Over-temperature protection circuit

Abstract

The utility model provides an over-temperature protection circuit, which comprises at least two temperature detection units and an over-temperature protection driving circuit, the temperature detection units are used for detecting temperatures at different positions in a power device and outputting detection signals, and the over-temperature protection driving circuit outputs trigger signals according to the detection signals. And when the trigger signal indicates over-temperature, the trigger signal controls the power device to be turned off. According to the utility model, the temperature at different positions in the power device can be detected, and the plurality of temperature detection units are dispersedly distributed at the corresponding positions of the power device to detect the local heat of the power device, so that the temperature of the power device can be detected more comprehensively and more accurately, and the power device is more convenient to use. And the risk of thermal failure of the power device is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of power devices, in particular to an over-temperature protection circuit. Background Art

[0002] At present, some power devices usually integrate power devices. When the power devices work, they will generate heat, resulting in an increase in the temperature of the power devices. When the temperature of the power devices is too high, the power devices are prone to thermal failure. In order to avoid thermal failure of the power devices, a conventional power device will be provided with an over-temperature protection circuit. However, the current over-temperature protection circuit usually only includes one temperature detection element, so the position of the temperature detection element in the power device is particularly important.

[0003] However, a power device may integrate multiple power devices, and it is difficult to predict in advance the heat generated by each power device during operation. It is difficult to accurately arrange the temperature detection element around the power device with the highest heat generation; at the same time, for a power device with an area of up to several square millimeters, the temperature at different positions within the power device may differ by more than 20 °C, and the detection result of a single temperature detection element may not be able to detect the temperature at a position with a higher temperature within the power device.

[0004] Therefore, a single temperature detection element cannot accurately detect the temperature of the power device, resulting in a relatively high risk of thermal failure of the power device. Summary of the Utility Model

[0005] The purpose of the utility model is to provide an over-temperature protection circuit for reducing the risk of thermal failure of power devices.

[0006] In order to achieve the above purpose, the utility model provides an over-temperature protection circuit, including:

[0007] At least two temperature detection units for detecting the temperature at different positions within the power device and outputting detection signals;

[0008] An over-temperature protection drive circuit for outputting a trigger signal according to the detection signal, and when the trigger signal indicates over-temperature, the trigger signal controls the power device to turn off.

[0009] Optionally, the over-temperature protection drive circuit includes:

[0010] A first current biasing unit for providing a first biasing current for each of the temperature detection units;

[0011] At least two over-temperature protection units, each over-temperature protection unit is connected between the power supply terminal and the ground terminal, each of the over-temperature protection units is connected to the corresponding temperature detection unit, receives a reference voltage and the corresponding detection signal, and outputs a corresponding comparison signal; and,

[0012] A trigger unit, connected to each of the over-temperature protection units, is configured to output the trigger signal indicating over-temperature according to any one of the comparison signals indicating over-temperature.

[0013] Optionally, when the temperature coefficient of the temperature detection unit connected to the over-temperature protection unit is a negative temperature coefficient, the over-temperature protection unit receives the corresponding detection signal and outputs a corresponding comparison signal indicating over-temperature when the corresponding detection signal is less than the reference voltage.

[0014] Optionally, when the temperature coefficient of the temperature detection unit connected to the over-temperature protection unit is a positive temperature coefficient, the over-temperature protection unit receives the corresponding detection signal and outputs a corresponding comparison signal indicating over-temperature when the corresponding detection signal is greater than the reference voltage.

[0015] Optionally, each of the over-temperature protection units includes:

[0016] A second current biasing unit, configured to provide a second bias current and a third bias current; and

[0017] A comparison unit, connected to the second current biasing unit and the corresponding temperature detection unit, receives the reference voltage, the second bias current, the third bias current, and the corresponding detection signal, compares the magnitude of the corresponding detection signal with the reference voltage, and outputs the corresponding comparison signal.

[0018] Optionally, the first current biasing unit includes a first transistor, at least two second transistors, and a first current source. The first ends of the first transistor and each of the second transistors are connected to a power supply terminal. After the control terminals of the first transistor and each of the second transistors are connected, they are connected to the second end of the first transistor and the first end of the first current source. The second end of the first current source is grounded, and the second end of each of the second transistors provides the first bias current.

[0019] Optionally, the second current biasing units in each of the over-temperature protection units share the first current source in the first current biasing unit.

[0020] Optionally, the second current biasing unit includes a third transistor and a fourth transistor. The first ends of the third transistor and the fourth transistor are both connected to the power supply terminal. After the control terminals of the third transistor and the fourth transistor are connected to each other, they are connected to the control terminal of the corresponding second transistor. The second ends of the third transistor and the fourth transistor respectively provide the second bias current and the third bias current.

[0021] Optionally, the second current biasing unit includes a third transistor and a first resistor. The first ends of the third transistor and the first resistor are both connected to the power supply terminal. The control terminal of the third transistor is connected to the control terminal of the corresponding second transistor. The second ends of the third transistor and the first resistor respectively provide the second bias current and the third bias current.

