Control signal conversion interface circuit and automobile control system

Abstract

The utility model provides a kind of control signal conversion interface circuit and automobile control system, it is related to electronic circuit technical field, comprising: voltage regulating unit, for adjusting and voltage stabilizing to input voltage;Undervoltage detection unit is connected to the voltage regulating unit, for detecting whether input voltage is below preset threshold;Output drive unit is connected to the undervoltage detection unit and the voltage regulating unit respectively, for controlling output state according to undervoltage detection result;Wherein, the voltage regulating unit output adjustment node voltage, the adjustment node simultaneously provides operating voltage for the undervoltage detection unit and output drive unit.Improved the response speed and reliability of circuit, effectively solved the technical problem of big voltage fluctuation of automobile power system.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuit technology, and in particular to a control signal conversion interface circuit and an automotive control system. Background Technology

[0002] With the rapid development of automotive electronics technology, on-board electronic control units are being used more and more widely in modern cars. However, the operating environment of automotive power systems is extremely harsh, and there are many complex electrical characteristics problems.

[0003] The voltage fluctuation range of automotive power systems is extremely wide, posing a serious challenge to the stable operation of electronic control units. Therefore, there is an urgent need for a control signal conversion interface circuit that can adapt to the wide voltage range of automotive power systems. Utility Model Content

[0004] This invention provides a control signal conversion interface circuit and an automotive control system to solve the problem in the prior art of needing a control signal conversion interface circuit that can adapt to a wide voltage range of automotive power systems.

[0005] This utility model provides a control signal conversion interface circuit, including: The voltage regulation unit is used to regulate and stabilize the input voltage; An undervoltage detection unit, connected to the voltage regulation unit, is used to detect whether the input voltage is lower than a preset threshold. An output drive unit is connected to the undervoltage detection unit and the voltage regulation unit respectively, and is used to control the output state according to the undervoltage detection result; The voltage regulation unit outputs a regulation node voltage, and the regulation node simultaneously provides operating voltage for the undervoltage detection unit and the output drive unit.

[0006] According to the control signal conversion interface circuit provided by this utility model, the voltage regulation unit is connected to the voltage input unit, and the voltage input unit includes: A current-limiting resistor, the first end of which is connected to the positive terminal of the power supply, is used to limit the input surge current; A reverse protection diode, wherein the anode of the reverse protection diode is connected to the second terminal of the current-limiting resistor, and the cathode of the reverse protection diode is connected to an internal power supply node to provide an input voltage.

[0007] According to the control signal conversion interface circuit provided by this utility model, the voltage regulation unit includes: A filter capacitor, wherein the first end of the filter capacitor is connected to the internal power node, and the second end of the filter capacitor is connected to the ground terminal. A step-down resistor, the first end of which is connected to the internal power supply node, and the second end of which is connected to the adjustment node; A pull-down resistor, with its first end connected to the adjustment node and its second end connected to the ground terminal; A clamping Zener diode, wherein the cathode of the clamping Zener diode is connected to the regulating node, and the anode of the clamping Zener diode is connected to the ground terminal; A voltage-stabilizing capacitor, the first end of which is connected to the adjustment node, and the second end of which is connected to the ground terminal.

[0008] According to the control signal conversion interface circuit provided by this utility model, the undervoltage detection unit includes: The first transistor is an NPN transistor with a built-in bias resistor; A base bias resistor, wherein the first end of the base bias resistor is connected to the adjustment node, and the second end of the base bias resistor is connected to the base of the first transistor; A base-emitter resistor, wherein the first end of the base-emitter resistor is connected to the base of the first transistor, and the second end of the base-emitter resistor is connected to the emitter of the first transistor; A reference Zener diode, wherein the cathode of the reference Zener diode is connected to the emitter of the first transistor, and the anode of the reference Zener diode is connected to the ground terminal; A collector load resistor, the first end of which is connected to the adjustment node, and the second end of which is connected to the collector of the first transistor.

[0009] According to the control signal conversion interface circuit provided by this utility model, the output driving unit includes: A coupling resistor, wherein a first end of the coupling resistor is connected to the collector of the first transistor, and a second end of the coupling resistor is connected to the control node; A pull-up resistor, wherein the first end of the pull-up resistor is connected to the adjustment node, and the second end of the pull-up resistor is connected to the control node; The second transistor is a PNP transistor with a built-in bias resistor. The emitter of the second transistor is connected to the adjustment node, the base of the second transistor is connected to the control node, and the collector of the second transistor serves as the output terminal.

