Over-temperature protection circuit, method and chip
By adopting the combination of the first constant current source module, the second constant current source module and the comparative circuit module in the chip, the problems of complexity and high cost of traditional over-temperature protection circuits are solved, and the over-temperature protection effect with a simple structure and low cost are achieved.
Patent Information
- Application Number
- CN202311370622.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-10-20
- Publication Date
- 2025-04-22
AI Technical Summary
Traditional over-temperature protection circuits are relatively complex and occupy a large area, which increases the cost of the chip.
An over-temperature protection circuit including a first constant current source module, a second constant current source module and a comparison circuit module is adopted. The voltage changing with the ambient temperature is obtained through the thermistor, and compared with the reference voltage built into the comparison circuit module, and the current output by the constant current source module is controlled to achieve temperature protection.
It realizes a simple structure and low cost over-temperature protection circuit, avoiding the aging and damage of the circuit or chip at a high temperature for a long time.
Smart Images
Figure CN119864764A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of integrated circuits, and in particular to an over-temperature protection circuit, method and chip. Background Art
[0002] In order to ensure the performance of integrated circuits, it is necessary to design an over-temperature protection circuit inside the chip. When the chip temperature exceeds the reasonable operating temperature, the high-power module in the chip is turned off to protect the chip and the entire system, especially some high-power chips.
[0003] like Figure 1 The simplified schematic diagram of the conventional over-temperature protection circuit shown in FIG. 1 mainly consists of a bandgap reference source 3, a temperature detection circuit 2 and a comparator 1. The bandgap reference source 3 is used to generate a reference voltage V1 that is independent of temperature; the temperature detection circuit 2 is equivalent to a temperature sensor, which outputs a voltage V2 that is linearly related to the temperature. Generally, V2 will gradually decrease with the increase of temperature; the comparator 1 compares V1 and V2. When the temperature is low, V2 is greater than V1, and the output terminal OUT outputs a voltage representing logic "0". When the temperature gradually increases and exceeds a certain value, V2 is less than V1, and the output terminal OUT outputs a voltage representing logic "1", indicating that the chip temperature has exceeded the designed threshold temperature point.
[0004] However, the above-mentioned over-temperature protection circuit is relatively complex, occupies a large area, and increases the cost of the chip.
[0005] It should be noted that the information disclosed in the background technology section of the invention is only intended to deepen the understanding of the general background technology of the invention, and should not be regarded as an admission or suggestion in any form that the information constitutes prior art already known to those skilled in the art. Summary of the invention
[0006] The object of the present invention is to provide an over-temperature protection circuit, method and chip to solve the problem that the traditional over-temperature protection circuit is relatively complex, occupies a large area and increases the cost of the chip.
[0007] In order to solve the above technical problems, the present invention provides an over-temperature protection circuit, comprising:
[0008] A first constant current source module, used for outputting a first current to the thermistor;
[0009] A second constant current source module, used for outputting a second current to the thermistor, wherein the output ends of the first constant current source module and the second constant current source module are commonly connected to the first end of the thermistor, and the second end of the thermistor is connected to the ground end;
[0010] A comparison circuit module is used to provide an internal reference voltage for comparison with the input voltage of the thermistor, wherein the first end of the thermistor is connected to the input end of the comparison circuit module, and the output end of the comparison circuit module is sequentially connected to a first inverter and a second inverter, and the output end of the first inverter is also connected to the first constant current source module, so as to control the first current output by the first constant current source module, thereby changing the input voltage of the thermistor, and the thermistor is a positive temperature coefficient thermistor.
[0011] Preferably, it further comprises a first PMOS tube, wherein the source and drain of the first PMOS tube are respectively connected to the power supply voltage and the reference current, and the gate and drain of the first PMOS tube are interconnected.
[0012] Preferably, the first constant current source module includes a second PMOS tube and a sixth PMOS tube, the drain of the second PMOS tube is connected to the source of the sixth PMOS tube, the gate of the sixth PMOS tube is connected to the output end of the first inverter, and the drain of the sixth PMOS tube is connected to the first end of the thermistor, wherein the source of the second PMOS tube is connected to the power supply voltage, and the gate of the second PMOS tube is connected to the gate of the first PMOS tube.
