Over-temperature protection circuit, charging protection circuit and electronic equipment

Abstract

The present disclosure relates to an over-temperature protection circuit, a charging protection circuit and an electronic device. The over-temperature protection circuit includes: a temperature detection circuit for detecting the temperature of an electronic device; a switch unit, a first end for coupling with a charging device, and a second end for coupling with a ground terminal; a hysteresis circuit, a first end coupled with the temperature detection circuit, and a second end coupled with a control end of the switch unit. Since the temperature of the electronic device is greater than the first temperature threshold or less than the second temperature threshold, the temperature detection circuit causes the voltage output by the hysteresis circuit to change, and the switch unit is controlled to be turned on or off to stop charging or charge the electronic device. Since the temperature of the electronic device is less than or equal to the first temperature threshold and greater than or equal to the second temperature threshold, the temperature detection circuit causes the voltage output by the hysteresis circuit to remain unchanged, and the state of the switch unit remains unchanged to avoid repeated changes in the charging state of the electronic device in a short time to reduce the possibility of failure of the electronic device.

Description

Technical Field

[0001] The present disclosure relates to the field of charging technology, and in particular to an over-temperature protection circuit, a charging protection circuit and an electronic device. Background Art

[0002] At present, during the charging process of an electronic device, when the temperature of the electronic device is too high, the over-temperature protection circuit will disconnect the charging device and the electronic device to reduce the temperature of the electronic device. However, as the temperature of the electronic device changes, the over-temperature protection circuit will cause the electronic device to repeatedly charge and disconnect in a short period of time, causing damage to the electronic device. Utility Model Content

[0003] In order to overcome the problems existing in the related art, the present disclosure provides an over-temperature protection circuit, a charging protection circuit and an electronic device.

[0004] According to a first aspect of the present disclosure, an over-temperature protection circuit is provided, the over-temperature protection circuit comprising:

[0005] A temperature detection circuit, wherein the temperature detection circuit is used to detect the temperature of the electronic device;

[0006] A switch unit, wherein a first end of the switch unit is used to couple with a charging device, and a second end of the switch unit is used to couple with a ground terminal;

[0007] A hysteresis circuit, wherein a first end of the hysteresis circuit is coupled to the temperature detection circuit, and a second end of the hysteresis circuit is coupled to the control end of the switch unit.

[0008] In some embodiments of the present disclosure, the hysteresis circuit includes:

[0009] A first comparator, wherein a first input terminal of the first comparator is coupled to the temperature detection circuit, and an output terminal of the first comparator is coupled to a control terminal of the switch unit;

[0010] a first feedback circuit, wherein a first terminal of the first feedback circuit is coupled to the output terminal of the first comparator, a second terminal of the first feedback circuit is coupled to the second input terminal of the first comparator, and a third terminal of the first feedback circuit is used to couple to the ground terminal;

[0011] A first voltage bias circuit, wherein a first end of the first voltage bias circuit is coupled to the output end of the first comparator and the first end of the first feedback circuit, a second end of the first voltage bias circuit is coupled to the second input end of the first comparator, and a third end of the first voltage bias circuit is used to couple to a power supply.

[0012] In some embodiments of the present disclosure, the first feedback circuit includes:

[0013] a first resistor, wherein a first end of the first resistor is coupled to the output end of the first comparator, and a second end of the first resistor is coupled to the second input end of the first comparator;

[0014] A second resistor, wherein a first end of the second resistor is coupled to the second input end of the first comparator, and a second end of the second resistor is used to be coupled to the ground end.

[0015] In some embodiments of the present disclosure, the first voltage bias circuit includes:

[0016] a third resistor, wherein a first end of the third resistor is coupled to the output end of the first comparator and the first end of the first resistor, and a second end of the third resistor is used to couple to the power supply;

[0017] A fourth resistor, wherein a first end of the fourth resistor is coupled to the second input end of the first comparator, and a second end of the fourth resistor is used to couple to the power supply.

[0018] In some embodiments of the present disclosure, the first resistor, the second resistor, the third resistor and the fourth resistor have the same resistance value.

[0019] In some embodiments of the present disclosure, the hysteresis circuit includes:

[0020] A second comparator, wherein a first input terminal of the second comparator is coupled to the temperature detection circuit, and an output terminal of the second comparator is coupled to the control terminal of the switch unit;

[0021] a second feedback circuit, wherein a first terminal of the second feedback circuit is coupled to the output terminal of the second comparator, and a second terminal of the second feedback circuit is coupled to the second input terminal of the second comparator;

[0022] A second voltage bias circuit, wherein the first end of the second voltage bias circuit is used to couple with a power supply, the second end of the second voltage bias circuit is used to couple with the ground end, and the third end of the second voltage bias circuit is coupled with the third end of the second feedback circuit.

[0023] In some embodiments of the present disclosure, the second feedback circuit includes:

[0024] a fifth resistor, wherein a first end of the fifth resistor is coupled to the output end of the second comparator, and a second end of the fifth resistor is coupled to the second input end of the second comparator;

[0025] A sixth resistor, wherein a first end of the sixth resistor is coupled to the second input end of the second comparator, and a second end of the sixth resistor is coupled to the third end of the second voltage bias circuit.

[0026] In some embodiments of the present disclosure, the second voltage bias circuit includes:

[0027] a seventh resistor, wherein a first end of the seventh resistor is used to be coupled to the power supply, and a second end of the seventh resistor is coupled to a third end of the second feedback circuit;

[0028] An eighth resistor, wherein a first end of the eighth resistor is coupled to the second end of the seventh resistor, and a second end of the eighth resistor is used to couple to the ground end.