[0022] Optionally, the second current biasing units in each over-temperature protection unit share the second current source in one of the second current biasing units.

[0023] Optionally, the second current biasing unit includes a third transistor and a fourth transistor. One of the second current biasing units further includes a tenth transistor and a second current source. The first ends of the third transistor, the fourth transistor, and the tenth transistor are all connected to the power supply terminal. The control terminals of the third transistor and the fourth transistor are connected to each other and then connected to the control terminal of the tenth transistor, the second end of the tenth transistor, and the first end of the second current source. The second end of the second current source is grounded. The second ends of the third transistor and the fourth transistor respectively provide the second bias current and the third bias current.

[0024] Optionally, the second current biasing unit includes a third transistor and a first resistor. One of the second current biasing units further includes a tenth transistor and a second current source. The first ends of the third transistor, the first resistor, and the tenth transistor are all connected to the power supply terminal. The control terminal of the third transistor is connected to the control terminal of the tenth transistor, the second end of the tenth transistor, and the first end of the second current source. The second end of the second current source is grounded. The second ends of the third transistor and the first resistor respectively output the second bias current and the third bias current.

[0025] Optionally, the comparison unit includes a fifth transistor, a sixth transistor, a seventh transistor, an eighth transistor, and a ninth transistor;

[0026] The first ends of the fifth transistor and the sixth transistor are connected and then connected to the second current biasing unit for receiving the second bias current. One of the control terminals of the fifth transistor and the sixth transistor is connected to the corresponding temperature detection unit to receive the detection signal, and the other is for receiving the reference voltage;

[0027] The second end and the control terminal of the seventh transistor are connected and then connected to the second end of the fifth transistor and the control terminal of the eighth transistor. The second end of the eighth transistor is connected to the second end of the sixth transistor. The first ends of the seventh transistor and the eighth transistor are grounded; and,

[0028] The second terminal of the ninth transistor is connected to the second current biasing unit for receiving the third biasing current. The first terminal of the ninth transistor is grounded. The control terminal of the ninth transistor is connected to the second terminal of the eighth transistor. A node between the second terminal of the ninth transistor and the second current biasing unit outputs the comparison signal.

[0029] Optionally, when the temperature coefficient of the temperature detection unit is a negative temperature coefficient, the control terminal of the fifth transistor is connected to the corresponding temperature detection unit, and the reference voltage is input to the control terminal of the sixth transistor; when the temperature coefficient of the temperature detection unit is a positive temperature coefficient, the control terminal of the sixth transistor is connected to the corresponding temperature detection unit, and the reference voltage is input to the control terminal of the fifth transistor.

[0030] Optionally, one of the at least two over-temperature protection units further includes a filtering unit. The reference voltage is input to the input terminal of the comparison unit of each over-temperature protection unit via the filtering unit. Each over-temperature protection unit shares the filtering unit in one of the over-temperature protection units.

[0031] Optionally, the over-temperature protection unit further includes a filtering unit. The filtering unit includes a second resistor and a capacitor. The first terminal of the second resistor receives the reference voltage. The second terminal of the second resistor is connected to the first terminal of the capacitor and the control terminal of the fifth transistor or the sixth transistor in any one of the comparison units to provide the reference voltage for any one of the comparison units. The second terminal of the capacitor is grounded.

[0032] Optionally, the at least two over-temperature protection units further include respective filtering units. Each filtering unit includes a second resistor and a capacitor. The first terminal of each second resistor receives the reference voltage. The second terminal of each second resistor is connected to the first terminal of the corresponding capacitor and the control terminal of the fifth transistor or the sixth transistor in the corresponding comparison unit. The second terminal of each capacitor is grounded.

[0033] Optionally, the temperature detection unit is a triode, MOS transistor, diode or resistor having a temperature coefficient.

[0034] Optionally, the trigger unit includes an OR gate. Each input terminal of the OR gate is connected to the corresponding over-temperature protection unit to receive the corresponding comparison signal. The output terminal of the OR gate outputs the trigger signal.

[0035] Optionally, the temperature detection units are dispersedly distributed at corresponding positions of the power device.

[0036] Optionally, the temperature detection units are evenly distributed within the power device.

[0037] Optionally, the temperature detection units are unevenly distributed within the power device.

[0038] Optionally, the temperature detection unit is configured to detect the temperature of a local part of the power device.

[0039] Optionally, the over-temperature protection driving circuit is located outside the power device.

[0040] In the over-temperature protection circuit provided by the present utility model, it includes at least two temperature detection units and an over-temperature protection driving circuit. The temperature detection units are configured to detect the temperatures at different positions within the power device and output detection signals. The over-temperature protection driving circuit outputs a trigger signal according to the detection signals. When the trigger signal indicates over-temperature, the trigger signal controls the power device to turn off.

[0041] The present utility model can detect the temperatures at different positions within the power device. By dispersedly distributing multiple temperature detection units at corresponding positions of the power device, it detects the local heat of the power device, so as to more comprehensively and accurately detect the temperature of the power device and reduce the risk of thermal failure of the power device.

