CN217063251U - Load open circuit protection circuit - Google Patents
Load open circuit protection circuit Download PDFInfo
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- CN217063251U CN217063251U CN202220053920.XU CN202220053920U CN217063251U CN 217063251 U CN217063251 U CN 217063251U CN 202220053920 U CN202220053920 U CN 202220053920U CN 217063251 U CN217063251 U CN 217063251U
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Abstract
The utility model discloses a load open circuit protection circuit, which comprises a sampling module, a sampling module and a control module, wherein the sampling module is connected with a power supply voltage and is used for outputting a first sampling voltage when a load is connected or outputting a second sampling voltage when the load is open circuit; the protection module is connected with the sampling module and used for outputting a first control signal according to the first sampling voltage or outputting a second control signal according to the second sampling voltage; the second control signal is used for controlling the test equipment to stop working. The utility model discloses a control test equipment normal work when load access, control test equipment disconnection stop work when the load is opened circuit, form a positive feedback process, and then avoid test equipment still continuing work and appear taking some hot plug phenomenon behind the load disconnection, realized that test equipment does not insert the real-time quick protection when load or load put aside.
Description
Technical Field
The utility model relates to an electronic circuit technical field, in particular to load open circuit protection circuit and test equipment.
Background
In the production of electronic products, the electronic product test or inspection requires frequent access to equipment (which may be power supply or signal), and the safety is implemented by connecting the electronic product (referred to as a load, hereinafter referred to as a load in general) and then powering on the equipment, and before pulling out the load, the equipment needs to be turned off. However, in actual operation, the load is pulled out when the equipment is still working, so that the equipment is still in a working state, and hot plugging is performed when the load is connected again, so that the equipment or the load is easily damaged.
Thus, the prior art has yet to be improved and enhanced.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a load open circuit protection circuit can effectively avoid the hot plug phenomenon of test equipment when connecting the load, and then realizes the effective protection to load or test equipment.
In order to achieve the purpose, the utility model adopts the following technical proposal:
the embodiment of the application provides a load open circuit protection circuit, includes:
the sampling module is connected with a power supply voltage and used for outputting a first sampling voltage when a load is connected or outputting a second sampling voltage when the load is open;
the protection module is connected with the sampling module and used for outputting a first control signal according to the first sampling voltage or outputting a second control signal according to the second sampling voltage; the second control signal is used for controlling the test equipment to stop working.
In the load open-circuit protection circuit of some embodiments, the load open-circuit protection circuit further includes:
and the maintaining module is connected with the protection module, is connected with the power supply voltage, and is used for controlling the protection module to continuously output the second control signal according to the power supply voltage when the protection module outputs the second control signal.
In the load open-circuit protection circuit of some embodiments, the sampling module includes:
the sampling unit is connected to power supply voltage and used for outputting first sampling voltage according to current flowing through a load when the load is connected;
and the amplifying unit is connected with the sampling unit and is used for amplifying the first sampling voltage.
In the load open circuit protection circuit of some embodiments, the protection module includes:
the switch unit is connected with the sampling module and used for being switched on according to the first sampling voltage or being switched off according to the second sampling voltage;
and the protection unit is used for outputting a first control signal when the switch unit is switched on or outputting a second control signal when the switch unit is switched off.
In the load open-circuit protection circuit of some embodiments, the sampling unit includes a first resistor; when a load is connected, one end of the first resistor is connected to a power supply voltage, and the other end of the first resistor is connected with the amplifying unit and the load; when the load is in an open circuit, one end of the first resistor is connected to the power supply voltage, and the other end of the first resistor is connected with the amplifying unit.
In the load open-circuit protection circuit of some embodiments, the amplifying unit includes a first capacitor, a second capacitor and an operational amplifier, pin 3 of the operational amplifier is connected to the other end of the first resistor, pin 2 of the operational amplifier is connected to the power supply voltage, pin 7 of the operational amplifier and one end of the first capacitor are both connected to the positive terminal, pin 4 of the operational amplifier and one end of the second capacitor are both connected to the negative terminal, the output terminal of the operational amplifier is connected to the protection module, the other end of the first capacitor is grounded, and the other end of the second capacitor is grounded.