[0013] Preferably, the second constant current source module includes a third PMOS tube, the drain of the third PMOS tube is connected to the first end of the thermistor, the source of the third PMOS tube is connected to the power supply voltage, and the gate of the third PMOS tube is connected to the gate of the first PMOS tube.
[0014] Preferably, the comparison circuit module comprises a first amplifier unit and a second amplifier unit which are connected in sequence.
[0015] Preferably, the first amplifier unit includes a fourth PMOS tube and a first NPN transistor, the drain of the fourth PMOS tube is connected to the collector of the first NPN transistor, the base of the first NPN transistor is connected to the first end of the thermistor, the emitter of the first NPN transistor and the second end of the thermistor are commonly connected to the ground end, the gate of the fourth PMOS tube is interconnected with the gate of the first PMOS tube, and the source of the fourth PMOS tube is connected to the power supply voltage.
[0016] Preferably, the second amplifier unit includes a fifth PMOS tube and a second NMOS tube, the drain of the fifth PMOS tube is connected to the drain of the second NMOS tube, the source of the second NMOS tube is connected to the ground terminal, and the gate of the second NMOS tube is connected to the collector of the first NPN transistor.
[0017] Preferably, the drain of the fifth PMOS tube is connected to the first inverter, the source of the fifth PMOS tube is connected to the power supply voltage, and the gate of the fifth PMOS tube is connected to the gate of the first PMOS tube.
[0018] The present invention also provides an over-temperature protection method, which uses the over-temperature protection circuit as described above, and also includes the following steps:
[0019] The voltage that changes with the ambient temperature is obtained through the thermistor and compared with the reference voltage built into the comparison circuit module. The comparison result is output through the first inverter and the second inverter, wherein:
[0020] The output end of the first inverter is connected to the first constant current source module to control the first current output by the first constant current source module. When the ambient temperature rises to exceed the required second temperature value, the first inverter outputs a first reference voltage, and the first constant current source module outputs the first current; when the ambient temperature drops to less than the first temperature value, the first inverter outputs a second reference voltage, the first constant current source module is disconnected and does not output the first current, and the first temperature value is less than the second temperature value.
[0021] The present invention also provides a chip, comprising the over-temperature protection circuit as described above.
[0022] In the over-temperature protection circuit and method provided by the present invention, the first current and the second current are input into the thermistor through the first constant current source module and the second constant current source module, and the thermistor inputs the comparison circuit module for comparison and output. Compared with the traditional scheme, it has the advantages of simple structure and low cost, and by introducing the first inverter to control the second current of the first constant current source module, the comparison circuit module can make the first inverter output the second reference voltage only when the ambient temperature drops back to the first temperature value, and the second inverter outputs the first reference voltage indicating that the temperature has returned to normal, thereby preventing the circuit or chip from being aged and damaged under high temperature for a long time.
[0023] The chip provided by the present invention and the over-temperature protection circuit provided by the present invention belong to the same inventive concept. Therefore, the chip provided by the present invention at least has all the advantages of the over-temperature protection circuit provided by the present invention, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 It is a simplified schematic diagram of a conventional over-temperature protection circuit;
[0025] Figure 2 is a circuit diagram of an over-temperature protection circuit provided by an embodiment of the present invention;
[0026] Figure 3Schematic diagram of a voltage curve of a thermistor in one embodiment of the present invention.
[0027] Figure 1 middle,
[0028] 1. Comparator; 2. Temperature detection circuit; 3. Bandgap reference source.