[0042] Further, the over-temperature protection units of the present utility model can share a filtering unit, thus saving costs. Or each over-temperature protection unit can have its own filtering unit, so that the comparison unit receives the reference voltage filtered by an independent filtering unit, thereby avoiding interference between comparison units and improving the accuracy of temperature detection;

[0043] Further, the first bias current, the second bias current, and the third bias current of the present utility model can be generated by sharing a first current source, thus saving costs. Or they can be generated by different current sources, thereby eliminating the influence of the comparison unit on the temperature detection unit and improving the accuracy of temperature detection. Description of the Drawings

[0044] Figure 1 Circuit diagram of the over-temperature protection circuit provided in Embodiment 1 of the present invention;

[0045] Figure 2 Schematic diagram of the positions of the temperature detection units on the power device provided in Embodiment 1 of the present invention;

[0046] Figure 3 Circuit diagram of the over-temperature protection circuit provided in Embodiment 2 of the present invention;

[0047] Figure 4 Circuit diagram of the over-temperature protection circuit provided in Embodiment 3 of the present invention;

[0048] Figure 5 The circuit diagram of the over-temperature protection circuit provided in the fourth embodiment of the present invention;

[0049] Figure 6 The circuit diagram of the over-temperature protection circuit provided in the fifth embodiment of the present invention;

[0050] Wherein, the reference numerals are:

[0051] 100 - over-temperature protection unit; 101 - first current biasing unit; 102 - second current biasing unit; 200 - temperature detection unit; 300 - comparison unit; 400 - trigger unit;

[0052] MP1 - first transistor; MP2 - second transistor; MP3 - third transistor; MP4 - fourth transistor; MP5 - fifth transistor; MP6 - sixth transistor; MN7 - seventh transistor; MN8 - eighth transistor; MN9 - ninth transistor; MP10 - tenth transistor; I1 - first current source; I2 - second current source; VREF - reference voltage; R1 - first resistor; R2 - second resistor; C - capacitor; COMP - comparison signal; OUT - trigger signal; OR - OR gate. Detailed implementation manners

[0053] The following will describe the detailed implementation manners of the present utility model in more detail with reference to the schematic diagrams. According to the following description, the advantages and features of the present utility model will be clearer. It should be noted that the drawings are all in a very simplified form and use non-precise scales, only for the purpose of conveniently and clearly assisting in explaining the embodiments of the present utility model.

[0054] Embodiment 1

[0055] Figure 1 For the circuit diagram of the over-temperature protection circuit provided in this embodiment. As Figure 1 shown, the over-temperature protection circuit includes n (n≥2) temperature detection units 200 and an over-temperature protection driving circuit. Wherein, the temperature detection unit 200 is used to detect the temperature at different positions in the power device and output a detection signal, and the over-temperature protection driving circuit outputs a trigger signal OUT according to the detection signal. When the trigger signal OUT indicates over-temperature, the trigger signal OUT controls the power device to turn off.

[0056] The over-temperature protection driving circuit includes a first current biasing unit 101, n over-temperature protection units 100, and a trigger unit 400. Each of the over-temperature protection units 100 includes a second current biasing unit 102 and a comparison unit 300. Among them, the first current biasing unit 101 is configured to provide a first biasing current for each of the temperature detection units 200. Each over-temperature protection unit 100 is connected between a power supply terminal VDD and a ground terminal GND. Each of the over-temperature protection units 100 is connected to a corresponding one of the temperature detection units 200 to receive a reference voltage VREF and a corresponding detection signal, and output a corresponding comparison signal COMP. The trigger unit 400 is connected to each of the over-temperature protection units 100 and is configured to output a trigger signal OUT indicating over-temperature according to any one of the comparison signals COMP indicating over-temperature.

[0057] Specifically, the first current biasing unit 101 is configured to provide a first biasing current for each of the temperature detection units 200. Specifically, the first current biasing unit 101 is an active current mirror, which includes a first transistor MP1, n second transistors MP2, and a first current source I1. A first end of the first transistor MP1 and each of the second transistors MP2 is connected to the power supply terminal. After the control ends of the first transistor MP1 and each of the second transistors MP2 are connected, they are connected to a second end of the first transistor MP1 and a first end of the first current source I1. A second end of the first current source I1 is grounded. A second end of each of the second transistors MP2 is connected to a first end of a corresponding one of the temperature detection units 200 to provide the first biasing current for the corresponding temperature detection unit 200, and a second end of the temperature detection unit 200 is grounded.

[0058] The temperature detection units 200 are arranged at different positions in the power device and are configured to detect the temperatures at different positions in the power device and output the detection signals. In this embodiment, the power device is a power device, and the over-temperature protection circuit is configured to perform over-temperature protection on the power device. It should be noted that when the temperature at the position where the temperature detection unit 200 is located changes, the voltage on the first end of the temperature detection unit 200 also changes accordingly. The voltage signal on the first end of the temperature detection unit 200 is the detection signal output by the temperature detection unit 200. The temperature detection unit 200 is configured to detect the local temperature of the power device.

