High-side driving output circuit

Abstract

The utility model discloses a high-side driving output circuit, comprising an output module which is connected between a power supply and an output end and comprises a switching device; the control module is connected with the control end of the switching device, and the switching device is controlled by the control module to be switched on or switched off; the overcurrent protection module is connected between the power supply and the control module; the overcurrent protection module comprises a current acquisition device and closes the switching device through the control module when the current flowing through the current acquisition device exceeds a preset value; and an over-temperature protection module connected between the control module and the output end, wherein the over-temperature protection module comprises a temperature acquisition device and turns off the switching device through the control module when the temperature detected by the temperature acquisition device exceeds a preset value. The circuit provided by the utility model has the functions of over-temperature protection, over-current protection and short-circuit protection, can prevent peripheral equipment or modules from being damaged, enables the output power supply voltage to be stable and reliable, and is wide in applicability.

Description

Technical Field

[0001] The utility model relates to the field of circuits, in particular to a high-side output drive circuit technology. Background Art

[0002] In the known circuit design field, when a power supply supplies power to an electronic device, it is necessary to control the power-on sequence of some circuit modules in the internal circuit of the device, or it is necessary to control the on / off of the power of some circuit modules, or it is necessary to control the on / off of external devices when providing power to external devices.

[0003] There are two basic ways to drive a load: low-side drive and high-side drive. Low-side drives are usually used for loads related to the powertrain, such as motors and heaters. High-side drives are often used for fuel pumps and body-related functions, such as seats, lighting, wipers, and fans.

[0004] The controller products of the underlying driver of intelligent driving will be interconnected with many peripherals, such as IMU (Inertial Measurement Unit) modules, sound and light warning devices, laser radar, wheel speed meter modules, battery charging control modules, etc. When supplying power to circuit modules and peripherals, it is necessary not only to control the power on and off of the circuit, but also to consider that the driving circuit should be able to be cut off immediately in the event of a short circuit to protect the circuit from dangers such as overcurrent breakdown, overvoltage damage, and overheating and fire. In addition, the requirements of the load on the power supply at the moment of circuit startup should also be considered.

[0005] In the circuit design of the prior art, the short-circuit protection circuits currently used are generally current detection ICs, most of which do not have over-temperature and short-circuit detection functions. Even if some circuits have these functions, their structures are relatively complex and the prices are relatively expensive.

[0006] Therefore, it is beneficial to design a circuit that can realize high-side drive output that supports over-current protection and over-temperature protection functions and reduce the requirements on power supply capability at the startup moment. Utility Model Content

[0007] In order to solve at least one of the problems existing in the above-mentioned prior art, the utility model provides a high-side drive output circuit, comprising:

[0008] An output module, connected between the power supply and the output terminal, including a switch device;

[0009] A control module is connected to the control end of the switch device, and the switch device is controlled to be turned on or off by the control module;

[0010] An overcurrent protection module connected between the power supply and the control module, the overcurrent protection module includes a current acquisition device and closes the switch device through the control module when the current flowing through the current acquisition device exceeds a preset value,

[0011] The over-temperature protection module is connected between the control module and the output end. The over-temperature protection module includes a temperature acquisition device and closes the switch device through the control module when the temperature detected by the temperature acquisition device exceeds a preset value.

[0012] The utility model provides a short-circuit protection function for the high-side drive output, and realizes overvoltage and overtemperature detection functions, so that the equipment connected to the circuit will not be damaged by faults such as power short circuit, overvoltage and overtemperature, and has the characteristics of wide applicability.

[0013] In some embodiments of the present invention, the control module is further connected to a signal input terminal receiving an input signal, and the switch device can also be turned on or off by the control module according to a high level state, a low level state or a high impedance state of the input signal, so that:

[0014] When the input signal is at a high level, the output module outputs a voltage signal corresponding to the voltage of the power supply;

[0015] When the input signal changes from high level to low level or high impedance state, the output module does not output any signal.

[0016] This implementation can use both the circuit's own hardware and software to comprehensively protect the switch device to be protected or the circuit's subsequent load. When the circuit hardware protection mechanism fails, the circuit can continue to be protected by software. That is, when an abnormality is found, the signal received at the signal input end is converted into a low level or a high impedance state, so that the switch device can be turned off, forming a redundant protection mechanism, thereby achieving the purpose of protecting the switch device and the external device or load.

[0017] In some embodiments of the present invention, the circuit further includes a voltage protection module connected between the output module and the output end, for controlling the input signal received by the signal input end to be converted to a high impedance state or a low level state when the output voltage is abnormal.

[0018] This implementation enables the circuit to also have an overvoltage or undervoltage detection protection function, and can cut off the output in time when the voltage is abnormal.

[0019] Furthermore, in some embodiments of the present invention, the control module includes a first control switch device and a second control switch device, the control end of the second control switch device is connected to the signal input end and the first control switch device, and the control end of the first control switch device is connected to the overcurrent protection module and the overtemperature protection module.

[0020] In some embodiments of the present invention, the overcurrent protection module includes a first comparator, one of the input ends of the first comparator is connected to the current acquisition device, and the output end is connected to the control end of the first control switch device; the overtemperature protection module includes a second comparator, one of the input ends of the second comparator is connected to the temperature acquisition device, and the output end is connected to the control end of the first control switch device.

[0021] Furthermore, in some embodiments of the present invention, the first comparator inputs a reference voltage through a first voltage-dividing circuit, the first voltage-dividing circuit includes a series resistor having one end connected to a power supply and the other end connected to ground, and the other input end of the first comparator is connected to the connection end of the two series resistors; the second comparator inputs a reference voltage through a second voltage-dividing circuit, the second voltage-dividing circuit includes a series resistor having one end connected to a power supply and the other end connected to ground, and the other input end of the second comparator is connected to the connection end of the two series resistors.

[0022] In some embodiments of the utility model, the control module also includes a third voltage-dividing circuit, and the overcurrent protection module and the over-temperature protection module are connected to the control end of the first control switch device through the third voltage-dividing circuit, so that the first control switch device is turned on through the third voltage-dividing circuit, wherein the third voltage-dividing circuit includes a series resistor with one end connected to the output end of the overcurrent protection module and the over-temperature protection module and the other end connected to the ground, wherein the connection end of the two resistors in the series resistor is connected to the control end of the first control switch device.

