Temperature protection signal generation circuit and temperature protection point adjustment method

Abstract

Disclosed are a temperature protection signal generating circuit and a temperature protection point adjustment method. The non-inverting input terminal of the comparator in the temperature protection signal generating circuit selectively accesses a detection signal or a reference signal through a first switch, and the inverting input terminal accesses a detection signal or a reference signal through a second switch or is connected to the output terminal of the comparator, so as to obtain a temperature protection signal by comparing the detection signal and the reference signal through the comparator. The detection signal and the reference signal are obtained by detection, and a reference voltage target value is calculated based on the reference signal and the detection signal; the reference signal is adjusted according to the reference voltage target value and the first reference signal, or the reference signal is adjusted according to the reference voltage target value and the second detection signal, so that the reference signal corresponds to the reference signal at the target protection temperature. The temperature protection signal generating circuit and the temperature protection point adjustment method proposed by the present invention have a simple circuit structure, a simple and easy adjustment process, and a high adjustment accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic circuits, and in particular to a temperature protection signal generating circuit and a temperature protection point adjustment method. Background Art

[0002] In electronic devices, if the temperature of the system or chip is too high or too low, it will affect the service life and reliability of the components or chips in the system. It is usually necessary to set a temperature protection point. When the temperature exceeds or falls below this point, temperature protection is performed to achieve over-temperature protection (for example, disconnecting the power supply at high temperature) or under-temperature regulation control (for example, controlling the heating device to heat at low temperature).

[0003] In over-temperature protection, if Figure 1 As shown, the comparator U1 compares the detection signal V2 and the reference signal V1 to provide an over-temperature protection signal OTP, and the system or chip performs over-temperature protection (for example, disconnecting the power supply, etc.) according to the over-temperature protection signal OTP, wherein at least one of the detection signal V2 and the reference signal V1 is a temperature-sensitive signal, so that the temperature-voltage characteristic curves of the detection signal V2 and the reference signal V1 have an intersection, and the temperature of the intersection corresponds to the state reversal point of the over-temperature protection signal OTP provided by the output end of the comparator U1, corresponding to the temperature protection point Totp.

[0004] In actual applications, the state of the comparator U1, the state of the detection signal V2, and the state of the reference signal V1 often deviate from the ideal state, causing the actual temperature protection point Totp to deviate from the target temperature protection point set according to the ideal value, thereby reducing the reliability of the temperature protection.

[0005] The test of the temperature protection point in the prior art requires controlling the temperature for simulation, which has high cost for temperature control and high cost for adjusting the temperature protection point. Summary of the Invention

[0006] In view of the above problems, the purpose of the present invention is to provide a temperature protection signal generating circuit and a temperature protection point adjustment method, so as to conveniently realize the actual temperature protection point adjustment of the temperature protection signal generating circuit and reduce the adjustment cost of the temperature protection point.

[0007] According to one aspect of the present invention, a temperature protection signal generating circuit is provided. The temperature protection signal generating circuit includes: a comparator, a first switch, a second switch and a reference signal adjustment circuit, wherein:

[0008] The reference signal adjustment circuit receives a reference voltage and outputs a reference signal.

[0009] The non-inverting input terminal of the comparator receives the reference signal or the detection signal through the first switch, and the inverting input terminal of the comparator receives the reference signal or the detection signal through the second switch or is connected to the output terminal of the comparator.

[0010] At least one of the detection signal and the reference signal is a temperature-sensitive voltage signal, and the comparator outputs a temperature protection signal based on a comparison between the detection signal and the reference signal.

[0011] Optionally, in a trimming environment, the temperature protection signal generating circuit detects and obtains a detection signal and a reference signal. When the inverting input terminal of the comparator is connected to the output terminal of the comparator via the second switch, the temperature protection signal generating circuit enables the non-inverting input terminal of the comparator to receive the reference signal via the first switch, so as to detect and obtain a first reference signal at the output terminal of the comparator.

[0012] Based on the detection signal and the reference signal, a reference voltage target value of the temperature protection signal generating circuit in a trimming environment is obtained through calculation and processing, and the reference signal is adjusted according to the reference voltage target value and the first reference signal, so that the reference signal corresponds to the reference signal at the target protection temperature.

[0013] Optionally, in a trimming environment, the temperature protection signal generating circuit detects and obtains a detection signal and a reference signal. When the inverting input terminal of the comparator is connected to the output terminal of the comparator via the second switch, the temperature protection signal generating circuit enables the non-inverting input terminal of the comparator to receive the detection signal via the first switch, so as to detect at the output terminal of the comparator and obtain a second detection signal.