[0010] According to the control signal conversion interface circuit provided by this utility model, the circuit further includes an output voltage divider unit, the output voltage divider unit comprising: A first voltage divider resistor, the first end of which is connected to the output terminal; The second voltage divider resistor has its first end connected to the second end of the first voltage divider resistor to form an enable node, and its second end connected to the ground terminal. The resistance of the first voltage divider resistor is greater than the resistance of the second voltage divider resistor.

[0011] According to the control signal conversion interface circuit provided by this utility model, the step-down resistor also serves as the current-limiting resistor for the clamping Zener diode; When the clamping Zener diode is turned on, the voltage at the regulating node is clamped to the regulated value of the clamping Zener diode.

[0012] According to the control signal conversion interface circuit provided by this utility model, the collector load resistor also serves as the current limiting resistor of the reference Zener diode; The minimum output voltage of the control signal conversion interface circuit is determined by the voltage regulation value of the reference Zener diode, the base-emitter voltage drop of the first transistor, and the voltage drop across the base bias resistor.

[0013] According to the control signal conversion interface circuit provided by this utility model, the circuit is specifically used for: When the input voltage is lower than the undervoltage threshold, the base-emitter control current of the first and second transistors gradually decreases until they are cut off, and the output terminal outputs a low level. When the input voltage is higher than the undervoltage threshold and lower than the overvoltage threshold, the first transistor and the second transistor are turned on, and the output terminal outputs a high level. When the input voltage exceeds the overvoltage threshold, the output is clamped to the preset maximum voltage.

[0014] This utility model also provides an automotive control system, including the control signal conversion interface circuit as described in any of the above claims.

[0015] The control signal conversion interface circuit and automotive control system provided by this utility model achieve comprehensive power management functions through the coordinated operation of a voltage regulation unit, an undervoltage detection unit, and an output drive unit. The unified power supply architecture, through which the regulation node simultaneously provides the operating voltage for both the undervoltage detection unit and the output drive unit, eliminates the need for a separate auxiliary power supply module, significantly simplifying the circuit structure and reducing system costs. The undervoltage detection unit monitors the input voltage status in real time, and the output drive unit controls the output status based on the detection results. In the event of undervoltage, it promptly shuts down the output protection circuit, and restores the output when the voltage returns to normal, ensuring stable system operation. This improves the circuit's response speed and reliability, effectively solving the technical challenges of large voltage fluctuations and harsh operating environments in automotive power systems. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the control signal conversion interface circuit structure provided by this utility model; Figure 2 A schematic diagram of the circuit operating current provided by this utility model; Figure 3 This is a schematic diagram showing the parameter values ​​of the circuit elements provided in this application; Figure 4 A schematic diagram of the structure of the automobile control system provided by this utility model. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0019] Figure 1 This is a schematic diagram of the control signal conversion interface circuit structure provided by this utility model, as shown below. Figure 1 As shown, the control signal conversion interface circuit 02 includes: a voltage regulation unit for regulating and stabilizing the input voltage; an undervoltage detection unit connected to the voltage regulation unit for detecting whether the input voltage is lower than a preset threshold; and an output drive unit connected to both the undervoltage detection unit and the voltage regulation unit for controlling the output state based on the undervoltage detection result. The voltage regulation unit outputs a regulation node voltage, and the regulation node simultaneously provides operating voltage to both the undervoltage detection unit and the output drive unit.

[0020] In this application, a voltage regulation unit is used to regulate and stabilize the input voltage, and its output terminal forms an adjustment node. The input terminal of the undervoltage detection unit is connected to the adjustment node of the voltage regulation unit, and is used to detect whether the input voltage is lower than a preset threshold. The input terminal of the output drive unit is connected to both the output terminal of the undervoltage detection unit and the adjustment node of the voltage regulation unit, and is used to control the output state based on the undervoltage detection result.

[0021] In terms of circuit connections, the voltage output from the regulating node of the voltage regulating unit simultaneously provides operating voltage for both the undervoltage detection unit and the output drive unit. Specifically, the power supply terminals of both the undervoltage detection unit and the output drive unit are connected to the regulating node, from which they obtain their operating voltage. This connection method eliminates the need for an additional auxiliary power supply, simplifying the circuit structure.

