Ground drift processing circuit, thermal management system control unit and vehicle electronic control unit

Abstract

The present invention relates to the technical field of ground drift processing circuits, and discloses a ground drift processing circuit, a thermal management system control unit, and a vehicle electronic control unit. The ground drift processing circuit includes a Zener diode, a first resistor, a second resistor, and a switching transistor. The cathode of the Zener diode is connected to an analog signal output terminal, and the anode of the Zener diode is connected to one end of the first resistor. The other end of the first resistor is connected to a control terminal of the switching transistor. One end of the second resistor is connected to a power supply, and the other end of the second resistor is connected to a connection terminal of the switching transistor and a digital signal input terminal. The other connection terminal of the switching transistor is grounded. The switching transistor is configured to be turned off when the voltage drift of a low-level signal at the analog signal output terminal is greater than a first preset voltage and less than a second preset voltage, wherein the second preset voltage is greater than the first preset voltage. The present invention can avoid signal distortion caused by ground plane drift in the electronic control unit.

Description

Technical Field

[0001] The present invention relates to the technical field of ground drift processing circuits, and in particular to a ground drift processing circuit, a thermal management system control unit, and an electronic control unit of a vehicle. Background Art

[0002] In the vehicle's Thermal Management Control Unit (TMCU) circuit, line coupling or floating circuits can cause ground plane drift (referred to as ground drift) on the TMCU, resulting in signal distortion and inversion of high-level and low-level signals at the output. This can cause TMCU malfunction and disrupt control logic.

[0003] Currently, transistors can be used to control ground drift, but they can only control low-threshold ground drift and have difficulty controlling high-threshold ground drift. For example, if the voltage drift of a low-level signal at the input does not exceed 0.7V (i.e., the low threshold), the transistor can control the output to maintain the corresponding electrical signal, preventing the high and low signals from reversing at the output. However, if the voltage drift of the low-level signal at the input exceeds 0.7V, the transistor will be unable to suppress the ground drift, potentially causing the high and low signals at the output to reverse. Summary of the Invention

[0004] In view of this, the present invention provides a ground drift processing circuit, a thermal management system control unit, and a vehicle electronic control unit to solve the problem of signal distortion (high and low signal inversion) caused by ground plane drift of the electronic control unit.

[0005] In a first aspect, the present invention provides a ground drift processing circuit, which includes a Zener diode, a first resistor, a second resistor, and a switching tube; the cathode of the Zener diode is connected to the analog signal output end, and the anode of the Zener diode is connected to one end of the first resistor; the other end of the first resistor is connected to the control end of the switching tube; one end of the second resistor is connected to a power supply, and the other end of the second resistor is connected to a connection end of the switching tube and a digital signal input end; the other connection end of the switching tube is grounded; the switching tube is configured to be in an off state when the voltage drift of the low-level signal at the analog signal output end is greater than a first preset voltage and the voltage drift is less than a second preset voltage, and the second preset voltage is greater than the first preset voltage.

[0006] The ground drift processing circuit provided by the present invention, by providing a Zener diode connected in series with the control terminal of the switching tube, can put the switching tube into a turned-off state when the voltage drift of the low-level signal at the analog signal output terminal is greater than a first preset voltage and less than a second preset voltage, thereby avoiding signal detection errors and electrical signal inversion caused by abnormal conditions, thereby improving system reliability.

[0007] In an optional implementation, the ground drift processing circuit further includes an anti-reverse diode; the anode of the anti-reverse diode is connected to the analog signal output terminal, and the cathode of the anti-reverse diode is connected to the cathode of the Zener diode.

[0008] In this embodiment, by providing an anti-reverse diode, interference between other circuits connected to the analog signal output terminal and the ground drift processing circuit can be avoided.

[0009] In an optional implementation, the second preset voltage is the sum of the breakdown voltage of the Zener diode, the breakdown voltage of the anti-reverse diode, and the turn-on voltage of the switch tube.

[0010] In this embodiment, by adjusting the model of the Zener diode, the staff can flexibly adjust the second preset voltage.

[0011] In an optional embodiment, the breakdown voltage of the Zener diode is one of 1.8V, 2.4V, 3.3V, 3.6V and 5.6V.

[0012] In an optional implementation, the ground drift processing circuit further includes a third resistor; one end of the third resistor is connected to the anode of the anti-reverse diode, and the other end of the third resistor is connected to the analog signal output end.

[0013] In this embodiment, by adjusting the resistance values of the third resistor and the first resistor, the leakage current can be effectively reduced, thereby improving the reliability and stability of the ground drift processing circuit.