[0014] Based on the detection signal and the reference signal, the reference voltage target value of the temperature protection signal generating circuit in the trimming environment is obtained through calculation and processing, and the reference signal is adjusted according to the reference voltage target value and the second detection signal, so that the reference signal corresponds to the reference signal at the target protection temperature.

[0015] Optionally, the reference signal adjustment circuit includes an input terminal for receiving the reference voltage and an output terminal for outputting the reference signal, and the reference signal adjustment circuit includes:

[0016] A first resistor and a second resistor are sequentially connected in series between the input terminal of the reference signal conditioning circuit and the ground, and the middle node between the first resistor and the second resistor is the output terminal of the reference signal conditioning circuit, wherein,

[0017] At least one of the first resistor and the second resistor is a variable resistor, and the level of the reference signal is adjusted by adjusting the variable resistor.

[0018] Optionally, the temperature protection signal generating circuit further includes:

[0019] A transistor, wherein the base of the transistor is connected to the collector, the collector of the transistor is connected to the output end of the current source, the emitter of the transistor is grounded, and the collector of the transistor provides the detection signal.

[0020] Optionally, there are multiple transistors, which are sequentially connected in series between the output end of the current source and the ground, and the collector of at least one of the multiple transistors provides the detection signal.

[0021] Optionally, the reference signal adjustment circuit includes an input terminal for receiving the reference voltage and an output terminal for outputting the reference signal, and the reference signal adjustment circuit includes:

[0022] a plurality of resistors connected in series between an input terminal of the reference signal conditioning circuit and ground; and

[0023] The third switch includes a common terminal connected to the output terminal of the reference signal adjustment circuit and a plurality of fixed contact terminals connected to each adjacent node of the plurality of resistors.

[0024] According to another aspect of the present invention, a method for adjusting a temperature protection point is provided, comprising:

[0025] In a trimming environment, the detection signal and the reference signal are detected respectively. When the inverting input terminal of the comparator is connected to the output terminal of the comparator, the non-inverting input terminal of the comparator receives the reference signal to detect at the output terminal of the comparator to obtain a first reference signal, or the non-inverting input terminal of the comparator receives the detection signal to detect at the output terminal of the comparator to obtain a second detection signal; the temperature protection performs temperature protection according to the temperature protection signal obtained by comparing the detection signal with the reference signal;

[0026] Calculate and obtain a reference voltage target value based on the reference signal, the detection signal and its temperature characteristics, and the target protection temperature;

[0027] The reference signal is adjusted according to the reference voltage target value and the first reference signal, or according to the reference voltage target value and the second detection signal, so that the reference signal corresponds to the base signal at the target protection temperature.

[0028] Optionally, the reference signal is a voltage signal with a zero temperature coefficient or a positive temperature coefficient, and the detection signal is a voltage signal with a negative temperature coefficient, a zero temperature coefficient or a positive temperature coefficient.

[0029] Optionally, the reference signal is provided by an intermediate node of a first resistor and a second resistor connected in series between a reference voltage output path and ground, at least one of the first resistor and the second resistor is a variable resistor, and the reference signal is adjusted by adjusting the resistance of the variable resistor.

[0030] Optionally, the detection signal is a voltage signal between the base and emitter of a transistor, the transistor is connected between the output end of the current source and the ground, and the base of the transistor is connected to the collector.

[0031] Optionally, the temperature protection signal is obtained through a comparator.

[0032] The non-inverting input terminal of the comparator receives the reference signal or the detection signal through the first switch,

[0033] The inverting input terminal of the comparator receives the reference signal or the detection signal through a second switch, or is connected to the output terminal of the comparator.

[0034] By selecting the conduction paths of the first switch and the second switch, at least one of the second detection signal, the first reference signal and the temperature protection signal is selectively obtained at the output end of the comparator.

[0035] Optionally, the step of adjusting the reference signal according to the reference voltage target value and the first reference signal specifically includes:

[0036] The inverting input terminal of the comparator is connected to the output terminal of the comparator, and the non-inverting input terminal of the comparator receives the reference signal to detect and obtain a first reference signal at the output terminal of the comparator, and the reference signal is adjusted so that the first reference signal detected after the reference signal is adjusted matches the reference voltage target value.

