CN215867048U - Short circuit detection circuit - Google Patents
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- CN215867048U CN215867048U CN202121191308.0U CN202121191308U CN215867048U CN 215867048 U CN215867048 U CN 215867048U CN 202121191308 U CN202121191308 U CN 202121191308U CN 215867048 U CN215867048 U CN 215867048U
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Abstract
The utility model relates to a short circuit detection circuit, which comprises a first detection end, a second detection end, a constant current circuit, a constant voltage circuit, a current amplification circuit, a defective product prompt circuit, a defective product alarm circuit, a non-defective product prompt circuit, a first drive circuit, a second drive circuit, a third drive circuit and a power supply VCC; the first driving circuit is respectively connected with the good product prompting circuit and the second detection end, the first end of the second switching tube, the anode of the diode D1, the good product prompting circuit and the defective product prompting circuit are all connected with a power supply VCC, and the second driving circuit is respectively connected with the first driving circuit, the second detection end and the defective product prompting circuit; the whole circuit structure is ingenious and reasonable in design, stability and reliability in the detection process are guaranteed, whether short circuit conditions exist or not can be independently known, and the conditions can be independently prompted without interference; the short circuit detection device can not damage detected products and can meet the short circuit detection requirements of different occasions.
Description
Technical Field
The utility model relates to the technical field of earphone production, in particular to a short circuit detection circuit which is mainly applied to earphones.
Background
The smaller the earphone is, the smaller the loudspeaker becomes, and the smaller the loudspeaker becomes, which results in the need to make the wiring board on the loudspeaker small. However, taking into account the adhesion of the bronze foil to the board, the use of the board surface is maximized, with the bronze foil edges being almost flush with the board edges.
The thickness of the base material of the wiring board is usually 0.2mm plus the thickness of 0.1mm of glue, namely the distance between a bonding wire and a loudspeaker metal basin frame is usually only about 0.3mm, and in the production operation process, when a voice coil wire and a loudspeaker input lead are welded, the probability of short circuit between a welding point and the metal basin frame is very high, which is inconsistent with the adhesion problem in the front and can only be improved in the production operation.
The short circuit is absolutely necessary to be detected and intercepted, a special instrument is very good to detect, however, the number of production lines is not two, and dozens of short circuit detection instruments are needed when a workshop is still, namely dozens of lines need to be used. The instruments are not specially used for detecting short circuits, but integrate the short circuit detection function, such as a multimeter, an LCR bridge, a wire detector and an on-off detector, can detect short circuits, if the instruments are used for detecting short circuits, certain materials are inevitably used, the production line is particularly large in required quantity, and the purchase of the instruments for detecting short circuits is obviously unlikely.
Certainly, one can say that 3V, 5V, 12V and 24V are directly used for detecting and driving the indicator light and the buzzer, the on state indicates short circuit, and the off state indicates no welding short circuit, so that the short circuit defective product is intercepted. The circuit is not good enough in reasonability, and stability and reliability in the detection process are difficult to guarantee. In addition, although the conventional detection circuit can realize functions, the voltage and the current are high. For the light emitting diode, the driving current is usually about 3 milliamperes, the diameter of a voice coil wire of an earphone speaker is very small, and the earphone speaker is easily blown when the current is too large. The driving current of the buzzer and the industrial control indicator light is much larger than that of the light-emitting diode, generally, the driving current is dozens of milliamperes to hundreds of milliamperes, obviously, in order to detect, the product is damaged, and the product is not feasible, so that a circuit specially used for detecting the short circuit is needed to support. In addition, the conventional short-circuit detection circuit can indicate whether the product is good or not through a single industrial control indicator lamp, and once the industrial control indicator lamp is damaged, the indication of a detection result is difficult to obtain.
Therefore, in the present patent application, the applicant has elaborated a short detection circuit to solve the above-mentioned problems.
SUMMERY OF THE UTILITY MODEL
Aiming at the defects of the prior art, the utility model mainly aims to provide a short-circuit detection circuit, which has the advantages that the overall circuit structure is skillfully and reasonably designed, the stability and the reliability in the detection process are ensured, whether the short-circuit condition exists or not can be independently known, the condition can be independently prompted, and the short-circuit condition and the condition do not interfere with each other; the short circuit detection device can not damage detected products and can meet the short circuit detection requirements of different occasions.