[0023] Furthermore, in some embodiments of the present invention, the control module also includes a fourth voltage-dividing circuit, and the second control switch device is connected to the control end of the switch device through the fourth voltage-dividing circuit, so that the switch device is closed through the fourth voltage-dividing circuit, wherein the fourth voltage-dividing circuit includes a series resistor with one end connected to the current collection device of the overcurrent protection module and the other end grounded through the second control switch device, wherein the connection end of the two resistors in the series resistor is connected to the control end of the switch device.

[0024] Furthermore, in some embodiments of the present invention, the control module also includes a fifth voltage-dividing circuit, which includes a series resistor with one end connected to the signal input end and the other end connected to the ground, wherein the connecting end of the two resistors in the series resistor is connected to the control end of the second control switch device.

[0025] Optionally or in combination, in some embodiments of the utility model, the voltage protection module includes a voltage acquisition output interface for acquiring a voltage state corresponding to the output voltage of the output end, and the voltage protection module also includes a sixth voltage divider circuit, the sixth voltage divider circuit includes a series resistor having one end connected to the output end and the other end grounded, wherein the connecting ends of two resistors in the series resistor are connected to the voltage acquisition output interface.

[0026] This implementation can monitor the state of the output voltage in real time through the voltage acquisition output interface to ensure that the output voltage is stable, reliable and meets the demand.

[0027] Optionally or in combination, in some embodiments of the utility model, the over-temperature protection module includes a temperature detection output interface for outputting parameters corresponding to the collected temperature, and the over-temperature protection module also includes a series resistor connected to the temperature collection device, one end of the series resistor is connected to the temperature detection output interface, and the other end is grounded, and the connecting end of the two resistors in the series resistor is connected to the temperature collection device.

[0028] This implementation can monitor the temperature of the device or module in real time through the temperature detection output interface, ensure that the temperature of the device or module is within a normal range, and reduce the risk of damage.

[0029] Optionally or additionally, in some embodiments of the utility model, the overcurrent protection module also includes a diode, wherein the positive electrode of the diode is connected to the output end of the first comparator, and the negative electrode of the diode is connected to one end of the third voltage divider circuit; the overtemperature protection module also includes a diode, wherein the positive electrode of the diode is connected to the output end of the second comparator, and the negative electrode of the diode is connected to one end of the third voltage divider circuit.

[0030] This implementation can reduce the risk of damage to the circuit or external load caused by reverse polarity of the power supply.

[0031] Additionally, in some embodiments of the present invention, the circuit may further include a protection device having one end connected to the control end of the switch device and the other end connected to the power supply.

[0032] This protection device can maintain the stable voltage required by the switching device, prevent the switching device from being broken down, and increase the conduction time of the switching device, reduce the instantaneous impact of the load on the power supply, and reduce the risk of output overshoot of the switching device.

[0033] Preferably, in the above implementation of the present invention, the protection device may be a capacitor.

[0034] Preferably, the switch device is a PMOS field effect transistor, the first control switch device and the second control switch device are selected from triodes or field effect transistors, the current acquisition device is a current sampling resistor, and the temperature acquisition device is a temperature sampling resistor.

[0035] Among them, the use of PMOS tubes as switch devices can save the additional and more complicated boost circuit required by the existing circuit structure where the switch devices are NMOS tubes, thereby reducing manufacturing costs and system power consumption.

[0036] Specifically, in some embodiments of the present invention, the first control switch device and the second control switch device are NPN transistors.

[0037] In this case, the source of the switching device is connected to one end of the current sampling resistor and one end of the series resistor of the fourth voltage divider circuit, the gate is connected to the connection end of two resistors in the series resistor of the fourth voltage divider circuit, the drain is connected to the output end, one end of the temperature sampling resistor and one end of the series resistor of the sixth voltage divider circuit, and the other end of the series resistor of the sixth voltage divider circuit is grounded.

[0038] The base of the first control switch device is connected to the connection end of two resistors in the series resistor of the third voltage divider circuit, the collector is connected to the base of the second control switch device and the connection end of two resistors in the series resistor of the fifth voltage divider circuit, and the emitter is grounded.

[0039] The collector of the second control switch device is connected to the other end of the series resistor of the fourth voltage divider circuit, and the emitter is grounded.

[0040] One input end of the first comparator is connected to one end of the current sampling resistor, and the other end of the current sampling resistor is connected to the power supply; the other input end of the first comparator is connected to the connection end of two resistors in the series resistor of the first voltage divider circuit, one end of the series resistor of the first voltage divider circuit is connected to the power supply, and the other end is grounded; the output end of the first comparator is connected to one end of the series resistor of the third voltage divider circuit, and the other end of the series resistor of the third voltage divider circuit is grounded,

[0041] One input end of the second comparator is connected to the other end of the temperature sampling resistor; the other input end of the second comparator is connected to the connection end of two resistors in the series resistor of the second voltage divider circuit, one end of the series resistor of the second voltage divider circuit is connected to the power supply, and the other end is grounded; the output end of the second comparator is connected to one end of the series resistor of the third voltage divider circuit,

[0042] One end of the series resistor of the fifth voltage divider circuit is connected to the signal input end, and the other end is grounded; the other end of the temperature sampling resistor is also connected to the connection end of the two resistors of the series resistor, one end of the series resistor is connected to the temperature detection output interface, and the other end is grounded.

[0043] The high-side drive output circuit provided by the utility model has a specific circuit structure design. When supplying power to external devices and internal modules of the controller to control power on and off, the circuit is designed with overcurrent protection and overtemperature protection, so that the circuit can be immediately cut off in the case of overcurrent and / or overtemperature, and has the functions of overtemperature protection, overcurrent protection and short-circuit protection, and reduces the impact of the startup instantaneous impact current on the power supply when the high-side drive output terminal is connected to a capacitive load; the overvoltage protection and overtemperature protection circuits can ensure that the output of the switch device is turned off in time when the MCU is working abnormally, avoiding damage to the peripherals or modules. This makes the high-side output have the function of ensuring that the load can be started and shut down normally, making the output power supply voltage stable and reliable, and has a wide range of applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a structural schematic diagram of a high-side drive output circuit provided in one embodiment of the utility model.

[0045] Figure 2 A schematic structural diagram of a high-side drive output circuit provided in another embodiment of the present invention.