[0037] Optionally, the step of adjusting the reference signal according to the reference voltage target value and the second detection signal specifically includes:

[0038] The reference signal is adjusted to match Vref-(V2'-V2), wherein Vref is the reference voltage target value, V2' is the second detection signal, V2 is the detection signal, and the second detection signal is a signal obtained by processing the detection signal through a comparator.

[0039] The non-inverting input terminal of the comparator in the temperature protection signal generating circuit provided by the present invention is selectively connected to the detection signal or the reference signal through the first switch, and the inverting input terminal is connected to the detection signal or the reference signal or connected to the output terminal of the comparator through the second switch, so as to obtain the temperature protection signal by comparing the detection signal and the reference signal through the comparator. The detection signal and the reference signal are obtained by detection, and the reference voltage target value is calculated based on the reference signal and the detection signal. The reference signal is adjusted according to the reference voltage target value and the first reference signal, or the reference signal is adjusted according to the reference voltage target value and the second detection signal, so that the reference signal corresponds to the reference signal at the target protection temperature. The temperature protection signal generating circuit and the temperature protection point adjustment method proposed by the present invention have a simple circuit structure, a simple and easy adjustment process, and a high adjustment accuracy. The present invention facilitates the detection and adjustment of the temperature protection point at room temperature, provides a strong guarantee for the accuracy of temperature protection, and reduces the cost of temperature protection point adjustment. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The above and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0041] Figure 1 shows a schematic diagram of a temperature protection signal generating circuit according to the prior art;

[0042] Figure 2A 、 Figure 2B and Figure 2C shows the temperature-voltage characteristic curves of some signals of the temperature protection signal generating circuit according to an embodiment of the present invention;

[0043] Figure 3 A schematic diagram showing the principle of temperature protection signal generation of a temperature protection signal generation circuit according to an embodiment of the present invention is shown;

[0044] Figure 4 A schematic diagram showing the detection principle of some signals of a temperature protection signal generating circuit according to an embodiment of the present invention is shown;

[0045] Figure 5 A schematic structural diagram of a temperature protection signal generating circuit according to an embodiment of the present invention is shown;

[0046] Figure 6 A schematic diagram showing the reference signal adjustment principle of a temperature protection signal generating circuit according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0047] Various embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. In each of the accompanying drawings, identical elements are represented by identical or similar reference numerals. For the sake of clarity, the various parts in the accompanying drawings are not drawn to scale.

[0048] The specific implementation of the present invention is further described in detail below with reference to the accompanying drawings and examples.

[0049] Figure 2A 、 Figure 2B and Figure 2C FIG. 4 shows temperature-voltage characteristic curves of some signals of a temperature protection signal generating circuit according to an embodiment of the present invention.

[0050] like Figure 2A 、 Figure 2B and Figure 2C As shown, Figure 2A The corresponding reference signal V1 is a zero temperature coefficient voltage signal, and the detection signal V2 is a negative temperature coefficient voltage signal; Figure 2B The corresponding reference signal V1 is a positive temperature coefficient voltage signal, and the detection signal V2 is a zero temperature coefficient voltage signal; Figure 2C The corresponding reference signal V1 is a positive temperature coefficient voltage signal, and the detection signal V2 is a negative temperature coefficient voltage signal; the temperature-voltage characteristic curves of the reference signal V1 and the detection signal V2 intersect with each other, and the intersection corresponds to the temperature protection point Totp.

[0051] The temperature protection point adjustment method of the embodiment of the present invention detects the level values ​​of the reference signal V1 and the detection signal V2 in the adjustment environment, obtains the first reference signal and the second detection signal respectively, and calculates the reference voltage target value in the temperature protection circuit adjustment environment according to the reference signal V1, the detection signal V2 and their temperature characteristics and the target protection temperature (the reference voltage target value has not yet eliminated the influence of the offset value of the comparator), adjusts the reference signal according to the reference voltage target value and the first reference signal, or adjusts the reference signal according to the reference voltage target value and the second detection signal, so that the reference signal corresponds to the reference signal at the target protection temperature, thereby eliminating the adjustment error caused by the change of the detection signal due to the difference between the adjustment environment temperature and the target protection temperature, and eliminating the influence of the offset value of the comparator. Figure 2A 、 Figure 2B and Figure 2C , that is, the temperature characteristic curve of the reference signal V1 is shifted up and down, so that the intersection of the temperature-voltage characteristic curves of the reference signal V1 and the detection signal V2 is offset to match the target temperature protection signal. The temperature characteristic specifically refers to the temperature coefficient, which can be one of a positive temperature coefficient, a negative temperature coefficient, and a zero temperature coefficient.