In the load open-circuit protection circuit of some embodiments, the switch unit includes a second resistor, a third resistor, a zener diode, and a first triode, one end of the second resistor is connected to the sampling module, the other end of the second resistor, one end of the third resistor, and a negative electrode of the zener diode are all connected to a base of the first triode, the other end of the third resistor and an anode of the zener diode are all grounded, an emitter of the first triode is grounded, and a collector of the first triode is connected to the protection unit.
In the load open-circuit protection circuit of some embodiments, the protection unit includes a fourth resistor, a second triode, and a diode; the base electrode of the second triode is connected with one end of the fourth resistor and the collector electrode of the first triode, the other end of the fourth resistor is connected with electricity, the collector electrode of the second triode is connected with the negative electrode of the diode, the emitting electrode of the second triode is grounded, and the positive electrode of the diode is connected with the enabling signal output end.
In the load open-circuit protection circuit of some embodiments, the maintaining module comprises a fifth resistor, a sixth resistor, a seventh resistor and a third triode; one end of a fifth resistor and one end of a seventh resistor are both connected with a power supply voltage, the other end of the fifth resistor and one end of a sixth resistor are both connected with the base electrode of a third triode, the other end of the seventh resistor is connected with the emitting electrode of the third triode and the other end of the fourth resistor, the other end of the sixth resistor is connected with the collector electrode of the second triode, and the collector electrode of the third triode is connected with the base electrode of the second triode.
In some embodiments, the load open protection circuit further includes a third transistor.
Compared with the prior art, the utility model provides a load open circuit protection circuit through control test equipment normal work when the load is cut in, then control test equipment disconnection stop work when the load is opened a way, forms a positive feedback process, and then avoids test equipment still continuing work and appear taking some hot plug phenomenon behind load disconnection, has realized that test equipment does not insert the real-time quick protection when load or load put aside.
Drawings
Fig. 1 is a block diagram of the load open circuit protection circuit provided by the present invention.
Fig. 2 is a block diagram of a maintaining module in the load open-circuit protection circuit according to the present invention.
Fig. 3 is a block diagram of the sampling module and the protection module in the load open circuit protection circuit provided by the present invention.
Fig. 4 is a schematic circuit diagram of the load open circuit protection circuit provided by the present invention.
Detailed Description
An object of the utility model is to provide a load open circuit protection circuit can effectively avoid the hot plug phenomenon of test equipment when connecting the load, and then realizes the effective protection to load or test equipment.
In order to make the purpose, technical solution and effect of the present invention clearer and clearer, the following description refers to the accompanying drawings and examples to further explain the present invention in detail. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the invention.
Referring to fig. 1, the present invention provides an open load protection circuit 10, in which the open load protection circuit 10 is connected to a testing device 30, and is used to effectively protect the testing device 30 or a load 20 according to the connection condition of the load 20. Specifically, the load open circuit protection circuit 10 includes a sampling module 100 and a protection module 200; the sampling module 100 is connected to a power supply voltage P _ OUT, and is configured to output a first sampling voltage when the load 20 is connected, or output a second sampling voltage when the load 20 is open; the protection module 200 is connected with the sampling module 100 and is used for outputting a first control signal according to the first sampling voltage or outputting a second control signal according to the second sampling voltage; wherein the second control signal is used to control the test equipment 30 to stop working.
Specifically, when the load 20 is connected, the sampling module 100 is connected to the load 20 at this time, and the current flowing through the sampling module 100 is the current of the load 20, then the sampling module 100 outputs a first sampling voltage according to the current of the load 20, where the first sampling voltage is not 0. When the load 20 is not open, the sampling module 100 has no current, and accordingly outputs the second sampling voltage, where the voltage value corresponding to the second sampling voltage is 0. If the sampling module 100 outputs the first sampling voltage, the protection module 200 outputs a first control signal according to the first sampling voltage, and if the sampling module 100 outputs the second sampling voltage, the protection module 200 outputs a second control signal according to the second sampling voltage, where the first control signal is an enable signal ENA with a high level in this embodiment to control the test equipment 30 to normally operate, and the enable signal ENA with a low level in the second control signal to control the test equipment 30 to stop operating. That is the utility model discloses a control test equipment 30 and normally work when load 20 inserts, then control test equipment 30 disconnection stop work when load 20 opens the way, form a positive feedback process, and then avoid test equipment 30 still continuing work and appear taking some hot plug phenomena behind load 20 disconnection, realized that test equipment 30 does not insert real-time quick protection, the no time delay when load 20 or load 20 put aside.