[0022] During operation, the voltage regulation unit receives and adjusts the external input voltage, outputting the regulated voltage at the regulation node. The undervoltage detection unit monitors the voltage level at the regulation node; when the voltage falls below a set threshold, the undervoltage detection unit outputs a corresponding detection signal. The output drive unit controls the output level based on the detection signal from the undervoltage detection unit.

[0023] The control signal conversion interface circuit in this embodiment, through the cooperation of the voltage regulation unit, the undervoltage detection unit, and the output drive unit, realizes the functions of monitoring the input voltage and controlling the output. It can shut down the output in time when the input voltage is abnormal, thus protecting the downstream circuit.

[0024] The voltage regulation unit in the control signal conversion interface circuit 02 is connected to the voltage input unit 01, which includes a current-limiting resistor R1 and a reverse-biased diode D1. The first terminal of the current-limiting resistor R1 is connected to the positive terminal of the power supply, and the second terminal is connected to the anode of the reverse-biased diode D1. The cathode of the reverse-biased diode D1 is connected to the internal power supply node VIN, providing the input voltage to the voltage regulation unit.

[0025] The circuit also includes an output voltage divider unit 03, which includes a first voltage divider resistor (Rload1), the first end of which is connected to the output terminal (VOUT). The second voltage divider resistor (Rload2) has its first end connected to the second end of the first voltage divider resistor (Rload1) to form an enable node, and its second end is connected to the ground terminal (GND). The resistance of the first voltage divider resistor (Rload1) is greater than the resistance of the second voltage divider resistor (Rload2).

[0026] More specifically, to further illustrate the connection relationships of the various components, in this application, the current-limiting resistor R1 is placed at the very beginning of the circuit to limit the input inrush current. When the power supply is first connected or a transient surge occurs, the current-limiting resistor R1 can limit the peak current and protect the downstream circuit components. Depending on the application requirements of automotive electronics, the resistance value of the current-limiting resistor R1 is typically selected in the range of 100Ω to 1kΩ.

[0027] The reverse protection diode D1 is connected in series after the current-limiting resistor R1. Its unidirectional conductivity prevents damage to the circuit when the power supply is reversed. Under normal connection, the reverse protection diode D1 conducts in the forward direction; when the power supply polarity is reversed, the reverse protection diode D1 is cut off, blocking the reverse current.

[0028] This embodiment provides input protection for the circuit by setting a voltage input unit at the front end of the voltage regulation unit, thereby improving the reliability of the circuit in harsh power supply environments.

[0029] The voltage regulation unit includes a filter capacitor C1, a step-down resistor R2, a pull-down resistor R3, a clamping Zener diode D2, and a Zener capacitor C2.

[0030] The first terminal of the filter capacitor C1 is connected to the internal power supply node VIN, and the second terminal is connected to the ground terminal GND. The filter capacitor C1 filters the input power supply, removing high-frequency ripple and noise interference.

[0031] The first terminal of the buck resistor R2 is connected to the internal power supply node VIN, and the second terminal is connected to the regulating node. The first terminal of the pull-down resistor R3 is connected to the regulating node, and the second terminal is connected to the ground terminal GND. The buck resistor R2 and the pull-down resistor R3 form a voltage divider network, which reduces the input voltage proportionally.

[0032] The cathode of the clamping Zener diode D2 is connected to the regulating node, and the anode is connected to the ground terminal GND. The clamping Zener diode D2 is a 12V Zener diode. When the voltage at the regulating node reaches 12V, the clamping Zener diode D2 conducts, clamping the voltage at the regulating node at 12V.

[0033] The first terminal of the voltage regulator capacitor C2 is connected to the regulating node, and the second terminal is connected to the ground terminal GND. The voltage regulator capacitor C2 filters and regulates the voltage at the regulating node, improving voltage stability.

[0034] The voltage regulation unit in this embodiment achieves regulation and limiting of the input voltage through a combination of voltage division and clamping, providing a stable operating voltage for the subsequent circuits.

[0035] More specifically, the undervoltage detection unit includes a first transistor Q1, a base bias resistor R5, a base-emitter resistor R6, a reference Zener diode D3, and a collector load resistor R4.

[0036] The first transistor Q1 is an NPN transistor with a built-in bias resistor. The first terminal of the base bias resistor R5 is connected to the adjustment node, and the second terminal is connected to the base of the first transistor Q1 to provide bias current to the base.