[0059] For example, Figure 2 is a schematic diagram of the positions of the temperature detection units 200 provided in this embodiment on the power device, as shown in Figure 2As shown, the temperature detection unit 200 may be dispersedly distributed at corresponding positions of the power device, but it should not be limited thereto. The temperature detection unit 200 may also be uniformly distributed or non-uniformly distributed within the power device.

[0060] It should be noted that Figure 2 4 of the temperature detection units 200 are schematically shown in [reference], but it should be understood that the number of the temperature detection units 200 is not limited to 4, and may also be 2, 3, 5 or more.

[0061] Further, the temperature detection unit 200 may be a temperature detection element with a temperature coefficient, such as a triode, MOS transistor, diode or resistor with a temperature coefficient. The temperature coefficient of the temperature detection unit 200 may be a negative temperature coefficient or a positive temperature coefficient. In this embodiment, the temperature coefficient of the temperature detection unit 200 is a negative temperature coefficient.

[0062] The second current biasing unit 102 is used to provide a second bias current and a third bias current. The second current biasing unit 102 in each over-temperature protection unit 100 may share the first current source I1 in the first current biasing unit 101. Specifically, the second current biasing unit 102 includes a third transistor MP3 and a fourth transistor MP4. The first ends of the third transistor MP3 and the fourth transistor MP4 are both connected to the power supply terminal. The control ends of the third transistor MP3 and the fourth transistor MP4 are connected to each other and then connected to the control end of the corresponding second transistor MP2. The second ends of the third transistor MP3 and the fourth transistor MP4 respectively provide the second bias current and the third bias current.

[0063] Please continue to refer to Figure 1 , the comparison unit 300 is connected to the corresponding temperature detection unit 200 and the corresponding second current biasing unit 102, receives the reference voltage VREF, the second bias current, the third bias current and the corresponding detection signal. The comparison unit 300 compares the magnitude of the corresponding detection signal with the reference voltage VREF and outputs the comparison signal COMP.

[0064] In this embodiment, the comparison unit 300 includes a fifth transistor MP5, a sixth transistor MP6, a seventh transistor MN7, an eighth transistor MN8 and a ninth transistor MN9. Among them, the fifth transistor MP5 and the sixth transistor MP6 form a differential pair transistor, and the seventh transistor MN7 and the eighth transistor MN8 form an active load.

[0065] The first ends of the fifth transistor MP5 and the sixth transistor MP6 are both connected to the second end of the third transistor MP3 to receive the second bias current. The control end of the fifth transistor MP5 is connected to the first end of the corresponding temperature detection unit 200 to receive the detection signal. The control end of the sixth transistor MP6 is used to input the reference voltage VREF. The second end and the control end of the seventh transistor MN7 are connected and then connected to the second end of the fifth transistor MP5 and the control end of the eighth transistor MN8. The second end of the eighth transistor MN8 is connected to the second end of the sixth transistor MP6. The first ends of the seventh transistor MN7 and the eighth transistor MN8 are grounded. The second end of the ninth transistor MN9 is connected to the second end of the fourth transistor MP4 to receive the third bias current. The first end of the ninth transistor MN9 is grounded. The control end of the ninth transistor MN9 is connected to the second end of the eighth transistor MN8. The node between the second end of the ninth transistor MN9 and the second end of the fourth transistor MP4 outputs the comparison signal COMP.

[0066] It should be understood that the voltage at the node between the second end of the eighth transistor MN8 and the second end of the sixth transistor MP6 can represent the magnitude relationship between the detection signal and the reference voltage VREF. The ninth transistor MN9 can perform level conversion on the voltage at the node between the second end of the eighth transistor MN8 and the second end of the sixth transistor MP6 to improve the driving ability, thereby outputting the comparison signal COMP. The comparison signal COMP can also represent the magnitude relationship between the detection signal and the reference voltage VREF.

[0067] Further, in this embodiment, one of the at least two over-temperature protection units further includes a filtering unit. The reference voltage is input to the input end of the comparison unit of each over-temperature protection unit via the filtering unit. Each over-temperature protection unit shares the filtering unit in one of the over-temperature protection units. The filtering unit includes a second resistor R2 and a capacitor C. The first end of the second resistor R2 receives the reference voltage VREF. The second end of the second resistor R2 is connected to the first end of the capacitor C and the control end of the sixth transistor MP6 in any one of the comparison units 300. The second end of the capacitor C is grounded. The node between the second end of the second resistor R2 and the first end of the capacitor C is connected to the control end of the sixth transistor MP6 in other comparison units 300 to provide the reference voltage VREF for other comparison units 300.

[0068] The trigger unit 400 is connected to each of the over-temperature protection units 100, specifically to the comparison unit 300 of each of the over-temperature protection units 100, and is configured to receive all the comparison signals COMP. When any one of the comparison signals COMP indicates that the detection signal is less than the reference voltage VREF, it indicates that the temperature of the power device has exceeded the set temperature, and the trigger signal OUT indicating over-temperature is output. When the trigger signal OUT indicates over-temperature, the trigger signal OUT can control the power device to stop working. It can be seen that in this embodiment, the temperature at different positions within the power device can be detected. By dispersedly distributing multiple temperature detection units at corresponding positions of the power device, the local heat of the power device is detected, so that the temperature of the power device can be detected more comprehensively and accurately, reducing the risk of thermal failure of the power device.