[0046] Figure 3 It is a schematic diagram of the structure of each module in the high-side drive output circuit provided in one embodiment of the utility model.

[0047] Figure 4 It is a circuit diagram of a high-side drive output circuit provided in one embodiment of the utility model. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical scheme and advantages of the utility model clearer, the utility model is further described in detail below in conjunction with the accompanying drawings and specific embodiments. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the utility model can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to facilitate a more thorough understanding of the utility model and to fully convey the concept of the utility model to those skilled in the art.

[0049] refer to Figure 1 , shows a schematic diagram of the structure of a high-side drive output circuit provided by an embodiment of the utility model. Figure 1 As shown, the high-side drive output circuit provided by the utility model mainly includes an over-current protection module 10 , an over-temperature protection module 20 , a control module 30 , an output module 40 and an output terminal 50 .

[0050] The output module 40 is connected between the power supply and the output terminal 50, and includes a switch device 401. The switch device 401 is connected to the output terminal 50 and can output a signal in a high-side driving manner.

[0051] The control module 30 is connected to the control end of the switch device 401, and the switch device 401 is turned on or off by the control module 30. In other words, the function of the control module 30 is to control the output of the switch device 401.

[0052] The overcurrent protection module 10 is connected between the power supply and the control module 30. The overcurrent protection module 10 includes a current acquisition device 101 and closes the switch device 401 through the control module 30 when the current flowing through the current acquisition device 101 exceeds a preset value to realize the overcurrent protection function for the peripheral interface.

[0053] The over-temperature protection module 20 is connected between the control module 30 and the output end 50. The over-temperature protection module 20 includes a temperature acquisition device 201 and closes the switch device 401 through the control module 30 when the temperature detected by the temperature acquisition device 201 exceeds a preset value, so as to realize the over-temperature protection function of the internal circuit and the peripheral interface.

[0054] Based on the above structure, during the startup process or normal operation of the high-side drive output circuit, when the current detected by the current acquisition device in the overcurrent protection module exceeds the range that the circuit can withstand (a preset value can be set accordingly), that is, when overcurrent occurs, the control module 30 will turn off the switch device 401; and when the temperature detected by the temperature acquisition device in the overtemperature protection module exceeds the range that the circuit or the device therein can withstand (a preset value can be set accordingly), that is, when overtemperature occurs, the control module 30 will turn off the switch device 401. Regardless of whether a single overcurrent or overtemperature phenomenon occurs, or an overtemperature and overcurrent phenomenon occurs simultaneously, the circuit provided by the utility model can cut off the output in time, which can not only ensure that the circuit or the subsequent load (including peripherals) will not be damaged by excessive current or excessive temperature, but also reduce the negative impact on the power supply. The above circuit structure can realize a high-side drive output with overcurrent protection function and overtemperature protection function during and after the power supply is powered on, so that the output power supply voltage is stable and reliable, and has a wide range of applicability.

[0055] In some implementations, the high-side driver output circuit provided by the present invention may further include a receiving signal input terminal 60. For example, referring to Figure 2 , shows a schematic structural diagram of a high-side drive output circuit provided in another embodiment of the utility model.

[0056] The signal input terminal 10 is used to receive an input signal, and the state of the input signal can be a high level or a low level, or a high impedance state. In particular, the input signal can be an IO control signal of the MCU, or a power supply voltage signal.

[0057] The control module 30 can also be connected to the signal input terminal 60, so that the switch device 401 can also be turned on or off by the control module 30 according to the high or low level state or high impedance state of the input signal, so that:

[0058] When the input signal is at a high level, the output module 40 outputs a voltage signal corresponding to the voltage of the power supply;

[0059] When the input signal changes from a high level to a low level or a high impedance state, the output module 40 does not output a signal.

[0060] In this case, the switch device 401 is actually controlled to be turned on or off by the control module 30 through the signal output by the overcurrent protection module 10 and / or the overtemperature protection module 20 and the high or low level state or high impedance state of the input signal.

[0061] When the input signal is at a high level and the detected current and / or temperature do not exceed the preset value, the output module 40 outputs a voltage signal corresponding to the voltage of the power supply;

[0062] When the input signal changes from a high level to a low level or a high impedance state, or at least one of the detected current and / or temperature exceeds a preset value, the output module 40 does not output a signal.

[0063] The advantage of this arrangement is that it can use both the circuit's own hardware and software to provide comprehensive protection for the switch device or the circuit's subsequent load when outputting signals, and can use software to continue protecting the circuit when the circuit's hardware protection mechanism fails, that is: when an abnormality is detected, by converting the signal received at the signal input end into a low level or high impedance state, the switch device can be turned off by changes in the input signal, forming a redundant protection mechanism, which can continue to protect the switch device and external equipment or load when the overcurrent protection module and the overtemperature protection module fail.

[0064] like Figure 2 As shown, advantageously, the high-side driver output circuit provided by the utility model can also include a voltage protection module 70 connected between the output module 40 and the output terminal 50, which is used to control the input signal received by the signal input terminal 60 to be converted to a high impedance state or a low level state when the output voltage is abnormal.

[0065] Therefore, the circuit also has an overvoltage or undervoltage detection protection function and can cut off the output in time when the voltage is abnormal.

[0066] refer to Figure 3 , shows a schematic diagram of the structure of each module in the high-side driver output circuit provided in an embodiment of the utility model.

[0067] Exemplarily, the control module 30 may include a first control switch device 301 and a second control switch device 302, the control end of the second control switch device 302 is connected to the signal input end 60 and the first control switch device 301, and the control end of the first control switch device 301 is connected to the overcurrent protection module 10 and the overtemperature protection module 20.

[0068] Exemplarily, the overcurrent protection module 10 may include a first comparator 102, one of the input ends of the first comparator 102 is connected to the current acquisition device 101, and the output end is connected to the control end of the first control switch device 301; the overtemperature protection module 20 may include a second comparator 202, one of the input ends of the second comparator 202 is connected to the temperature acquisition device 201, and the output end is connected to the control end of the first control switch device 301.

[0069] Further exemplarily, the first comparator 102 may input a reference voltage through a first voltage divider circuit 103. Specifically, the first voltage divider circuit 103 may include a series resistor having one end connected to a power supply and the other end grounded, and the other input end of the first comparator 102 is connected to the connection end of the two series resistors. The second comparator 202 may input a reference voltage through a second voltage divider circuit 203. Specifically, the second voltage divider circuit 203 may include a series resistor having one end connected to a power supply and the other end grounded, and the other input end of the second comparator 202 is connected to the connection end of the two series resistors.