[0037] The first end of the base-emitter resistor R6 is connected to the base of the first transistor Q1, and the second end is connected to the emitter of the first transistor Q1. The base-emitter resistor R6 bridges the base and emitter, providing a path for base charge discharge.

[0038] The cathode of the reference Zener diode D3 is connected to the emitter of the first transistor Q1, and the anode is connected to the ground terminal GND.

[0039] Optionally, the reference Zener diode D3 is a 3.6V Zener diode, providing a stable reference potential for the emitter of the first transistor Q1.

[0040] The first terminal of the collector load resistor R4 is connected to the adjustment node, and the second terminal is connected to the collector of the first transistor Q1. The resistance of the collector load resistor R4 is 3kΩ, serving as the collector load of the first transistor Q1.

[0041] When the regulating node voltage is high enough, the current through the base bias resistor R5 turns on the first transistor Q1; when the regulating node voltage is too low, the first transistor Q1 is turned off, and its collector is pulled high by the collector load resistor R4.

[0042] The undervoltage detection unit in this embodiment detects voltage through a transistor circuit, and can accurately determine whether the input voltage is lower than a set threshold.

[0043] Optionally, the output driving unit includes a coupling resistor R7, a pull-up resistor R8, and a second transistor Q2.

[0044] The first terminal of coupling resistor R7 is connected to the collector of the first transistor Q1, and the second terminal is connected to the control node. Coupling resistor R7 couples the output signal of the undervoltage detection unit to the output driver stage.

[0045] The first end of the pull-up resistor R8 is connected to the adjustment node, and the second end is connected to the control node. The pull-up resistor R8 and the coupling resistor R7 together form a voltage divider network to control the base potential of the second transistor Q2.

[0046] The second transistor Q2 is a PNP transistor with a built-in bias resistor. The emitter of the second transistor Q2 is connected to the adjustment node, the base is connected to the control node, and the collector serves as the output terminal VOUT.

[0047] When the first transistor Q1 is turned on, its collector voltage decreases, pulling down the control node voltage through the coupling resistor R7. This forward-biases the base-emitter junction of the second transistor Q2, turning it on and causing the output VOUT to go high. When the first transistor Q1 is turned off, the control node is pulled high by the pull-up resistor R8, turning off the second transistor Q2 and causing the output VOUT to go low.

[0048] The output drive unit in this embodiment realizes power amplification and level conversion of the undervoltage detection signal, and can reliably drive the subsequent load.

[0049] Optionally, the output voltage divider unit includes a first voltage divider resistor Rload1 and a second voltage divider resistor Rload2. The first terminal of the first voltage divider resistor Rload1 is connected to the output terminal VOUT, and the second terminal is connected to the enable node. The first terminal of the second voltage divider resistor Rload2 is connected to the enable node, and the second terminal is connected to the ground terminal GND.

[0050] In an optional embodiment, the first voltage divider resistor Rload1 has a resistance of 20kΩ, and the second voltage divider resistor Rload2 has a resistance of 10kΩ. The resistance of the first voltage divider resistor Rload1 is greater than the resistance of the second voltage divider resistor Rload2, forming a voltage division ratio of 2:1.

[0051] When the output VOUT outputs 12V, the enable node voltage is 4.0V; when the input voltage is 6.5V, causing the output VOUT to output 4.7V, the enable node voltage is 1.56V. The enable node is connected to the enable pin of the power supply chip, providing the power supply chip with an enable control signal.

[0052] This embodiment uses an output voltage divider unit to convert the output voltage to the enable voltage, enabling the circuit to directly drive the enable pin of the power chip.

[0053] Optionally, the step-down resistor R2, in addition to forming a voltage divider network with the pull-down resistor R3, also serves as a current-limiting resistor for the clamping Zener diode D2. When the input voltage rises to 12V, the clamping Zener diode D2 turns on. At this time, the step-down resistor R2 limits the current flowing through the clamping Zener diode D2, protecting it from overcurrent damage. When the clamping Zener diode D2 is on, the regulating node voltage is clamped to 12V.

[0054] According to the circuit parameters, the resistance of the step-down resistor R2 is 1kΩ, which can effectively limit the clamping current. Even if the input voltage reaches 35V, the maximum current through the step-down resistor R2 is limited to a safe range.

[0055] In this embodiment, the dual-function design of the step-down resistor R2 simplifies the circuit structure and improves the reliability of the circuit.