[0029] In some embodiments of the present disclosure, the hysteresis circuit is used to turn on the switch unit when the temperature of the electronic device is greater than a first temperature threshold; and to turn off the switch unit when the temperature of the electronic device is less than a second temperature threshold; wherein the first temperature threshold is greater than the second temperature threshold.

[0030] In some embodiments of the present disclosure, the temperature detection circuit includes a temperature detection unit and a ninth resistor; the temperature detection unit and the ninth resistor are coupled in series between a power supply and the ground terminal; wherein the first end of the hysteresis circuit is coupled between the temperature detection unit and the ninth resistor.

[0031] In some embodiments of the present disclosure, the temperature detection unit includes a thermistor with a negative temperature coefficient; the first end of the ninth resistor is used to couple to the power supply, and the second end of the ninth resistor is coupled to the first end of the thermistor and the first end of the hysteresis circuit; the second end of the thermistor is used to couple to the ground terminal.

[0032] In some embodiments of the present disclosure, the temperature detection unit is disposed close to an interface of the electronic device.

[0033] In some embodiments of the present disclosure, the first end of the switch unit is used to couple with a power supply terminal of an interface of the electronic device, and the power supply terminal is used to couple with the charging device.

[0034] According to a second aspect of the present disclosure, a charging protection circuit is provided, wherein the charging protection circuit includes the over-temperature protection circuit as described above.

[0035] According to a third aspect of the present disclosure, a charging device is provided, the charging device comprising the over-temperature protection circuit as described above, or the charging protection circuit as described above.

[0036] The technical solution provided by the embodiments of the present disclosure may have the following beneficial effects:

[0037] The over-temperature protection circuit includes a temperature detection circuit, a switch unit and a hysteresis circuit. The hysteresis circuit is coupled between the temperature detection circuit and the switch unit, and the switch unit is coupled between the charging device and the ground terminal. Since the temperature of the electronic device is greater than the first temperature threshold or less than the second temperature threshold, the temperature detection circuit changes the voltage output by the hysteresis circuit, and the switch unit is controlled to be turned on or off to stop charging or charge the electronic device. Since the temperature of the electronic device is less than or equal to the first temperature threshold and greater than or equal to the second temperature threshold, the temperature detection circuit keeps the voltage output by the hysteresis circuit unchanged, and the state of the switch unit remains unchanged to avoid repeated changes in the charging state of the electronic device in a short time to reduce the possibility of failure of the electronic device. At the same time, since the switch unit does not need to be repeatedly turned on and off to protect the electronic device from over-temperature, the switching loss of the switch unit is reduced, thereby reducing the charging loss of the electronic device.

[0038] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings herein are incorporated in and constitute a part of the specification, illustrate embodiments consistent with the present utility model, and together with the description, are used to explain the principles of the present utility model.

[0040] Figure 1 It is a structural schematic diagram of an over-temperature protection circuit;

[0041] Figure 2 It is a waveform diagram of an over-temperature protection circuit;

[0042] Figure 3 is a structural schematic diagram of an over-temperature protection circuit provided by an exemplary embodiment of the present disclosure;

[0043] Figure 4 is a structural schematic diagram of an over-temperature protection circuit provided by another exemplary embodiment of the present disclosure;

[0044] Figure 5 is a structural schematic diagram of an over-temperature protection circuit provided by another exemplary embodiment of the present disclosure;

[0045] Figure 6-1 is an equivalent circuit diagram of a hysteresis circuit provided by an exemplary embodiment of the present disclosure;

[0046] Figure 6-2 is an equivalent circuit diagram of a hysteresis circuit provided by another exemplary embodiment of the present disclosure;

[0047] Figure 7 is a structural schematic diagram of an over-temperature protection circuit provided by another exemplary embodiment of the present disclosure;

[0048] Figure 8 is a structural schematic diagram of an over-temperature protection circuit provided by another exemplary embodiment of the present disclosure;

[0049] Fig. 9 is a system block diagram of an electronic device provided by an exemplary embodiment of the present disclosure.

[0050] In the figure:

[0051] 10-temperature detection circuit; 20-switch unit; 30-hysteresis circuit; 31-first feedback circuit; 32-first voltage bias circuit; 33-second feedback circuit; 34-second voltage bias circuit; 40-charging device; 400-electronic device; 402-processing component; 404-memory; 406-power supply component; 408-multimedia component; 410-audio component; 412-input and output interface; 414-sensor component; 416-communication component; 420-processor; R1-first resistor; R2-second resistor; R3-third resistor; R4-fourth resistor; R5-fifth resistor; R6-sixth resistor; R7-seventh resistor; R8-eighth resistor; R9-ninth resistor; RT-thermistor; C-comparator; C1-first comparator; C2-second comparator; T-transistor; D-diode; VBUS-power supply terminal; VCC-power supply; GND-ground terminal. DETAILED DESCRIPTION

[0052] Here, exemplary embodiments will be described in detail, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the utility model. On the contrary, they are only examples of devices and methods consistent with some aspects of the utility model as detailed in the attached claims. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0053] At present, during the charging process of an electronic device, when the temperature of the electronic device is too high, the over-temperature protection circuit disconnects the charging device and the electronic device to reduce the temperature of the electronic device. After the disconnection between the charging device and the electronic device, the charging device stops charging the electronic device, and the temperature of the electronic device gradually decreases to avoid malfunction.