[0069] It should be noted that when the temperature coefficient of the temperature detection unit 200 is a positive temperature coefficient, the control terminal of the sixth transistor MP6 is connected to the first terminal of the temperature detection unit 200 to receive the detection signal, while the control terminal of the fifth transistor MP5 is configured to receive the reference voltage VREF. At this time, the second terminal of the second resistor R2 is connected to the first terminal of the capacitor C and the control terminal of the fifth transistor MP5 in any one of the comparison units 300, and the node between the second terminal of the second resistor R2 and the first terminal of the capacitor C is connected to the control terminal of the fifth transistor MP5 in other comparison units 300 to provide the reference voltage VREF for other comparison units 300.

[0070] Furthermore, when the temperature coefficient of the temperature detection unit 200 is a positive temperature coefficient, when any one of the comparison signals COMP indicates that the detection signal is greater than the reference voltage VREF, it indicates that the temperature of the power device has exceeded the set temperature, and the trigger signal OUT indicating over-temperature is output. When the trigger signal OUT indicates over-temperature, the trigger signal OUT can be used to control the power device to stop working.

[0071] In this embodiment, the trigger unit 400 is an n-input OR gate OR. Each input terminal of the OR gate OR is connected to the corresponding comparison unit 300 to receive the corresponding comparison signal COMP, and the output terminal of the OR gate OR outputs the trigger signal OUT.

[0072] In some embodiments, the trigger unit 400 can also be built by one or more other logic devices, and no further examples will be given here.

[0073] In this embodiment, the first transistor MP1, the second transistor MP2, the third transistor MP3, the fourth transistor MP4, the fifth transistor MP5, and the sixth transistor MP6 are all PMOS transistors, and the seventh transistor MN7, the eighth transistor MN8, and the ninth transistor MN9 are all NMOS transistors.

[0074] The first ends of the first transistor MP1, the second transistor MP2, the third transistor MP3, the fourth transistor MP4, the fifth transistor MP5, the sixth transistor MP6, the seventh transistor MN7, the eighth transistor MN8, and the ninth transistor MN9 are their source electrodes; the second ends of the first transistor MP1, the second transistor MP2, the third transistor MP3, the fourth transistor MP4, the fifth transistor MP5, the sixth transistor MP6, the seventh transistor MN7, the eighth transistor MN8, and the ninth transistor MN9 are their drain electrodes; the control ends of the first transistor MP1, the second transistor MP2, the third transistor MP3, the fourth transistor MP4, the fifth transistor MP5, the sixth transistor MP6, the seventh transistor MN7, the eighth transistor MN8, and the ninth transistor MN9 are their gate electrodes.

[0075] Of course, in some embodiments, the first transistor MP1, the second transistor MP2, the third transistor MP3, the fourth transistor MP4, the fifth transistor MP5, the sixth transistor MP6, the seventh transistor MN7, the eighth transistor MN8, and the ninth transistor MN9 can also all be triodes. In this case, the first ends of the first transistor MP1, the second transistor MP2, the third transistor MP3, the fourth transistor MP4, the fifth transistor MP5, the sixth transistor MP6, the seventh transistor MN7, the eighth transistor MN8, and the ninth transistor MN9 are their emitter electrodes; the second ends of the first transistor MP1, the second transistor MP2, the third transistor MP3, the fourth transistor MP4, the fifth transistor MP5, the sixth transistor MP6, the seventh transistor MN7, the eighth transistor MN8, and the ninth transistor MN9 are their collector electrodes; the control ends of the first transistor MP1, the second transistor MP2, the third transistor MP3, the fourth transistor MP4, the fifth transistor P5, the sixth transistor MP6, the seventh transistor MN7, the eighth transistor MN8, and the ninth transistor MN9 are their base electrodes.

[0076] Embodiment 2

[0077] Figure 3 Schematic diagram of the over-temperature protection circuit provided in this embodiment. As Figure 3 shown, the difference from the first embodiment is that in this embodiment, the second current biasing unit 102 includes the third transistor MP3 and the fourth transistor MP4, and one of the second current biasing units 102 further includes the tenth transistor MP10 and the second current source I2.

[0078] Specifically, the first ends of the third transistor MP3, the fourth transistor MP4, and the tenth transistor MP10 are all connected to the power supply terminal. The control ends of the third transistor MP3, the fourth transistor MP4, and the tenth transistor MP10 are connected to each other and then connected to the second end of the tenth transistor MP10 and the first end of the second current source I2. The second end of the second current source I2 is grounded. In this way, the second ends of the third transistor MP3 and the fourth transistor MP4 can also provide the second bias current and the third bias current respectively.

[0079] In this embodiment, the tenth transistor MP10 is a PMOS transistor. The first end of the tenth transistor MP10 is its source electrode, the second end of the tenth transistor MP10 is its drain electrode, and the control end of the tenth transistor MP10 is its gate electrode. Of course, in some embodiments, the tenth transistor MP10 can also be a triode. At this time, the first end of the tenth transistor MP10 is its emitter, the second end of the tenth transistor MP10 is its collector, and the control end of the tenth transistor MP10 is its base electrode.