In order to achieve the purpose, the utility model adopts the following technical scheme:
a short circuit detection circuit comprises a first detection end, a second detection end, a constant current circuit, a constant voltage circuit, a current amplification circuit, a defective product prompt circuit, a good product prompt circuit, a first drive circuit for driving the good product prompt circuit, a second drive circuit for driving the defective product prompt circuit and a power supply VCC for supplying power;
the constant current circuit is respectively connected with the second detection end and a power supply VCC;
the constant voltage circuit comprises a first switching tube and a resistor R7, the first detection end is connected with the control end of the first switching tube, the control end of the first switching tube is connected with the constant current circuit through a resistor R7, and the second end of the first switching tube is connected with the second detection end;
the current amplifying circuit comprises a resistor R3 and a second switch tube, the first end of the first switch tube is connected with the control end of the second switch tube through a resistor R3, the second end of the second switch tube is connected with a first drive circuit, the first drive circuit is respectively connected with a good product prompting circuit and a second detection end, the first end of the second switch tube, the anode of a diode D1, the good product prompting circuit and the defective product prompting circuit are all connected with a power VCC, and the second drive circuit is respectively connected with the first drive circuit, the second detection end and the defective product prompting circuit;
the defective product alarm circuit is respectively connected with a third driving circuit and a power supply VCC, and the third driving circuit is respectively connected with a first driving circuit and a second detection end.
Preferably, the constant current circuit comprises a diode D1, a diode D2, a resistor R1, a resistor R2 and a third switching tube, wherein the negative electrode of the diode D1 is connected in series with the diode D2 in the forward direction and then connected with the control end of the third switching tube, and the control end of the third switching tube is connected with the second detection end through a resistor R1; the first end of the third switch tube is connected with a power supply VCC through a resistor R2, and the control end of the first switch tube is connected with the second end of the third switch tube through a resistor R7.
As a preferable scheme, the second switching tubes are all PNP tubes, the emitter of the PNP tube is the first end of the second switching tube, the collector of the PNP tube is the second end of the second switching tube, and the base of the PNP tube is the control end of the second switching tube.
Preferably, the first switching tube is an NPN tube, a base of the NPN tube is a control terminal of the first switching tube, a collector of the NPN tube is a first terminal of the first switching tube, and an emitter of the NPN tube is a second terminal of the first switching tube.
As a preferred scheme, the non-defective product prompting circuit comprises a first halogen lamp, and the first driving circuit comprises a resistor R4 and a fourth switching tube;
the control end of the fourth switch tube is connected with the second end of the second switch tube through a resistor R4, the first end of the fourth switch tube is connected with one end of the first halogen lamp and the second driving circuit respectively, the second end of the fourth switch tube is connected with the second detection end, and the other end of the first halogen lamp is connected with a power supply VCC.
As a preferable scheme, the defective product prompting circuit comprises a second halogen lamp, and the second driving circuit comprises a resistor R5 and a fifth switching tube;
the control end of fifth switch tube passes through the control end that resistance R5 connects the fourth switch tube, the one end of second halogen lamp is connected to the first end of fifth switch tube, the second end of fifth switch tube is connected the second and is detected the end, the other end of second halogen lamp connects the power VCC.
Preferably, the fourth switching tube is an NPN tube, a base of the NPN tube is a control end of the fourth switching tube, a collector of the NPN tube is a first end of the fourth switching tube, and an emitter of the NPN tube is a second end of the fourth switching tube.
Preferably, the fifth switching tube is an NPN tube, a base of the NPN tube is a control terminal of the fifth switching tube, a collector of the NPN tube is a first terminal of the fifth switching tube, and an emitter of the NPN tube is a second terminal of the fifth switching tube.
Compared with the prior art, the utility model has obvious advantages and beneficial effects, particularly: the overall circuit structure is ingenious and reasonable in design, stability and reliability in the detection process are guaranteed, when good products or defective products appear, whether short circuit conditions exist can be independently known through the corresponding prompting circuit, and the defective product prompting circuit and the good product prompting circuit independently prompt the conditions and do not interfere with each other; particularly, through the cooperation of the constant current circuit, the constant voltage circuit and the current amplifying circuit, the highest detection voltage between the first detection end and the second detection end is ensured to be 0.7V, the detected product cannot be damaged, and the short circuit detection requirements of different occasions can be met;
secondly, through the cooperation of defective products alarm circuit and third drive circuit, the suggestion of further directly perceived defective products is known, is favorable to taking corresponding measure in time.
To more clearly illustrate the structural features and effects of the present invention, the following detailed description is given with reference to the accompanying drawings and specific embodiments.
