LCD display panel dc-dc circuit for suppressing vehicle-mounted strong surge

Abstract

The application relates to an LCD display panel DC-DC circuit for inhibiting strong vehicle-mounted surges. The LCD display panel DC-DC circuit for inhibiting strong vehicle-mounted surges comprises an input protection module and a step-down output module. The input protection module comprises an input end, a first damping unit, a first filter unit, a surge clamping unit, a second filter unit, a second damping unit and a buffer unit. The first damping unit is electrically connected with the input end, the first filter unit is electrically connected with the first damping unit, the surge clamping unit is electrically connected with the first filter unit, the second filter unit is electrically connected with the surge clamping unit, the second damping unit is electrically connected with the second filter unit, and the buffer unit is electrically connected with the second damping unit. The step-down output module is electrically connected with the buffer unit. The scheme provided by the application can perform input protection on the vehicle-mounted DC-DC circuit, thereby effectively inhibiting the transient high voltage generated by the vehicle-mounted load throwing and protecting the step-down chip and the subsequent circuit.

Description

Technical Field

[0001] This invention relates to the field of circuit design technology, and in particular to a DC-DC circuit for suppressing strong surges in automotive LCD display panels. Background Technology

[0002] In related technologies, current automotive DC-DC circuits lack sufficient input protection, making it difficult to effectively suppress instantaneous high voltage generated by load dumping, which can easily damage the step-down chip and subsequent circuits. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a DC-DC circuit for suppressing strong surges in vehicle-mounted LCD display panels. This circuit can provide input protection for vehicle-mounted DC-DC circuits, thereby effectively suppressing instantaneous high voltage generated by load dumping in vehicles and protecting the step-down chip and subsequent circuits.

[0004] The objective of this invention is achieved through the following technical solution: The first aspect of this application provides a DC-DC circuit for suppressing strong surges in an LCD display panel, comprising: an input protection module including an input terminal, a first damping unit, a first filtering unit, a surge clamping unit, a second filtering unit, a second damping unit, and a buffer unit; the first damping unit is electrically connected to the input terminal, the first filtering unit is electrically connected to the first damping unit, the surge clamping unit is electrically connected to the first filtering unit, the second filtering unit is electrically connected to the surge clamping unit, the second damping unit is electrically connected to the second filtering unit, and the buffer unit is electrically connected to the second damping unit; and a step-down output module electrically connected to the buffer unit.

[0005] The first damping unit includes resistors R1, R2, R3, and R4. The first end of resistor R1 is electrically connected to the first end of resistor R2, the second end of resistor R1 is electrically connected to the second end of resistor R2, the first end of resistor R2 is electrically connected to the first end of resistor R3, the second end of resistor R2 is electrically connected to the second end of resistor R3, the first end of resistor R3 is electrically connected to the first end of resistor R4, the second end of resistor R3 is electrically connected to the second end of resistor R4, and the input terminal is electrically connected to the first end of resistor R3.

[0006] The first damping unit further includes an inductor L1, with the first end of the resistor R4 electrically connected to the first end of the inductor L1, and the second end of the resistor R4 electrically connected to the second end of the inductor L1.

[0007] The first filter unit includes capacitors C1, C2, C3, and C4. The first terminal of capacitor C1 is electrically connected to the second terminal of resistor R3, and the second terminal of capacitor C1 is grounded. The first terminal of capacitor C2 is electrically connected to the first terminal of capacitor C1, and the second terminal of capacitor C2 is grounded. The first terminal of capacitor C3 is electrically connected to the first terminal of capacitor C2, and the second terminal of capacitor C3 is grounded. The first terminal of capacitor C4 is electrically connected to the first terminal of capacitor C3, and the second terminal of capacitor C4 is grounded.

[0008] The surge clamping unit includes diode D1 and diode D2. The first end of diode D1 is electrically connected to the first end of capacitor C4, and the second end of diode D1 is grounded. The first end of diode D2 is electrically connected to the first end of diode D1, and the second end of diode D2 is grounded.