[0014] In an optional embodiment, the switch tube is a triode or a metal oxide semiconductor field effect transistor.

[0015] In an optional implementation, the ground drift processing circuit further includes a bypass capacitor; one end of the bypass capacitor is grounded, and the other end of the bypass capacitor is connected to the control end of the switch tube and the other end of the first resistor.

[0016] In this embodiment, by providing a bypass capacitor, power supply noise in the ground drift processing circuit can be filtered out, voltage mutations can be suppressed, circuit stability can be maintained, and the ripple suppression capability of the power supply can be improved, thereby ensuring that the voltage fluctuation of the power supply is within an allowable range.

[0017] In an optional implementation, the ground drift processing circuit further includes a bias resistor; one end of the bias resistor is grounded, and the other end of the bias resistor is connected to the control end of the switch tube and the other end of the first resistor.

[0018] In this embodiment, the bias resistor limits the current flowing into the transistor base, protecting the transistor from damage caused by excessive base current. It also maintains the collector current within the designed range, preventing the switch from misfiring. Furthermore, when temperature or other conditions change, properly designed bias resistors can compensate for changes in transistor parameters and maintain stable circuit operation.

[0019] In a second aspect, the present invention provides a thermal management system control unit, comprising the ground drift processing circuit of the first aspect or any corresponding embodiment thereof.

[0020] In a third aspect, the present invention provides an electronic control unit for a vehicle, comprising the ground drift processing circuit of the first aspect or any corresponding embodiment thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 2 is a schematic structural diagram of a ground drift processing circuit according to an embodiment of the present invention;

[0023] Figure 2 is a schematic structural diagram of another ground drift processing circuit according to an embodiment of the present invention;

[0024] Figure 3 FIG. 4 is a structural diagram of another ground drift processing circuit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0026] The ground drift processing circuit provided by the present invention is applied to control units such as a TMCU or a vehicle's electronic control unit (ECU). The ground drift processing circuit provided by the present invention can avoid signal distortion (high and low signal inversion) caused by ground plane drift of the ECU.

[0027] The ground drift processing circuit provided in this application is described in detail below with reference to the accompanying drawings.

[0028] like Figure 1 As shown, the ground drift processing circuit provided by the present invention includes a Zener diode D21, a first resistor R104, a second resistor R103 and a switch tube Q5.

[0029] The negative electrode (cathode) of the Zener diode D21 is connected to the analog signal output terminal CPSR, the positive electrode (anode) of the Zener diode D21 is connected to one end of the first resistor R104, the other end of the first resistor R104 is connected to the control terminal of the switch Q5, one end of the second resistor R103 is connected to a power supply (e.g., a +5V voltage source), the other end of the second resistor R103 is connected to one connection terminal of the switch Q5 and the digital signal input terminal CPSR_IN, and the other connection terminal of the switch Q5 is grounded. That is, the control terminal of the switch Q5 is connected in series with the first resistor R104 and the Zener diode D21 and then connected to the analog signal output terminal CPSR, one connection terminal of the switch Q5 is connected in series with the second resistor R103 and then connected to the power supply, one connection terminal of the switch Q5 is also connected to the digital signal input terminal CPSR_IN, and the other connection terminal of the switch Q5 is grounded.

[0030] Specifically, the first resistor R104 (current limiting resistor) is used to limit the driving current of the switch tube Q5 to ensure that the switch tube operates within a preset current range and prevent the switch tube from being overheated or damaged or having unstable performance due to excessive current.

[0031] The switch Q5 is configured to be turned off when the voltage drift of the low-level signal at the analog signal output terminal CPSR exceeds a first preset voltage and is less than a second preset voltage, thereby preventing inversion of the electrical signal corresponding to the digital signal input terminal CPSR_IN. The first preset voltage is a voltage drift that can be handled by a conventional ground drift processing circuit, such as 0.7V, 0.5V, or 0.3V. The second preset voltage is determined based on the breakdown voltage of the Zener diode D21 and the conduction voltage of the switch Q5, and is greater than the first preset voltage.

[0032] Exemplarily, the second preset voltage may be the sum of the breakdown voltage of the Zener diode D21 and the turn-on voltage of the switch tube Q5. For example, if the breakdown voltage of the Zener diode D21 is 5.6V and the turn-on voltage of the switch tube Q5 is 0.4V, the second preset voltage may be 6V.