[0054] In the related art, an over-temperature protection circuit is provided, such as Figure 1As shown, the over-temperature protection circuit includes a transistor T, a diode D, a first resistor R1, a second resistor R2, a third resistor R3, a thermistor RT and a comparator C. The in-phase input terminal of the comparator C is coupled to the second end of the second resistor R2 and the first end of the third resistor R3, the inverting input terminal of the comparator C is coupled to the second end of the first resistor R1 and the first end of the thermistor RT, the output terminal of the comparator C is coupled to the control terminal of the transistor T, the first end of the comparator C, the first end of the first resistor R1 and the first end of the second resistor R2 are coupled to the power supply VCC, and the second end of the comparator C is used to couple to the ground terminal GND. The second end of the thermistor RT and the second end of the third resistor R3 are both used to couple to the ground terminal GND. The transistor T is coupled in parallel with the diode D, and the transistor T is coupled between the power supply terminal VBUS and the ground terminal GND of the electronic device. The power supply terminal VBUS is used to couple to a charging device. The transistor T is turned on or off by the level output by the comparator C, and the power supply terminal VBUS and the ground terminal GND are short-circuited or disconnected to stop or charge the electronic device, so as to avoid the temperature of the electronic device being too high during the charging process. Figure 2 As shown, during the charging process of the electronic device, the temperature of the electronic device will continue to rise, and the resistance of the thermistor RT decreases due to the temperature increase, causing the voltage at the inverting input terminal of the comparator C to decrease. When the temperature of the electronic device is higher than the preset temperature threshold, the voltage at the inverting input terminal of the comparator C is greater than the voltage at the inverting input terminal of the comparator C, and the comparator C outputs a high level to turn on the transistor T. The power supply terminal VBUS of the electronic device is short-circuited with the ground terminal GND to trigger the overcurrent protection of the charging device, and the charging device stops charging the electronic device, thereby reducing the temperature of the electronic device. When the temperature of the electronic device begins to decrease, the resistance of the thermistor RT increases due to the temperature decrease, causing the voltage at the inverting input terminal of the comparator C to gradually increase. When the temperature of the electronic device is lower than the preset temperature threshold, the voltage at the inverting input terminal of the comparator C is lower than the voltage at the inverting input terminal of the comparator C, and the comparator C outputs a low level to turn off the transistor T. The power supply terminal VBUS of the electronic device is no longer short-circuited with the ground terminal GND, and the charging device charges the electronic device. However, when the temperature of the electronic device is higher than the preset temperature threshold again, the charging device stops charging the electronic device again. When the temperature of the electronic device is lower than the preset temperature threshold again, the charging device charges the electronic device again, and the cycle continues until the charging is completed. x Indicates the temperature of the electronic device, R x Indicates the resistance of thermistor RT, C x Represents the output level of comparator C, V x represents the voltage of the power supply terminal VBUS, and S represents the preset temperature threshold. Since the over-temperature protection circuit causes the transistor T to be repeatedly turned on and off in a short period of time, the charging state of the electronic device changes repeatedly in a short period of time, causing damage to the electronic device.

[0055] Based on this, the present disclosure provides an over-temperature protection circuit. After the temperature of the electronic device is less than or equal to a first threshold, the charging state of the electronic device will not change. Instead, the charging state of the electronic device will change after a period of time when the temperature of the electronic device drops to less than a second temperature threshold. This can avoid repeated changes in the charging state of the electronic device in a short period of time to reduce the possibility of malfunction of the electronic device.

[0056] An exemplary embodiment of the present disclosure provides an over-temperature protection circuit. Figure 3 As shown, the over-temperature protection circuit includes a temperature detection circuit 10, a switch unit 20 and a hysteresis circuit 30. The temperature detection circuit 10 is used to detect the temperature of the electronic device. The first end of the switch unit 20 is used to couple with the charging device 40, the second end of the switch unit 20 is used to couple with the ground terminal GND, the first end of the hysteresis circuit 30 is coupled with the temperature detection circuit 10, and the second end of the hysteresis circuit 30 is coupled with the control end of the switch unit 20.

[0057] In this embodiment, the over-temperature protection circuit includes a temperature detection circuit, a switch unit and a hysteresis circuit. The hysteresis circuit is coupled between the temperature detection circuit and the switch unit, and the switch unit is coupled between the charging device and the ground terminal. Since the temperature of the electronic device is greater than the first temperature threshold or less than the second temperature threshold, the temperature detection circuit changes the voltage output by the hysteresis circuit, and the switch unit is controlled to be turned on or off to stop charging or charge the electronic device. Since the temperature of the electronic device is less than or equal to the first temperature threshold and greater than or equal to the second temperature threshold, the temperature detection circuit keeps the voltage output by the hysteresis circuit unchanged, and the state of the switch unit remains unchanged to avoid repeated changes in the charging state of the electronic device in a short time to reduce the possibility of failure of the electronic device. At the same time, since the switch unit does not need to be repeatedly turned on and off to protect the electronic device from over-temperature, the switching loss of the switch unit is reduced, thereby reducing the charging loss of the electronic device.

[0058] In one embodiment, if Figure 4As shown, the hysteresis circuit 30 includes a first comparator C1, a first feedback circuit 31 and a first voltage bias circuit 32. The first input terminal of the first comparator C1 is coupled to the temperature detection circuit 10, and the output terminal of the first comparator C1 is coupled to the control terminal of the switch unit 20. The first terminal of the first feedback circuit 31 is coupled to the output terminal of the first comparator C1, the second terminal of the first feedback circuit 31 is coupled to the second input terminal of the first comparator C1, and the third terminal of the first feedback circuit 31 is used to couple to the ground terminal GND. The first terminal of the first voltage bias circuit 32 is coupled to the output terminal of the first comparator C1 and the first terminal of the first feedback circuit 31, the second terminal of the first voltage bias circuit 32 is coupled to the second input terminal of the first comparator C1, and the third terminal of the first voltage bias circuit 32 is used to couple to the power supply VCC.