[0009] The second filter unit includes capacitors C5, C6, C7, and C8. The first terminal of capacitor C5 is electrically connected to the first terminal of diode D2, and the second terminal of capacitor C5 is grounded. The first terminal of capacitor C6 is electrically connected to the first terminal of capacitor C5, and the second terminal of capacitor C6 is grounded. The first terminal of capacitor C7 is electrically connected to the first terminal of capacitor C6, and the second terminal of capacitor C7 is grounded. The first terminal of capacitor C8 is electrically connected to the first terminal of capacitor C7, and the second terminal of capacitor C8 is grounded.

[0010] The second damping unit includes a resistor R5 and an inductor L2. The first end of the resistor R5 is electrically connected to the second end of the capacitor C8 and the second end of the inductor L2, respectively. The second end of the resistor R5 is electrically connected to the second end of the inductor L2.

[0011] The buffer unit includes a resistor R6, the first end of which is electrically connected to the second end of the resistor R5, and the second end of the resistor R6 is electrically connected to the step-down output module.

[0012] The step-down output module includes a chip U1, capacitors C9 and C10, a resistor R7, and a capacitor C11. The chip U1 is electrically connected to the second terminal of the resistor R6. The first terminals of capacitors C9 and C10 are respectively electrically connected to the chip U1. The second terminals of capacitors C9 and C10 are both grounded. The first terminal of resistor R7 is electrically connected to the second terminal of resistor R6 and the second terminal of resistor R7 is electrically connected to the chip U1. The first terminal of capacitor C11 is electrically connected to the chip U1, and the second terminal of capacitor C11 is grounded.

[0013] The step-down output module also includes a capacitor C13, a resistor R11, a resistor R10, and a resistor R13. The first end of the capacitor C13 is electrically connected to the chip U1. The first end of the resistor R11 is electrically connected to the first end of the capacitor C13. The second end of the capacitor C13 is electrically connected to the second end of the resistor R11. The first end of the resistor R10 is electrically connected to the first end of the resistor R11. The second end of the resistor R10 is electrically connected to the second end of the resistor R11. The resistor R13 is electrically connected to the chip U1.

[0014] Compared with the prior art, the present invention has at least the following advantages: This application, by setting a first damping unit, a first filtering unit, a surge clamping unit, a second filtering unit, a second damping unit, and a buffer unit after the input terminal, can suppress load dumping and EMI interference, reduce output ripple, ensure the normal operation of the LCD panel, and avoid abnormalities such as screen flickering, screen distortion, and black screen. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below.

[0016] Figure 1 This is a functional block diagram of the DC-DC circuit for suppressing strong surges in an LCD display panel in an embodiment of the present invention. Figure 2 This is a circuit diagram of an input protection module according to an embodiment of the present invention; Figure 3 This is a circuit diagram of a step-down output module according to an embodiment of the present invention. Detailed Implementation

[0017] Embodiments of this application will now be described in more detail with reference to the accompanying drawings. While embodiments of this application are shown in the drawings, it should be understood that this application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make this application more thorough and complete, and to fully convey the scope of this application to those skilled in the art.

[0018] It should be understood that although the terms "first," "second," "third," etc., may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0019] Unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0020] Current automotive DC-DC circuits lack sufficient input protection, making it difficult to effectively suppress instantaneous high voltage generated by load dumping, which can easily damage the step-down chip and subsequent circuits.

[0021] To address the aforementioned issues, this application provides an LCD display panel DC-DC circuit for suppressing strong surges in vehicle-mounted circuits. This circuit provides input protection for the vehicle-mounted DC-DC circuit, effectively suppressing instantaneous high voltage generated by load dumping and protecting the step-down chip and subsequent circuitry.

[0022] The technical solutions of the embodiments of this application are described in detail below with reference to the accompanying drawings.

[0023] See Figure 1 A DC-DC circuit for suppressing strong surges in an LCD display panel for vehicles includes: an input protection module 100 and a step-down output module 200. The input protection module 100 includes an input terminal, a first damping unit, a first filtering unit, a surge clamping unit, a second filtering unit, a second damping unit, and a buffer unit. The first damping unit is electrically connected to the input terminal, the first filtering unit is electrically connected to the first damping unit, the surge clamping unit is electrically connected to the first filtering unit, the second filtering unit is electrically connected to the surge clamping unit, the second damping unit is electrically connected to the second filtering unit, and the buffer unit is electrically connected to the second damping unit. The step-down output module 200 is electrically connected to the buffer unit.