[0033] It should be understood that a Zener diode is a special type of diode. When a Zener diode is reverse biased, once the voltage exceeds its rated Zener voltage (also known as breakdown voltage), it will enter avalanche breakdown or Zener breakdown state. In this state, current can pass through the diode, and the voltage across it remains relatively stable, even when the current varies to a certain extent. This characteristic makes Zener diodes play an important role in voltage-stabilized power supplies, voltage reference circuits, overvoltage protection circuits, and voltage clamping circuits. The Zener voltage of a Zener diode can be controlled through the doping process during manufacturing. Common Zener voltage values cover a wide range, ranging from a few volts to hundreds of volts.

[0034] The low-level signal can be a voltage value close to or equal to the ground potential (generally 0V). Specifically, for different logic level standards and systems, the voltage value corresponding to the low-level signal is different. For example, when using the logic level standard of a 12V power supply, in some vehicle networks (such as the Controller Area Network (CAN) bus), the logic low-level signal may be defined as approximately 0.5V to 2V.

[0035] The following describes the ground drift processing circuit provided by the present invention, taking as an example a first preset voltage of 0.7V, a breakdown voltage of Zener diode D21 of 5.6V, a turn-on voltage of switch Q5 of 0.4V, and a voltage corresponding to a low-level signal being 0V under normal circumstances. In this case, the second preset voltage can be 6V = 5.6V + 0.4V.

[0036] Specifically, under normal circumstances, when the analog signal output terminal CPSR outputs an electrical signal at a low level (typically 0V), the Zener diode D21 is in a reverse cutoff state, and the switch Q5 is also in a cutoff state. At this time, the voltage at the digital signal input terminal CPSR_IN is pulled to the voltage of the power supply by the second resistor R103 (i.e., the pull-up resistor), that is, the output electrical signal at the digital signal input terminal CPSR_IN is a high level signal. In an abnormal situation such as voltage drift at the analog signal output terminal CPSR due to line coupling or a floating circuit, assuming that the low level signal drifts to 4V, the voltage drift is greater than the first preset voltage and less than the second preset voltage, at this time, the Zener diode D21 is still not turned on, the switch Q5 is still in the off state, and the digital signal input terminal CPSR_IN still outputs a high level signal, avoiding signal detection errors and electrical signal inversion problems caused by abnormal conditions, thereby improving system reliability.

[0037] The ground drift processing circuit provided by the present invention, by providing a Zener diode connected in series with the control terminal of the switching tube, can put the switching tube into a turned-off state when the voltage drift of the low-level signal at the analog signal output terminal is greater than a first preset voltage and less than a second preset voltage, thereby avoiding signal detection errors and electrical signal inversion caused by abnormal conditions, thereby improving system reliability.

[0038] It should be noted that when the voltage drift of the low-level signal at the analog signal output terminal is less than or equal to the first preset voltage, the switch Q5 remains in the off state, thereby preventing inversion of the electrical signal corresponding to the digital signal input terminal CPSR_IN. In other words, the ground drift processing circuit provided by the present invention can handle not only low-threshold ground drift (e.g., 0.7V) but also high-threshold ground drift, thereby improving the accuracy of the control logic of the electronic control unit.

[0039] For example, the analog signal output terminal CPSR may be connected to a power supply via a high-voltage relay, and the digital signal input terminal CPSR_IN may be connected to a logic unit or a logic processor (eg, a microcontroller unit (MCU) or a TMCU, etc.).

[0040] It should be understood that a high-voltage relay is designed to perform switching functions in high-voltage systems. Unlike conventional relays, high-voltage relays can withstand and switch voltages of thousands or even tens of kilovolts. High-voltage relays operate on a similar principle to low-voltage relays, using relatively small control signals to control the on and off of high-voltage circuits. High-voltage relays offer advantages such as high insulation strength, powerful arc-extinguishing capability, and high reliability, ensuring the reliability and safety of circuits in high-voltage environments.

[0041] The present invention does not limit the specific structure of the switch tube Q5. For example, the switch tube Q5 can be a triode or a metal-oxide-semiconductor field-effect transistor (MOSFET). Figure 2 As shown, the switch tube Q5 can be an NPN transistor. In this case, the control end of the switch tube Q5 in the above description is the base of the NPN transistor, one connection end of the switch tube Q5 is the collector of the NPN transistor, and the other connection end of the switch tube Q5 is the emitter of the NPN transistor.

[0042] It should be understood that a triode is a type of bipolar junction transistor (BJT), consisting of a base (B), a collector (C), and an emitter (E). A triode can regulate a large current between the collector and emitter by controlling a small current in the base.

