CN206117116U - Over -voltage and under -voltage protection circuit - Google Patents
Over -voltage and under -voltage protection circuit Download PDFInfo
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- CN206117116U CN206117116U CN201621037968.2U CN201621037968U CN206117116U CN 206117116 U CN206117116 U CN 206117116U CN 201621037968 U CN201621037968 U CN 201621037968U CN 206117116 U CN206117116 U CN 206117116U
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Abstract
The utility model relates to an over -voltage and under -voltage protection circuit. Over -voltage and under -voltage protection circuit includes rectifier module, partial pressure sampling module, overvoltage protection module, under -voltage protection module, control module, switch module. Wherein, the overvoltage protection module is through judging, when a sample voltage of input is greater than reference voltage ( overpressure condition ), control module control switch module switches on, with the commercial power disconnection that the switch module is connected, no longer supplies power to the load to reach the effect of protection load. Under -voltage protection module is through judging, when the 2nd sample voltage of input is lighter than reference voltage ( undervoltage condition ), control module control switch module switches on, with the commercial power disconnection that the switch module is connected, no longer supplies power to the load to reach the effect of protection load. The effect of protection load just can be reached through the aforesaid control over -voltage and under -voltage protection circuit simple, small, with low costs.
Description
Technical Field
The utility model relates to a power protection circuit especially relates to excessive pressure undervoltage protection circuit.
Background
The laser welding is a novel welding process and has the characteristics of high welding energy density, small heat influence range, small deformation and exquisite welding line. The laser welding technology has a molten pool purification effect, can purify welding materials, is particularly beneficial to welding of the same or different materials, and is suitable for welding of materials such as the same or different metal materials and plastics. The welding stability may be affected by the interference of power supply signals of a power grid in the laser welding process, and if a laser power supply is in overvoltage, a laser is fatally damaged; meanwhile, the undervoltage input of the power grid may cause stress aggravation of the laser power supply module, increase of the input power supply, and accelerate of the service life of the damage power supply, so that the stability of the laser is affected.
The traditional laser power supply over-voltage and under-voltage protection is to perform over-voltage and under-voltage treatment by using an over-voltage and under-voltage protector or by using a mode of comparing two operational amplifiers and the like. However, the above-mentioned over-under-voltage processing method has high cost, many elements, large volume and complicated control.
SUMMERY OF THE UTILITY MODEL
In view of the above, there is a need to provide an undervoltage protection circuit with simple control, small size and low cost.
An overvoltage and undervoltage protection circuit comprises a rectification filtering module, a partial pressure sampling module, an overvoltage protection module, an undervoltage protection module, a control module and a switch module;
the rectification filter module is connected with a mains supply and is used for outputting a stable voltage value;
the partial pressure sampling module includes: the input end is connected with the output end of the rectification filter module, the first output end is used for outputting a first sampling voltage, and the second output end is used for outputting a second sampling voltage;
the first output end, the overvoltage protection module, the control module and the switch module are sequentially connected;
the second output end, the under-voltage protection module, the control module and the switch module are connected in sequence; wherein,
the overvoltage protection module and the undervoltage protection module are used for respectively judging the sizes of the first sampling voltage, the second sampling voltage and the reference voltage;
the control module is used for controlling the switch module to be switched on when the first sampling voltage is greater than the reference voltage, so that the commercial power connected with the switch module is disconnected; and when the second sampling voltage is less than the reference voltage, controlling the switch module to be switched on to disconnect the commercial power connected with the switch module.
In one embodiment, the voltage division sampling module comprises a first resistor, a second resistor and a third resistor; one end of the first resistor is connected with the output end of the rectification filter module, and the other end of the first resistor is respectively connected with the second resistor and the third resistor;
the other end of the second resistor is connected with the input end of the overvoltage protection module;
the other end of the third resistor is connected with the input end of the undervoltage protection module.
In one embodiment, the overvoltage protection module comprises a fourth resistor, a fifth resistor and a first three-terminal adjustable shunt reference source;
the fourth resistor is grounded through the fifth resistor, and the other end of the fourth resistor is connected with the second resistor and a first input end used for receiving a judgment signal of the overvoltage protection module in the control module respectively;
the reference end of the first three-end adjustable shunt reference source is connected with the connection point of the fourth resistor and the fifth resistor; the cathode of the first three-terminal adjustable shunt reference source is connected with the first input end of the control module, and the anode of the first three-terminal adjustable shunt reference source is grounded.