Drawings
Fig. 1 is a schematic circuit diagram of an embodiment of the present invention.
The reference numbers illustrate:
11. a first detection terminal 12 and a second detection terminal
13. Constant current circuit 14 and constant voltage circuit
15. Current amplifying circuit
21. Non-defective product indication circuit 22 and defective product indication circuit
23. First and second drive circuits 24 and 24
25. Defective alarm circuit 26 and third drive circuit
Detailed Description
The utility model is further described with reference to the following detailed description and accompanying drawings.
As shown in fig. 1, a short circuit detection circuit is mainly applied to an earphone, and certainly not limited to a short circuit between a bonding pad in the earphone and a metal frame, but also can be used for other types of short circuit detection, such as short circuit test of each network copper foil of a PCB board, lead on-off test, and the like. A short circuit detection circuit comprises a first detection end 11, a second detection end 12, a constant current circuit 13, a constant voltage circuit 14, a current amplification circuit 15, a good product prompt circuit 21, a defective product prompt circuit 22, a first drive circuit 23 for driving the good product prompt circuit 21, a second drive circuit 24 for driving the defective product prompt circuit 22 and a power supply VCC for supplying power;
the constant current circuit is respectively connected with the second detection end and a power supply VCC; in this embodiment, the constant current circuit 13 includes a diode D1, a diode D2, a resistor R1, a resistor R2, and a third switching tube Q1, the negative electrode of the diode D1 is connected in series with a diode D2 in the forward direction and then connected to the control terminal of the third switching tube Q1, the control terminal of the third switching tube Q1 is connected to the second detection terminal 12 through a resistor R1, and the resistor R1 is a bias resistor of the third switching tube Q1 and a voltage-stabilizing current-limiting resistor of the diode D1 and the diode D2; the first end of the third switch tube Q1 is connected to the power source VCC through a resistor R2, and the resistor R2 is a current sampling resistor.
The constant voltage circuit 14 comprises a first switching tube Q3 and a resistor R7, the first detection end 11 is connected with the control end of a first switching tube Q3, the control end of the first switching tube Q3 is connected with the second end of a third switching tube Q1 of the constant current circuit through a resistor R7, and the second end of the first switching tube Q3 is connected with the second detection end 12;
the current amplifying circuit 15 includes a resistor R3 and a second switching tube Q2, a first end of the first switching tube Q3 is connected to a control end of the second switching tube Q2 through the resistor R3, and a second end of the second switching tube Q2 is connected to the first driving circuit 23.
In this embodiment, the third switch tube Q1 and the second switch tube Q2 are both PNP tubes, the emitter of the PNP tube is the first end of the third switch tube Q1 or the second switch tube Q2, the collector of the PNP tube is the second end of the third switch tube Q1 or the second switch tube Q2, and the base of the PNP tube is the control end of the third switch tube Q1 or the second switch tube Q2.
The first switch Q3 is an NPN transistor, a base of the NPN transistor is a control terminal of the first switch Q3, a collector of the NPN transistor is a first terminal of the first switch Q3, and an emitter of the NPN transistor is a second terminal of the first switch Q3.
In this embodiment, the good product indicating circuit 21 includes a first halogen lamp DS1, the first driving circuit 23 includes a resistor R4 and a fourth switching tube Q4, the defective product indicating circuit 22 includes a second halogen lamp DS2, and the second driving circuit 24 includes a resistor R5 and a fifth switching tube Q5;
the control end of the fourth switch tube Q4 is connected with the second end of the second switch tube Q2 through a resistor R4, the first end of the fourth switch tube Q4 is connected with one end of the first halogen lamp DS1 and the second drive circuit 24 respectively, the second end of the fourth switch tube Q4 is connected with the second detection end 12, and the other end of the first halogen lamp DS1 is connected with a power supply VCC.
The control end of the fifth switch tube Q5 is connected with the control end of the fourth switch tube Q4 through a resistor R5, the first end of the fifth switch tube Q5 is connected with one end of a second halogen lamp DS2, the second end of the fifth switch tube Q5 is connected with the second detection end 12, and the other end of the second halogen lamp DS2 is connected with a power supply VCC.
In this embodiment, the fourth switching transistor Q4 and the fifth switching transistor Q5 are both NPN transistors, a base of each NPN transistor is a control end of the fourth switching transistor Q4 or the fifth switching transistor Q5, a collector of each NPN transistor is a first end of the fourth switching transistor Q4 or the fifth switching transistor Q5, and an emitter of each NPN transistor is a second end of the fourth switching transistor Q4 or the fifth switching transistor Q5.