[0080] Compared with the first embodiment, in this embodiment, the second current sources in the second current biasing units in each over-temperature protection unit share the second current source in one of the second current biasing units. Specifically, one of all the over-temperature protection units includes its own current source, such as the second current source I2. Then, the other over-temperature protection units among all the over-temperature protection units share the second current source I2 in this over-temperature protection unit. Therefore, in this embodiment, the generation of the second bias current and the third bias current is generated by different current sources from the generation of the first bias current, eliminating the influence of the comparison unit 300 on the temperature detection unit 200 and improving the accuracy of temperature detection.

[0081] Embodiment Three

[0082] Figure 4 Schematic diagram of the over-temperature protection circuit provided in this embodiment. As Figure 4As shown, the difference from the first embodiment is that, in this embodiment, the second current biasing unit 102 includes the third transistor MP3 and the first resistor R1. The first ends of the third transistor MP3 and the first resistor R1 are both connected to the power supply terminal. The control terminals of the third transistor MP3 are connected to each other and then connected to the control terminal of the corresponding second transistor MP2. The second ends of the third transistor MP3 and the first resistor R1 respectively provide the second bias current and the third bias current.

[0083] Compared with the first embodiment, in this embodiment, the first resistor R1 is used to replace the fourth transistor MP4. There is no parasitic capacitance C path between the node between the second end of the ninth transistor MN9 and the second end of the first resistor R1 and between the third transistor MP3 and the second transistor MP2, avoiding the problem that when the voltage swing at the node between the second end of the ninth transistor MN9 and the second end of the first resistor R1 is large, it causes fluctuations in the first bias current, the second bias current, and the third bias current, and further leads to inaccurate temperature detection, thereby improving the accuracy of temperature detection.

[0084] Embodiment Four

[0085] Figure 5 This is a schematic structural diagram of the overtemperature protection circuit provided in this embodiment. As Figure 5 shown, the difference from the first embodiment is that, in this embodiment, the second current biasing unit 102 includes the third transistor MP3 and the first resistor R1, and one of the second current biasing units 102 further includes a tenth transistor MP10 and a second current source I2.

[0086] Specifically, the first ends of the third transistor MP3, the first resistor R1, and the tenth transistor MP10 are all connected to the power supply terminal. The control terminals of the third transistor MP3 and the tenth transistor MP10 are connected to each other and then connected to the second end of the tenth transistor MP10 and the first end of the second current source I2. The second end of the second current source I2 is grounded. In this way, the second ends of the third transistor MP3 and the first resistor R1 can also provide and output the second bias current and the third bias current.

[0087] In this embodiment, the tenth transistor MP10 is a PMOS transistor. The first end of the tenth transistor MP10 is its source electrode, the second end of the tenth transistor P10 is its drain electrode, and the control end of the tenth transistor MP10 is its gate electrode. Of course, in some embodiments, the tenth transistor MP10 can also be a triode. In this case, the first end of the tenth transistor MP10 is its emitter, the second end of the tenth transistor MP10 is its collector, and the control end of the tenth transistor MP10 is its base electrode.

[0088] Compared with the first embodiment, in this embodiment, the first bias current, the second bias current, and the third bias current are generated by different current mirrors, eliminating the influence of the comparison unit 300 on the temperature detection unit 200 and improving the accuracy of temperature detection.

[0089] At the same time, the first resistor R1 is used to replace the fourth transistor MP4. There is no parasitic capacitance C path between the node between the second end of the ninth transistor MN9 and the second end of the first resistor R1 and between the third transistor MP3 and the second transistor MP2, avoiding the problem that when the voltage swing at the node between the second end of the ninth transistor MN9 and the second end of the first resistor R1 is large, the first bias current, the second bias current, and the third bias current fluctuate, resulting in inaccurate temperature detection, and improving the accuracy of temperature detection.

[0090] Embodiment Five

[0091] Figure 6 is a schematic structural diagram of the over-temperature protection circuit provided in this embodiment. As Figure 6 shown, the difference from the first embodiment is that in this embodiment, the over-temperature protection circuit further includes n filtering units, and the filtering units correspond to the comparison unit 300 one by one. Each filtering unit includes a second resistor R2 and a capacitor C. The first end of the second resistor R2 receives the reference voltage VREF. The second end of the second resistor R2 is connected to the first end of the capacitor C and the control end of the sixth transistor MP6 in the corresponding comparison unit 300, and the second end of the capacitor C is grounded.

[0092] Compared with the first embodiment, in this embodiment, the filtering units correspond to the comparison unit 300 one by one, and the comparison unit 300 receives the reference voltage VREF filtered by the independent filtering units, thereby avoiding interference between the comparison units 300 and improving the accuracy of temperature detection.