[0043] A transistor is usually composed of two back-to-back PN junctions. Depending on the arrangement of the PN junctions, transistors can be divided into two types: NPN and PNP. The operating modes of a transistor generally include amplification mode, saturation mode, and cutoff mode.

[0044] Specifically, the amplification mode refers to the following: under appropriate bias conditions, injecting a small signal current into the base can cause a large change in the collector current, achieving current amplification. Specifically, the saturation mode refers to the following: when the base current is large enough, the transistor can operate in a saturated state. At this time, the voltage between the collector and emitter is very small, the current flowing through is large, and the transistor acts as a switch. Specifically, the cutoff mode refers to the following: when the base does not have sufficient forward bias current, the transistor is in the cutoff state, and the current between the collector and emitter is almost zero.

[0045] Further, if Figure 2 As shown, the ground drift processing circuit also includes an anti-reverse diode D20, wherein the positive electrode (anode) of the anti-reverse diode D20 is connected to the analog signal output terminal CPSR, and the negative electrode (cathode) of the anti-reverse diode D20 is connected to one end of the Zener diode D21, that is, the control end of the switch tube Q5 is connected in series with the first resistor R104, the Zener diode D21 and the anti-reverse diode D20, and then connected to the analog signal output terminal CPSR.

[0046] Specifically, a reverse current protection diode, also known as a blocking diode, freewheeling diode, or reverse protection diode, is a semiconductor diode used to prevent reverse current flow. It has unidirectional conductivity, meaning it conducts under forward voltage and blocks under reverse voltage. In a circuit, when the current in the load is forced to change suddenly, Faraday's law of electromagnetic induction generates a reverse voltage across the inductor. This voltage can be very high, sufficient to damage the semiconductor components in the driving circuit. When reverse voltage appears, the reverse current protection diode immediately turns on, providing a low-impedance path for the reverse current, allowing the current to flow smoothly through the diode instead of through other expensive or fragile circuit components, thus providing protection.

[0047] In this embodiment, by providing the anti-reverse diode D20, interference between other circuits connected to the analog signal output terminal CPSR and the ground drift processing circuit can be avoided.

[0048] Exemplarily, the second preset voltage may be the sum of the breakdown voltage of the Zener diode D21 , the breakdown voltage D20 of the anti-reverse diode, and the turn-on voltage of the switch tube Q5 .

[0049] The present invention can flexibly set the second preset voltage by adjusting the breakdown voltage of the Zener diode D21. For example, the breakdown voltage of the Zener diode D21 can be one of 1.8V, 2.4V, 3.3V, 3.6V, and 5.6V. For example, if the second preset voltage is 6.7V, the breakdown voltage of the anti-reverse diode D20 is 0.7V, and the turn-on voltage of the switch tube Q5 is 0.4V, then the breakdown voltage of the Zener diode D21 can be 5.6V.

[0050] In some optional embodiments, such as Figure 2 As shown, the ground drift processing circuit further includes a third resistor R6, wherein one end of the third resistor R6 is connected to the anode of the anti-reverse diode D20, and one end of the third resistor R6 is connected to the analog signal output terminal CPSR.

[0051] Specifically, the third resistor R6 is also a current-limiting resistor, and is used to adjust the leakage current in the ground drift processing circuit.

[0052] It should be understood that leakage current refers to the tiny amount of current generated in semiconductor devices (such as diodes, transistors, and insulated-gate field-effect transistors), which ideally should be off or non-conducting, due to factors such as material imperfections, temperature, and voltage. In an ideal semiconductor component, when the device is in the off state, the current should theoretically be zero, but in reality, a certain amount of leakage current always exists.

[0053] The presence of leakage current will have a certain impact on the performance of semiconductor devices. Leakage current means that a small current still flows when no current is needed, causing unnecessary energy loss and increasing the power consumption of the device. In addition, continuous leakage current will generate heat inside the semiconductor device and increase the temperature. If the heat dissipation is not properly handled, it may cause the device to overheat, thereby affecting the performance of the switch tube (such as the response speed of the switch) and reliability.

[0054] The present invention can effectively reduce leakage current by adjusting the resistance values of the third resistor R6 and the first resistor R104, thereby improving the reliability and stability of the ground drift processing circuit.