In one embodiment, the overvoltage protection module comprises a sixth resistor, a seventh resistor and a second three-terminal adjustable shunt reference source;
the first end of the sixth resistor is connected with the reference end of the second three-end adjustable shunt reference source; a second end of the sixth resistor is connected with the third resistor and the seventh resistor respectively; the other end of the seventh resistor is grounded; the cathode of the second three-end adjustable shunt reference source is connected with a second input end of the control module, which is used for receiving the judgment signal of the undervoltage protection module; and the anode of the second three-end adjustable shunt reference source is grounded.
In one embodiment, the control module comprises a photoelectric coupler, an eighth resistor and a ninth resistor;
the anode of the luminous source of the photoelectric coupler is respectively connected with the partial pressure sampling module and the overvoltage protection module through the eighth resistor, and the cathode of the luminous source of the photoelectric coupler is connected with the undervoltage protection module;
one end of a light receiver of the photoelectric coupler is connected with a direct-current power supply through the ninth resistor; and the output end of a light receiver of the photoelectric coupler is connected with the switch module.
In one embodiment, the power supply further comprises a shunt module, wherein the shunt module comprises a first triode and a second triode;
the base electrode of the first triode is connected with the emitting electrode of the second triode, and the emitting electrode of the first triode is respectively connected with the first input end of the control module, the partial pressure sampling module and the overvoltage protection module; the collector of the first triode is respectively connected with the base of the second diode and the output end of the undervoltage protection module; and the collector electrode of the second triode is connected with the input end of the undervoltage protection module.
In one embodiment, the shunt module further comprises a tenth resistor, an eleventh resistor and a twelfth resistor;
the tenth resistor is connected in series between the base electrode and the emitting electrode of the first triode; one end of the eleventh resistor is connected with the voltage division sampling module, and the other end of the eleventh resistor is connected with the output end of the undervoltage protection module; the twelfth resistor is connected in series between the collector of the first triode and the output end of the undervoltage protection module.
In one embodiment, the switch module comprises a third triode, a relay and a thirteenth resistor;
the base electrode of the third triode is connected with the output end of the light receiver of the photoelectric coupler, the collector electrode of the third triode is grounded, and the emitter electrode of the third triode is connected with a direct-current power supply through the thirteenth resistor and the electronic coil of the relay;
the normally closed switch of the relay is connected between the commercial power and the load in series, and is disconnected when the electronic coil of the relay is electrified; the base electrode of the triode is the input end of the switch module, and the normally closed switch of the relay is the output end of the switch module.
In one embodiment, the switch module further includes a fourteenth resistor, one end of the fourteenth resistor is connected to the anode of the third transistor, and the other end of the fourteenth resistor is grounded.
In one embodiment, the third transistor is a PNP transistor.
In the overvoltage and undervoltage protection circuit, the voltage division sampling module comprises an input end connected with an output end of the rectification filter module, a first output end used for outputting the first sampling voltage and a second output end used for outputting the second sampling voltage. The overvoltage protection module and the undervoltage protection module are used for respectively judging the sizes of the first sampling voltage, the second sampling voltage and the reference voltage. The control module is used for controlling the switch module to be switched on when the first sampling voltage is greater than the reference voltage, so that the commercial power connected with the switch module is disconnected; when the second sampling voltage is smaller than the reference voltage, the switch module is controlled to be switched on, so that the commercial power connected with the switch module is disconnected, the load is not powered any more, and the effect of protecting the load is achieved. The overvoltage and undervoltage protection circuit with simple control, small volume and low cost can achieve the effect of protecting the load.
Drawings
FIG. 1 is a block diagram of an under-voltage and over-voltage protection circuit;
fig. 2 is a circuit diagram of an overvoltage-undervoltage protection voltage circuit.
