CN202121789292 U CN 202121789292U CN 215934449 U CN215934449 U CN 215934449U
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Abstract
The utility model relates to an overvoltage protection and undervoltage protection circuit of an electric welding machine, which comprises a protection chip and a feedback winding, wherein the protection chip is connected with the feedback winding; an output control pin of the protection chip is connected with a grounding end of the primary winding and used for controlling the primary winding through a switch; the rectified bus voltage is coupled to a feedback winding through a primary winding of a transformer, a generated feedback signal is divided by a voltage dividing circuit and then is input to an over-voltage and under-voltage protection pin to detect the Idem current flowing into the chip, and when the Idem current is greater than or less than an input over-voltage protection current threshold value or an input under-voltage protection current threshold value of the protection chip, the input over-voltage protection and under-voltage protection functions of the chip are triggered; and the output of the power tube of the protection chip is turned off, so that the auxiliary power output voltage is turned off, the power supply of the main chip of the electric welding machine is further turned off, the PWM output signal and the driving circuit of the electric welding machine are turned off, and the functions of inputting overvoltage protection and undervoltage protection are achieved.
Description
Technical Field
The utility model relates to the field of overvoltage and undervoltage protection circuits, in particular to an overvoltage protection and undervoltage protection circuit of an electric welding machine.
Background
The input voltage of the single-phase electric welding machine is generally 220VAC, and when the input power grid fluctuates, the input voltage can be higher than 220VAC, and sometimes the input voltage can be higher than 300 VAC. When the welder is connected with wrong high input voltage and the welder does not have input overvoltage protection, the damage of power switching devices (IGBT, MOS tube and the like) is easily caused. Many current welding machines have the problems that overvoltage protection does not exist, or overvoltage protection is simple, overvoltage protection voltage precision is not enough, and the like.
SUMMERY OF THE UTILITY MODEL
In view of this, an object of the present invention is to provide an overvoltage protection and undervoltage protection circuit for an electric welding machine, which performs input overvoltage and undervoltage protection for the electric welding machine through input undervoltage protection of an auxiliary power supply chip, and can turn off an output voltage when an input voltage is higher than a set value, thereby turning off a drive of a power tube, playing a role in protecting a power switch device, and having characteristics of good stability and high precision.
The utility model relates to an overvoltage protection and undervoltage protection circuit of an electric welding machine, which comprises a transformer, a protection chip and a feedback winding, wherein the feedback winding is coupled with a primary winding of the transformer, one end of the feedback winding is grounded, the other end of the feedback winding is grounded through a feeder line, the feeder line is provided with a voltage division circuit, the voltage division circuit is connected to an overvoltage and undervoltage protection pin of the protection chip, and the feeder line is used for inputting a feedback signal subjected to voltage division to the overvoltage and undervoltage protection pin of the protection chip; and an output control pin of the protection chip is connected with the grounding end of the primary winding and is used for controlling the primary winding in a switching mode.
Further, the protection chip is a switching power supply chip.
Furthermore, the voltage dividing circuit comprises a first voltage dividing resistor and a second voltage dividing resistor which are arranged on the feeder line in series, and an overvoltage and undervoltage protection pin of the protection chip is connected between the first voltage dividing resistor and the second voltage dividing resistor.
Furthermore, an output circuit is arranged on a secondary winding of the transformer and connected with a feedback pin of the protection chip through an optical coupler.
Further, the protection chip takes electricity from a primary winding of the transformer.
The utility model has the beneficial effects that: according to the overvoltage protection and undervoltage protection circuit of the electric welding machine, a primary winding of a transformer is rectified through a rectifier, rectified bus voltage is coupled to a feedback winding through the primary winding of the transformer, a generated feedback signal is divided by a voltage dividing circuit and then input to an overvoltage and undervoltage protection pin to detect Idem current flowing into a chip, and when the Idem current is larger than an input overvoltage protection current threshold value of a protection chip, an input overvoltage protection function of the chip is triggered; when the Idem current is smaller than the input undervoltage protection current threshold of the protection chip, triggering the input undervoltage protection function of the protection chip; when the overvoltage protection function and the undervoltage protection function of the protection chip are triggered, the output of the power tube of the protection chip is cut off, so that the auxiliary power output voltage is cut off, the power supply of the main chip of the electric welding machine is further cut off, the PWM output signal and the driving circuit of the electric welding machine are cut off, and the functions of inputting overvoltage protection and undervoltage protection are achieved,
drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and that for a person skilled in the art, other relevant drawings can be obtained from the drawings without inventive effort:
FIG. 1 is a signal flow diagram of the feedback winding and feed line of the present invention;
fig. 2 is a schematic structural diagram of the present invention.