[0024] It should be noted that by setting a first damping unit, a first filtering unit, a surge clamping unit, a second filtering unit, a second damping unit, and a buffer unit after the input terminal, this application can suppress load dumping and EMI interference, reduce output ripple, ensure the normal operation of the LCD panel, and avoid abnormalities such as screen flickering, screen distortion, and black screen.

[0025] See Figure 2 In one embodiment, the first damping unit includes resistors R1, R2, R3, and R4. The first end of resistor R1 is electrically connected to the first end of resistor R2, and the second end of resistor R1 is electrically connected to the second end of resistor R2. The first end of resistor R2 is electrically connected to the first end of resistor R3, and the second end of resistor R2 is electrically connected to the second end of resistor R3. The first end of resistor R3 is electrically connected to the first end of resistor R4, and the second end of resistor R4 is electrically connected to the second end of resistor R4. The input terminal is electrically connected to the first end of resistor R3. Specifically, the first damping unit also includes an inductor L1, with the first end of resistor R4 electrically connected to the first end of inductor L1, and the second end of resistor R4 electrically connected to the second end of inductor L1.

[0026] It should be noted that the input is a 12V power supply. The 1uH inductor L1 is connected in series at the front end of the vehicle's 12V input. Its other end is connected in parallel with four 0Ω resistors R1, R2, R3 and R4 to form a first-stage damping network. This network is used to suppress the resonance phenomenon of the LC network caused by strong surges and load jumps, and to avoid voltage overshoot caused by resonance.

[0027] See Figure 2 In one embodiment, the first filter unit includes capacitors C1, C2, C3, and C4. The first terminal of capacitor C1 is electrically connected to the second terminal of resistor R3, and the second terminal of capacitor C1 is grounded. The first terminal of capacitor C2 is electrically connected to the first terminal of capacitor C1, and the second terminal of capacitor C2 is grounded. The first terminal of capacitor C3 is electrically connected to the first terminal of capacitor C2, and the second terminal of capacitor C3 is grounded. The first terminal of capacitor C4 is electrically connected to the first terminal of capacitor C3, and the second terminal of capacitor C4 is grounded.

[0028] It should be noted that the first filter unit, consisting of 100nF capacitor C1, 100nF capacitor C2, 10uF capacitor C3, and 10uF capacitor C4 connected in parallel, performs preliminary filtering on the 12V input voltage of the vehicle, filtering out high-frequency spike interference and low-frequency voltage fluctuations on the input side, while absorbing some surge energy and reducing the impact of strong surges on the subsequent TVS clamping module.

[0029] See Figure 2In one embodiment, the surge clamping unit includes diode D1 and diode D2. The first end of diode D1 is electrically connected to the first end of capacitor C4, and the second end of diode D1 is grounded. The first end of diode D2 is electrically connected to the first end of diode D1, and the second end of diode D2 is grounded.

[0030] It should be noted that the surge clamping unit can accurately clamp and suppress strong surges from the vehicle input, such as the instantaneous high voltage of 36V load dump, quickly limiting the input voltage to a safe range and preventing subsequent chip damage.

[0031] See Figure 2 In one embodiment, the second filter unit includes capacitors C5, C6, C7, and C8. The first terminal of capacitor C5 is electrically connected to the first terminal of diode D2, and the second terminal of capacitor C5 is grounded. The first terminal of capacitor C6 is electrically connected to the first terminal of capacitor C5, and the second terminal of capacitor C6 is grounded. The first terminal of capacitor C7 is electrically connected to the first terminal of capacitor C6, and the second terminal of capacitor C7 is grounded. The first terminal of capacitor C8 is electrically connected to the first terminal of capacitor C7, and the second terminal of capacitor C8 is grounded.