Detailed Description
In order to facilitate understanding of the present invention, the present invention will be described more fully hereinafter with reference to the accompanying drawings. The preferred embodiments of the present invention are shown in the drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
Fig. 1 is a block diagram of an overvoltage and undervoltage protection circuit, which includes a rectifying and filtering module 110, a voltage division and sampling module 120, an overvoltage protection module 130, an undervoltage protection module 140, a control module 150, and a switch module 160. The rectifying and filtering module 110 is connected to the mains supply and is configured to output a stable voltage value. The voltage division sampling module 120 includes an input terminal connected to the output terminal of the rectifying and filtering module 110, a first output terminal for outputting a first sampling voltage, and a second output terminal for outputting a second sampling voltage to the overvoltage protection module 130. A first output end of the voltage division sampling module 120 is connected to an input end of the under-voltage protection module 140, and a second output end of the voltage division sampling module 120 is connected to an input end of the over-voltage protection module 130. The output ends of the overvoltage protection module 130 and the undervoltage protection module 140 are respectively connected with the input end of the control module 150; the overvoltage protection module 130 and the undervoltage protection module 140 are configured to respectively determine the first sampling voltage, the second sampling voltage, and the reference voltage. The output end of the control module 150 is connected to the switch module 160, and the control module 150 is used for controlling the on/off of the switch module 160, that is, for controlling the connection state between the output end of the switch module 160 and the commercial power. In this embodiment, the output terminal of the switch module 160 is connected to the laser power supply
By judging, when the input first sampling voltage is greater than the reference voltage (i.e., an overvoltage state), the overvoltage protection module 130 controls the switch module 160 to be turned on by the control module 150, and the commercial power connected to the switch module 160 is turned off, so that the load is no longer supplied with power, thereby achieving the effect of protecting the load. When the first sampling voltage is smaller than the reference voltage, the switch module 160 is turned on, and the commercial power supplies power to the load. By judging that the input second sampling voltage is smaller than the reference voltage (under-voltage state), the under-voltage protection module 140 controls the switch module 160 to be turned on by the control module 150, the commercial power connected to the switch module 160 is turned off, and no power is supplied to the load, so as to achieve the effect of protecting the load. When the second sampling voltage is greater than the reference voltage, the switch module 160 is turned on, and the commercial power supplies power to the load.
As shown in fig. 2, which is a circuit diagram of the under-voltage protection circuit, the rectifying and filtering module 110 includes a rectifying bridge D1 and a filtering capacitor C1. When the circuit is started, the current is rectified by the rectifier bridge D1 and then filtered by the filter capacitor C1, so that a stable voltage value U is obtained0And outputs the result to the divided voltage sampling module 120.
The voltage division and sampling module 120 includes a first resistor R1, a second resistor R2, and a third resistor R3. One end of the first resistor R1 is connected to the output end of the rectifying and filtering module 110, and the other end of the first resistor R1 is connected to the second resistor R2 and the third resistor R3, respectively. The other end of the second resistor R2 (as the first output end of the voltage division sampling module 120) is connected to the input end of the overvoltage protection module 130; the other end of the third resistor R3 (as the second output end of the voltage division sampling module 120) is connected to the input end of the undervoltage protection module 140.
The overvoltage protection module 130 includes a fourth resistor R4, a fifth resistor R5, and a first three-terminal adjustable shunt reference source U1. The fourth resistor R4 is grounded via the fifth resistor R5, and the other end of the fourth resistor R4 is connected to the second resistor R2 and the first input terminal of the control module 150, respectively. The reference end of the first three-end adjustable shunt reference source U1 is connected with the connection point of a fourth resistor R4 and a fifth resistor R5; the cathode of the first three-terminal adjustable shunt reference source U1 is connected to the first input terminal of the control module 150, and the anode of the first three-terminal adjustable shunt reference source U1 is grounded.
The overvoltage protection module 130 comprises a sixth resistor R6, a seventh resistor R7 and a second three-terminal adjustable shunt reference source U2. A first end of the sixth resistor R6 is connected with a reference end of the second three-end adjustable shunt reference source U1; a second end of the sixth resistor R6 is connected with the third resistor R3 and the seventh resistor R7 respectively; the other end of the seventh resistor R7 is connected to ground. The cathode of the second three-terminal adjustable shunt reference source U2 is connected with a second input end of the control module 150; the anode of the second three-terminal adjustable shunt reference source U2 is grounded. In this embodiment, the seventh resistor R7 is an adjustable resistor, and the voltage value across the seventh resistor can be adjusted.
