Temperature protection circuit and connector

Abstract

The utility model relates to a temperature protection circuit and a connector, the temperature protection circuit comprises a comparator, an MOS tube and a joint, the anti-phase end of the comparator is connected with one end of a first resistor and one end of a first temperature sensor with a negative temperature coefficient, and the in-phase end of the comparator is connected with one end of a second resistor and one end of a second temperature sensor with a negative temperature coefficient; the second resistor, the other end of the first temperature sensor and the power end of the comparator are connected with the positive electrode of the connector, the output end of the comparator is connected with the grid electrode of the MOS tube, the first resistor, the other end of the second temperature sensor and the ground end of the comparator are connected with the source electrode of the MOS tube, and the drain electrode of the MOS tube is connected with the negative electrode of the connector. The connector is simple and ingenious in structural design, power supply of the connector can be cut off when the temperature of the connector is too high due to various reasons, and therefore the hidden danger of fire disasters is effectively avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of connectors, in particular to a temperature protection circuit and a connector. Background Art

[0002] Connectors such as USB connectors and DC connectors become loose or oxidized after a long period of use, which increases the contact impedance of the connector. Existing connectors do not have temperature protection. When a large current passes through the connector, a large amount of heat will be generated. When the heat is too large, the temperature of the connector will be too high, which may cause a fire hazard.

[0003] How to design a temperature protection circuit and connector that can cut off the power supply to the connector when the temperature of the connector is too high due to various reasons, thereby avoiding the potential fire hazard, is a topic that the inventor has devoted himself to studying. Utility Model Content

[0004] The utility model aims to provide a temperature protection circuit and a connector, which have a simple and ingenious structural design and can cut off the power supply of the connector when the temperature of the connector is too high due to various reasons, thereby effectively avoiding the hidden danger of fire.

[0005] In order to achieve the above-mentioned purpose, the technical solution of the utility model is: a temperature protection circuit, which includes a comparator, a MOS tube and a connector, the inverting end of the comparator is connected to one end of a first resistor and one end of a first temperature sensor with a negative temperature coefficient, the non-inverting end of the comparator is connected to one end of a second resistor and one end of a second temperature sensor with a negative temperature coefficient, the other end of the second resistor, the other end of the first temperature sensor and the power supply end of the comparator are connected to the positive electrode of the connector, the output end of the comparator is connected to the gate of the MOS tube, the other end of the first resistor, the other end of the second temperature sensor and the ground end of the comparator are connected to the source of the MOS tube, and the drain of the MOS tube is connected to the negative electrode of the connector.

[0006] The utility model discloses a temperature protection circuit, wherein the other end of the first resistor, the other end of the second temperature sensor, the ground end of the comparator and the source of the MOS tube are all grounded.

[0007] The utility model provides a temperature protection circuit, wherein a third resistor is connected between the output end and the in-phase end of the comparator.

[0008] The utility model discloses a temperature protection circuit, wherein when the temperature is normal, the resistance values ​​of the first temperature sensor and the second temperature sensor are relatively large, the voltage division value of the first temperature sensor and the first resistor is lower than the voltage division value of the second temperature sensor and the second resistor, and the comparator outputs a high level, which drives the MOS tube to conduct and work.

[0009] The utility model provides a temperature protection circuit, wherein the temperature point at which the temperature protection circuit enters protection is calculated using: RT is a parameter of the first temperature sensor and the second temperature sensor, R is a parameter of the first resistor and the second resistor, and R3 is the resistance value of the third resistor. When the temperature to be protected is determined, the value of RT is determined, and the relationship between R and R3 can be calculated.

[0010] The utility model discloses a temperature protection circuit, wherein the temperature calculation for releasing the protection adopts: RT*RT*R3 / (RT+R3)=R*R.