[0032] It should be noted that the second-stage filter capacitor group, consisting of 10uF capacitor C5, 10uF capacitor C6, 100nF capacitor C7, and 100nF capacitor C8 connected in parallel, performs secondary filtering on the voltage after TVS clamping, filtering out high-frequency interference and voltage ripple remaining after surge clamping, and further stabilizing the input voltage.

[0033] See Figure 2 In one embodiment, the second damping unit includes a resistor R5 and an inductor L2. The first end of the resistor R5 is electrically connected to the second end of the capacitor C8 and the second end of the inductor L2, respectively, and the second end of the resistor R5 is electrically connected to the second end of the inductor L2.

[0034] It should be noted that the 1uH inductor L2 and the 0Ω resistor R5 are connected in parallel to form a two-stage damping network, which helps to suppress LC resonance, weaken voltage spikes, and ensure that the voltage after two stages of damping filtering is stable, providing a clean input voltage to the VIN terminal of the buck chip.

[0035] See Figure 2 In one embodiment, the buffer unit includes a resistor R6, the first end of which is electrically connected to the second end of a resistor R5, and the second end of the resistor R6 is electrically connected to the buck output module.

[0036] It should be noted that resistor R6 is used to limit instantaneous inrush current and prevent a large instantaneous current from flowing into VIN after power-on or a surge.

[0037] See Figure 3In one embodiment, the step-down output module 200 includes a chip U1, a capacitor C9, a capacitor C10, a resistor R7, and a capacitor C11. The chip U1 is electrically connected to the second end of the resistor R6. The first ends of the capacitors C9 and C10 are respectively electrically connected to the chip U1. The second ends of the capacitors C9 and C10 are both grounded. The first end of the resistor R7 is electrically connected to the second end of the resistor R6 and is also electrically connected to the chip U1. The first end of the capacitor C11 is electrically connected to the chip U1 and is also grounded.

[0038] It should be noted that the model of chip U1 can be RTQ2104BGSP-QA, which is a step-down chip. The VIN pin of the step-down chip is connected to the output terminal VIN of the input protection module. A 10uF capacitor C9 and a 100nF capacitor C10 are connected in parallel to ground to completely eliminate residual high-frequency noise. This also ensures that when the internal switch of chip U1 pumps current, the capacitors can provide instantaneous power, guaranteeing that VIN remains stable and is not pulled low or jittered by the internal operation of chip U1, ultimately providing chip U1 with a clean DC current. The EN pin, through a 10kΩ enable control resistor R7, is also connected to the output terminal VIN of the input protection filter module to control chip start-up and shutdown. The VCC pin is the output signal of the internal 5V linear regulator, powered by VIN, and connected to ground with a 10uF capacitor C11 to ensure the normal operation of chip U1.

[0039] See Figure 3 In another embodiment, the step-down output module 200 further includes an inductor L3, capacitors C14, C15, C16, and C17, a resistor R12, and a ferrite bead B1. The first end of the inductor L3 is electrically connected to the chip U1, and the second end of the inductor L3 is electrically connected to the first ends of capacitors C14, C15, C16, and C17, respectively. The second ends of capacitors C14, C15, C16, and C17 are grounded, respectively. The first end of the resistor R12 is electrically connected to the first end of capacitor C17 and the first end of ferrite bead B1, respectively, and the second end of the resistor R12 is electrically connected to the second end of ferrite bead B1.

[0040] It should be noted that the pulsating voltage output from the SW pin of chip U1 is connected in series with inductor L3. The output of inductor L3 is connected to an output filter capacitor bank consisting of four capacitors C14-C17 connected in parallel to ground, forming an LC low-pass filter network. This network converts the high-frequency switching square wave output from the SW pin into a smooth DC voltage, while suppressing switching noise and voltage ripple. A ferrite bead (B1) and a 0Ω current-limiting resistor (R12) are connected in series at the output of the capacitor bank. The ferrite bead further absorbs high-frequency EMI interference, preventing noise coupling to the downstream load. The current-limiting resistor (R12) serves both current limiting and adjustment reserve functions, ensuring a stable and clean output voltage and preventing display abnormalities on the LCD panel due to ripple or interference. Finally, a +5V voltage is output to the power supply pin of the automotive LCD display panel.