[0055] For example, the relationship between the third resistor R6 and the leakage current can be expressed as follows:

[0056] I=(V CPSR -(V f +V r +V Be)) / (R6+R104) (1)

[0057] Where I represents the leakage current, V CPSR Indicates the voltage of the analog signal output terminal CPSR, V f Indicates the breakdown voltage of the anti-reverse diode, V r Indicates the breakdown voltage of the Zener diode, V Be Indicates the on-state voltage of the switch tube Q5.

[0058] like Figure 3 As shown, the ground drift processing circuit further includes a bypass capacitor C89. One end of the bypass capacitor C89 is grounded, and the other end of the bypass capacitor C89 is connected to the control terminal of the switch Q5 and the other end of the first resistor R104. In other words, the bypass capacitor C89, the first resistor R104, and the control terminal of the switch Q5 are all connected to the first contact a1.

[0059] Specifically, bypass capacitors provide a low-impedance AC path, helping to filter out power supply noise, suppress voltage fluctuations, maintain stable circuit operation, and improve the power supply's ripple suppression capability, ensuring that power supply voltage fluctuations remain within an acceptable range. Furthermore, when the power supply voltage changes rapidly, bypass capacitors can replenish or absorb current by storing and releasing charge, thereby maintaining voltage stability.

[0060] like Figure 3 As shown, in some optional embodiments, the ground drift processing circuit further includes a bias resistor R105, one end of which is grounded, and the other end of which is connected to the control terminal of the switch Q5 and the other end of the first resistor R104. That is, the bias resistor R105, the first resistor R104, and the control terminal of the switch Q5 are all connected to the second contact a2.

[0061] Specifically, bias resistor R105 limits the current flowing into the transistor's base, protecting it from damage caused by excessive base current. It also maintains the collector current within the designed range, preventing the switch from misfiring. Furthermore, when temperature or other conditions change, properly designed bias resistors can compensate for changes in transistor parameters and maintain stable circuit operation.

[0062] For example, Figure 3 As shown, the ground drift processing circuit also includes a second capacitor C90, where one end of the second capacitor C90 is grounded, and the other end of the second capacitor C90 is connected to the digital signal input terminal CPSR_IN. Specifically, the provision of the second capacitor C90 can improve the circuit's responsiveness to high-frequency signals. At the same time, the second capacitor C90 can act as a low-pass filter to reduce the impact of high-frequency noise on the output signal.

[0063] Below Figure 3 Taking the ground drift processing circuit provided by the present invention as an example, the working state is described in detail, wherein: Figure 3 For example, the breakdown voltage of the anti-reverse diode D20 is 0.7V, the breakdown voltage of the Zener diode D21 is 5.6V, and the turn-on voltage of the switch tube Q5 is 0.4V, but the present invention is not limited thereto.

[0064] Specifically, when the input signal of the analog signal output terminal CPSR is a high level signal (for example, when the voltage of the analog signal output terminal CPSR is a typical value of 13V), V CPSR The voltage passes through the third resistor R6 (current limiting resistor), the anti-reverse diode D20 and the Zener diode D21. Since the voltage difference between the cathode and anode of the Zener diode D21 is higher than 5.6V, the Zener diode D21 is in the reverse breakdown working state, and the current flows through the first resistor R104 (base current limiting resistor), the bias resistor R105 and the bypass capacitor C89. At this time, for the switch tube Q5, there is a base voltage V b >Collector voltage V c >Emitter voltage V e , the switch tube Q5 is in saturation state, and the voltage of the digital signal input terminal CPSR_IN is pulled down to 0V.

[0065] When the input signal of the analog signal output terminal CPSR is a low level signal (for example, when the voltage of the analog signal output terminal CPSR is a typical value of 0V), no current flows through the anti-reverse diode D20, and the Zener diode D21 is in a reverse cutoff working state. At this time, for the switch tube Q5, there is V b <V c , the switch tube Q5 is in the cut-off state, and the voltage of the digital signal input terminal CPSR_IN is pulled to 5V by the second resistor R103 (pull-up resistor).

[0066] When the voltage of the analog signal output terminal CPSR drifts due to line coupling or floating circuit, for example, the voltage of the low-level signal drifts to 4V, and the minimum voltage of the analog signal output terminal CPSR that turns on the switch tube Q5 is the breakdown voltage V of the anti-reverse diode D20. f + Breakdown voltage of Zener diode D21 V r +The conduction voltage of the switch tube Q5 is V Be =0.7V+5.6V+0.4V=6.7V. Therefore, at this time, the switch tube Q5 is still in the cut-off state, and the digital signal input terminal CPSR_IN does not cause signal detection errors due to the abnormal state, thereby improving the reliability of the system.