[0093] In summary, in the over-temperature protection circuit provided by the embodiment of the present utility model, it includes at least two temperature detection units and an over-temperature protection drive circuit. The temperature detection unit is used to detect the temperatures at different positions inside the power device and output a detection signal. The over-temperature protection drive circuit outputs a trigger signal according to the detection signal. When the trigger signal indicates over-temperature, the trigger signal controls the power device to turn off. The present utility model can detect the temperatures at different positions inside the power device. By dispersedly distributing multiple temperature detection units at corresponding positions of the power device, the heat of the local part of the power device is detected, so that the temperature of the power device can be detected more comprehensively and accurately, and the risk of thermal failure of the power device is reduced.

[0094] It should be noted that the various embodiments in this specification are described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. The same or similar parts among the various embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the description in the method part.

[0095] It should also be noted that although the present utility model has been disclosed above with preferred embodiments, the above embodiments are not intended to limit the present utility model. For any person skilled in the art, without departing from the scope of the technical solution of the present utility model, many possible changes and modifications can be made to the technical solution of the present utility model by using the technical content disclosed above, or it can be modified into an equivalent embodiment with equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present utility model without departing from the content of the technical solution of the present utility model still belong to the scope of protection of the technical solution of the present utility model.

[0096] It should also be understood that unless otherwise specified or indicated, the terms "first", "second", "third", etc. in the specification are only used to distinguish each component, element, step, etc. in the specification, rather than to represent the logical relationship or sequence relationship, etc. between each component, element, step.

[0097] In addition, it should be recognized that the terms described herein are only used to describe specific embodiments and are not intended to limit the scope of the present utility model. It must be noted that the singular forms "a" and "an" used herein and in the appended claims include plural referents unless the context clearly dictates otherwise. For example, the reference to "a step" or "a device" means a reference to one or more steps or devices and may include secondary steps as well as secondary devices. All conjunctions used should be understood in their broadest sense. Also, the word "or" should be understood to have the definition of a logical "or" rather than a logical "exclusive or" unless the context clearly dictates otherwise. In addition, the implementation of the methods and / or devices in the embodiments of the present utility model may include performing the selected tasks manually, automatically, or in combination.

Claims

1. An over-temperature protection circuit, characterized in that: include: At least two temperature detection units, used to detect the temperature at different positions in the power device and output a detection signal; The over-temperature protection driving circuit is used to output a trigger signal according to the detection signal, and when the trigger signal indicates over-temperature, the trigger signal controls the power device to shut down.

2. The over-temperature protection circuit according to claim 1, characterized in that: The over-temperature protection driving circuit comprises: A first current bias unit, providing a first bias current for each of the temperature detection units; at least two over-temperature protection units, each of which is connected between a power supply terminal and a ground terminal, each of which is connected to a corresponding temperature detection unit, receives a reference voltage and a corresponding detection signal, and outputs a corresponding comparison signal; and A trigger unit is connected to each of the over-temperature protection units and is used to output the trigger signal indicating over-temperature according to any comparison signal indicating over-temperature.

3. The over-temperature protection circuit according to claim 2, characterized in that: When the temperature coefficient of the temperature detection unit connected to the over-temperature protection unit is a negative temperature coefficient, the over-temperature protection unit receives the corresponding detection signal, and outputs the comparison signal indicating over-temperature when the corresponding detection signal is less than the reference voltage.

4. The over-temperature protection circuit according to claim 2, characterized in that: When the temperature coefficient of the temperature detection unit connected to the over-temperature protection unit is a positive temperature coefficient, the over-temperature protection unit receives the corresponding detection signal, and outputs the comparison signal indicating over-temperature when the corresponding detection signal is greater than the reference voltage.

5. The over-temperature protection circuit according to any one of claims 2 to 4, characterized in that: Each of the over-temperature protection units comprises: a second current bias unit, configured to provide a second bias current and a third bias current; and A comparison unit is connected to the second current bias unit and the corresponding temperature detection unit, receives the reference voltage, the second bias current, the third bias current and the corresponding detection signal, compares the corresponding detection signal with the reference voltage, and outputs the corresponding comparison signal.

6. The over-temperature protection circuit according to claim 5, characterized in that: The first current bias unit includes a first transistor, at least two second transistors and a first current source, the first transistor and the first end of each of the second transistors are connected to a power supply end, the first transistor is connected to the control end of each of the second transistors and then connected to the second end of the first transistor and the first end of the first current source, the second end of the first current source is grounded, and the second end of each of the second transistors provides the first bias current.

7. The over-temperature protection circuit according to claim 6, characterized in that: The second current biasing unit in each of the over-temperature protection units shares the first current source in the first current biasing unit.

8. The over-temperature protection circuit according to claim 7, characterized in that: The second current bias unit includes a third transistor and a fourth transistor, wherein the first ends of the third transistor and the fourth transistor are both connected to the power supply end, the control ends of the third transistor and the fourth transistor are connected to each other and then connected to the corresponding control end of the second transistor, and the second ends of the third transistor and the fourth transistor provide the second bias current and the third bias current respectively.