Further, referring to fig. 2 together, the load open-circuit protection circuit 10 further includes a maintaining module 300 connected to the protection module 200 and connected to the supply voltage VCC, for controlling the protection module 200 to continuously output the second control signal according to the supply voltage VCC when the protection module 200 outputs the second control signal, that is, when the load 20 of the testing device 30 is open and the protection module 200 controls the testing device 30 to stop working, the maintaining module 300 controls the protection module 200 to continuously output the second control signal, so that the testing device 30 stops working continuously, the working state of the testing device 30 is locked, and the working state is not recovered, thereby preventing the testing device 30 from being powered on and working without being connected to the load 20.
Further, referring to fig. 3, the sampling module 100 includes a sampling unit 110 connected to the power voltage P _ OUT, and configured to output a first sampling voltage according to a current flowing through the load 20 when the load 20 is connected; and an amplifying unit 120 connected to the sampling unit 110, for amplifying the first sampling voltage. When the load 20 is connected, the sampling unit 110 samples and outputs a first sampling voltage, and then the voltage is amplified by the amplifying unit 120 and then output to the protection module 200, so that the protection module 200 can effectively control the test equipment 30 to normally operate.
Further, the protection module 200 includes a switch unit 210 connected to the sampling module 100, and configured to be turned on according to the first sampling voltage or turned off according to the second sampling voltage; the protection unit 220 is configured to output a first control signal when the switching unit 210 is turned on, or output a second control signal when the switching unit 210 is turned off. When the load 20 is connected, the switch unit 210 is turned on, and the protection unit 220 correspondingly outputs a first control signal according to the feedback of the switch unit 210 to control the test equipment 30 to normally operate; when the load 20 is open-circuited, the switch unit 210 is turned off, and the protection unit 220 outputs a second control signal according to the feedback of the switch unit 210 to control the test equipment 30 to stop working, so as to achieve the purpose of open-circuit protection of the load 20.
Further, referring to fig. 4, the sampling unit 110 includes a first resistor R1; when the load 20 is connected, one end of the first resistor R1 is connected to the power voltage P _ OUT, and the other end of the first resistor R1 is connected to the amplifying unit 120 and the load 20; when the load 20 is open, one end of the first resistor R1 is connected to the power supply voltage P _ OUT, and the other end of the first resistor R1 is connected to the amplifying unit 120. The first resistor R1 in this embodiment is a sampling resistor, and when the load 20 is connected, the current flowing through the sampling resistor is the current of the load 20, and then a corresponding first sampling voltage is output to the amplifying unit 120 for amplification; when the load 20 is not connected, the current on the sampling resistor is 0, and then the corresponding second sampling voltage is 0, so that different sampling voltages are output according to the access state of the load 20 through the setting of the sampling circuit, so that the subsequent protection module 200 controls the working state of the test equipment 30 according to different sampling voltages, and a positive feedback control process is realized, thereby achieving the open-circuit protection effect of the load 20.
Furthermore, the amplifying unit 120 includes a first capacitor C1, a second capacitor C2, and an operational amplifier OP1, wherein the 3 rd pin of the operational amplifier OP1 is connected to the other end of the first resistor R1, the 2 nd pin of the operational amplifier OP1 is connected to the power voltage P _ OUT, the 7 th pin of the operational amplifier OP1 and one end of the first capacitor C1 are both connected to the positive terminal, the 4 th pin of the operational amplifier OP1 and one end of the second capacitor C2 are both connected to the negative terminal, the output terminal of the operational amplifier OP1 is connected to the protection module 200, the other end of the first capacitor C1 is grounded, and the other end of the second capacitor C2 is grounded. In this embodiment, the operational amplifier OP1 is a low-drift precision instrumentation amplifier, and the amplification factor thereof is determined by the resistance value connected between the 8 th pin and the 1 st pin of the operational amplifier OP1, when the 8 th pin and the 1 st pin of the operational amplifier OP1 are not connected with a resistor (open circuit), the amplification factor is 10, in this embodiment, the condition that the 8 th pin and the 1 st pin of the operational amplifier OP1 are not connected with a resistor is adopted to amplify the first sampling voltage, so as to facilitate the subsequent conduction of the control switch unit 210.