[0029] Figure 2 middle,
[0030] 100, a first constant current source module; 200, a second constant current source module; 300, a comparison circuit module; 301, a first amplifier unit; 302, a second amplifier unit. DETAILED DESCRIPTION
[0031] The over-temperature protection circuit, method and chip proposed in the present invention are further described in detail below in conjunction with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the drawings are all in a very simplified form and are all in an inaccurate proportion, which is only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. It should be understood that the drawings in the specification do not necessarily show the specific structure of the present invention in proportion, and the illustrative features used to illustrate certain principles of the present invention in the drawings in the specification will also adopt a slightly simplified drawing method. The specific design features of the present invention disclosed herein include, for example, specific dimensions, directions, positions and shapes, which will be determined in part by the specific environment to be applied and used. And, in the embodiments described below, sometimes the same figure mark is used in common between different drawings to represent the same part or a part with the same function, and its repeated description is omitted. In this specification, similar numbers and letters are used to represent similar items, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.
[0032] 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. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.
[0033] 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 invention. 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.
[0034] The inventors have found that common over-temperature protection circuits have problems such as complex structure, large occupied area and high cost.
[0035] Based on this, the core idea of the present invention is to compare and output through the first constant current source module, the second constant current source module and the thermistor input comparison circuit module, which has the advantages of simple structure and low cost compared with traditional solutions.
[0036] Specifically, Figure 2 As shown, an over-temperature protection circuit includes:
[0037] The first constant current source module 100 is used to output a first current I to the thermistor R1 A (unlabeled);
[0038] The second constant current source module 200 is used to output a second current I to the thermistor R1 B (not marked), the output ends of the first constant current source module 100 and the second constant current source module 200 are connected to the first end of the thermistor R1, and the second end of the thermistor R1 is connected to the ground end GND;
[0039] The comparison circuit module 300 is used to provide an internal reference voltage Vth for comparison with the input voltage of the thermistor R1. The first end of the thermistor R1 is connected to the input end of the comparison circuit module 300. The output end of the comparison circuit module 300 is connected to the first inverter INV1 and the second inverter INV2 in sequence. The output end of the first inverter INV1 is also connected to the first constant current source module 100, and is used to control the first current I output by the first constant current source module 100. A , thereby changing the input voltage of the thermistor R1. The thermistor R1 is a positive temperature coefficient thermistor.
[0040] Here, the thermistor R1 is described as a positive temperature coefficient thermistor.
[0041] The comparison output is performed through the voltage input comparison circuit module 300 of the thermistor R1, and the output result is changed when the temperature exceeds the tolerable second temperature value (T2), and the output is normally performed when the temperature drops below the first temperature value (T1), and the output of the first constant current source module 100 is controlled based on the output result of the first inverter INV1, so that the first temperature value and the second temperature value are different (T1≠T2), and the second temperature value is greater than the first temperature value (T2>T1), thereby ensuring that the ambient temperature can be reduced to a safe range, and the structure is simple and the cost is low.
[0042] The resistance of thermistor R1 will increase with the increase of temperature. When the temperature is normal, the resistance of thermistor R1 is small. Figure 2 In the embodiment, the voltage at the first node NETA is less than the reference voltage Vth provided by the comparison circuit module 300, the third node NETC of the comparison circuit module 300 outputs the first reference voltage, the first inverter INV1 outputs the second reference voltage, the output terminal OUT outputs the first reference voltage, and the sixth PMOS tube P6 is in the disconnected state. At this time, the voltage at the first node NETA changes with temperature as shown in FIG. Figure 3 As shown in L1.
[0043] The first reference voltage can also be considered as the minimum input voltage to maintain the output as logic "0", and the second reference voltage can also be considered as the maximum input voltage to maintain the output as logic "1". Obviously, the first reference voltage can also be the maximum input voltage to maintain the output as logic "1", and the second reference voltage is the minimum input voltage to maintain the output as logic "0", which can be set according to the circuit connected to the output terminal OUT. Here, the first reference voltage is the voltage of logic "0" and the second reference voltage is the voltage of logic "1" as an example for explanation.