The control module 150 includes a photo-coupler U3, an eighth resistor R8, and a ninth resistor R9. The photocoupler U3 is an electric-to-optical-to-electric conversion device that transmits an electric signal using light as a medium. It is composed of two parts of luminous source and light receiver. The light source and the light receiver are assembled in the same closed shell and are isolated from each other by a transparent insulator. In this embodiment, the light emitting source of the photocoupler U3 is a photo transistor, and the light receiving device of the photocoupler U3 is a photo transistor. The anode of the light emitting diode is connected with the second resistor R2 and the cathode of the first three-terminal adjustable shunt reference source U1 through the eighth resistor R8. The cathode of the light emitting diode is connected with the cathode of a second three-end adjustable shunt reference source U2; one end (collector of the phototriode) of a light receiver of the photoelectric coupler U3 is connected with a direct-current power supply VCC through a ninth resistor R9; the output terminal of the light receiver (emitter of the phototransistor) of the photocoupler U3 is connected to the input terminal of the switching module 160. In this embodiment, the dc power supply VCC is a 12-volt dc power supply.
The undervoltage overvoltage protection circuit further comprises a shunt module 170, and the shunt module 170 includes a first transistor Q1, a second transistor Q2, a tenth resistor R10, an eleventh resistor R11, and a twelfth resistor R12. In this embodiment, the first transistor Q1 and the second transistor Q2 are both PNP transistors. The base electrode of the first triode Q1 is connected with the emitter electrode of the second triode Q2, and the emitter electrode of the first triode Q1 is respectively connected with the eighth resistor R8, the second resistor R2 and the fourth resistor R4. The tenth resistor R10 is connected in series between the base and the emitter of the first transistor Q1. A collector of the first triode Q1 is connected with a base of the second diode Q2 and a cathode of a light emitting diode of the photoelectric coupler U3 and a cathode of a second three-end adjustable shunt reference source U2 through a twelfth resistor R12 respectively; the collector of the second triode Q2 is connected to the sixth resistor and the seventh resistor, respectively. One end of the eleventh resistor R11 is connected with the second resistor R2, and the other end of the eleventh resistor R11 is respectively connected with the cathode of the second three-terminal adjustable shunt reference source U2 and the twelfth resistor R12. When the shunt module 170 is in an under-voltage operating state, the shunt module can be used for sharing a part of current of the photoelectric coupler U3, so that an overcurrent protection effect is achieved.
The switching module 160 includes a third transistor Q3, a relay K1, and a fourteenth resistor R14. The third transistor Q3 is a PNP transistor. The base of the third triode Q3 is connected with the output end (the emitter of the phototriode) of the light receiver of the photocoupler U3, and the collector of the third triode Q3 is grounded. An emitter of the third transistor Q3 is connected to the dc power supply VCC via a thirteenth resistor R13 and an electric coil of the relay K1. The normally closed switch of the relay K1 is connected in series between the commercial power and the load, and when the electronic coil of the relay K1 is electrified, the normally closed switch of the relay K1 is disconnected; the base of the transistor Q3 is the input terminal of the switch module 160, and the normally closed switch of the relay K1 is the output terminal of the switch module 160. The fourteenth resistor R14 is a clamping resistor, one end of the fourteenth resistor R14 is connected to the anode of the third transistor Q3, and the other end of the fourteenth resistor R14 is grounded. When the photocoupler U3 is abnormal, the clamp resistor R14 of the photocoupler U3 has a protective effect on the third triode Q3.
The reference voltage of the reference end of the first three-end adjustable shunt reference source U1 is 2.5V, the first resistor R1 and the second resistor R2 in the voltage division sampling module 120 sample the rectified and filtered voltage Uo and output a first sampling voltage, and the first sampling voltage and the reference voltage are judged, if the first sampling voltage is less than 2.5V, the anode-cathode of the first three-end adjustable shunt reference source U1 is not conducted, the photocoupler U3 is normally conducted, the third triode Q3 is further controlled to be not conducted, the relay K1 does not work, and the input of the mains supply is kept; if the first sampling voltage is greater than 2.5V, the anode-cathode of the first three-end adjustable shunt reference source U1 is conducted, so that the photoelectric coupler U3 cannot be conducted, the third triode Q3 is controlled to be conducted, an electronic coil connected with the emitter of the third triode Q3 and the relay K1 is electrified, the normally closed switch of the relay K1 is disconnected, namely the commercial power and the load are disconnected, and the safety of power input of a laser is guaranteed later.