Furthermore, the switching unit 210 includes a second resistor R2, a third resistor R3, a zener diode ZD1, and a first transistor Q1, one end of the second resistor R2 is connected to the sampling module 100, the other end of the second resistor R2, one end of the third resistor R3, and a negative electrode of the zener diode ZD1 are all connected to a base of the first transistor Q1, the other end of the third resistor R3 and a positive electrode of the zener diode ZD1 are all grounded, an emitter of the first transistor Q1 is grounded, and a collector of the first transistor Q1 is connected to the protection unit 220; the arrangement of the zener diode ZD1 in this embodiment can effectively avoid the BE junction breakdown of the first triode Q1. When load 20 normally connects, sampling circuit has the electric current to flow through, first triode Q1 saturation this moment switches on, when load 20 disconnection, sampling resistor does not have the electric current, the last voltage drop of sampling resistor is 0, first triode Q1 ends this moment, from this through first triode Q1 the state alright with the connection condition of feedback load 20, circuit structure design is simple, and for the electric current that adopts singlechip to detect load 20, the operation output instruction through the singlechip cuts off output, the operation of singlechip has time, there is the time delay, the effect of real-time protection can not reach, the utility model discloses load 20 open circuit protection can reach the effect of real-time protection.
Further, the protection unit 220 includes a fourth resistor R4, a second transistor Q2, and a diode D1; the base of the second triode Q2 is connected with one end of a fourth resistor R4 and the collector of the first triode Q1, the other end of the fourth resistor R4 is connected with electricity, the collector of the second triode Q2 is connected with the negative electrode of a diode D1, the emitter of the second triode Q2 is grounded, and the anode of the diode D1 is connected with the output end of an enable signal ENA. When the first triode Q1 is turned on, the base of the second triode Q2 is at a low level, the second triode Q2 is turned off, so that the point a is at a high level, the enable signal ENA at this time is at a high level, and the enable signal ENA is set to be valid at a low level, so that the test equipment 30 can normally work by the enable signal ENA at the high level; when the first triode Q1 is turned off, the base of the second triode Q2 is at a high level, and the second triode Q2 is in saturation conduction, so that the point a is at a low level, and since the device is set to be enabled at a low level, the testing device 30 is turned off at this moment according to the enable signal ENA, and further, the working state of the testing device 30 is effectively controlled.
Furthermore, the sustain module 300 includes a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, and a third transistor Q3; one end of a fifth resistor R5 and one end of a seventh resistor R7 are both connected to a power supply voltage VCC, the other end of the fifth resistor R5 and one end of a sixth resistor R6 are both connected with the base of a third triode Q3, the other end of the seventh resistor R7 is connected with the emitter of the third triode Q3 and the other end of a fourth resistor R4, the other end of the sixth resistor R6 is connected with the collector of a second triode Q2, and the collector of the third triode Q3 is connected with the base of a second triode Q2; in this embodiment, the third transistor Q3 is a PNP transistor. When the second transistor Q2 is turned on in saturation, the third transistor Q3 is turned on in saturation, the power supply voltage VCC is continuously applied to the base of the second transistor Q2, the base of the second transistor Q2 is clamped at a high level, and the second transistor Q2 is turned on continuously, so that the enable signal ENA is continuously at a low level, and the corresponding testing device 30 continues to stop working and does not recover.