[0070] Exemplarily, the control module 30 may further include a third voltage divider circuit 303, and the overcurrent protection module 10 and the overtemperature protection module 20 are connected to the control end of the first control switch device 301 through the third voltage divider circuit 303, so that the first control switch device 301 is turned on through the third voltage divider circuit 303. Specifically, the third voltage divider circuit 303 may include a series resistor having one end connected to the output end of the overcurrent protection module 10 and the overtemperature protection module 20 and the other end connected to the ground, wherein the connection end of the two resistors in the series resistor is connected to the control end of the first control switch device 301.

[0071] Further, the control module 30 may also include a fourth voltage-dividing circuit 304, and the second control switch device 302 is connected to the control end of the switch device 401 through the fourth voltage-dividing circuit 304, so that the switch device 401 is turned off through the fourth voltage-dividing circuit 304. Specifically, the fourth voltage-dividing circuit 304 may include a series resistor having one end connected to the current acquisition device 101 of the overcurrent protection module and the other end grounded through the second control switch device 302, wherein the connection end of the two resistors in the series resistor is connected to the control end of the switch device 401.

[0072] Furthermore, the control module 30 may further include a fifth voltage divider circuit 305. Specifically, the fifth voltage divider circuit 305 may include a series resistor having one end connected to the signal input terminal 60 and the other end grounded, wherein the connection end of the two resistors in the series resistor is connected to the control terminal of the second control switch device 302.

[0073] Advantageously, the voltage protection module 70 may include a voltage acquisition output interface 701 for acquiring a voltage state corresponding to the output voltage of the output terminal 50. The voltage protection module 70 may also include a sixth voltage divider circuit 702, the sixth voltage divider circuit 702 including a series resistor having one end connected to the output terminal and the other end grounded, wherein the connection end of two resistors in the series resistor is connected to the voltage acquisition output interface 701.

[0074] This implementation can monitor the state of the output voltage in real time through the voltage acquisition output interface to ensure that the output voltage is stable, reliable and meets the demand.

[0075] Those skilled in the art should understand that there are many ways to collect the output voltage of the output terminal 50. The present invention only exemplarily adopts a relatively simple way, and the specific collection and monitoring means can be set accordingly according to the specific requirements in actual applications, and the present invention will not be described in detail here.

[0076] Advantageously, the over-temperature protection module 20 may include a temperature detection output interface 204 for outputting parameters corresponding to the collected temperature. Specifically, the over-temperature protection module 20 may include a series resistor connected to the temperature collection device 201, one end of the series resistor is connected to the temperature detection output interface 204, the other end is grounded, and the connection end of the two resistors in the series resistor is connected to the temperature collection device 201.

[0077] This implementation can monitor the temperature of the device or module in real time through the temperature detection output interface, ensure that the temperature of the device or module is within a normal range, and reduce the risk of damage.

[0078] Optionally or additionally, in some embodiments of the utility model, the overcurrent protection module 10 may further include a diode, wherein the positive electrode of the diode is connected to the output end of the first comparator 102, and the negative electrode of the diode is connected to one end of the third voltage divider circuit 303; the overtemperature protection module 20 may further include a diode, wherein the positive electrode of the diode is connected to the output end of the second comparator 202, and the negative electrode of the diode is connected to one end of the third voltage divider circuit 303.

[0079] This implementation can reduce the risk of damage to the circuit or external load caused by reverse polarity of the power supply.

[0080] The specific circuit structure can be found in the following text. Figure 3A circuit diagram provided by one embodiment of the utility model is shown.

[0081] Those skilled in the art can set the specific structures of the first voltage divider circuit 103, the second voltage divider circuit 203, the third voltage divider circuit 303, the fourth voltage divider circuit 304, the fifth voltage divider circuit 305, and the sixth voltage divider circuit 702 accordingly according to actual needs. Those skilled in the art should understand that the control module, the overcurrent protection module, and the overtemperature protection module can also adopt other forms, as long as the switch device can stop working when the current and / or temperature exceeds the preset threshold, and the switch device will not shut down automatically when the voltage is within the tolerable range of the circuit. As for the control mode of the second control switch device 302 turning on / off the switch device 401 and the first control switch device 301 turning on / off the second control switch device 302, it depends on the selected first and second control switch devices and the type of switch device (NMOS, PMOS, NPN, PNP, etc.), and those skilled in the art can select the corresponding appropriate device type and its output mode for the switch device according to actual needs and conditions, so as to select the control mode of the overcurrent protection module and / or the overtemperature protection module and / or the control module for the switch device under different conditions. The following text will be explained with examples of specific device types.

[0082] Additionally, in some implementations of the present invention, the circuit may further include a protection device having one end connected to the control end of the switch device 401 and the other end connected to the power supply.

[0083] This protection device can maintain the stable voltage required by the switching device, prevent the switching device from being broken down, and increase the conduction time of the switching device, reduce the instantaneous impact of the load on the power supply, and reduce the risk of output overshoot of the switching device.

[0084] Preferably, in the above implementation of the present invention, the protection device may be a capacitor.

[0085] In some embodiments, the switch device 401 may be a PMOS field effect transistor, the first control switch device 301 and the second control switch device 302 are selected from triodes or field effect transistors, the current acquisition device 101 may be a current sampling resistor, and the temperature acquisition device 201 may be a temperature sampling resistor.

[0086] Among them, the use of PMOS tubes as switch devices can save the additional and more complicated boost circuit required by the existing circuit structure where the switch devices are NMOS tubes, thereby reducing manufacturing costs and system power consumption.

[0087] Exemplarily, the first control switch device 301 and the second control switch device 302 are NPN transistors.