[0052] Among them, the adjustment environment is any suitable environment, and generally the normal temperature of 25 degrees Celsius can be selected. The temperature protection point adjustment method of the embodiment of the present invention uses the temperature-voltage characteristic curve for adjustment. The parameters of the hardware that provides the reference signal V1 and the detection signal V2 are not easy to change with temperature, that is, the slope of the temperature-voltage characteristic curve of the reference signal V1 and the detection signal V2 does not change with temperature. There are no special requirements for the temperature of the detection environment for detecting and obtaining the first reference signal and the second detection signal. The detection is convenient and effective, and the corresponding adjustment is also simple and effective.

[0053] Figure 3 A schematic diagram showing the temperature protection signal generation principle of a temperature protection signal generation circuit according to an embodiment of the present invention is shown.

[0054] like Figure 3 As shown, in the temperature protection signal generating circuit of the embodiment of the present invention, a first resistor R1 and a second resistor R2 are sequentially connected in series between the bandgap reference voltage signal output terminal of the bandgap reference voltage signal generating circuit 10 and the ground, and a reference signal V1 is provided at the middle node between the first resistor R1 and the second resistor R2.

[0055] The base and collector of transistor Q1 are connected, and the collector is connected to the output end of current source A1. The emitter is grounded, so that the voltage Vbe between the base and emitter of transistor Q1 is output at the collector of transistor Q1 to provide a detection signal V2. In an optional embodiment, transistor Q1 is a transistor with a negative temperature coefficient. The temperature characteristic of the voltage Vbe between the base and emitter of transistor Q1 is generally 1.5 to 2 mV / °C, that is, for every degree Celsius increase in temperature, the amplitude of Vbe decreases by 1.5 to 2 millivolts. In an optional embodiment, the detection signal V2 is provided by a device connected between the current source and ground. The voltage temperature coefficient of the device can be one of a positive temperature coefficient, a negative temperature coefficient, and a zero temperature coefficient. In other words, the present invention does not specifically limit the provision of the detection signal V2. In one embodiment of the present invention, the detection signal V2 is provided by a thermistor connected between the current source and ground.

[0056] The comparator U1 has a non-inverting input terminal receiving a detection signal V2 and an inverting input terminal receiving a reference signal V1. The comparator U1 compares the detection signal V2 with the reference signal V1 and outputs an over-temperature protection signal OTP.

[0057] In this embodiment, the second resistor R2 is a variable resistor. By adjusting the resistance of the second resistor R2, the voltage divided by the first resistor R1 and the second resistor R2 is adjusted, thereby adjusting the level of the reference signal V1 relative to the bandgap reference voltage Vgb (in this embodiment, the bandgap reference voltage, but in alternative embodiments, other reference voltages can also be used) to adjust the temperature protection point. In alternative embodiments, the first resistor R1 is designed as a variable resistor, or both the first resistor R1 and the second resistor R2 are selected as variable resistors, and multiple adjustment nodes are preset to provide more optional preset values ​​for the reference signal V1, facilitate digital adjustment, and improve the adjustment speed of the temperature protection point.

[0058] Figure 4 A schematic diagram showing the detection principle of part of the signals of the temperature protection signal generating circuit according to an embodiment of the present invention is shown.

[0059] like Figure 4 As shown, the temperature protection signal generating circuit of the embodiment of the present invention connects the inverting input terminal and the output terminal of the comparator U1, constructs the comparator U1 into a voltage follower, and connects the reference signal V1 to the non-inverting input terminal of the comparator U1. The reference signal V1 is directly detected by the comparator U1 to obtain a first reference signal, without setting up other detection units, thereby avoiding an increase in cost. In addition, the first reference signal obtained by detecting the reference signal V1 by the comparator U1 includes the offset value of the comparator U1, thereby overcoming the influence of the offset value of the comparator U1.

[0060] Similarly, in another embodiment, the voltage follower function of the comparator U1 can be used to detect the detection signal V2 to obtain a second detection signal. The second detection signal includes the offset value of the comparator U1, thereby overcoming the influence of the offset value of the comparator U1. According to the first reference signal or the second detection signal including the offset value of the comparator U1, combined with the calculated reference voltage target value, the influence of the offset value of the comparator U1 can be eliminated, and there is no need to further adjust the offset influence of the comparator U1, thereby improving the adjustment efficiency of the temperature protection point, improving the accuracy of the over-temperature protection signal provided by the temperature protection signal generating circuit, and improving the reliability of the over-temperature protection.