[0056] In an optional embodiment, the collector load resistor R4 serves not only as the collector load of the first transistor Q1 but also as the current-limiting resistor for the reference Zener diode D3. The collector load resistor R4 has a resistance of 3kΩ, which provides a suitable operating current for the reference Zener diode D3.

[0057] The minimum output voltage of the control signal conversion interface circuit is determined by the Zener voltage of the reference Zener diode D3, the base-emitter voltage drop of the first transistor Q1, and the voltage drop across the base bias resistor R5. The Zener voltage of the reference Zener diode D3 is 3.6V, the base-emitter turn-on voltage drop of the first transistor Q1 is approximately 0.7V, and a certain voltage drop is required across the base bias resistor R5 to provide the base current. These voltages determine the minimum regulation node voltage required to turn on the first transistor Q1, and thus determine the undervoltage threshold of the circuit.

[0058] When the input voltage is 6.5V, after passing through the voltage divider network, the adjustment node voltage just turns on the first transistor Q1. At this time, the output terminal VOUT outputs 4.7V, and the corresponding enable node voltage is 1.56V, which meets the minimum enable requirement of the power chip.

[0059] In an optional embodiment, the circuit is specifically used for: When the input voltage is lower than the undervoltage threshold, the base-emitter control current of the first transistor (Q1) and the second transistor (Q2) gradually decreases until it is cut off, and the output terminal (VOUT) outputs a low level. When the input voltage is higher than the undervoltage threshold and lower than the overvoltage threshold, the first transistor (Q1) and the second transistor (Q2) are turned on, and the output terminal (VOUT) outputs a high level; When the input voltage exceeds the overvoltage threshold, the output (VOUT) is clamped to the preset maximum voltage.

[0060] For example, when the input voltage is below 6.5V, the regulating node voltage is insufficient, and the base current of the first transistor Q1 gradually decreases. Since the reference regulator D3 fixes the emitter potential at 3.6V, and the base potential is insufficient to overcome the base-emitter forward voltage drop, the first transistor Q1 is turned off. The turn-off of Q1 causes its collector to be pulled high by the collector load resistor R4, increasing the controlling node voltage. The base-emitter junction of the second transistor Q2 is reverse-biased and turned off, resulting in a low-level output at the output terminal VOUT.

[0061] When the input voltage is within the range of 6.5V to 35V, the regulating node receives sufficient voltage, and the first transistor Q1 turns on. The turn-on of Q1 pulls its collector low, reducing the control node voltage. This causes the second transistor Q2 to turn on, with its base-emitter junction forward-biased, and the output VOUT to go high. The output voltage varies with the input voltage but will not exceed the regulating node voltage.

[0062] When the input voltage exceeds the value required to bring the regulating node to 12V, the clamping Zener diode D2 turns on, clamping the regulating node voltage at 12V. At this time, no matter how high the input voltage increases, the output voltage VOUT is limited to 12V, and the enable node voltage is maintained at 4.0V, meeting the operating requirements of the power supply chip.

[0063] This embodiment demonstrates the complete operation of the circuit, including three states: undervoltage protection, normal operation, and overvoltage clamping, ensuring reliable operation over a wide input voltage range.