A first resistor R1 and a third resistor R3 in the voltage division sampling module 120 sample the rectified and filtered voltage Uo, output a second sampling voltage, and determine the magnitude of the second sampling voltage and the reference voltage, if the first sampling voltage is less than 2.5V, the anode-cathode of the first three-terminal adjustable shunt reference source U1 is not conducted, the primary side of the optoelectronic coupler U3 is not conducted, further control the conduction of the third triode Q3, an electronic coil of the relay K1 connected with the emitter of the third triode Q3 is powered on, and the normally closed switch of the relay K1 is turned off, that is. If the second sampling voltage is greater than 2.5V, the primary side of the photoelectric coupler U3 is turned on, and then the third triode Q3 is controlled not to be turned on, and K1 does not work, and the input of the commercial power supply is maintained.
Therefore, when the mains supply circuit is over-voltage or under-voltage, the over-voltage protection module 130 and the under-voltage protection module 140 correspondingly perform the action of controlling the switch module 160 to be on, so that the mains supply is disconnected from the load, and the safety of the laser power input is ensured.
When the first sampling voltage input by the overvoltage protection module 130 of the overvoltage and undervoltage protection circuit is greater than the reference voltage (overvoltage state), the control module 150 controls the switch module 160 to be turned on, the commercial power connected to the switch module 160 is turned off, and no power is supplied to the load, so as to achieve the effect of protecting the load. When the first sampling voltage is smaller than the reference voltage, the switch module 160 is turned on, and the commercial power supplies power to the load (laser power supply). When the second sampling voltage input by the under-voltage protection module 140 is smaller than the reference voltage (under-voltage state), the control module 150 controls the switch module 160 to be turned on, the commercial power connected to the switch module 160 is turned off, and no power is supplied to the load any more, so as to achieve the effect of protecting the load. When the second sampling voltage is greater than the reference voltage, the switch module 160 is turned on, and the commercial power supplies power to the load (laser power supply). Therefore, the laser power supply is protected when abnormal phenomena such as overvoltage and undervoltage occur, and the laser power supply is prevented from being damaged.
The overvoltage and undervoltage protection circuit has the advantages of simple control, small volume, low cost and the like, and protects the preceding power supply input of the laser power supply, thereby protecting the safety of the laser and improving the reliability of the laser power supply.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.
Claims (10)
1. An overvoltage and undervoltage protection circuit is characterized by comprising a rectification filtering module, a voltage division sampling module, an overvoltage protection module, an undervoltage protection module, a control module and a switch module;
the rectification filter module is connected with a mains supply and is used for outputting a stable voltage value;
the partial pressure sampling module includes: the input end is connected with the output end of the rectification filter module, the first output end is used for outputting a first sampling voltage, and the second output end is used for outputting a second sampling voltage;
the first output end, the overvoltage protection module, the control module and the switch module are sequentially connected;
the second output end, the under-voltage protection module, the control module and the switch module are connected in sequence; wherein,
the overvoltage protection module and the undervoltage protection module are respectively used for judging the magnitude of the first sampling voltage, the magnitude of the second sampling voltage and the magnitude of the reference voltage;
the control module is used for controlling the switch module to be switched on when the first sampling voltage is greater than the reference voltage, so that the commercial power connected with the switch module is disconnected; and when the second sampling voltage is less than the reference voltage, controlling the switch module to be switched on to disconnect the commercial power connected with the switch module.
2. The undervoltage protection circuit of claim 1, wherein the voltage-dividing sampling module comprises a first resistor, a second resistor, and a third resistor; one end of the first resistor is connected with the output end of the rectification filter module, and the other end of the first resistor is respectively connected with the second resistor and the third resistor;
the other end of the second resistor is connected with the input end of the overvoltage protection module;
the other end of the third resistor is connected with the input end of the undervoltage protection module.
3. The under-voltage and overvoltage protection circuit according to claim 2, wherein the over-voltage protection module comprises a fourth resistor, a fifth resistor and a first three-terminal adjustable shunt reference source;
the fourth resistor is grounded through the fifth resistor, and the other end of the fourth resistor is connected with the second resistor and a first input end used for receiving a judgment signal of the overvoltage protection module in the control module respectively;
the reference end of the first three-end adjustable shunt reference source is connected with the connection point of the fourth resistor and the fifth resistor; the cathode of the first three-terminal adjustable shunt reference source is connected with the first input end of the control module, and the anode of the first three-terminal adjustable shunt reference source is grounded.