9. The over-temperature protection circuit according to claim 7, characterized in that: The second current bias unit includes a third transistor and a first resistor, the first ends of the third transistor and the first resistor are both connected to the power supply end, the control end of the third transistor is connected to the corresponding control end of the second transistor, and the second ends of the third transistor and the first resistor provide the second bias current and the third bias current respectively.

10. The over-temperature protection circuit according to claim 6, characterized in that: The second current biasing units in each of the over-temperature protection units share the second current source in one of the second current biasing units.

11. The over-temperature protection circuit according to claim 10, characterized in that: The second current bias unit includes a third transistor and a fourth transistor, wherein one of the second current bias units further includes a tenth transistor and a second current source, the first ends of the third transistor, the fourth transistor and the tenth transistor are all connected to the power supply end, the control ends of the third transistor and the fourth transistor are connected to each other and then connected to the control end of the tenth transistor, the second end of the tenth transistor and the first end of the second current source, the second end of the second current source is grounded, and the second ends of the third transistor and the fourth transistor provide the second bias current and the third bias current respectively.

12. The over-temperature protection circuit according to claim 10, characterized in that: The second current bias unit includes a third transistor and a first resistor, wherein one of the second current bias units further includes a tenth transistor and a second current source, the first end of the third transistor, the first resistor and the tenth transistor are all connected to the power supply end, the control end of the third transistor is connected to the control end of the tenth transistor, the second end of the tenth transistor and the first end of the second current source, the second end of the second current source is grounded, and the second ends of the third transistor and the first resistor output the second bias current and the third bias current respectively.

13. The over-temperature protection circuit according to claim 5, characterized in that: The comparison unit includes a fifth transistor, a sixth transistor, a seventh transistor, an eighth transistor and a ninth transistor; The first ends of the fifth transistor and the sixth transistor are connected to the second current bias unit to receive the second bias current, one of the control ends of the fifth transistor and the sixth transistor is connected to the corresponding temperature detection unit to receive the detection signal, and the other is used to receive the reference voltage; The second end of the seventh transistor is connected to the control end and then connected to the second end of the fifth transistor and the control end of the eighth transistor, the second end of the eighth transistor is connected to the second end of the sixth transistor, and the first ends of the seventh transistor and the eighth transistor are grounded; and The second end of the ninth transistor is connected to the second current bias unit for receiving the third bias current, the first end of the ninth transistor is grounded, the control end of the ninth transistor is connected to the second end of the eighth transistor, and the node between the second end of the ninth transistor and the second current bias unit outputs the comparison signal.

14. The over-temperature protection circuit according to claim 13, characterized in that: When the temperature coefficient of the temperature detection unit is a negative temperature coefficient, the control end of the fifth transistor is connected to the corresponding temperature detection unit, and the control end of the sixth transistor is input with the reference voltage; When the temperature coefficient of the temperature detection unit is a positive temperature coefficient, the control end of the sixth transistor is connected to the corresponding temperature detection unit, and the control end of the fifth transistor is input with the reference voltage.

15. The over-temperature protection circuit according to claim 5, characterized in that: One of the at least two over-temperature protection units further includes a filter unit, and the reference voltage is input to the input end of the comparison unit of each over-temperature protection unit via the filter unit, and each of the over-temperature protection units shares the filter unit in the one over-temperature protection unit.

16. The over-temperature protection circuit according to claim 13, characterized in that: The over-temperature protection unit also includes a filtering unit, which includes a second resistor and a capacitor, wherein the first end of the second resistor receives the reference voltage, the second end of the second resistor is connected to the first end of the capacitor and the control end of the fifth transistor or the sixth transistor in any one of the comparison units to provide the reference voltage for any one of the comparison units, and the second end of the capacitor is grounded.

17. The over-temperature protection circuit according to claim 13, characterized in that: The at least two over-temperature protection units also include respective filtering units, each of the filtering units includes a second resistor and a capacitor, the first end of each of the second resistors receives the reference voltage, the second end of each of the second resistors is connected to the first end of the corresponding capacitor and the control end of the fifth transistor or the sixth transistor in the corresponding comparison unit, and the second end of each of the capacitors is grounded.

18. The over-temperature protection circuit according to claim 1, characterized in that: The temperature detection unit is a triode, a MOS tube, a diode or a resistor with a temperature coefficient.

19. The over-temperature protection circuit according to claim 2, characterized in that: The trigger unit comprises an OR gate, each input end of the OR gate is connected to a corresponding over-temperature protection unit to receive the corresponding comparison signal, and the output end of the OR gate outputs the trigger signal.

20. The over-temperature protection circuit according to claim 1, characterized in that: The temperature detection units are distributed in a dispersed manner at corresponding positions of the power device.

21. The over-temperature protection circuit according to claim 17, characterized in that: The temperature detection units are evenly distributed in the power device.

22. The over-temperature protection circuit according to claim 17, characterized in that: The temperature detection units are non-uniformly distributed in the power device.

23. The over-temperature protection circuit according to claim 1, characterized in that: The temperature detection unit is used to detect the local temperature of the power device.

24. The over-temperature protection circuit according to claim 1, characterized in that: The over-temperature protection driving circuit is located outside the power device.

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