[0059] In this embodiment, since the hysteresis circuit includes a first feedback circuit and a first comparator, the voltage at the second input terminal of the first comparator can be changed by the first feedback circuit when the level of the output terminal of the first comparator changes. Since the temperature detection circuit is coupled to the first input terminal of the first comparator, when the voltage of the second input terminal of the first comparator changes, the voltage output by the temperature detection circuit that causes the level of the output terminal of the first comparator to change is different to correspond to different first temperature thresholds and second temperature thresholds. Since the hysteresis circuit only includes the first feedback circuit and the first comparator, the first temperature threshold is infinite or the second temperature threshold is 0°C, and the over-temperature protection circuit cannot perform over-temperature protection. By adding a first voltage bias circuit to the hysteresis circuit for voltage biasing, the first temperature threshold or the second temperature threshold can be set to a temperature that the electronic device can reach during the charging process, thereby improving the reliability of the over-temperature protection circuit.

[0060] Exemplarily, the first input terminal of the first comparator C1 may be an inverting input terminal, and the second input terminal of the first comparator C1 may be a non-inverting input terminal.

[0061] Exemplarily, the first comparator C1 is configured to be coupled to both the power supply VCC and the ground terminal GND.

[0062] In one embodiment, if Figure 5 As shown, the first feedback circuit 31 includes a first resistor R1 and a second resistor R2. The first end of the first resistor R1 is coupled to the output end of the first comparator C1, and the second end of the first resistor R1 is coupled to the second input end of the first comparator C1. The first end of the second resistor R2 is coupled to the second input end of the first comparator C1, and the second end of the second resistor R2 is used to couple to the ground end GND.

[0063] In this embodiment, since the first resistor is coupled between the output terminal of the first comparator and the second input terminal of the first comparator, and the second resistor is coupled between the second input terminal of the first comparator and the ground terminal, the first resistor and the second resistor change the voltage of the second input terminal of the first comparator when the level of the output terminal of the first comparator changes by means of voltage division. By using the first resistor and the second resistor to divide the voltage so that the voltage of the second input terminal of the first comparator changes with the level of the output terminal of the first comparator, the structure of the first feedback circuit is simple, thereby reducing the complexity of the over-temperature protection circuit structure.

[0064] In one embodiment, the first voltage bias circuit 32 includes a third resistor R3 and a fourth resistor R4. A first end of the third resistor R3 is coupled to the output end of the first comparator C1 and the first end of the first resistor R1, and a second end of the third resistor R3 is used to couple to the power supply VCC. A first end of the fourth resistor R4 is coupled to the second input end of the first comparator C1, and a second end of the fourth resistor R4 is used to couple to the power supply VCC.

[0065] In this embodiment, since the third resistor and the fourth resistor are both used to couple with the power supply and are respectively coupled with the first resistor and the second resistor, the third resistor and the fourth resistor can be combined with the first resistor and the second resistor to bias the voltage. By adding the third resistor and the fourth resistor and combining the first resistor and the second resistor to bias the voltage, the first temperature threshold or the second temperature threshold can be set to a temperature that the electronic device can reach during the charging process, thereby improving the reliability of the over-temperature protection circuit and reducing the complexity of the over-temperature protection circuit structure.

[0066] In one embodiment, the first resistor R1 , the second resistor R2 , the third resistor R3 , and the fourth resistor R4 have the same resistance value.

[0067] In this embodiment, by setting the resistance values ​​of the first resistor, the second resistor, the third resistor and the fourth resistor to the same resistance value, the complexity of the over-temperature protection circuit design is reduced while being able to set the first temperature threshold or the second temperature threshold to a temperature that the electronic device can reach during the charging process.

[0068] Exemplarily, the resistance values ​​of the first resistor R1 , the second resistor R2 , the third resistor R3 , and the fourth resistor R4 may all be 5KΩ, 10KΩ, 20KΩ, etc.

[0069] Exemplarily, the voltage of the power supply VCC is U, and the resistance values ​​of the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 are the same. When the first comparator C1 outputs a high level, the equivalent circuit of the hysteresis circuit 30 is as follows: Figure 6-1As shown, the voltage at the second input terminal of the first comparator C1 is 2U / 3. When the first comparator outputs a low level, the equivalent circuit of the hysteresis circuit 30 is as follows: Figure 6-2 As shown, the voltage at the second input terminal of the first comparator C1 is U / 3.

[0070] Exemplarily, the resistance values ​​of the first resistor R1 , the second resistor R2 , the third resistor R3 , and the fourth resistor R4 may all be different or partially the same or partially different.

[0071] For example, Figure 5 As shown, the switch unit 20 may include a transistor T. When the transistor T is an N-type field effect transistor, the drain of the transistor T is coupled to the charging device 40 , the source of the transistor T is coupled to the ground terminal GND, and the gate of the transistor T is coupled to the second end of the hysteresis circuit 30 .

[0072] Exemplarily, the switch unit 20 may further include a diode D, wherein an anode of the diode D is coupled to a source of the transistor T, and a cathode of the diode D is coupled to a drain of the transistor T. The diode D may be a body transistor of the transistor T.

[0073] It can be understood that the transistor T can also be a P-type field effect transistor.