[0088] In this example: the source of the switch device 401 is connected to one end of the current sampling resistor and one end of the series resistor of the fourth voltage divider circuit 304, the gate is connected to the connection end of two resistors in the series resistor of the fourth voltage divider circuit 304, the drain is connected to the output end, one end of the temperature sampling resistor and one end of the series resistor of the sixth voltage divider circuit 702, and the other end of the series resistor of the sixth voltage divider circuit 702 is grounded;

[0089] The base of the first control switch device 301 is connected to the connection end of two resistors in series of the third voltage divider circuit 303, the collector is connected to the base of the second control switch device 302 and the connection end of two resistors in series of the fifth voltage divider circuit 305, and the emitter is grounded;

[0090] The collector of the second control switch device 302 is connected to the other end of the series resistor of the fourth voltage divider circuit 304, and the emitter is grounded;

[0091] One input end of the first comparator is connected to one end of the current sampling resistor, and the other end of the current sampling resistor is connected to the power supply; the other input end of the first comparator is connected to the connection end of two resistors in the series resistor of the first voltage divider circuit 103, one end of the series resistor of the first voltage divider circuit 103 is connected to the power supply, and the other end is grounded; the output end of the first comparator is connected to one end of the series resistor of the third voltage divider circuit 303, and the other end of the series resistor of the third voltage divider circuit 303 is grounded;

[0092] One input end of the second comparator 202 is connected to the other end of the temperature sampling resistor; the other input end of the second comparator 202 is connected to the connection end of two resistors in the series resistor of the second voltage divider circuit 203, one end of the series resistor of the second voltage divider circuit 203 is connected to the power supply, and the other end is grounded; the output end of the second comparator 202 is connected to one end of the series resistor of the third voltage divider circuit 303;

[0093] One end of the series resistor of the fifth voltage divider circuit 305 is connected to the signal input end, and the other end is grounded; the other end of the temperature sampling resistor is also connected to the connection end of the two resistors of the series resistor, one end of the series resistor is connected to the temperature detection output interface 204, and the other end is grounded.

[0094] Regarding the selection of each switch device in the circuit provided by the utility model, those skilled in the art can understand that the first, second, and third switch protection devices in the utility model can be triodes, or alternatively, MOS tubes. These switch devices can be switch devices of the same type, for example, all MOS tubes, or all triodes; alternatively, some of them can be MOS tubes and the other part can be triodes. Regardless of the type of switch device each switch device is, those skilled in the art can make corresponding adaptive deformations to the corresponding structures in the above circuits according to the working principles of the corresponding switch devices.

[0095] The circuit provided by an embodiment of the present invention is specifically described below by taking the switch device 401 as a PMOS transistor Q1 , the first control switch device 301 as an NPN transistor T1 , and the second control switch device 302 as an NPN transistor T2 as an example.

[0096] refer to Figure 4 , which shows a specific implementation of the high-side drive output circuit of the utility model.

[0097] In the circuit, the power supply is VDD, the signal input terminal 60 is Control_Signal_IN, and the output terminal 50 is Vout. The output module 40 can be regarded as a switch device Q1.

[0098] Figure 4 Most of the control circuit can be regarded as a control module 30, which includes a first control switch device T1, a second control switch device T2, a third voltage divider circuit composed of series resistors R3 and R4, a fourth voltage divider circuit composed of series resistors R5 and R6, and a fifth voltage divider circuit composed of series resistors R7 and R8.

[0099] Figure 4 Most of the overcurrent detection circuit in the overcurrent protection module 10 can be regarded as the overcurrent protection module 10. The current acquisition device in the overcurrent protection module 10 is the current sampling resistor RT1, the first comparator 102 is the comparator U1, and the first comparator 102 inputs the reference voltage Vref1 through the first voltage divider circuit 103 composed of series resistors R1 and R2.

[0100] Figure 4 Most of the over-temperature detection circuit in the over-temperature protection module 20 can be regarded as an over-temperature protection module 20. The temperature acquisition device 201 in the over-temperature protection module 20 is a temperature sampling resistor RT2, the second comparator 202 is a comparator U2, and the second comparator 202 inputs a reference voltage Vref2 through a second voltage divider circuit 203 composed of series resistors R13 and R14. The over-temperature protection module 20 also includes a temperature detection output interface Temp_Dect_Signal and series resistors R11 and R12.

[0101] Figure 4 The overvoltage / undervoltage detection circuit in the embodiment can be regarded as a voltage protection module 70. The voltage protection module 70 includes a sixth voltage dividing circuit composed of series resistors R9 and R10 and a voltage acquisition output interface Voltage_Dect_Signal.

[0102] Still Figure 4 As shown, the overcurrent protection module and the overtemperature protection module further include diodes D1 and D2, respectively.

[0103] The connection relationship and corresponding functions of each circuit component are described in detail below.

[0104] The circuit includes resistors R1 / R2 / R3 / R4 / R5 / R7 / R8 / R9 / R10 / R11 / 12 / R13 / R14, a current sampling resistor RT1, a temperature acquisition resistor RT2, capacitors C1 / C2, comparators U1 / U2, transistors T1 / T2, diodes D1 / D2 and a MOS tube Q1.

[0105] One end of the resistor R1 is connected to the input box IN+ of the comparator U1, one end of the resistor R2, and the other end is connected to VDD. The function of R1 is to form a voltage divider circuit with R2 to provide a reference voltage Vref1 for the other input terminal IN- of U1.

[0106] One end of the resistor R2 is connected to IN+ of U1, one end of R1, and the other end is connected to GND. The function of R2 is to form a voltage divider circuit with R1 to provide a reference voltage Vref1 for IN- of U1.

[0107] One end of the resistor R3 is connected to the base of the transistor T1 and one end of R4, and the other end is connected to the cathode of the diode D1 and the cathode of the diode D2. Its function is to provide current limiting for the base of the transistor T1 when the comparator U1 / U2 outputs a high level.

[0108] One end of resistor R4 is connected to the base of transistor T1 and one end of R3, and the other end is connected to GND. It has two functions. The first function is to form a voltage divider circuit with R3 when U1 / U2 outputs a high level to provide the voltage required for transistor T1 to turn on; the second function is to ensure that transistor T1 is in a closed state when U1 / U2 outputs a low level.

[0109] One end of resistor R5 is connected to one end of current detection resistor RT1, the source of MOS tube, one end of capacitor C1, and IN- of U1. The other end is connected to one end of capacitor C1, one end of R6, and the gate of MOS tube Q1. It has two functions. The first function is that when transistor T2 is turned on, it forms a voltage divider circuit in series with R6 to prevent the gate voltage of MOS from being too high to damage Q1, and also prevent the collector current IC of the transistor from being too large to damage T2. It is the collector current limiting resistor of transistor T2; the second function is that when transistor T2 is turned off, it acts as a pull-up resistor of the gate of MOS tube Q1 to ensure that MOS tube Q1 is in the off state.