Detailed Description
As shown in fig. 1-2: the overvoltage protection and undervoltage protection circuit of the electric welding machine comprises a transformer T1, a protection chip U1 and a feedback winding Nf, wherein the protection chip U1 is a switching power supply chip, a power supply pin VDD of the protection chip U1 is connected to a bus of the transformer T1 and takes power from a primary winding Np of a transformer T1, the feedback winding Nf is coupled with the primary winding Np of a transformer T1, one end of the feedback winding Nf is grounded, the other end of the feedback winding Nf is provided with a feeder line, the feeder line is grounded after being connected in series with a first divider resistor R6 and a second divider resistor R7, an overvoltage and undervoltage protection pin DEM of a protection chip U1 is connected between the first divider resistor R6 and the second divider resistor R7, and the feeder line is used for inputting a feedback signal after voltage division to the overvoltage and undervoltage protection pin of the protection chip U1; an output control pin (power tube Drain) Drain of the protection chip U1 is connected to the ground terminal of the primary winding Np for switching control of the primary winding Np.
In addition, an output circuit is arranged on a secondary winding of the transformer T1, the output circuit is provided with two output ends according to different coil turns of the secondary winding, the input end of the optical coupler U2 is used for inputting the difference value to a feedback pin FB of the protection chip after comparing the difference value of the two output ends, the difference value is fed back to a bus of a primary winding Np of the transformer, and the output signal is fed back to the primary winding through acquiring an output signal, so that the output signal is more stable.
The specific implementation principle is as follows:
(1) the primary winding of the transformer T1 is rectified by a bridge rectifier;
(2) the rectified bus voltage Vbus is coupled to a feedback winding Nf through a primary winding Np of a transformer, and a generated feedback signal Vf is divided by a first voltage dividing resistor R6 and a second voltage dividing resistor R7, converted into a current signal Idem and then input to an overvoltage and undervoltage protection pin DEM;
(3) the protection chip U1 detects the Idem current flowing into the chip, and when the Idem current is larger than the input overvoltage protection current threshold of the protection chip U1, the input overvoltage protection function of the chip is triggered; when the Idem current is smaller than the input undervoltage protection current threshold of the protection chip, triggering the input undervoltage protection function of the protection chip; when the overvoltage protection function and the undervoltage protection function of the protection chip are triggered, the output of a power tube inside the protection chip is turned off (namely the Drain and the source of an MOS tube inside the protection chip are turned off), because the grounding end of the primary coil Np is connected with a Drain pin of the protection chip, which is equivalent to the Drain of the MOS tube inside the protection chip U1, the electric signal of the primary coil cannot flow from the Drain to the emitter (namely a CS pin), and thus the primary winding Np is turned off;
(4) after the primary winding Np is closed, the output circuit of the secondary coil cannot supply power to the main chip of the electric welding machine, so that the functions of input overvoltage protection and undervoltage protection are achieved.
Finally, the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all of them should be covered in the claims of the present invention.
Claims (5)
1. The utility model provides an overvoltage protection and undervoltage protection's of electric welding circuit which characterized in that: the over-voltage and under-voltage protection circuit comprises a transformer, a protection chip and a feedback winding, wherein the feedback winding is coupled with a primary winding of the transformer, one end of the feedback winding is grounded, the other end of the feedback winding is grounded through a feeder line, a voltage division circuit is arranged on the feeder line and is connected to an over-voltage and under-voltage protection pin of the protection chip, and the feeder line is used for inputting a feedback signal subjected to voltage division to the over-voltage and under-voltage protection pin of the protection chip; and an output control pin of the protection chip is connected with the grounding end of the primary winding and is used for controlling the primary winding in a switching mode.
2. The circuit for the over-voltage protection and the under-voltage protection of the electric welding machine according to claim 1, characterized in that: the protection chip is a switching power supply chip.
3. The circuit for the over-voltage protection and the under-voltage protection of the electric welding machine according to claim 1, characterized in that: the voltage dividing circuit comprises a first voltage dividing resistor and a second voltage dividing resistor which are arranged on the feeder line in series, and an overvoltage and undervoltage protection pin of the protection chip is connected between the first voltage dividing resistor and the second voltage dividing resistor.
4. The circuit for the over-voltage protection and the under-voltage protection of the electric welding machine according to claim 1, characterized in that: and an output circuit is arranged on a secondary winding of the transformer and is connected with a feedback pin of the protection chip through an optical coupler.
5. The circuit for the over-voltage protection and the under-voltage protection of the electric welding machine according to claim 1, characterized in that: the protection chip takes electricity from the primary winding of the transformer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121789292.3U CN215934449U (en) | 2021-08-03 | 2021-08-03 | Overvoltage protection and undervoltage protection circuit of electric welding machine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121789292.3U CN215934449U (en) | 2021-08-03 | 2021-08-03 | Overvoltage protection and undervoltage protection circuit of electric welding machine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN215934449U true CN215934449U (en) | 2022-03-01 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202121789292.3U Active CN215934449U (en) | 2021-08-03 | 2021-08-03 | Overvoltage protection and undervoltage protection circuit of electric welding machine |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN215934449U (en) |
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2021
- 2021-08-03 CN CN202121789292.3U patent/CN215934449U/en active Active
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