[0011] A connector, comprising a PCB and a temperature protection circuit, wherein the positive electrode of the connector of the temperature protection circuit is connected to the positive copper foil of the PCB, the positive copper foil and the negative copper foil of the PCB are respectively connected to the positive and negative electrodes of a cable, the positive and negative electrodes of the cable are used to be connected to the positive and negative electrodes of a power supply, the negative copper foil of the PCB is connected to the negative electrode of the connector through the MOS tube, and the MOS tube, the first temperature sensor, and the second temperature sensor are all connected to the PCB.

[0012] In the connector of the utility model, the first temperature sensor is arranged near the position where the positive electrode copper foil is connected to the positive electrode of the connector.

[0013] In the connector of the utility model, the second temperature sensor is arranged near the position where the negative electrode copper foil is connected to the negative electrode of the connector.

[0014] In the connector of the utility model, the second temperature sensor is arranged at the upper end of the negative electrode copper foil.

[0015] After adopting the above scheme, the temperature protection circuit and connector of the utility model can achieve the best protection speed and effect by setting the first temperature sensor and the second temperature sensor with negative temperature coefficients, and placing the first temperature sensor and the second temperature sensor near the positive and negative poles of the connector respectively. The structural design of the utility model is simple and ingenious, and can cut off the power supply of the connector when the temperature of the connector is too high due to various reasons, thereby effectively avoiding the hidden danger of fire. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the temperature protection circuit of the utility model;

[0017] Figure 2 It is a schematic diagram of the structure of an embodiment of the connector of the utility model.

[0018] Number Description:

[0019] 1- Comparator 2- MOS tube

[0020] 3-Connector 4-First resistor

[0021] 5-First temperature sensor 6-Second resistor

[0022] 7- Second temperature sensor 8- Connector

[0023] 9- The third resistor 10- The positive pole of the cable

[0024] 11-Cable negative pole DETAILED DESCRIPTION

[0025] The present invention is described below based on the embodiments shown in the accompanying drawings. The embodiments disclosed this time can be considered to be illustrative in all aspects and not restrictive. The scope of the present invention is not limited by the description of the following embodiments, but is only shown by the scope of the claims, and includes all variations with the same meaning as the scope of the claims and within the scope of the claims.

[0026] The structure of a temperature protection circuit and a connector of the utility model is described below in conjunction with specific embodiments.

[0027] like Figure 1 The schematic diagram of the structure of the temperature protection circuit of the utility model shown in the figure includes a comparator 1, a MOS tube 2 and a connector 3. The inverting end of the comparator 1 is connected to one end of the first resistor 4 and one end of the first temperature sensor 5 of NTC, i.e., a negative temperature coefficient. The in-phase end of the comparator 1 is connected to one end of the second resistor 6 and one end of the second temperature sensor 7 of a negative temperature coefficient. The other end of the second resistor 6, the other end of the first temperature sensor 5 and the power supply end of the comparator 1 are connected to the positive electrode of the connector 3. The MOS tube of this embodiment adopts an N-type MOS tube. The output end of the comparator 1 is connected to the gate of the MOS tube 2, and the other end of the first resistor 4, the other end of the second temperature sensor 7 and the ground end of the comparator 1 are connected to the source of the MOS tube 2. The other end of the first resistor 4, the other end of the second temperature sensor 7, the ground end of the comparator 1 and the source of the MOS tube 2 of this embodiment are all grounded. The drain of the MOS tube 2 is connected to the negative electrode of the connector 3. A third resistor 8 is connected between the output end and the in-phase end of the comparator 1 to form a positive feedback circuit.