[0061] Figure 5 A schematic structural diagram of a temperature protection signal generating circuit according to an embodiment of the present invention is shown.

[0062] like Figure 5 As shown, the temperature protection signal generating circuit according to the embodiment of the present invention includes a comparator U1 , a first switch S1 , a second switch S2 , a first resistor R1 , a second resistor R2 , and a transistor Q1 .

[0063] The first resistor R1 and the second resistor R2 form a reference voltage adjustment circuit and are connected in series between the bandgap reference voltage signal output terminal (bandgap reference voltage output path) of the bandgap reference voltage signal generating circuit 10 and ground. The node between the first resistor R1 and the second resistor R2 provides a reference signal V1 to the reference signal output terminal. In this embodiment, the resistor R2 is a variable resistor to adjust the level of the reference signal V1.

[0064] Transistor Q1 is a temperature-sensitive device with its base connected to the collector, its emitter grounded, and its collector connected to the output of current source A1. Driven by current source A1, its collector outputs its PN junction voltage, i.e., the voltage Vbe between the base and the emitter. Vbe is the detection signal V2. In this embodiment, there is one transistor Q1. In an alternative embodiment, there are multiple transistors Q1, which are sequentially connected in series between the output of current source A1 and ground. The detection signal V2 is provided at the collector of at least one of the multiple transistors Q1. Multiple transistors Q1 are connected in series, and the voltage values ​​provided by the collectors of different transistors Q1 vary. This voltage can also be used to adjust the level of the detection signal V2, as well as to adjust the intersection point of the detection signal V2 and the reference signal V1, thereby adjusting the temperature protection point.

[0065] The common terminal of the first switch S1 is connected to the non-inverting input terminal of the comparator U1, the fixed contact S11 of the first switch S1 receives the detection signal V2, and the fixed contact S12 receives the reference signal V1. The common terminal of the second switch S2 is connected to the inverting input terminal of the comparator U1, the fixed contact S21 of the second switch S2 is connected to the middle node of the first resistor R1 and the second resistor R2, and the fixed contact S22 is connected to the output terminal of the comparator U1. Figures 3 to 5As can be seen, by selecting the conductive path of the first switch S1, the non-inverting input terminal of the comparator U1 is coupled to the detection signal terminal to receive the detection signal V2, and by selecting the conductive path of the second switch S2, the inverting input terminal of the comparator U1 is coupled to the reference signal terminal to receive the reference signal V1. In this connection state, the detection signal V2 and the reference signal V1 can be detected and obtained, or the detection signal V2 and the reference signal V1 can be detected and obtained without the above connection relationship. During adjustment, by selecting the conductive path of the second switch S2, the inverting input terminal of the comparator U1 is connected to the output terminal, configuring the comparator U1 as a voltage follower. By selecting the conductive path of the switch S1, the reference signal V1 is connected to the non-inverting input terminal of the comparator U1, so that the first reference signal V1' can be detected at the output terminal of the comparator U1. The reference voltage target value Vref is calculated based on the temperature characteristics of the detection signal V2 and the reference signal V1. The value of the first reference signal V1' is adjusted by adjusting the resistance of the second resistor R2, and the first reference signal V1' is trimmed to the reference voltage target value Vref. This ensures that the first reference signal detected after the reference signal adjustment matches the reference voltage target value. This eliminates the adjustment error caused by the change in the detection signal due to the difference between the adjustment environment temperature and the target protection temperature, and eliminates the influence of the comparator offset value, thereby achieving the adjustment of the temperature protection point. The matching of the first reference signal detected after the reference signal adjustment with the reference voltage target value means that the adjusted first reference signal is equal to the reference voltage target value, or that the difference between the adjusted first reference signal and the reference voltage target value is within an allowable range.

[0066] In this embodiment, reference signal V1 is a divided voltage of the bandgap reference voltage. Therefore, when adjusting the resistance of second resistor R2, the divided voltage value remains constant with temperature. In another embodiment, reference signal V1 is derived from a voltage-dividing resistor group with a positive or negative temperature coefficient. The voltage-dividing resistor group may include a first resistor R1 and a second resistor R2. In this case, the offset value from the voltage-dividing resistor group needs to be accounted for during trimming to achieve precise trimming.