In order to better warn the defective products, the electronic device further comprises a defective product alarm circuit 25 and a third driving circuit 26 for driving the defective product alarm circuit 25, wherein the defective product alarm circuit 25 is respectively connected with the third driving circuit 26 and the power source VCC, and the third driving circuit 26 is respectively connected with the first driving circuit 23 and the second detection terminal 12.
The defective product alarm circuit 25 includes a buzzer B1, and the third driving circuit 26 includes a resistor R6 and a sixth switching tube Q6;
the control end of the sixth switch tube Q6 is connected with the first driving circuit 23 through a resistor R6, the first end of the sixth switch tube Q6 is connected with one end of the buzzer, the second end of the sixth switch tube Q6 is connected with the second detection end 12, and the other end of the buzzer is connected with the power supply VCC.
In this embodiment, the sixth switch Q6 is an NPN transistor, a base of the NPN transistor is a control terminal of the sixth switch Q6, a collector of the NPN transistor is a first terminal of the sixth switch Q6, and an emitter of the NPN transistor is a second terminal of the sixth switch Q6.
It should be noted that, neither the third switching tube Q1 nor the second switching tube Q2 is limited to a PNP tube, but may also be a PMOS tube, which is not limited herein; the first switch transistor Q3, the fourth switch transistor Q4, the fifth switch transistor Q5 and the sixth switch transistor Q6 are not limited to NPN transistors, but may be NMOS transistors, and are not limited herein.
The following working principle is explained in general:
PNP transistors adopted by the diode D1, the diode D2 and a third switching tube Q1 are all common silicon transistors, the voltage drop of PN junctions is 0.7V, the 0.7V voltage drop at two ends of the diode D2 is used for offsetting the BE junction voltage drop of the third switching tube Q1, and the 0.7V voltage drop at two ends of the third switching tube Q1 provides constant reference voltage for a resistor R2;
according to the current amplification characteristics of the triode, Ice＝Ibe*β；
In the formula: beta is the direct current amplification factor of the triode, Ie＝Ice+Ibe；
The amplification factor of the third switching tube Q1 is usually not less than 250 times, so that the current impact of IBE on IE is very small, and there is the following formula:
the resistor R2, the CE electrode of the third switch tube Q1, the resistor R7 and the BE electrode of the first switch tube Q3 are connected in series, the current in the loop is always constant and is 35 milliamperes of the set current, the first switch tube Q3 is also a common silicon transistor, the BE junction of the first switch tube Q3 is limited to 0.7 volt, the first detection end 11 and the second detection end 12 are connected in parallel, the highest voltage between the first detection end 11 and the second detection end 12 is also 0.7 volt, and the first switch tube Q3 is a constant voltage circuit.
If a short circuit between a bonding wire and a metal basin frame occurs in the earphone, the voltage between the first detection end 11 and the second detection end 12 becomes 0V, the first switch tube Q3, the second switch tube Q2 and the fourth switch tube Q4 are not conducted, the fifth switch tube Q5 and the sixth switch tube Q6 are both conducted, at the moment, the second halogen lamp DS2 is lightened, and the buzzer B1 gives an alarm sound to display that the short circuit exists in the earphone;
on the contrary, if the short circuit between the bonding wire and the metal frame does not occur in the earphone, the voltage between the first detection end 11 and the second detection end 12 becomes 0.7v, the first switch tube Q3, the second switch tube Q2 and the fourth switch tube Q4 are all turned on, the fifth switch tube Q5 and the sixth switch tube Q6 are not turned on, at this time, only the first halogen lamp DS1 is lighted, and the short circuit does not exist in the earphone.
The utility model has the design key points that the overall circuit structure is skillfully and reasonably designed, the stability and the reliability in the detection process are ensured, when good products or defective products appear, whether a short circuit condition exists can be independently known through a corresponding prompting circuit, and the defective product prompting circuit and the good product prompting circuit independently prompt the condition and do not interfere with each other; particularly, through the cooperation of the constant current circuit, the constant voltage circuit and the current amplifying circuit, the highest detection voltage between the first detection end and the second detection end is ensured to be 0.7V, the detected product cannot be damaged, and the short circuit detection requirements of different occasions can be met;
secondly, through the cooperation of defective products alarm circuit and third drive circuit, the suggestion of further directly perceived defective products is known, is favorable to taking corresponding measure in time.