[0028] When the temperature is normal, the resistance of the first temperature sensor 5 and the second temperature sensor 7 is relatively large, the voltage division value of the first temperature sensor 5 and the first resistor 4 is lower than the voltage division value of the second temperature sensor 7 and the second resistor 6, the comparator 1 outputs a high level, and the high level drives the MOS tube 2 to conduct normally. At this time, the connector 3 can normally supply power to the load connected to its rear end. The third resistor 8 is positively fed back to the in-phase end, so that the voltage division of the second resistor 6 and the second temperature sensor 7 is correspondingly increased. When the temperature of the connector 3 increases, the first temperature sensor 5 and the second temperature sensor 7 become smaller, the voltage division of the first temperature sensor 5 and the first resistor 4 becomes higher, and the voltage division of the second resistor 6 and the second temperature sensor 7 becomes lower. At this time, the comparator 1 outputs a low level, the MOS tube 2 will turn off the load current, and the connector 3 has no current flowing through, and no heat will be generated. When the comparator 1 outputs a low level, the third resistor 8 is positively fed back to the in-phase end, so that the voltage of the in-phase end is further reduced. The purpose of the positive feedback of the third resistor 8 is to make the protection temperature have a certain hysteresis, and will not be repeatedly turned on and off at a temperature point where protection is entered, so as to avoid the load being repeatedly powered on and damaged. The level of the protection temperature can be determined by adjusting the size of the first resistor 4 and the second resistor 6 .

[0029] The temperature point for entering protection is calculated as:

[0030] By resistor voltage division calculation, when [R2*R3 / (R2+R3)] / RT2=RT1 / R1, that is, when R2 and R3 are connected in parallel and then divided by RT2, the voltage at the in-phase terminal of the comparator 1 is equal to the voltage at the inverting terminal, where RT1 is the first temperature sensor 5, RT2 is the second temperature sensor 7, R1 is the first resistor 4, R2 is the second resistor 6, and R3 is the third resistor 8. Here, RT1 and RT2 are selected to have the same parameter RT, and R1 and R2 also use the same parameter R. Then R*R*R3 / (R+R3)=RT*RT.

[0031]

[0032] By using formula (1), once the temperature to be protected is determined, the resistance value of RT is determined, and the relationship between R and R3 can be calculated.

[0033] When temperature protection is activated, the temperature calculation for releasing the protection is:

[0034] According to the resistor voltage division calculation, R2 and (R3 in parallel with RT2) divide the voltage, at this time:

[0035] RT1 / R1=R2 / [RT2*R3 / (RT2+R3)], when R1=R2=R; RT1=RT2=RT.

[0036] RT*RT*R3 / (RT+R3)=R*R Formula (2)

[0037] After we determine the protection temperature through formula (1), we can calculate the relationship between R and R3 through formula (1). We select data from it and substitute it into formula (2) to calculate the RT value, and convert the protection release temperature through the NTC temperature resistance table.

[0038] like Figure 2 The schematic diagram of the structure of the embodiment of the utility model connector shown in FIG. Figure 1 The temperature protection circuit shown. The positive electrode of the connector 3 of the temperature protection circuit is riveted to the positive copper foil of the PCB9. The positive copper foil and the negative copper foil of the PCB9 are respectively welded to the positive electrode 10 of the cable and the negative electrode 11 of the cable. The positive electrode 10 of the cable and the negative electrode 11 of the cable are used to connect to the positive and negative electrodes of the power supply. The negative copper foil of the PCB9 is connected to the negative electrode of the connector 3 through the MOS tube 2. The MOS tube 2 is used to cut off the power supply circuit of the connector 3 when the temperature is abnormal. The MOS tube 2, the first temperature sensor 5 and the second temperature sensor 7 are all connected to the PCB9.

[0039] The first temperature sensor 5 is used to detect the temperature of the positive electrode connector of the power supply, so the first temperature sensor 5 is arranged near the connection between the positive electrode copper foil and the positive electrode (pin 1) of the connector 3, as close to the connector 3 as possible. Since one end of the first temperature sensor 5 itself is connected to the positive electrode of the power supply, the first temperature sensor 5 can well detect the temperature of the positive electrode of the connector 3. The heat of the positive electrode of the connector 3 can be quickly conducted to the pad connected to the positive electrode of the first temperature sensor 5 through the positive electrode 10 of the cable, and then to the temperature-sensitive material inside the first temperature sensor 5.