[0067] In this embodiment, the detection signal V2 is a voltage signal with a negative temperature coefficient. During temperature protection comparison, the detection signal V2 is connected to the non-inverting input of the comparator U1, and the reference signal V1 (the value of the reference signal V1 is adjusted due to the change in the resistance of the second resistor R2) is connected to the inverting input of the comparator U1. When the temperature exceeds the temperature protection point, the temperature protection signal OTP output by the comparator U1 flips from a high level to a low level. In an alternative embodiment, the detection signal V2 is connected to the inverting input of the comparator U1, and the reference signal V1 is connected to the non-inverting input of the comparator U1. When the temperature exceeds the temperature protection point, the temperature protection signal OTP output by the comparator U1 flips from a low level to a high level. In another embodiment, the corresponding switch S2 further includes a third fixed contact to receive the detection signal V2 input, providing different flipping modes for the temperature protection signal OTP, so as to adapt to the flipping mode requirements of different temperature protection actuators, thereby improving the applicability of the temperature protection signal generation circuit of the present invention.

[0068] In an optional embodiment, for example, the target protection temperature is 135 degrees Celsius, and V2 = 600mV and V1 = 400mV are measured under a trimming environment with a normal temperature of 25 degrees Celsius, that is, the detection signal is 600 millivolts and the reference signal is 400 millivolts. At the same time, with each increase of 1 degree Celsius in temperature, the Vbe voltage of the transistor Q1 drops by 2 millivolts. The temperature protection point corresponding to the current V1 value is calculated to be (600mV-400mV) / 2mV / ℃+25℃=125℃, which is 10℃ different from the required target temperature protection point of 135℃. The voltage difference between the corresponding reference signal and the detection signal at 25 degrees Celsius is also 10℃*2mV / ℃=20mV, that is, the reference signal V1 corresponding to the first reference signal needs to be trimmed to 380mV, that is, based on the detection signal V2 and the reference signal V1, the reference voltage target value of the temperature protection signal generating circuit under the trimming environment is calculated and processed to be 380mV. In addition, the offset value of the comparator also needs to be considered. By adjusting the resistance value of the second resistor R2, the adjustment error caused by the change in the detection signal due to the difference between the adjustment ambient temperature and the target protection temperature is eliminated, and the influence of the offset value of the comparator is also eliminated.

[0069] In another embodiment of the present invention, Figure 5, detecting and acquiring the detection signal V2 and the reference signal V1. Then, by selecting the conductive path of the first switch S1, the non-inverting input terminal of the comparator U1 is coupled to the detection signal terminal to receive the detection signal V2, and by selecting the conductive path of the second switch S2, the inverting input terminal of the comparator U1 is coupled to the output terminal of the comparator U1. The comparator U1 is constructed as a voltage follower to detect and acquire the second detection signal V2' at the output terminal of the comparator U1. The second detection signal V2' is equal to the sum of the detection signal V2 and the offset value of the comparator. During adjustment, the reference voltage target value Vref is calculated based on the temperature characteristics of the detection signal V2 and the reference signal V1. According to the reference voltage target value Vref, the detection signal V2 and the second detection signal V2', the resistance value of the second resistor R2 is adjusted, thereby adjusting the value of the reference signal V1 (i.e., the voltage divided value of the first resistor R1 and the second resistor R2 after the resistance value of R2 is adjusted), so that the adjusted reference signal V1 matches Vref-(V2'-V2), thereby achieving the adjustment of the temperature protection point. Wherein, Vref is the reference voltage target value, V2' is the second detection signal, and V2 is the detection signal. Wherein, the adjusted reference signal V1 matches Vref-(V2'-V2) means that the adjusted reference signal V1 is equal to Vref-(V2'-V2), or the difference between the adjusted reference signal V1 and Vref-(V2'-V2) is within the allowable range. When performing temperature protection comparison, the non-inverting input terminal of the comparator can be coupled to the detection signal V2, and the inverting input terminal of the comparator can be coupled to the adjusted reference signal V1. In this embodiment, the temperature characteristics of the reference signal V1 and the detection signal V2 can also be obtained by detection of the comparator U1, which can reduce the influence of process deviation and further improve the accuracy of the temperature protection signal provided by the temperature protection signal generating circuit.

[0070] Figure 6 A schematic diagram showing the reference signal adjustment principle of a temperature protection signal generating circuit according to an embodiment of the present invention is shown.