[0110] One end of resistor R6 is connected to one end of R5, one end of capacitor C1, and the gate of MOS tube Q1, and the other end is connected to the collector of transistor T2. Its function is to form a voltage divider circuit in series with R5 when transistor T2 is turned on, to prevent the gate voltage of MOS from being too high to damage Q1, and to prevent the collector current IC of the transistor from being too large to damage T2, and it is the collector current limiting resistor of transistor T2;

[0111] One end of the resistor R7 is connected to the control signal Control-Signal-IN, and the other end is connected to the base of the transistor T2, one end of R8, and one end of the capacitor C2. Its function is to provide current limiting for the base of the transistor T2 when Control-Signal-IN is at a high level.

[0112] One end of resistor R8 is connected to the collector of transistor T1, the base of transistor T2, one end of R7, one end of C2, and the other end is connected to GND. It has two functions. The first function is to form a voltage divider circuit with R7 when Control-Signal-IN2 outputs a high level to provide the voltage required for transistor T2 to turn on. The second function is to ensure that transistor T2 is in a closed state when Control-Signal-IN is in a high impedance state / low level.

[0113] One end of resistor R9 is connected to the drain of MOS tube Q1 and one end of temperature acquisition resistor RT2, and the other end is connected to one end of R10 and analog signal acquisition IO of MCU. Its function is to form a voltage divider circuit in series with R10 to provide a suitable voltage acquisition signal.

[0114] One end of resistor R10 is connected to one end of R9 and the analog signal acquisition IO of MCU, and the other end is connected to GND. Its function is to form a voltage divider circuit in series with R9 to provide a suitable voltage acquisition signal.

[0115] One end of resistor R11 is connected to IN+ of comparator U2, one end of temperature acquisition resistor RT2, one end of R12, and the other end is connected to analog signal acquisition IO of MCU. Its function is to serve as a current limiting resistor of MCU analog signal acquisition IO to prevent excessive current from damaging MCU.

[0116] One end of resistor R12 is connected to IN+ of comparator U2, one end of temperature acquisition resistor RT2, one end of R11, and the other end is connected to GND. Its function is to form a voltage divider circuit with temperature acquisition resistor RT2. It is used for the input of IN+ of comparator U2.

[0117] One end of resistor R13 is connected to IN- of U2 and one end of R14, and the other end is connected to VDD. The function of R13 is to form a voltage divider circuit with R14 to provide a reference voltage Vref2 for IN+ of U2.

[0118] One end of the resistor R14 is connected to IN- of U2 and one end of R13, and the other end is connected to GND. The function of R14 is to form a voltage divider circuit with R13 to provide a reference voltage Vref2 for IN+ of U2.

[0119] One end of the current sampling resistor RT1 is connected to the power supply VDD, and the other end is connected to IN- of the comparator U1, one end of R5, one end of C1, and the source of Q1. Its function is that when a short circuit occurs in the circuit, the current Iload will generate a voltage VRT1 at RT1, and the size of the short-circuit current can be set by changing the value of RT1.

[0120] One end of the temperature sampling resistor RT2 is connected to the drain of the MOS tube Q1, and the other end is connected to IN+ of the comparator U2, one end of R11, and one end of R12. Its function is that when the temperature rises, the resistance of RT2 changes with the temperature, and the voltage at IN+ of U2 also changes accordingly, which can be used for temperature detection and over-temperature shutdown control of the MCU.

[0121] One end of capacitor C1 is connected to one end of RT1, one end of R5, the source of Q1, and IN- of U1, and the other end is connected to one end of R5, one end of R6, and the gate of Q1. Its function is to delay the opening time of MOS tube Q1 and reduce the risk of MOS output overshoot.

[0122] One end of capacitor C2 is connected to one end of R7, one end of R8, the collector of T1, and the base of T2, and the other end is connected to GND. Its function is filtering to ensure the stability of the base level of T2.

[0123] One end of the comparator U1 is connected to the anode of the diode D1, one end is connected to one end of RT1, one end of R5, one end of C1, and the source of Q1, one end is connected to one end of R1 and one end of R2, one end is connected to VDD, and one end is connected to GND. Its function is to compare the voltages at IN+ and IN- when a short circuit occurs, output a control signal, and shut down the high-side drive circuit.

[0124] One end of the comparator U2 is connected to the anode of the diode D2, one end is connected to one end of RT2, one end of R11, one end of R12, one end is connected to one end of R13, one end of R14, one end is connected to VDD, and one end is connected to GND. Its function is to compare the voltages at IN+ and IN- when overtemperature occurs, output a control signal, and shut down the high-side drive circuit.

[0125] The base of transistor T1 is connected to one end of R3 and one end of R4, the collector is connected to one end of R7, one end of R8, one end of C2, and the base of T2, and the emitter is connected to GND. Its function is that when a short circuit / overtemperature fault occurs, transistor T1 is turned on and the base of transistor T2 is pulled down, thereby disconnecting MOS tube Q2 and shutting down the output protection circuit.

[0126] The base of transistor T2 is connected to one end of R7, one end of R8, one end of C2, and the collector of T1, the collector is connected to one end of R6, and the emitter is connected to GND. Its function is to control the on / off of Q1 by controlling the on / off of T2.

[0127] The positive electrode of diode D1 is connected to one end of comparator U1, and the negative electrode is connected to one end of R3 and the negative electrode of D2. Its function is to prevent the output of U2 from being pulled down by U1 when it is high, so that transistor T1 cannot be turned on.

[0128] The positive electrode of diode D2 is connected to one end of comparator U2, and the negative electrode is connected to one end of R3 and the negative electrode of D1. Its function is to prevent the output of U1 from being pulled down by U2 when it is high, so that transistor T1 cannot be turned on.

[0129] The gate of MOS tube Q1 is connected to one end of R6, one end of C1, and one end of R5, the source is connected to one end of C1, one end of R5, one end of RT1, and one end of U1, and the drain is connected to one end of RT2 and the analog signal detection IO of MCU. Its function is to provide power output for the high-side drive circuit.

[0130] It is understandable that the MOS tubes used in the above solution, such as Q1 / Q2, can be replaced by triodes, and T1 can also be replaced by a MOS tube.