[0040] The second temperature sensor 7 is used to detect the temperature at the position of the negative electrode connector of the power supply, so the second temperature sensor 7 is arranged near the position where the negative electrode copper foil is connected to the negative electrode (pin 2) of the connector 3, as close to the connector 3 as possible, so as to achieve the best protection speed and effect. In this embodiment, the second temperature sensor 7 is not directly connected to the negative electrode of the connector 3, but is placed at the upper end of the negative electrode copper foil. The pad of the second temperature sensor 7 connected to the negative electrode is connected to the circuit through the hole, so that the heat of the negative electrode can be transferred to the negative electrode copper foil near the second temperature sensor 7 through the negative electrode 11 of the cable. Because the second temperature sensor 7 is close to the negative electrode copper foil, it can quickly sense the negative electrode temperature of the connector 3.

[0041] The above-described embodiments are merely descriptions of preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary engineering and technical personnel in the field shall fall within the protection scope of the claims of the present invention.

Claims

1. A temperature protection circuit, characterized in that: The invention comprises a comparator, a MOS tube and a joint, wherein the inverting end of the comparator is connected to one end of a first resistor and one end of a first temperature sensor with a negative temperature coefficient, the non-inverting end of the comparator is connected to one end of a second resistor and one end of a second temperature sensor with a negative temperature coefficient, the other end of the second resistor, the other end of the first temperature sensor and the power supply end of the comparator are connected to the positive electrode of the joint, the output end of the comparator is connected to the gate of the MOS tube, the other end of the first resistor, the other end of the second temperature sensor and the ground end of the comparator are connected to the source of the MOS tube, and the drain of the MOS tube is connected to the negative electrode of the joint.

2. A temperature protection circuit as claimed in claim 1, characterized in that: The other end of the first resistor, the other end of the second temperature sensor, the ground end of the comparator and the source of the MOS tube are all grounded.

3. A temperature protection circuit as claimed in claim 2, characterized in that: A third resistor is connected between the output terminal and the non-inverting terminal of the comparator.

4. A temperature protection circuit as claimed in claim 1, characterized in that: When the temperature is normal, the resistance values ​​of the first temperature sensor and the second temperature sensor are relatively large, the voltage division value of the first temperature sensor and the first resistor is lower than the voltage division value of the second temperature sensor and the second resistor, and the comparator outputs a high level, which drives the MOS tube to turn on and work.

5. A temperature protection circuit as claimed in claim 3, characterized in that: The temperature point at which the temperature protection circuit enters protection is calculated using: RT is a parameter of the first temperature sensor and the second temperature sensor, R is a parameter of the first resistor and the second resistor, and R3 is a resistance value of the third resistor.

6. A temperature protection circuit as claimed in claim 5, characterized in that: The temperature calculation for releasing the protection is: RT*RT*R3 / (RT+R3)=R*R.

7. A connector, characterized in that: It comprises a PCB and a temperature protection circuit as described in any one of claims 1 to 6, wherein the positive electrode of the connector of the temperature protection circuit is connected to the positive copper foil of the PCB, the positive copper foil and the negative copper foil of the PCB are respectively connected to the positive and negative electrodes of the cable, the positive and negative electrodes of the cable are used to be connected to the positive and negative electrodes of the power supply, the negative copper foil of the PCB is connected to the negative electrode of the connector through the MOS tube, and the MOS tube, the first temperature sensor, and the second temperature sensor are all connected to the PCB.

8. The connector according to claim 7, wherein: The first temperature sensor is disposed near a portion where the positive electrode copper foil is connected to the positive electrode of the connector.

9. The connector according to claim 7, characterized in that: The second temperature sensor is disposed near a location where the negative electrode copper foil is connected to the negative electrode of the connector.

10. The connector according to claim 9, characterized in that The second temperature sensor is arranged at the upper end of the negative electrode copper foil.

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