[0067] The present invention further provides a thermal management system control unit, comprising the ground drift processing circuit provided by any one of the above embodiments.

[0068] Specifically, TMCU is an intelligent electronic control device used to manage and optimize the heat dissipation performance of various devices or systems (such as automobiles, electronic equipment, data centers, etc.). TMCU monitors and adjusts the temperature conditions inside the equipment by integrating sensors, actuators and advanced software algorithms to ensure that each component operates within the appropriate operating temperature range, thereby improving system efficiency, extending equipment life and ensuring safety. In the automotive field, the thermal management system control unit is mainly responsible for monitoring and controlling the temperature of engine coolant, battery pack, electric motor, electronic equipment and other parts. By receiving information from temperature sensors distributed throughout the vehicle, and then commanding actuators such as cooling fans, water pumps, coolant valves, and battery cooling systems to work according to preset strategies or real-time calculation results, it ensures that the entire thermal management system can effectively dissipate heat and maintain the optimal operating temperature, preventing performance degradation or damage caused by overheating.

[0069] The present invention further provides an electronic control unit for a vehicle, comprising the ground drift processing circuit provided by any one of the above embodiments.

[0070] Specifically, an electronic control unit (ECU) is a microprocessor widely used in automotive and other industrial fields. The ECU receives input signals from sensors and, based on pre-set control strategies, provides real-time monitoring and precise control of the engine, transmission, braking system, suspension system, and vehicle electronics. An ECU is a microcomputer with a built-in microprocessor, memory, input / output interfaces, and various control algorithms. In automotive applications, the ECU adjusts the engine's operating state, such as fuel injection rate, ignition timing, turbo pressure, and emission control, based on driving conditions, driver operation, and environmental factors to achieve optimal power output, fuel economy, and emission compliance.

[0071] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0072] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0073] It should be understood that various parts of the present invention can be implemented using hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0074] In the description of this specification, the description with reference to the terms "this embodiment", "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0075] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0076] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention. Such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A ground drift processing circuit, characterized in that: The ground drift processing circuit includes a Zener diode, a first resistor, a second resistor and a switch tube; The cathode of the Zener diode is connected to the analog signal output terminal, and the anode of the Zener diode is connected to one end of the first resistor; The other end of the first resistor is connected to the control end of the switch tube; One end of the second resistor is connected to the power supply, and the other end of the second resistor is connected to a connection end of the switch tube and the digital signal input end; The other connection end of the switching tube is grounded; the switching tube is used to be in an off state when the voltage drift of the low-level signal at the analog signal output end is greater than a first preset voltage and the voltage drift is less than a second preset voltage, and the second preset voltage is greater than the first preset voltage.

2. The ground drift processing circuit according to claim 1, characterized in that: The ground drift processing circuit also includes an anti-reverse diode; The anode of the anti-reverse diode is connected to the analog signal output terminal, and the cathode of the anti-reverse diode is connected to the cathode of the Zener diode.

3. The ground drift processing circuit according to claim 2, characterized in that: The second preset voltage is the sum of the breakdown voltage of the Zener diode, the breakdown voltage of the anti-reverse diode and the turn-on voltage of the switch tube.

4. The ground drift processing circuit according to claim 3, characterized in that: The breakdown voltage of the Zener diode is one of 1.8V, 2.4V, 3.3V, 3.6V and 5.6V.

5. The ground drift processing circuit according to any one of claims 2 to 4, characterized in that: The ground drift processing circuit further includes a third resistor; One end of the third resistor is connected to the anode of the anti-reverse diode, and the other end of the third resistor is connected to the analog signal output end.

6. The ground drift processing circuit according to any one of claims 1 to 4, characterized in that: The switch tube is a triode or a metal oxide semiconductor field effect transistor.

7. The ground drift processing circuit according to any one of claims 1 to 4, characterized in that: The ground drift processing circuit further includes a bypass capacitor; One end of the bypass capacitor is grounded, and the other end of the bypass capacitor is connected to the control end of the switch tube and the other end of the first resistor.

8. The ground drift processing circuit according to any one of claims 1 to 4, characterized in that: The ground drift processing circuit further includes a bias resistor; One end of the bias resistor is grounded, and the other end of the bias resistor is connected to the control end of the switch tube and the other end of the first resistor.

9. A thermal management system control unit, characterized in that: The method comprises the ground drift processing circuit according to any one of claims 1 to 8.

10. An electronic control unit for a vehicle, characterized in that: The method comprises the ground drift processing circuit according to any one of claims 1 to 8.

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