[0064] In another alternative embodiment, Figure 2 The circuit working current diagram provided by this utility model includes a voltage input unit 01, a control signal conversion interface circuit 02, and an output voltage divider unit 03. The circuit works on the principle that when the voltage source V1 changes, and ID2 < 0, the voltage regulator diode D2 is not regulated. Formula 1 can be obtained by calculating I = I' = I1 + I2 + I3. (V1-VD1-VOUT) / (R1+R2)=(VOUT) / R3+(VOUT-VD3-VBEQ1) / R5+((VOUT-VD3) / R4+)(VOUT-VD3-VBEQ2) / R8+VOUT / Rload)); Where VD3 is the regulated voltage value of D3, and VBEQ1 and VBEQ2 are the inter-electrode voltages of Q1 and Q2, respectively. From the above formula, the relationship between VOUT and V1 can be obtained. Within the reasonable value of the resistance between the base and emitter of Q1 and Q2, the required ratio of VOUT to V1 control signal voltage can be obtained by adjusting the values ​​of R3 and D3. For example, if the voltage source V1 of the main control part is in the range of 6.5~18V, the VOUT voltage after the control signal conversion interface circuit is designed to be about 4.5~12V, thus meeting the requirements of the subsequent control design. In this application example, the voltage source operates within the normal range of 6.5V to 18V from the vehicle power supply. However, considering voltage pulses from the vehicle power network, the maximum pulse voltage can reach 35V (ISO 7637-2 pulse 5b). Therefore, the power supply to the output voltage divider unit needs to be controlled in a way that comprehensively considers these voltage source ranges. More specifically, in one embodiment, when the maximum pulse voltage of the voltage source reaches 35V or higher, the Enable voltage of the output voltage divider unit needs to be controlled to be less than 5V to protect the power supply Enable pin; when the voltage source is within the normal operating voltage range of 6.5V to 18V, the Enable voltage of the output voltage divider unit needs to be greater than 1.3V to ensure that the power supply can be enabled and operate normally. Figure 3 This is a schematic diagram of the parameter values ​​for the circuit elements provided in this application, such as... Figure 3As shown, the circuit includes a voltage input unit 01, a control signal conversion interface circuit 02, and an output voltage divider unit 03. First, the current-limiting resistor R1 is 510Ω. Transistors Q1 and Q2 are selected with NPN resistors, with the resistor values ​​shown in the diagram above. Then, the VOUT output, after being divided by Rload1 and Rload2, controls the Enable pin of the power supply chip. Rload1 and Rload2 are 20KΩ and 10KΩ respectively. Simultaneously, the parameters determine that when VOUT outputs 12V, VEN=4.0V, which meets the operating voltage range of the chip's Enable pin. Therefore, a 12V Zener diode D2 is selected. To ensure that the VOUT output voltage is divided by Rload1 and Rload2 when the voltage source is 6.5V... Since the voltage after voltage reduction is greater than 1.3V, VOUT needs to be at least greater than 4V. From VOUT≈VD3+VBEQ1+VR5, we can confirm that the Zener diode D3 is a 3.6V Zener diode. Using the above formula, we can calculate the values ​​of R2, R3, and R4. Here, we take R2=1kΩ, R3=100kΩ, and R4=3kΩ respectively. Therefore, when the voltage source is 6.5V, VOUT=4.7V, i.e., VEN=1.56V, which meets the minimum enable control level of the power chip's Enable pin. When the voltage source is less than 6.5V, the current at the control electrodes of transistors Q1 and Q2 gradually decreases, which can turn off the VOUT output. Simultaneously, when the voltage source is 35V, VOUT is regulated to 12V, i.e., VEN=4.0V, which meets the maximum voltage range of the power chip's Enable pin. The minimum voltage range of the VOUT output voltage in the control signal conversion interface circuit is mainly controlled by adjusting the voltage regulation value of the D3 Zener diode. The minimum output voltage is approximately VD3+VBEQ1+VR5, where R4 also serves as the current limiting resistor for D3. The control signal conversion interface circuit mainly serves as a control signal conversion interface. Its load output current is I3_2. In order to ensure that the I3_2 current of Q2 satisfies the base of Q2 and the forward bias saturation conduction of the transmitter, the output load impedance should not be too low. This control signal conversion interface circuit and the voltage input unit are in a common ground single-ended level input control mode, which does not depend on the voltage module design in the control signal conversion interface circuit. When the voltage source V1 changes, and ID2>0, under the voltage regulation of the Zener diode D2, the output voltage VOUT of the control signal circuit is clamped to the voltage of VD2, that is, VOUT=VD2. R2 also acts as the current limiting resistor of D2 to protect the POWER IC part of the output voltage divider unit from high voltage impact damage.

[0065] Figure 4 A schematic diagram of the automotive control system structure provided by this utility model is shown below. Figure 4As shown, a control signal conversion interface circuit is included. In this automotive control system, the control signal conversion interface circuit is installed at the power input terminal of the control unit. The external automotive power supply is connected to the input terminal of the current-limiting resistor R1 via a wiring harness. After circuit processing, the output terminal VOUT is connected to the enable pin of the power integrated circuit through the enable signal generated by the voltage divider resistor.

[0066] The vehicle control system in this embodiment achieves wide voltage range adaptability and reliable protection functions by adopting this power interface circuit, thus meeting the application requirements of automotive electronics.

[0067] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A control signal conversion interface circuit, characterized in that, include: The voltage regulation unit is used to regulate and stabilize the input voltage; An undervoltage detection unit, connected to the voltage regulation unit, is used to detect whether the input voltage is lower than a preset threshold. An output drive unit is connected to the undervoltage detection unit and the voltage regulation unit respectively, and is used to control the output state according to the undervoltage detection result; The voltage regulation unit outputs a regulation node voltage, and the regulation node simultaneously provides operating voltage for the undervoltage detection unit and the output drive unit.