[0074] In one embodiment, if Figure 7 As shown, the hysteresis circuit 30 includes a second comparator C2, a second feedback circuit 33, and a second voltage bias circuit 34. The first input terminal of the second comparator C2 is coupled to the temperature detection circuit 10, and the output terminal of the second comparator C2 is coupled to the control terminal of the switch unit 20. The first terminal of the second feedback circuit 33 is coupled to the output terminal of the second comparator C2, and the second terminal of the second feedback circuit 33 is coupled to the second input terminal of the second comparator C2. The first terminal of the second voltage bias circuit 34 is used to couple with the power supply VCC, the second terminal of the second voltage bias circuit 34 is used to couple with the ground terminal GND, and the third terminal of the second voltage bias circuit 34 is coupled with the third terminal of the second feedback circuit 33.

[0075] In this embodiment, since the hysteresis circuit includes a second feedback circuit and a second comparator, the voltage at the second input terminal of the second comparator can be changed by the second feedback circuit when the level of the output terminal of the second comparator changes. Since the temperature detection circuit is coupled to the first input terminal of the second comparator, when the voltage at the second input terminal of the second comparator changes, the voltage output by the temperature detection circuit that causes the level of the output terminal of the second comparator to change is different to correspond to different first temperature thresholds and second temperature thresholds. Since the hysteresis circuit only includes the second feedback circuit and the second comparator, the first temperature threshold is infinite or the second temperature threshold is 0°C, and the over-temperature protection circuit cannot perform over-temperature protection. By adding a second voltage bias circuit to the hysteresis circuit for voltage biasing, the first temperature threshold or the second temperature threshold can be set to a temperature that the electronic device can reach during the charging process, thereby improving the reliability of the over-temperature protection circuit.

[0076] Exemplarily, the first input terminal of the second comparator C2 may be an inverting input terminal, and the second input terminal of the second comparator C2 may be a non-inverting input terminal.

[0077] Exemplarily, the second comparator C2 is coupled to both the power supply VCC and the ground terminal GND.

[0078] In one embodiment, if Figure 8 As shown, the second feedback circuit 33 includes a fifth resistor R5 and a sixth resistor R6. A first end of the fifth resistor R5 is coupled to the output end of the second comparator C2, and a second end of the fifth resistor R5 is coupled to the second input end of the second comparator C2. A first end of the sixth resistor R6 is coupled to the second input end of the second comparator C2, and a second end of the sixth resistor R6 is coupled to the third end of the second voltage bias circuit 34.

[0079] In this embodiment, since the fifth resistor is coupled between the output terminal of the second comparator and the second input terminal of the second comparator, and the sixth resistor is coupled between the second input terminal of the second comparator and the second voltage bias circuit, the fifth resistor and the sixth resistor change the voltage of the second input terminal of the second comparator by voltage division when the level of the output terminal of the second comparator changes. By using the fifth resistor and the sixth resistor to divide the voltage so that the voltage of the second input terminal of the second comparator changes with the level of the output terminal of the second comparator, the structure of the second feedback circuit is simple, thereby reducing the complexity of the over-temperature protection circuit structure.

[0080] In one embodiment, the second voltage bias circuit 34 includes a seventh resistor R7 and an eighth resistor R8. A first end of the seventh resistor R7 is used to couple with the power supply VCC, and a second end of the seventh resistor R7 is coupled with a third end of the second feedback circuit 33. A first end of the eighth resistor R8 is coupled with a second end of the seventh resistor R7, and a second end of the eighth resistor R8 is used to couple with the ground terminal GND.

[0081] In this embodiment, since the seventh resistor and the eighth resistor are coupled in series between the power supply and the ground terminal, and the voltage after voltage division is input into the third terminal of the second feedback circuit to bias the voltage, the first temperature threshold or the second temperature threshold can be set to a temperature that the electronic device can reach during the charging process, thereby improving the reliability of the over-temperature protection circuit and reducing the complexity of the over-temperature protection circuit structure.

[0082] In one embodiment, the hysteresis circuit 30 is used to turn on the switch unit 20 when the temperature of the electronic device is greater than a first temperature threshold, and to turn off the switch unit 20 when the temperature of the electronic device is less than a second temperature threshold, wherein the first temperature threshold is greater than the second temperature threshold.

[0083] In this embodiment, when the temperature of the electronic device is greater than the first temperature threshold, the temperature of the electronic device is too high, and continuing to charge the electronic device may cause the electronic device to malfunction. By turning on the switch unit to short-circuit the charging device when the temperature of the electronic device is greater than the first temperature threshold, the electronic device is prevented from malfunctioning. When the temperature of the electronic device is less than the second temperature threshold, the temperature of the electronic device has been reduced to a safe temperature, and charging the electronic device will not cause the electronic device to malfunction. By turning off the switch unit to avoid short-circuiting the charging device when the temperature of the electronic device is less than the second temperature threshold, the charging device continues to charge the electronic device. Compared with an over-temperature protection circuit with only one preset temperature threshold, the charging state of the electronic device is changed only when the temperature of the electronic device is greater than the first temperature threshold or less than the second temperature threshold. When the temperature of the electronic device is greater than or equal to the second temperature threshold and less than or equal to the first temperature threshold, the state of the switch unit remains unchanged, avoiding the repeated changes of the charging state of the electronic device in a short time to reduce the possibility of malfunction of the electronic device.

[0084] Exemplarily, when the difference between the first temperature threshold and the second temperature threshold is greater, the temperature of the electronic device needs to change within a wider range in order to change the level output by the hysteresis circuit 30 .