Claims (8)
1. A short detection circuit, characterized by: the circuit comprises a first detection end, a second detection end, a constant current circuit, a constant voltage circuit, a current amplification circuit, a defective product prompt circuit, a good product prompt circuit, a first drive circuit for driving the good product prompt circuit, a second drive circuit for driving the defective product prompt circuit and a power supply VCC for supplying power;
the constant current circuit is respectively connected with the second detection end and a power supply VCC;
the constant voltage circuit comprises a first switching tube and a resistor R7, the first detection end is connected with the control end of the first switching tube, the control end of the first switching tube is connected with the constant current circuit through a resistor R7, and the second end of the first switching tube is connected with the second detection end;
the current amplifying circuit comprises a resistor R3 and a second switch tube, the first end of the first switch tube is connected with the control end of the second switch tube through a resistor R3, the second end of the second switch tube is connected with a first drive circuit, the first drive circuit is respectively connected with a good product prompting circuit and a second detection end, the first end of the second switch tube, the anode of a diode D1, the good product prompting circuit and the defective product prompting circuit are all connected with a power VCC, and the second drive circuit is respectively connected with the first drive circuit, the second detection end and the defective product prompting circuit;
the defective product prompting circuit is respectively connected with a third driving circuit and a power supply VCC, and the third driving circuit is respectively connected with a first driving circuit and a second detection end.
2. The short detection circuit of claim 1, wherein: the constant current circuit comprises a diode D1, a diode D2, a resistor R1, a resistor R2 and a third switching tube, wherein the negative electrode of the diode D1 is connected with the control end of the third switching tube after being connected with a diode D2 in series in the forward direction, and the control end of the third switching tube is connected with a second detection end through a resistor R1; the first end of the third switch tube is connected with a power supply VCC through a resistor R2, and the control end of the first switch tube is connected with the second end of the third switch tube through a resistor R7.
3. The short detection circuit of claim 1, wherein: the second switch tube is a PNP tube, the emitter of the PNP tube is the first end of the second switch tube, the collector of the PNP tube is the second end of the second switch tube, and the base of the PNP tube is the control end of the second switch tube.
4. The short detection circuit of claim 1, wherein: the first switch tube is an NPN tube, the base electrode of the NPN tube is the control end of the first switch tube, the collector electrode of the NPN tube is the first end of the first switch tube, and the emitter electrode of the NPN tube is the second end of the first switch tube.
5. The short detection circuit of claim 1, wherein: the good product prompting circuit comprises a first halogen lamp, and the first driving circuit comprises a resistor R4 and a fourth switching tube;
the control end of the fourth switch tube is connected with the second end of the second switch tube through a resistor R4, the first end of the fourth switch tube is connected with one end of the first halogen lamp and the second driving circuit respectively, the second end of the fourth switch tube is connected with the second detection end, and the other end of the first halogen lamp is connected with a power supply VCC.
6. The short detection circuit of claim 5, wherein: the defective product prompting circuit comprises a second halogen lamp, and the second driving circuit comprises a resistor R5 and a fifth switching tube;
the control end of fifth switch tube passes through the control end that resistance R5 connects the fourth switch tube, the one end of second halogen lamp is connected to the first end of fifth switch tube, the second end of fifth switch tube is connected the second and is detected the end, the other end of second halogen lamp connects the power VCC.
7. The short detection circuit according to claim 5 or 6, wherein: the fourth switching tube is an NPN tube, the base electrode of the NPN tube is the control end of the fourth switching tube, the collector electrode of the NPN tube is the first end of the fourth switching tube, and the emitter electrode of the NPN tube is the second end of the fourth switching tube.
8. The short detection circuit of claim 6, wherein: the fifth switching tube is an NPN tube, the base electrode of the NPN tube is the control end of the fifth switching tube, the collector electrode of the NPN tube is the first end of the fifth switching tube, and the emitter electrode of the NPN tube is the second end of the fifth switching tube.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202121191308.0U CN215867048U (en) | 2021-05-31 | 2021-05-31 | Short circuit detection circuit |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202121191308.0U CN215867048U (en) | 2021-05-31 | 2021-05-31 | Short circuit detection circuit |
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| CN215867048U true CN215867048U (en) | 2022-02-18 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113466738A (en) * | 2021-05-31 | 2021-10-01 | 广东朝阳电子科技股份有限公司 | Short circuit detection circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113466738A (en) * | 2021-05-31 | 2021-10-01 | 广东朝阳电子科技股份有限公司 | Short circuit detection circuit |
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