[0131] The specific working principle of the circuit in this embodiment is as follows:

[0132] 1. When Control-Signal-In outputs a high level (especially, Control-Signal-In can be the IO control signal of the MCU or the power supply voltage signal), transistor T2 is turned on, and Vgs of Q1 is less than the Vgs (TH) turn-on threshold, and Q1 is turned on. At this time, Vout outputs voltage, Vout = VDD-RT1*Iload.

[0133] When a short circuit occurs in the circuit module or peripheral connected to Vout, the current flowing through the sampling resistor RT1 increases, and the voltage drop on RT1 becomes larger. When the voltage (VDD-VRT1) is less than Vref1, the comparator U1 outputs a high level, and the transistor T1 is turned on; the transistor T1 is turned on, so that the base of the transistor T2 is pulled down, and T2 is turned off; T2 is turned off, and the gate of Q1 is pulled up to the (VDD-VRT1) voltage by the resistor R5, which is greater than the Vgs (TH) turn-on threshold, and Q is turned off; thereby protecting Q1 from damage.

[0134] When the temperature of the circuit module or peripheral connected to Vout rises, the resistance of the RT2 temperature collection resistor decreases as the temperature rises, and the voltage division on the resistor R12 gradually increases. When the voltage is greater than Vref2, the comparator U2 outputs a high level, and the transistor T1 is turned on; the transistor T1 is turned on, so that the base of the transistor T2 is pulled down, and T2 is turned off; T2 is turned off, and the gate of Q1 is pulled up to the (VDD-VRT1*Iload) voltage by the resistor R5, which is greater than the Vgs (TH) turn-on threshold, and Q is turned off; thereby shutting down the peripherals to protect them from being damaged due to excessive temperature or catching fire.

[0135] 2. When CONTROL-SIGNAL-IN outputs a low level, T2 is turned off. At this time, the voltage Vgs on the gate of Q1 is greater than the turn-on voltage threshold Vgs (TH) of Q1 through resistor R5, so Q1 is in the off state.

[0136] 3. Voltage-Dect-Signal is the voltage detection input pin, which is connected to the analog signal acquisition pin of the MCU to monitor the high-side driver output voltage status in real time. When Vout is overvoltage / undervoltage, it can actively pull down the Control-Signal-IN signal to turn off Q1.

[0137] 4.Temp-Dect-Signal is the temperature detection output voltage, which can be used to monitor the temperature status of peripherals in real time by connecting to the analog signal acquisition pin of the MCU.

[0138] It should be noted that for switching devices, those skilled in the art can understand that for NPN transistors, the current relationship flowing through the collector (c), base (b), and emitter (e) is: Ie=Ib+Ic, Ic=β*Ib. When Ube>0.7V, that is, the emitter junction voltage Ube is forward biased, the transistor is turned on. When Ube<0.7V, that is, the emitter junction voltage Ube is reverse biased, the transistor is in a cut-off state, which is equivalent to the switch being disconnected. Among them, the transistor conduction voltage and other parameters are determined by the specific device selected. Correspondingly, the parameters of each voltage divider circuit are also selected according to the specification requirements of the device. This is common sense for those skilled in the art and will not be repeated. Similarly, for PNP transistors, when Ube<-0.7V, the transistor is turned on. When Ube>-0.7V, the transistor is turned off. Similarly, the specific circuit parameters need to be determined with reference to the specification requirements of the selected transistor.

[0139] It should be understood by those skilled in the art that the MOS tube needs to meet the condition of |Vg-Vs|>|Vgs(TH)| for it to be turned on. Specifically, for NMOS tubes, Vg-Vs>Vgs(TH), Vgs(TH) is the threshold voltage of the MOS tube, that is, the voltage difference between the G pole (gate) and the S pole (source) is greater than a certain value, the MOS tube will be turned on, but the voltage difference cannot be too large, otherwise the MOS tube will be burned out. Among them, the turn-on voltage and other parameters need to refer to the relevant specifications according to the specific device selected. Similarly, for PMOS tubes, Vg-Vs<Vgs(TH), that is, the voltage difference between the G pole and the S pole is less than a certain value, the MOS tube will be turned on (for PMOS tubes, Vgs(TH) is a negative value). Similarly, the specific parameters need to refer to the specifications of the specific device.

[0140] It should be understood by those skilled in the art that the specific parameters of the circuit components of the utility model can be adjusted according to actual conditions. The resistance values ​​of each component are not limited to those shown in the above circuit diagram. Diodes and transistors can also be replaced by other components that can achieve the same function.

[0141] The utility model provides a high-side drive output circuit. Since a short-circuit protection function and an overvoltage and overtemperature protection function are set for the high-side drive output, the circuit can be immediately cut off at least in the case of overcurrent and / or overtemperature, thereby reducing the influence of the startup instantaneous impact current on the power supply when the high-side drive output terminal is connected to a capacitive load; the overvoltage protection and overtemperature protection circuits can ensure that the output of the switching device is turned off in time when the MCU works abnormally, thereby the connected equipment can be protected from damage caused by power short circuit, overvoltage, overtemperature and other faults, so that the high-side output has the function of ensuring that the load can be started and shut down normally, and the output power supply voltage is stable and reliable, and has the characteristics of wide applicability.

[0142] It should be noted that the embodiments of the present application provide a hardware circuit that can solve the technical problems existing in the prior art, and do not limit the software design that may be involved. Those skilled in the art can design the software as needed to implement the required functions based on the hardware circuit provided by the present application.

[0143] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "embodiment", 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 application. 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.

[0144] In the present invention, the terms "connected", "connection", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; "connection" can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0145] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model and are not restrictive. Although the utility model is described in detail with reference to the embodiments, it should be understood by those skilled in the art that any modification or equivalent replacement of the technical solution of the utility model does not deviate from the spirit and scope of the technical solution of the utility model, and should be included in the scope of the claims of the utility model.

Claims

1. A high-side drive output circuit, characterized in that: include: An output module, connected between the power supply and the output terminal, including a switch device; A control module connected to the control end of the switch device, wherein the switch device is controlled to be turned on or off by the control module; An overcurrent protection module connected between the power supply and the control module, the overcurrent protection module comprising a current acquisition device and closing the switch device through the control module when the current flowing through the current acquisition device exceeds a preset value; An over-temperature protection module is connected between the control module and the output end, wherein the over-temperature protection module includes a temperature acquisition device and closes the switch device through the control module when the temperature detected by the temperature acquisition device exceeds a preset value.