[0085] In one embodiment, the temperature detection circuit 10 includes a temperature detection unit and a ninth resistor R9. The temperature detection unit and the ninth resistor R9 are coupled in series between the power supply VCC and the ground terminal GND. The first end of the hysteresis circuit 30 is coupled between the temperature detection unit and the ninth resistor R9.

[0086] In this embodiment, since the parameters of the temperature detection unit can change with the change of temperature, by connecting the ninth resistor in series between the power supply and the ground terminal, a voltage divider circuit can be formed so that the voltage output by the temperature detection circuit changes with the change of the temperature of the electronic device. Since the temperature detection circuit composed of the temperature detection unit and the ninth resistor can reflect the temperature of the electronic device, the structure of the temperature detection circuit is simple, thereby reducing the complexity of the over-temperature protection circuit structure.

[0087] In one embodiment, the temperature detection unit includes a thermistor RT with a negative temperature coefficient. The first end of the ninth resistor R9 is used to couple with the power supply VCC, and the second end of the ninth resistor R9 is coupled with the first end of the thermistor RT and the first end of the hysteresis circuit 30. The second end of the thermistor RT is used to couple with the ground terminal GND.

[0088] In this embodiment, since the thermistor has a simple structure and high sensitivity, by using the thermistor as a temperature detection unit, the temperature of the electronic device can be detected and the complexity of the temperature detection circuit structure can be reduced. Since the resistance of the thermistor with a negative temperature coefficient decreases as the temperature of the electronic device increases, by coupling the first end of the thermistor with the second end of the ninth resistor and the first end of the hysteresis circuit, the switch unit can be turned on when the temperature of the electronic device is greater than the first temperature threshold and turned off when the temperature of the electronic device is less than the second temperature threshold to improve the reliability of the over-temperature protection circuit.

[0089] Exemplarily, the temperature detection unit may further include a thermistor RT with a positive temperature coefficient. In this case, a first end of the thermistor RT is used to couple with the power supply VCC, and a second end of the thermistor RT is coupled with a first end of the ninth resistor R9 and a first end of the hysteresis circuit 30. A second end of the ninth resistor R9 is used to couple with the ground terminal GND.

[0090] In one embodiment, the temperature detection unit is disposed close to an interface of the electronic device.

[0091] In this embodiment, since the charging device charges the electronic device through the interface of the electronic device, the accuracy of temperature detection can be improved by arranging the temperature detection unit close to the interface of the electronic device.

[0092] Exemplarily, the temperature detection unit is disposed close to the interface of the electronic device, which may be to dispose the temperature detection unit within a preset range of the interface of the electronic device.

[0093] Exemplarily, the temperature detection unit may also be disposed close to a battery of the electronic device.

[0094] In one embodiment, if Figure 5 and Figure 8 As shown, the first end of the switch unit 20 is used to couple with the power supply terminal VBUS of the interface of the electronic device, and the power supply terminal VBUS is used to couple with the charging device 40 .

[0095] In this embodiment, by coupling the switch unit to the power supply terminal of the interface, when the switch unit is turned on, the voltage of the power supply terminal can be pulled down to the voltage of the ground terminal so that the charging device stops charging the electronic device, thereby improving the reliability of the over-temperature protection circuit.

[0096] An exemplary embodiment of the present disclosure provides an over-temperature protection circuit, such as Figure 5 As shown, the over-temperature protection circuit includes a transistor T, a diode D, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a ninth resistor R9, a thermistor RT and a first comparator C1. The non-inverting input terminal of the first comparator C1 is coupled to the second end of the first resistor R1, the first end of the second resistor R2 and the first end of the fourth resistor R4, the inverting input terminal of the first comparator C1 is coupled to the second end of the ninth resistor R9 and the first end of the thermistor RT, the output terminal of the first comparator C1 is coupled to the first end of the first resistor R1, the first end of the third resistor R3 and the gate of the transistor T, and the first comparator C1 is coupled to the power supply VCC and the ground terminal GND. The source of the transistor T is coupled to the anode of the diode D and the ground terminal GND, and the drain of the transistor T is coupled to the cathode of the diode D and the power supply terminal VBUS of the interface of the electronic device. The second end of the third resistor R3, the second end of the fourth resistor R4 and the first end of the ninth resistor R9 are all used to couple to the power supply VCC. The second end of the second resistor R2 and the second end of the thermistor RT are both coupled to the ground terminal GND.

[0097] Exemplarily, the voltage of the power supply VCC is 12V, and the resistance values ​​of the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 are all the same. When the temperature detected by the thermistor RT is 48°C, the resistance value of the thermistor RT is 5KΩ, and when the temperature of the thermistor RT is 35°C, the resistance value of the thermistor RT is 10KΩ. When the first comparator C1 outputs a high level, the voltage at the in-phase input terminal of the first comparator C1 is 8V. When the first comparator C1 outputs a low level, the voltage at the in-phase input terminal of the first comparator C1 is 4V. The working principle of the over-temperature protection circuit is as follows: During the charging process of the electronic device, when the temperature of the electronic device is higher than 48°C, the first comparator C1 outputs a high level to turn on the transistor T, and the power supply terminal VBUS and the ground terminal GND short-contact to trigger the over-current protection of the charging device 40, so that the charging device 40 stops charging the electronic device, thereby reducing the temperature of the electronic device. At this time, the voltage at the non-inverting input terminal of the first comparator C1 is 8V, the temperature of the electronic device gradually decreases, and the voltage at the inverting input terminal of the first comparator C1 gradually increases. When the temperature of the electronic device is lower than 35°C, the first comparator C1 outputs a low level to disconnect the transistor T, and the power supply terminal VBUS no longer short-circuits the charging device 40, so that the charging device 40 charges the electronic device. At this time, the voltage at the non-inverting input terminal of the first comparator C1 is 4V, and the temperature of the electronic device gradually increases, and this cycle continues until the charging is completed. Since the state of the switch unit 20 remains unchanged when the temperature of the electronic device is between 35°C and 48°C, the charging state of the electronic device is avoided from changing repeatedly in a short period of time to reduce the possibility of failure of the electronic device.