[0041] See Figure 3 In one embodiment, the step-down output module 200 further includes a capacitor C13, a resistor R11, a resistor R10, and a resistor R13. The first end of the capacitor C13 is electrically connected to the chip U1, the first end of the resistor R11 is electrically connected to the first end of the capacitor C13, the second end of the capacitor C13 is electrically connected to the second end of the resistor R11, the first end of the resistor R10 is electrically connected to the first end of the resistor R11, the second end of the resistor R10 is electrically connected to the second end of the resistor R11, and the resistor R13 is electrically connected to the chip U1.

[0042] It should be noted that this part is a feedback circuit. The feedback sampling point is taken from the +5V output node after the power inductor L3. The pulsating voltage output from the SW pin of the buck chip is divided by the feedback voltage divider resistors R10, R11, and R13 after passing through the power inductor L3. This voltage is then sent to the FB pin and compared with the internal reference voltage of the chip, forming a closed-loop feedback control. This dynamically adjusts the duty cycle of the buck chip's switching transistor to achieve precise voltage regulation of the +5V output voltage. The compensation capacitor C13 is connected in parallel across the feedback voltage divider resistor R11. It is used to perform phase compensation on the feedback loop, prevent loop oscillation, and filter out high-frequency noise interference in the output voltage, improving the stability and anti-interference capability of the power supply system and avoiding abnormal LCD display caused by voltage fluctuations or noise. The PGOOD pin is connected to the pull-up resistor R13 to ensure that the PGOOD signal remains at a stable high level when the chip is not powered on or not ready, avoiding accidental triggering of subsequent circuits. This signal can be used as an enable or fault indication signal for the subsequent LCD driver circuit, ensuring the safe and orderly power-on operation of the system. The BOOT pin is connected in series with a current-limiting resistor R8 and a bootstrap capacitor C12. This pin provides the gate drive voltage for the high-side MOSFET inside the buck converter chip. When the SW pin is low, the VCC power supply charges the bootstrap capacitor C12 through the current-limiting resistor R8. When the SW pin switches to high, the voltage across C12 is superimposed on the internal drive circuit, providing sufficient gate drive voltage for the high-side MOSFET and ensuring reliable MOSFET conduction. The current-limiting resistor R8 limits the capacitor charging current, protecting the internal circuitry of the chip. The charging and discharging process of the bootstrap capacitor C12 ensures the normal switching action of the switching transistor, which is crucial for the stable operation of the buck converter circuit and avoids output voltage instability or reduced switching efficiency due to insufficient drive.

[0043] The solution of this application has been described in detail above with reference to the accompanying drawings. In the above embodiments, the descriptions of each embodiment have different focuses; for parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments. Those skilled in the art should also understand that the actions and modules involved in the specification are not necessarily essential to this application. Furthermore, it is understood that the steps in the method of this application embodiment can be adjusted, combined, and deleted according to actual needs, and the modules in the device of this application embodiment can be combined, divided, and deleted according to actual needs.

[0044] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A DC-DC circuit for suppressing strong surges in an automotive LCD display panel, characterized in that, include: An input protection module includes an input terminal, a first damping unit, a first filtering unit, a surge clamping unit, a second filtering unit, a second damping unit, and a buffer unit. The first damping unit is electrically connected to the input terminal, the first filtering unit is electrically connected to the first damping unit, the surge clamping unit is electrically connected to the first filtering unit, the second filtering unit is electrically connected to the surge clamping unit, the second damping unit is electrically connected to the second filtering unit, and the buffer unit is electrically connected to the second damping unit. The step-down output module is electrically connected to the buffer unit.

2. The LCD display panel DC-DC circuit for suppressing strong surges in vehicles according to claim 1, characterized in that, The first damping unit includes resistors R1, R2, R3, and R4. The first end of resistor R1 is electrically connected to the first end of resistor R2, the second end of resistor R1 is electrically connected to the second end of resistor R2, the first end of resistor R2 is electrically connected to the first end of resistor R3, the second end of resistor R2 is electrically connected to the second end of resistor R3, the first end of resistor R3 is electrically connected to the first end of resistor R4, the second end of resistor R3 is electrically connected to the second end of resistor R4, and the input terminal is electrically connected to the first end of resistor R3.