4. The under-voltage and overvoltage protection circuit according to claim 2, wherein the over-voltage protection module comprises a sixth resistor, a seventh resistor and a second three-terminal adjustable shunt reference source;
the first end of the sixth resistor is connected with the reference end of the second three-end adjustable shunt reference source; a second end of the sixth resistor is connected with the third resistor and the seventh resistor respectively; the other end of the seventh resistor is grounded; the cathode of the second three-end adjustable shunt reference source is connected with a second input end, used for receiving a judgment signal of the undervoltage protection module, in the control module; and the anode of the second three-end adjustable shunt reference source is grounded.
5. The under-voltage and overvoltage protection circuit according to claim 1, wherein the control module comprises a photocoupler, an eighth resistor and a ninth resistor;
the anode of the luminous source of the photoelectric coupler is respectively connected with the partial pressure sampling module and the overvoltage protection module through the eighth resistor, and the cathode of the luminous source of the photoelectric coupler is connected with the undervoltage protection module;
one end of a light receiver of the photoelectric coupler is connected with a direct-current power supply through the ninth resistor; and the output end of a light receiver of the photoelectric coupler is connected with the switch module.
6. The under-voltage and over-voltage protection circuit according to claim 3, further comprising a shunt module, wherein the shunt module comprises a first transistor and a second transistor;
the base electrode of the first triode is connected with the emitting electrode of the second triode, and the emitting electrode of the first triode is respectively connected with the first input end of the control module, the partial pressure sampling module and the overvoltage protection module; the collector of the first triode is respectively connected with the base of the second triode and the output end of the undervoltage protection module; and the collector electrode of the second triode is connected with the input end of the undervoltage protection module.
7. The under-voltage and over-voltage protection circuit according to claim 6, wherein the shunt module further comprises a tenth resistor, an eleventh resistor and a twelfth resistor;
the tenth resistor is connected in series between the base electrode and the emitting electrode of the first triode; one end of the eleventh resistor is connected with the voltage division sampling module, and the other end of the eleventh resistor is connected with the output end of the undervoltage protection module; the twelfth resistor is connected in series between the collector of the first triode and the output end of the undervoltage protection module.
8. The undervoltage protection circuit of claim 5, wherein the switch module comprises a third transistor, a relay, and a thirteenth resistor;
the base electrode of the third triode is connected with the output end of the light receiver of the photoelectric coupler, the collector electrode of the third triode is grounded, and the emitter electrode of the third triode is connected with a direct-current power supply through the thirteenth resistor and the electronic coil of the relay;
the normally closed switch of the relay is connected between the commercial power and the load in series, and is disconnected when the electronic coil of the relay is electrified; the base electrode of the triode is the input end of the switch module, and the normally closed switch of the relay is the output end of the switch module.
9. The under-voltage and overvoltage protection circuit according to claim 8, wherein the switch module further comprises a fourteenth resistor, one end of the fourteenth resistor is connected to the anode of the third transistor, and the other end of the fourteenth resistor is grounded.
10. The undervoltage protection circuit of claim 8, wherein the third transistor is a PNP transistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621037968.2U CN206117116U (en) | 2016-09-05 | 2016-09-05 | Over -voltage and under -voltage protection circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621037968.2U CN206117116U (en) | 2016-09-05 | 2016-09-05 | Over -voltage and under -voltage protection circuit |
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| CN206117116U true CN206117116U (en) | 2017-04-19 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107069655A (en) * | 2017-06-06 | 2017-08-18 | 吉林省中赢高科技有限公司 | A kind of voltage protection circuit |
| CN111629162A (en) * | 2019-02-28 | 2020-09-04 | 青岛海尔多媒体有限公司 | Television control device, control method and television |
-
2016
- 2016-09-05 CN CN201621037968.2U patent/CN206117116U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107069655A (en) * | 2017-06-06 | 2017-08-18 | 吉林省中赢高科技有限公司 | A kind of voltage protection circuit |
| CN107069655B (en) * | 2017-06-06 | 2020-11-27 | 吉林省中赢高科技有限公司 | Voltage protection circuit |
| CN111629162A (en) * | 2019-02-28 | 2020-09-04 | 青岛海尔多媒体有限公司 | Television control device, control method and television |
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