In order to further understand the working principle of the load open-circuit protection circuit of the present invention, the working process of the load open-circuit protection circuit provided by the present invention is described in detail with reference to fig. 4:
the working current of the load 20 is set to be 1A, and the resistance value of the sampling resistor is 0.2 Ω. When the load 20 is connected, the current flowing through the sampling resistor is 1A, the voltage difference U between two ends of the sampling resistor is 1A × 0.2 Ω ═ 0.2V, the first sampling voltage received by the switching unit 210 after being amplified by the operational amplifier OP1 is 2V, and Vb1 obtained after voltage division by the second resistor R2 and the third resistor R3 is 1.5V or more and 0.7V (the PN junction voltage drop between the zener diode ZD1 and B-E of the first triode Q1 is not considered, the zener value ZD of the zener diode 1 is taken as 1V), and at this time, the first triode Q1 is in saturated conduction; when the load 20 is not connected, at this time, no current passes through the sampling resistor, the voltage drop across the sampling resistor is not 0, the voltage received by the switching unit 210 after passing through the operational amplifier OP1 is 0, at this time, Vb1 is 0, at this time, the first triode Q1 is turned off, Vb2 is at a high level, the second triode Q2 is in saturation conduction, at this time, the point a is at a low level, the enable signal ENA is at a low level, and since the test equipment 30 sets that the low level enable is valid, the test equipment 30 is turned off, thereby achieving the purpose of open-circuit protection of the load 20. When the second transistor Q2 is in saturation conduction, the fifth resistor R5 and the sixth resistor R6 divide the power supply voltage VCC, the divided voltage value is 1/2 power supply voltage VCC (generally, the power supply voltage VCCVCC is 3.3V), since Veb of the third diode D1 is greater than 0.7V, at this time, the third transistor Q3 is in conduction saturation, the power supply voltage VCC is continuously applied to the base of the second transistor Q2, so that the base of the second transistor Q2 is clamped at a high level, the second transistor Q2 is continuously conducted, and at this time, the influence of the load 20 and the test equipment 30 is not received, the enable signal ENA is kept at a low level, the control terminal of the test equipment 30 is locked, and the test equipment 30 continues to stop working and does not recover.
The load open-circuit protection circuit 10 in this embodiment may be applied to a screen test in a screen module production line: during commissioning of the panel module, an external contact screen is required to operate the panel, wherein the electrical screen is equivalent to the test equipment 30 and the panel is equivalent to the load 20. Since the external contact screens are frequent, the accesses are all carried out by plugging and unplugging through connecting wires. Firstly, the connecting line plugs are easily worn and disconnected by repeated plugging and unplugging, so that abnormal connection (disconnection or short circuit) is caused, and test misjudgment is caused; secondly, because some screen wares are energy supply equipment, just can the circular telegram after guaranteeing that the connecting wire connects the screen well, among the actual operation, because the operator forgets when pulling out the connecting wire after the last test and closes some screen wares, make some screen wares still be in the on-state, and then carried out electrified hot plug when reinserting the connecting wire and inserted, because electrified hot plug very easily produces spark or electrostatic damage screen or some screen wares, perhaps because the plug wearing and tearing of connecting wire cause contact failure, after inserting, it also can produce spark or electrostatic and cause screen or some screen wares to damage to open some screen wares. Therefore, through the arrangement of the load open-circuit protection circuit 10 in the embodiment, after the screen is connected through the connecting line, the point screen device normally works, after the connecting line of the screen is pulled out, the point screen device is disconnected to work under the protection effect of the load open-circuit protection circuit 10, and is continuously kept in a disconnected state until the connecting line is inserted again, so that the hot plug phenomenon of live lines can be avoided, and the damage of the point screen device and the screen of the screen during the test of the screen is avoided.
To sum up, the utility model provides a load open circuit protection circuit, including the sampling module, insert mains voltage for output first sampling voltage when the load inserts, or output second sampling voltage when the load opens a way; the protection module is connected with the sampling module and used for outputting a first control signal according to the first sampling voltage or outputting a second control signal according to the second sampling voltage; the second control signal is used for controlling the test equipment to stop working. The utility model discloses a control test equipment normal work when load access, control test equipment disconnection stop work when the load is opened circuit, form a positive feedback process, and then avoid test equipment still continuing work and appear taking some hot plug phenomenon behind the load disconnection, realized that test equipment does not insert the real-time quick protection when load or load put aside.
It should be understood that equivalents and modifications may be made thereto by those skilled in the art, and all such modifications and alterations are intended to fall within the scope of the appended claims.