[0071] like Figure 6 As shown, the reference signal adjustment circuit of the temperature protection signal generating circuit of the embodiment of the present invention includes a first resistor R1 and a second resistor R2. In this embodiment, the second resistor R2 is a variable resistor and includes three preset adjustment nodes, corresponding to the ends of the resistors R21, R22 and R23 away from the ground, and leading to the three fixed contact ends of the switch S3. The common end of the switch S3 is connected to the output end of the reference signal adjustment circuit. The node that actually outputs the reference signal V1 is selected by selecting the conduction path of the switch S3 to adjust the level of the reference signal V1. In this embodiment, the output node is selected without changing the total resistance of the first resistor R1 and the second resistor R2 between the output path of the reference voltage Vgb and the ground. The level corresponding to each preset adjustment node is well linearized, which facilitates the linear adjustment of the reference signal V1 and is easy to implement.

[0072] In an alternative embodiment, at least one of the first resistor R1 and the second resistor R2 is a variable resistor.

[0073] The temperature protection signal generating circuit provided by the present invention compares a reference signal and a detection signal through a comparator to provide a temperature protection signal, and controls the inverting input terminal of the comparator to be connected to the output terminal of the comparator through a second switch, so that the comparator is constructed as a voltage follower, and selects the non-inverting input terminal of the comparator to access the reference signal or the detection signal through the first switch, and obtains the first reference signal or the second detection signal through the comparator detection, so as to calculate the reference voltage target value actually corresponding to the temperature protection signal generating circuit based on the first reference signal or the second detection signal and the temperature characteristics of the reference signal and the detection signal and the ambient temperature during detection, and adjusts the reference signal so that the reference signal corresponds to the reference signal at the target protection temperature, thereby ensuring that the flip point of the temperature protection signal provided by the temperature protection signal generating circuit coincides with the target temperature point, and ensuring the reliability of temperature protection using the temperature protection signal.

[0074] The temperature protection point adjustment method provided by the present invention obtains a second detection signal or a first reference signal based on the detection of the detection signal and the reference signal, and calculates a reference voltage target value based on the second detection signal or the first reference signal and the temperature characteristics of the detection signal and the reference signal. The adjustment is convenient and effective, and improves the accuracy of the temperature protection signal obtained by comparing the detection signal and the reference signal.

[0075] While embodiments of the present invention have been described above, these embodiments do not exhaustively describe all details and do not limit the invention to the specific embodiments described. Obviously, many modifications and variations are possible based on the above description. These embodiments are selected and described in detail in this specification in order to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better utilize the present invention and its modifications. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A temperature protection signal generating circuit, characterized in that: include: A comparator, a first switch, a second switch and a reference signal adjustment circuit, wherein: The reference signal adjustment circuit receives a reference voltage and outputs a reference signal. The non-inverting input terminal of the comparator receives the reference signal or the detection signal through the first switch, and the inverting input terminal of the comparator receives the reference signal or the detection signal through the second switch or is connected to the output terminal of the comparator. At least one of the detection signal and the reference signal is a temperature-sensitive voltage signal, and the comparator outputs a temperature protection signal based on a comparison between the detection signal and the reference signal; In a trimming environment, the temperature protection signal generating circuit detects and obtains a detection signal and a reference signal. When the inverting input terminal of the comparator is connected to the output terminal of the comparator through the second switch, the temperature protection signal generating circuit enables the non-inverting input terminal of the comparator to receive the reference signal through the first switch to detect and obtain a first reference signal at the output terminal of the comparator; based on the detection signal and the reference signal, a reference voltage target value of the temperature protection signal generating circuit in the trimming environment is obtained through calculation and processing, and the reference signal is adjusted according to the reference voltage target value and the first reference signal, so that the first reference signal detected and obtained after the reference signal is adjusted matches the reference voltage target value, eliminates the trimming error caused by the change of the detection signal due to the difference between the trimming environment temperature and the target protection temperature, eliminates the influence of the offset value of the comparator, and realizes the trimming of the temperature protection point; or In a trimming environment, the temperature protection signal generating circuit detects and obtains a detection signal and a reference signal, and enables the non-inverting input terminal of the comparator to receive the detection signal through the first switch to detect and obtain a second detection signal at the output terminal of the comparator; based on the detection signal and the reference signal, the reference voltage target value of the temperature protection signal generating circuit in the trimming environment is obtained through calculation and processing, and the reference signal is adjusted according to the reference voltage target value and the second detection signal, so that the adjusted reference signal V1 is equal to Vref-(V2'-V2), or the difference between the adjusted reference signal V1 and Vref-(V2'-V2) is within an allowable range, wherein Vref is the reference voltage target value, V2' is the second detection signal, and V2 is the detection signal.