3. The LCD display panel DC-DC circuit for suppressing strong surges in vehicles according to claim 2, characterized in that, The first damping unit further includes an inductor L1, with the first end of the resistor R4 electrically connected to the first end of the inductor L1, and the second end of the resistor R4 electrically connected to the second end of the inductor L1.

4. The LCD display panel DC-DC circuit for suppressing strong surges in vehicles according to claim 2, characterized in that, The first filter unit includes capacitors C1, C2, C3, and C4. The first terminal of capacitor C1 is electrically connected to the second terminal of resistor R3, and the second terminal of capacitor C1 is grounded. The first terminal of capacitor C2 is electrically connected to the first terminal of capacitor C1, and the second terminal of capacitor C2 is grounded. The first terminal of capacitor C3 is electrically connected to the first terminal of capacitor C2, and the second terminal of capacitor C3 is grounded. The first terminal of capacitor C4 is electrically connected to the first terminal of capacitor C3, and the second terminal of capacitor C4 is grounded.

5. The LCD display panel DC-DC circuit for suppressing strong surges in vehicles according to claim 4, characterized in that, The surge clamping unit includes diode D1 and diode D2. The first end of diode D1 is electrically connected to the first end of capacitor C4, and the second end of diode D1 is grounded. The first end of diode D2 is electrically connected to the first end of diode D1, and the second end of diode D2 is grounded.

6. The LCD display panel DC-DC circuit for suppressing strong surges in vehicles according to claim 5, characterized in that, The second filter unit includes capacitors C5, C6, C7, and C8. The first terminal of capacitor C5 is electrically connected to the first terminal of diode D2, and the second terminal of capacitor C5 is grounded. The first terminal of capacitor C6 is electrically connected to the first terminal of capacitor C5, and the second terminal of capacitor C6 is grounded. The first terminal of capacitor C7 is electrically connected to the first terminal of capacitor C6, and the second terminal of capacitor C7 is grounded. The first terminal of capacitor C8 is electrically connected to the first terminal of capacitor C7, and the second terminal of capacitor C8 is grounded.

7. The LCD display panel DC-DC circuit for suppressing strong surges in vehicles according to claim 6, characterized in that, The second damping unit includes a resistor R5 and an inductor L2. The first end of the resistor R5 is electrically connected to the second end of the capacitor C8 and the second end of the inductor L2, respectively. The second end of the resistor R5 is electrically connected to the second end of the inductor L2.

8. The LCD display panel DC-DC circuit for suppressing strong surges in vehicles according to claim 7, characterized in that, The buffer unit includes a resistor R6, the first end of which is electrically connected to the second end of the resistor R5, and the second end of the resistor R6 is electrically connected to the step-down output module.

9. The LCD display panel DC-DC circuit for suppressing strong surges in vehicles according to claim 8, characterized in that, The step-down output module includes a chip U1, capacitors C9 and C10, a resistor R7, and a capacitor C11. The chip U1 is electrically connected to the second terminal of the resistor R6. The first terminals of capacitors C9 and C10 are respectively electrically connected to the chip U1. The second terminals of capacitors C9 and C10 are both grounded. The first terminal of resistor R7 is electrically connected to the second terminal of resistor R6 and the second terminal of resistor R7 is electrically connected to the chip U1. The first terminal of capacitor C11 is electrically connected to the chip U1, and the second terminal of capacitor C11 is grounded.

10. The LCD display panel DC-DC circuit for suppressing strong surges in vehicles according to claim 9, characterized in that, The step-down output module also includes a capacitor C13, a resistor R11, a resistor R10, and a resistor R13. The first end of the capacitor C13 is electrically connected to the chip U1. The first end of the resistor R11 is electrically connected to the first end of the capacitor C13. The second end of the capacitor C13 is electrically connected to the second end of the resistor R11. The first end of the resistor R10 is electrically connected to the first end of the resistor R11. The second end of the resistor R10 is electrically connected to the second end of the resistor R11. The resistor R13 is electrically connected to the chip U1.

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