2. The high-side drive output circuit according to claim 1, characterized in that: The control module is also connected to the signal input terminal receiving the input signal, and the switch device can also be turned on or off by the control module according to the high, low level state or high impedance state of the input signal, so that: When the input signal is at a high level, the output module outputs a voltage signal corresponding to the voltage of the power supply; When the input signal changes from a high level to a low level or a high impedance state, the output module does not output a signal.

3. The high-side drive output circuit according to claim 2, characterized in that: The circuit also includes a voltage protection module connected between the output module and the output end, which is used to control the input signal received by the signal input end to be converted into a high impedance state or a low level state when the output voltage is abnormal.

4. The high-side drive output circuit according to claim 3, characterized in that: The control module includes a first control switch device and a second control switch device, the control end of the second control switch device is connected to the signal input end and the first control switch device, and the control end of the first control switch device is connected to the overcurrent protection module and the overtemperature protection module.

5. The high-side drive output circuit according to claim 4, characterized in that: The overcurrent protection module comprises a first comparator, one of the input terminals of the first comparator is connected to the current acquisition device, and the output terminal is connected to the control terminal of the first control switch device; The over-temperature protection module includes a second comparator, one of the input terminals of the second comparator is connected to the temperature acquisition device, and the output terminal is connected to the control terminal of the first control switch device. The first comparator inputs a reference voltage through a first voltage divider circuit, the first voltage divider circuit includes a series resistor having one end connected to a power supply and the other end grounded, and the other input end of the first comparator is connected to the connection end of the two series resistors; The second comparator inputs a reference voltage through a second voltage divider circuit, which includes a series resistor with one end connected to the power supply and the other end grounded. The other input end of the second comparator is connected to the connection end of the two series resistors.

6. The high-side drive output circuit according to claim 5, characterized in that: The control module also includes: a third voltage-dividing circuit, wherein the overcurrent protection module and the overtemperature protection module are connected to the control end of the first control switch device through the third voltage-dividing circuit, so that the first control switch device is turned on through the third voltage-dividing circuit, wherein the third voltage-dividing circuit includes a series resistor having one end connected to the output ends of the overcurrent protection module and the overtemperature protection module and the other end grounded, and a connection end of two resistors in the series resistor is connected to the control end of the first control switch device; a fourth voltage-dividing circuit, wherein the second control switch device is connected to the control end of the switch device through the fourth voltage-dividing circuit, thereby closing the switch device through the fourth voltage-dividing circuit, wherein the fourth voltage-dividing circuit includes a series resistor having one end connected to the current acquisition device of the overcurrent protection module and the other end grounded through the second control switch device, and the connection end of the two resistors in the series resistor is connected to the control end of the switch device; A fifth voltage-dividing circuit includes a series resistor having one end connected to the signal input end and the other end grounded, wherein the connection end of two resistors in the series resistor is connected to the control end of the second control switch device.

7. The high-side drive output circuit according to claim 6, characterized in that: The voltage protection module includes a voltage acquisition output interface for acquiring a voltage state corresponding to the output voltage of the output end. The voltage protection module also includes a sixth voltage divider circuit, which includes a series resistor with one end connected to the output end and the other end grounded, wherein the connection ends of two resistors in the series resistor are connected to the voltage acquisition output interface.

8. The high-side driver output circuit according to claim 7, characterized in that: The over-temperature protection module includes a temperature detection output interface for outputting parameters corresponding to the collected temperature. The over-temperature protection module also includes a series resistor connected to the temperature collection device, one end of the series resistor is connected to the temperature detection output interface, and the other end is grounded. The connection ends of the two resistors in the series resistor are connected to the temperature collection device.

9. The high-side driver output circuit according to any one of claims 6 to 8, characterized in that: The overcurrent protection module further includes a diode, wherein an anode of the diode is connected to the output end of the first comparator, and a cathode of the diode is connected to one end of the third voltage divider circuit; The over-temperature protection module further includes a diode, wherein an anode of the diode is connected to the output end of the second comparator, and a cathode of the diode is connected to one end of the third voltage divider circuit.

10. The high-side drive output circuit according to claim 9, characterized in that: The switch device is a PMOS field effect transistor, the first control switch device and the second control switch device are NPN transistors, The current acquisition device is a current sampling resistor, and the temperature acquisition device is a temperature sampling resistor; The source of the switch device is connected to one end of the current sampling resistor and one end of the series resistor of the fourth voltage divider circuit, the gate is connected to the connection end of two resistors in the series resistor of the fourth voltage divider circuit, the drain is connected to the output end, one end of the temperature sampling resistor and one end of the series resistor of the sixth voltage divider circuit, and the other end of the series resistor of the sixth voltage divider circuit is grounded. The base of the first control switch device is connected to the connection end of two resistors in the series resistor of the third voltage divider circuit, the collector is connected to the base of the second control switch device and the connection end of two resistors in the series resistor of the fifth voltage divider circuit, and the emitter is grounded. The collector of the second control switch device is connected to the other end of the series resistor of the fourth voltage divider circuit, and the emitter is grounded. One input end of the first comparator is connected to one end of the current sampling resistor, and the other end of the current sampling resistor is connected to the power supply; the other input end of the first comparator is connected to the connection end of two resistors in the series resistor of the first voltage divider circuit, one end of the series resistor of the first voltage divider circuit is connected to the power supply, and the other end is grounded; the output end of the first comparator is connected to one end of the series resistor of the third voltage divider circuit, and the other end of the series resistor of the third voltage divider circuit is grounded, One input end of the second comparator is connected to the other end of the temperature sampling resistor; the other input end of the second comparator is connected to the connection end of two resistors in the series resistor of the second voltage divider circuit, one end of the series resistor of the second voltage divider circuit is connected to the power supply, and the other end is grounded; the output end of the second comparator is connected to one end of the series resistor of the third voltage divider circuit, One end of the series resistor of the fifth voltage divider circuit is connected to the signal input end, and the other end is grounded; the other end of the temperature sampling resistor is also connected to the connection end of the two resistors of the series resistor, one end of the series resistor is connected to the temperature detection output interface, and the other end is grounded.

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