[0044] When the temperature gradually rises and exceeds the temperature indicated by T2, the voltage of the first node NETA will exceed the reference voltage Vth, and the voltage of the third node NETC of the comparison circuit module 300 will jump from the first reference voltage to the second reference voltage, for example, from logic "0" to logic "1", causing the first inverter INV1 to output the first reference voltage (logic "0"), and the output terminal OUT outputs the second reference voltage (logic "1"), indicating that the temperature is too high. At the same time, the sixth PMOS tube P6 is turned on, and the curve of the voltage at the first node NETA changing with temperature is shown in L2. At this time, if the temperature continues to rise, the voltage at the first node NETA will still be greater than the reference voltage Vth, and the output of the third node NETC of the comparison circuit module 300, the values of the first inverter INV1 and the output terminal OUT will remain unchanged; if the temperature gradually decreases at this time, the voltage of the first node NETA will increase according to Figure 3L2 gradually decreases, and when the temperature drops below T1, the voltage of the first node NETA will be lower than the reference voltage Vth, and the output of the third node NETC of the comparison circuit module 300 jumps from the second reference voltage to the first reference voltage, for example, from logic "1" to logic "0", and the first inverter INV1 outputs the second reference voltage, or outputs logic "1", and the temperature returns to normal levels.
[0045] like Figure 2 As shown, it also includes a first PMOS tube P1, the source and drain of the first PMOS tube P1 are respectively connected to the power supply voltage VDD and the reference current, and the gate and drain of the first PMOS tube P1 are interconnected. Figure 2 As shown, the reference current is injected from the IBIAS port, and the value of the reference current has nothing to do with the temperature. After the reference current is input, it passes through the first PMOS tube P1 and is converted into a bias voltage at the fourth node NETD.
[0046] The first constant current source module 100 includes a second PMOS tube P2 and a sixth PMOS tube P6, wherein the drain of the second PMOS tube P2 is connected to the source of the sixth PMOS tube P6, the gate of the sixth PMOS tube P6 is connected to the output end of the first inverter INV1, and the drain of the sixth PMOS tube P6 is connected to the first end of the thermistor R1, wherein the source of the second PMOS tube P2 is connected to the power supply voltage VDD, and the gate of the second PMOS tube P2 is connected to the gate of the first PMOS tube P1.
[0047] The second constant current source module 200 includes a third PMOS tube P3, a drain of the third PMOS tube P3 is connected to the first end of the thermistor R1, a source of the third PMOS tube P3 is connected to the power supply voltage VDD, and a gate of the third PMOS tube P3 is connected to the gate of the first PMOS tube P1. Figure 2 The first node NETA is also the first end of the thermistor R1.
[0048] In this embodiment, the thermistor R1 is a positive temperature coefficient resistor, and the resistance value of the resistor increases with the increase of temperature. The curve of the voltage of the first node NETA changing with temperature is as follows: Figure 3 When the first inverter INV1 outputs the second reference voltage of logic "1", the sixth PMOS tube P6 is disconnected, and the voltage on the thermistor R1 (the voltage of the first node NETA) is:
[0049] V NetA_1 =R×I B
[0050] When the first inverter INV1 outputs the first reference voltage of logic “0”, the sixth PMOS tube P6 is turned on, and the voltage on the thermistor R1 (the voltage of the first node NETA) is:
[0051] V NetA_0 =R×(I B +I A )
[0052] Among them, I B represents the second current output by the second constant current source module 200, I A represents the second current output by the first constant current source module 100, and R represents the resistance of the temperature-sensitive resistor R1. The resistance of the temperature-sensitive resistor R1 increases with the increase of temperature. Figure 2 The current structure shown in FIG. 1 shows that the first current I of the first constant current source module 100 is A is much smaller than the second current I of the second constant current source module 200 B ,therefore, Figure 3 In the figure, L1 and L2 are similar, and the temperatures represented by T1 and T2 are approximately the same, and can be regarded as the same temperature value in actual use. If other circuits or chips are to be further protected, the first constant current source module 100 can be appropriately changed, such as connecting the source gate of the second PMOS tube P2 of the first constant current source module 100 to an external power supply to increase the first current I A , thereby increasing the difference between the temperature represented by T1 and the temperature represented by T2. When the ambient temperature drops to the temperature represented by T1, the corresponding value is output again, thereby preventing other circuits or chips from aging and being damaged due to being at a high temperature for a long time.