2. The temperature protection signal generating circuit according to claim 1, characterized in that: The reference signal conditioning circuit includes an input terminal for receiving the reference voltage and an output terminal for outputting the reference signal, and the reference signal conditioning circuit includes: A first resistor and a second resistor are sequentially connected in series between the input terminal of the reference signal conditioning circuit and the ground, and the middle node between the first resistor and the second resistor is the output terminal of the reference signal conditioning circuit, wherein, At least one of the first resistor and the second resistor is a variable resistor, and the level of the reference signal is adjusted by adjusting the variable resistor.

3. The temperature protection signal generating circuit according to claim 2, characterized in that: Also includes: A transistor, wherein the base of the transistor is connected to the collector, the collector of the transistor is connected to the output end of the current source, the emitter of the transistor is grounded, and the collector of the transistor provides the detection signal.

4. The temperature protection signal generating circuit according to claim 3, characterized in that: There are multiple transistors, which are sequentially connected in series between the output end of the current source and the ground. The collector of at least one of the multiple transistors provides the detection signal.

5. The temperature protection signal generating circuit according to claim 1, characterized in that: The reference signal conditioning circuit includes an input terminal for receiving the reference voltage and an output terminal for outputting the reference signal, and the reference signal conditioning circuit includes: a plurality of resistors connected in series between an input terminal of the reference signal conditioning circuit and ground; and The third switch includes a common terminal connected to the output terminal of the reference signal adjustment circuit and a plurality of fixed contact terminals connected to each adjacent node of the plurality of resistors.

6. A method for adjusting a temperature protection point, characterized in that: The temperature protection point adjustment method is applied to the temperature protection signal generating circuit according to any one of claims 1 to 5, comprising: In a trimming environment, the detection signal and the reference signal are detected separately, and when the inverting input terminal of the comparator is connected to the output terminal of the comparator, the non-inverting input terminal of the comparator receives the reference signal to detect at the output terminal of the comparator to obtain a first reference signal; a reference voltage target value is calculated based on the reference signal, the detection signal and its temperature characteristics and the target protection temperature, and the reference signal is adjusted according to the reference voltage target value and the first reference signal, so that the first reference signal detected after the reference signal is adjusted matches the reference voltage target value, eliminates the trimming error caused by the change of the detection signal due to the difference between the trimming environment temperature and the target protection temperature, eliminates the influence of the offset value of the comparator, and realizes the trimming of the temperature protection point; or In the trimming environment, the detection signal and the reference signal are detected respectively, so that the non-inverting input terminal of the comparator receives the detection signal to obtain a second detection signal by detection at the output terminal of the comparator; the temperature protection performs temperature protection according to the temperature protection signal obtained by comparing the detection signal and the reference signal; the reference signal is adjusted according to the reference voltage target value and the second detection signal, so that the adjusted reference signal V1 is equal to Vref-(V2'-V2), or the difference between the adjusted reference signal V1 and Vref-(V2'-V2) is within the allowable range, wherein Vref is the reference voltage target value, V2' is the second detection signal, and V2 is the detection signal.

7. The temperature protection point adjustment method according to claim 6, characterized in that: The reference signal is a voltage signal with a zero temperature coefficient or a positive temperature coefficient, and the detection signal is a voltage signal with a negative temperature coefficient, a zero temperature coefficient, or a positive temperature coefficient.

8. The temperature protection point adjustment method according to claim 6, characterized in that: The reference signal is provided by an intermediate node of a first resistor and a second resistor connected in series between a reference voltage output path and ground, at least one of the first resistor and the second resistor is a variable resistor, and the reference signal is adjusted by adjusting the resistance value of the variable resistor.

9. The temperature protection point adjustment method according to claim 6, characterized in that: The detection signal is a voltage signal between the base and emitter of a transistor, the transistor is connected between the output end of the current source and the ground, and the base of the transistor is connected to the collector.

10. The temperature protection point adjustment method according to claim 6, characterized in that: The temperature protection signal is obtained through a comparator. The non-inverting input terminal of the comparator receives the reference signal or the detection signal through the first switch, The inverting input terminal of the comparator receives the reference signal or the detection signal through a second switch, or is connected to the output terminal of the comparator. By selecting the conduction paths of the first switch and the second switch, at least one of the second detection signal, the first reference signal and the temperature protection signal is selectively obtained at the output end of the comparator.

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