2. The control signal conversion interface circuit according to claim 1, characterized in that, The voltage regulation unit is connected to the voltage input unit, and the voltage input unit includes: A current-limiting resistor, the first end of which is connected to the positive terminal of the power supply, is used to limit the input surge current; A reverse protection diode, wherein the anode of the reverse protection diode is connected to the second terminal of the current-limiting resistor, and the cathode of the reverse protection diode is connected to an internal power supply node to provide an input voltage.

3. The control signal conversion interface circuit according to claim 2, characterized in that, The voltage regulation unit includes: A filter capacitor, wherein the first end of the filter capacitor is connected to the internal power node, and the second end of the filter capacitor is connected to the ground terminal. A step-down resistor, the first end of which is connected to the internal power supply node, and the second end of which is connected to the adjustment node; A pull-down resistor, with its first end connected to the adjustment node and its second end connected to the ground terminal; A clamping Zener diode, wherein the cathode of the clamping Zener diode is connected to the regulating node, and the anode of the clamping Zener diode is connected to the ground terminal; A voltage-stabilizing capacitor, the first end of which is connected to the adjustment node, and the second end of which is connected to the ground terminal.

4. The control signal conversion interface circuit according to claim 3, characterized in that, The undervoltage detection unit includes: The first transistor is an NPN transistor with a built-in bias resistor; A base bias resistor, wherein the first end of the base bias resistor is connected to the adjustment node, and the second end of the base bias resistor is connected to the base of the first transistor; A base-emitter resistor, wherein the first end of the base-emitter resistor is connected to the base of the first transistor, and the second end of the base-emitter resistor is connected to the emitter of the first transistor; A reference Zener diode, wherein the cathode of the reference Zener diode is connected to the emitter of the first transistor, and the anode of the reference Zener diode is connected to the ground terminal; A collector load resistor, the first end of which is connected to the adjustment node, and the second end of which is connected to the collector of the first transistor.

5. The control signal conversion interface circuit according to claim 4, characterized in that, The output drive unit includes: A coupling resistor, wherein a first end of the coupling resistor is connected to the collector of the first transistor, and a second end of the coupling resistor is connected to the control node; A pull-up resistor, wherein the first end of the pull-up resistor is connected to the adjustment node, and the second end of the pull-up resistor is connected to the control node; The second transistor is a PNP transistor with a built-in bias resistor. The emitter of the second transistor is connected to the adjustment node, the base of the second transistor is connected to the control node, and the collector of the second transistor serves as the output terminal.

6. The control signal conversion interface circuit according to claim 5, characterized in that, The circuit further includes an output voltage divider unit, which includes: A first voltage divider resistor, the first end of which is connected to the output terminal; The second voltage divider resistor has its first end connected to the second end of the first voltage divider resistor to form an enable node, and its second end connected to the ground terminal. The resistance of the first voltage divider resistor is greater than the resistance of the second voltage divider resistor.

7. The control signal conversion interface circuit according to claim 3, characterized in that, The step-down resistor also serves as the current-limiting resistor for the clamping Zener diode; When the clamping Zener diode is turned on, the voltage at the regulating node is clamped to the regulated value of the clamping Zener diode.

8. The control signal conversion interface circuit according to claim 4, characterized in that, The collector load resistor also serves as the current-limiting resistor for the reference Zener diode; The minimum output voltage of the control signal conversion interface circuit is determined by the voltage regulation value of the reference Zener diode. The base-emitter voltage drop of the first transistor and the voltage drop across the base bias resistor are jointly determined.

9. The control signal conversion interface circuit according to claim 5, characterized in that, The circuit is specifically used for: When the input voltage is lower than the undervoltage threshold, the base-emitter control current of the first and second transistors gradually decreases until they are cut off, and the output terminal outputs a low level. When the input voltage is higher than the undervoltage threshold and lower than the overvoltage threshold, the first transistor and the second transistor are turned on, and the output terminal outputs a high level. When the input voltage exceeds the overvoltage threshold, the output is clamped to the preset maximum voltage.

10. A vehicle control system, characterized in that, Includes the control signal conversion interface circuit as described in any one of claims 1 to 9.

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