[0053] The comparison circuit module 300 includes a first amplifier unit 301 and a second amplifier unit 302 connected in sequence. The first amplifier unit 301 and the second amplifier unit 302 can be combined together to be regarded as a comparator with a built-in reference voltage Vth.
[0054] The first amplifier unit 301 includes a fourth PMOS transistor P4 and a first NPN transistor N1, the drain of the fourth PMOS transistor P4 is connected to the collector of the first NPN transistor N1, the base of the first NPN transistor N1 is connected to the first end of the thermistor R1, the emitter of the first NPN transistor N1 and the second end of the thermistor R1 are connected to the ground terminal GND, the gate of the fourth PMOS transistor P4 is interconnected with the gate of the first PMOS transistor P1, and the source of the fourth PMOS transistor P4 is connected to the power supply voltage VDD. The value of the reference voltage Vth of the comparison circuit module 300 is approximately equal to the turn-on voltage of the first NPN transistor N1.
[0055] The second amplifier unit 302 includes a fifth PMOS transistor P5 and a second NMOS transistor N2, the drain of the fifth PMOS transistor P5 is connected to the drain of the second NMOS transistor N2, the source of the second NMOS transistor N2 is connected to the ground terminal GND, the gate of the second NMOS transistor N2 is connected to the collector of the first NPN transistor N1. The drain of the fifth PMOS transistor P5 is connected to the first inverter INV1, the source of the fifth PMOS transistor P5 is connected to the power supply voltage VDD, and the gate of the fifth PMOS transistor P5 is connected to the gate of the first PMOS transistor P1.
[0056] In addition, the fourth node NETD is connected to the gate of the second PMOS tube P2, the gate of the third PMOS tube P3, the gate of the fourth PMOS tube P4 and the gate of the fifth PMOS tube P5, so the first PMOS tube P1 and the second PMOS tube P2, the third PMOS tube P3, the fourth PMOS tube P4 and the fifth PMOS tube P5 form a current mirror relationship. The second PMOS tube P2, the third PMOS tube P3, the fourth PMOS tube P4 and the fifth PMOS tube P5 can be equivalent to a constant current source that is independent of temperature, and the parameters flowing through each PMOS tube can be set according to the actual use situation, so that the current flowing through the second PMOS tube P2, the third PMOS tube P3, the fourth PMOS tube P4 and the fifth PMOS tube P5 is a multiple relationship with the reference current.
[0057] The present invention also provides an over-temperature protection method, which uses the over-temperature protection circuit as described above, and also includes the following steps:
[0058] The voltage that changes with temperature is obtained through the thermistor R1 and compared with the reference voltage Vth built into the comparison circuit module 300, and the comparison result is output through the first inverter INV1 and the second inverter INV2, wherein: the output terminal INV1 of the first inverter is connected to the first constant current source module 100 to control the first current I output by the first constant current source module 100 A .
[0059] When the ambient temperature rises to a value exceeding the required second temperature value T2, the first inverter INV1 outputs the first reference voltage, and the first constant current source module 100 outputs the first current I A When the ambient temperature drops below the first temperature value T1, the second inverter INV2 outputs the second reference voltage, and the first constant current source module 100 is disconnected and does not output the first current I A, the first temperature value T1 is less than the second temperature value T2. When the ambient temperature is greater than T2, the second inverter INV2 outputs a second reference voltage of logic "1", indicating that the ambient temperature exceeds, and when the ambient temperature drops below T1, the second inverter INV2 outputs a first reference voltage of logic "0", indicating that the ambient temperature reaches a normal level, wherein T2>T1.
[0060] The present invention also provides a chip, including the over-temperature protection circuit as described above. The chip here can be a high-power chip such as a switching power supply chip, a CAN transceiver chip, and a power amplifier chip.
[0061] In summary, it can be seen that in the over-temperature protection circuit, method and chip provided in the embodiments of the present invention, the comparison output is performed through the first constant current source module, the second constant current source module and the thermistor input comparison circuit module, which has the advantages of simple structure and low cost compared with traditional solutions.