[0098] In an exemplary embodiment, a charging protection circuit is provided, and the charging protection circuit includes the over-temperature protection circuit as described above.

[0099] In an exemplary embodiment, an electronic device is provided, the electronic device comprising the over-temperature protection circuit or the charging protection circuit as described above. The electronic device is, for example, a mobile phone, a laptop computer, a tablet computer, a wearable device, and the like.

[0100] refer to Fig. 9 As shown, electronic device 400 may include one or more of the following components: a processing component 402 , a memory 404 , a power component 406 , a multimedia component 408 , an audio component 410 , an input / output (I / O) interface 412 , a sensor component 414 , and a communication component 416 .

[0101] The processing component 402 generally controls the overall operation of the electronic device 400, such as operations associated with display, phone calls, data communications, camera operations, and recording operations. The processing component 402 may include one or more processors 420 to execute instructions to complete all or part of the steps of the above-mentioned method. In addition, the processing component 402 may include one or more modules to facilitate the interaction between the processing component 402 and other components. For example, the processing component 402 may include a multimedia module to facilitate the interaction between the multimedia component 408 and the processing component 402.

[0102] The memory 404 is configured to store various types of data to support operations on the electronic device 400. Examples of such data include instructions for any application or method operating on the electronic device 400, contact data, phone book data, messages, pictures, videos, etc. The memory 404 can be implemented by any type of volatile or non-volatile storage terminal or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk.

[0103] The power supply component 406 provides power to the various components of the electronic device 400. The power supply component 406 may include a power management system, one or more power supplies, and other components associated with generating, managing, and distributing power to the electronic device 400.

[0104] The multimedia component 408 includes a screen that provides an output interface between the electronic device 400 and the user. In some embodiments, the screen may include a liquid crystal display (LCD) and a touch panel (TP). If the screen includes a touch panel, the screen may be implemented as a touch screen to receive input signals from the user. The touch panel includes one or more touch sensors to sense touch, slide, and gestures on the touch panel. The touch sensor may not only sense the boundaries of the touch or slide action, but also detect the duration and pressure associated with the touch or slide operation. In some embodiments, the multimedia component 408 includes a front camera module and / or a rear camera module. When the electronic device 400 is in an operating mode, such as a shooting mode or a video mode, the front camera module and / or the rear camera module may receive external multimedia data. Each front camera module and the rear camera module may be a fixed optical lens system or have a focal length and optical zoom capability.

[0105] The audio component 410 is configured to output and / or input audio signals. For example, the audio component 410 includes a microphone (MIC), and when the electronic device 400 is in an operating mode, such as a call mode, a recording mode, and a voice recognition mode, the microphone is configured to receive an external audio signal. The received audio signal can be further stored in the memory 404 or sent via the communication component 416. In some embodiments, the audio component 410 also includes a speaker for outputting audio signals.

[0106] I / O interface 412 provides an interface between processing component 402 and peripheral interface modules, such as keyboards, click wheels, buttons, etc. These buttons may include but are not limited to: a home button, a volume button, a start button, and a lock button.

[0107] The sensor assembly 414 includes one or more sensors for providing various aspects of status assessment for the electronic device 400. For example, the sensor assembly 414 can detect the open / closed state of the electronic device 400, the relative positioning of components, such as the display and keypad of the electronic device 400, and the sensor assembly 414 can also detect the position change of the electronic device 400 or a component of the electronic device 400, the presence or absence of user contact with the electronic device 400, the orientation or acceleration / deceleration of the electronic device 400, and the temperature change of the electronic device 400. The sensor assembly 414 may include a proximity sensor configured to detect the presence of nearby objects without any physical contact. The sensor assembly 414 may also include an optical sensor, such as a CMOS or CCD image sensor, for use in imaging applications. In some embodiments, the sensor assembly 414 may also include an accelerometer, a gyroscope sensor, a magnetic sensor, a pressure sensor, or a temperature sensor.

[0108] The communication component 416 is configured to facilitate wired or wireless communication between the electronic device 400 and other terminals. The electronic device 400 can access a wireless network based on a communication standard, such as WiFi, 2G, 3G, 4G, 5G, or a combination thereof. In an exemplary embodiment, the communication component 416 receives a broadcast signal or broadcast-related information from an external broadcast management system via a broadcast channel. In an exemplary embodiment, the communication component 416 also includes a near field communication (NFC) module to facilitate short-range communication. For example, the NFC module can be implemented based on radio frequency identification (RFID) technology, infrared data association (IrDA) technology, ultra-wideband (UWB) technology, Bluetooth (BT) technology and other technologies.

[0109] In an exemplary embodiment, the electronic device 400 may be implemented by one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing terminals (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors, or other electronic components.

[0110] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0111] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present disclosure, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0112] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the utility model disclosed herein. The present disclosure is intended to cover any variations, uses or adaptations of the present disclosure, which follow the general principles of the present disclosure and include common knowledge or customary technical means in the art that are not disclosed in the present disclosure. The specification and examples are to be regarded as exemplary only, and the true scope and spirit of the present disclosure are indicated by the claims.