Claims (4)
1. A load open circuit protection circuit, comprising:
the sampling module is connected with a power supply voltage and used for outputting a first sampling voltage when a load is connected or outputting a second sampling voltage when the load is open;
the protection module is connected with the sampling module and used for outputting a first control signal according to the first sampling voltage or outputting a second control signal according to the second sampling voltage; the second control signal is used for controlling the test equipment to stop working;
the sampling module comprises:
the sampling unit is connected with a power supply voltage and used for outputting a first sampling voltage according to current flowing through a load when the load is connected;
the amplifying unit is connected with the sampling unit and is used for amplifying the first sampling voltage;
the sampling unit comprises a first resistor; when the load is connected, one end of the first resistor is connected to the power supply voltage, and the other end of the first resistor is connected with the amplifying unit and the load; when the load is in an open circuit, one end of the first resistor is connected to the power supply voltage, and the other end of the first resistor is connected with the amplifying unit; the amplifying unit comprises a first capacitor, a second capacitor and an operational amplifier, wherein a pin 3 of the operational amplifier is connected with the other end of the first resistor, a pin 2 of the operational amplifier is connected with the power supply voltage, a pin 7 of the operational amplifier and one end of the first capacitor are both connected with a positive electrode electric connection end, a pin 4 of the operational amplifier and one end of the second capacitor are both connected with a negative electrode electric connection end, the output end of the operational amplifier is connected with the protection module, the other end of the first capacitor is grounded, and the other end of the second capacitor is grounded;
the protection module includes:
the switching unit is connected with the sampling module and used for switching on according to the first sampling voltage or switching off according to the second sampling voltage;
the protection unit is used for outputting a first control signal when the switch unit is switched on or outputting a second control signal when the switch unit is switched off;
the switching unit comprises a second resistor, a third resistor, a voltage stabilizing diode and a first triode, one end of the second resistor is connected with the sampling module, the other end of the second resistor, one end of the third resistor and the negative electrode of the voltage stabilizing diode are all connected with the base electrode of the first triode, the other end of the third resistor and the positive electrode of the voltage stabilizing diode are all grounded, the emitting electrode of the first triode is grounded, and the collecting electrode of the first triode is connected with the protection unit; the protection unit comprises a fourth resistor, a second triode and a diode; the base electrode of the second triode is connected with one end of the fourth resistor and the collector electrode of the first triode, the other end of the fourth resistor is connected with electricity, the collector electrode of the second triode is connected with the negative electrode of the diode, the emitting electrode of the second triode is grounded, and the positive electrode of the diode is connected with the enabling signal output end.
2. The load open circuit protection circuit according to claim 1, further comprising:
and the maintaining module is connected with the protection module, is connected with the power supply voltage, and is used for controlling the protection module to continuously output the second control signal according to the power supply voltage when the protection module outputs the second control signal.
3. The load open circuit protection circuit according to claim 2, wherein the maintaining module comprises a fifth resistor, a sixth resistor, a seventh resistor and a third triode; one end of the fifth resistor and one end of the seventh resistor are both connected to the power supply voltage, the other end of the fifth resistor and one end of the sixth resistor are both connected to the base of the third triode, the other end of the seventh resistor is connected to the emitter of the third triode and the other end of the fourth resistor, the other end of the sixth resistor is connected to the collector of the second triode, and the collector of the third triode is connected to the base of the second triode.
4. The load open-circuit protection circuit according to claim 3, wherein the third transistor is a PNP type transistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220053920.XU CN217063251U (en) | 2022-01-10 | 2022-01-10 | Load open circuit protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220053920.XU CN217063251U (en) | 2022-01-10 | 2022-01-10 | Load open circuit protection circuit |
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| Publication Number | Publication Date |
|---|---|
| CN217063251U true CN217063251U (en) | 2022-07-26 |
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| CN202220053920.XU Active CN217063251U (en) | 2022-01-10 | 2022-01-10 | Load open circuit protection circuit |
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| CN (1) | CN217063251U (en) |
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2022
- 2022-01-10 CN CN202220053920.XU patent/CN217063251U/en active Active
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