[0062] The above description is only a description of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by a person skilled in the art in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.
Claims
1. An over-temperature protection circuit, characterized in that: include: A first constant current source module, used for outputting a first current to the thermistor; A second constant current source module, used for outputting a second current to the thermistor, wherein the output ends of the first constant current source module and the second constant current source module are commonly connected to the first end of the thermistor, and the second end of the thermistor is connected to the ground end; A comparison circuit module is used to provide an internal reference voltage for comparison with the input voltage of the thermistor, wherein the first end of the thermistor is connected to the input end of the comparison circuit module, and the output end of the comparison circuit module is sequentially connected to a first inverter and a second inverter, and the output end of the first inverter is also connected to the first constant current source module, so as to control the first current output by the first constant current source module, thereby changing the input voltage of the thermistor.
2. The over-temperature protection circuit according to claim 1, characterized in that: It also includes a first PMOS tube, wherein the source and drain of the first PMOS tube are respectively connected to the power supply voltage and the reference current, and the gate and drain of the first PMOS tube are interconnected.
3. The over-temperature protection circuit according to claim 2, characterized in that: The first constant current source module includes a second PMOS tube and a sixth PMOS tube, the drain of the second PMOS tube is connected to the source of the sixth PMOS tube, the gate of the sixth PMOS tube is connected to the output end of the first inverter, and the drain of the sixth PMOS tube is connected to the first end of the thermistor, wherein the source of the second PMOS tube is connected to the power supply voltage, and the gate of the second PMOS tube is connected to the gate of the first PMOS tube.
4. The over-temperature protection circuit according to claim 2, characterized in that: The second constant current source module includes a third PMOS tube, the drain of the third PMOS tube is connected to the first end of the thermistor, the source of the third PMOS tube is connected to the power supply voltage, and the gate of the third PMOS tube is connected to the gate of the first PMOS tube.
5. The over-temperature protection circuit according to claim 2, characterized in that: The comparison circuit module includes a first amplifier unit and a second amplifier unit connected in sequence.
6. The over-temperature protection circuit according to claim 5, characterized in that: The first amplifier unit includes a fourth PMOS tube and a first NPN transistor, the drain of the fourth PMOS tube is connected to the collector of the first NPN transistor, the base of the first NPN transistor is connected to the first end of the thermistor, the emitter of the first NPN transistor and the second end of the thermistor are commonly connected to the ground end, the gate of the fourth PMOS tube is interconnected with the gate of the first PMOS tube, and the source of the fourth PMOS tube is connected to the power supply voltage.
7. The over-temperature protection circuit according to claim 6, characterized in that: The second amplifier unit includes a fifth PMOS tube and a second NMOS tube, the drain of the fifth PMOS tube is connected to the drain of the second NMOS tube, the source of the second NMOS tube is connected to the ground terminal, and the gate of the second NMOS tube is connected to the collector of the first NPN transistor.
8. The over-temperature protection circuit according to claim 7, characterized in that: The drain of the fifth PMOS tube is connected to the first inverter, the source of the fifth PMOS tube is connected to the power supply voltage, and the gate of the fifth PMOS tube is connected to the gate of the first PMOS tube.
9. An over-temperature protection method, characterized in that: The over-temperature protection circuit according to any one of claims 1 to 8 further comprises the following steps: The voltage that changes with the ambient temperature is obtained through the thermistor and compared with the reference voltage built into the comparison circuit module. The comparison result is output through the first inverter and the second inverter, wherein: The output end of the first inverter is connected to the first constant current source module to control the first current output by the first constant current source module. When the ambient temperature rises to exceed the required second temperature value, the first inverter outputs a first reference voltage, and the first constant current source module outputs the first current; when the ambient temperature drops to less than the first temperature value, the first inverter outputs a second reference voltage, the first constant current source module is disconnected and does not output the first current, and the first temperature value is less than the second temperature value.
10. A chip, characterized in that: Comprising the over-temperature protection circuit as described in any one of claims 1-8.