[0113] It should be understood that the present disclosure is not limited to the exact structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. An over-temperature protection circuit, characterized in that: The over-temperature protection circuit comprises: A temperature detection circuit, wherein the temperature detection circuit is used to detect the temperature of the electronic device; A switch unit, wherein a first end of the switch unit is used to couple with a charging device, and a second end of the switch unit is used to couple with a ground terminal; A hysteresis circuit, wherein a first end of the hysteresis circuit is coupled to the temperature detection circuit, and a second end of the hysteresis circuit is coupled to the control end of the switch unit.

2. The over-temperature protection circuit according to claim 1, characterized in that: The hysteresis circuit comprises: A first comparator, wherein a first input terminal of the first comparator is coupled to the temperature detection circuit, and an output terminal of the first comparator is coupled to a control terminal of the switch unit; a first feedback circuit, wherein a first terminal of the first feedback circuit is coupled to the output terminal of the first comparator, a second terminal of the first feedback circuit is coupled to the second input terminal of the first comparator, and a third terminal of the first feedback circuit is used to couple to the ground terminal; A first voltage bias circuit, wherein a first end of the first voltage bias circuit is coupled to the output end of the first comparator and the first end of the first feedback circuit, a second end of the first voltage bias circuit is coupled to the second input end of the first comparator, and a third end of the first voltage bias circuit is used to couple to a power supply.

3. The over-temperature protection circuit according to claim 2, characterized in that: The first feedback circuit comprises: a first resistor, wherein a first end of the first resistor is coupled to the output end of the first comparator, and a second end of the first resistor is coupled to the second input end of the first comparator; A second resistor, wherein a first end of the second resistor is coupled to the second input end of the first comparator, and a second end of the second resistor is used to be coupled to the ground end.

4. The over-temperature protection circuit according to claim 3, characterized in that: The first voltage bias circuit comprises: a third resistor, wherein a first end of the third resistor is coupled to the output end of the first comparator and the first end of the first resistor, and a second end of the third resistor is used to couple to the power supply; A fourth resistor, wherein a first end of the fourth resistor is coupled to the second input end of the first comparator, and a second end of the fourth resistor is used to couple to the power supply.

5. The over-temperature protection circuit according to claim 4, characterized in that: The first resistor, the second resistor, the third resistor and the fourth resistor have the same resistance value.

6. The over-temperature protection circuit according to claim 1, characterized in that: The hysteresis circuit comprises: A second comparator, wherein a first input terminal of the second comparator is coupled to the temperature detection circuit, and an output terminal of the second comparator is coupled to the control terminal of the switch unit; a second feedback circuit, wherein a first terminal of the second feedback circuit is coupled to the output terminal of the second comparator, and a second terminal of the second feedback circuit is coupled to the second input terminal of the second comparator; A second voltage bias circuit, wherein the first end of the second voltage bias circuit is used to couple with a power supply, the second end of the second voltage bias circuit is used to couple with the ground end, and the third end of the second voltage bias circuit is coupled with the third end of the second feedback circuit.

7. The over-temperature protection circuit according to claim 6, characterized in that: The second feedback circuit comprises: a fifth resistor, wherein a first end of the fifth resistor is coupled to the output end of the second comparator, and a second end of the fifth resistor is coupled to the second input end of the second comparator; A sixth resistor, wherein a first end of the sixth resistor is coupled to the second input end of the second comparator, and a second end of the sixth resistor is coupled to the third end of the second voltage bias circuit.

8. The over-temperature protection circuit according to claim 6, characterized in that: The second voltage bias circuit comprises: a seventh resistor, wherein a first end of the seventh resistor is used to be coupled to the power supply, and a second end of the seventh resistor is coupled to a third end of the second feedback circuit; An eighth resistor, wherein a first end of the eighth resistor is coupled to the second end of the seventh resistor, and a second end of the eighth resistor is used to couple to the ground end.

9. The over-temperature protection circuit according to claim 1, characterized in that: The hysteresis circuit is used to turn on the switch unit when the temperature of the electronic device is greater than a first temperature threshold; and to turn off the switch unit when the temperature of the electronic device is less than a second temperature threshold; wherein the first temperature threshold is greater than the second temperature threshold.

10. The over-temperature protection circuit according to any one of claims 1 to 9, characterized in that: The temperature detection circuit includes a temperature detection unit and a ninth resistor; the temperature detection unit and the ninth resistor are coupled in series between a power supply and the ground terminal; wherein the first end of the hysteresis circuit is coupled between the temperature detection unit and the ninth resistor.

11. The over-temperature protection circuit according to claim 10, characterized in that: The temperature detection unit includes a thermistor with a negative temperature coefficient; the first end of the ninth resistor is used to couple with the power supply, and the second end of the ninth resistor is coupled with the first end of the thermistor and the first end of the hysteresis circuit; the second end of the thermistor is used to couple with the ground end.

12. The over-temperature protection circuit according to claim 10, characterized in that: The temperature detection unit is arranged close to the interface of the electronic device.

13. The over-temperature protection circuit according to any one of claims 1 to 9, characterized in that: The first end of the switch unit is used to couple with a power supply terminal of an interface of the electronic device, and the power supply terminal is used to couple with the charging device.

14. A charging protection circuit, characterized in that: The charging protection circuit comprises the over-temperature protection circuit as claimed in any one of claims 1 to 13.

15. An electronic device, characterized in that: The electronic device comprises the over-temperature protection circuit as described in any one of claims 1 to 13, or the charging protection circuit as described in claim 14.

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