An overvoltage protection structure for a fast charging PCBA board

Abstract

This utility model discloses an overvoltage protection structure for a fast-charging PCBA board, relating to the technical field of circuit board structures. It includes a PCB board, a TVS diode, a PWM main control chip, and a bottom support arm. The PCB board has rectangularly distributed positioning holes on its outer side. The PWM main control chip is soldered to the outer side of the PCB board. A protection mechanism is provided on the outer side of the PCB board to prevent abnormal increases in input and output voltage that could damage the device, and to cut off or clamp the high voltage in a very short time. An outer shielding cover is provided at the bottom of the PCB board, and a heat dissipation mechanism is provided inside the PCB board. This heat dissipation mechanism addresses the issue of a sudden surge in junction temperature caused by a large instantaneous current generated when the TVS diode is clamped under high voltage. During the installation of the fast-charging PCB board, a bottom-mounted vortex fan significantly improves the heat dissipation efficiency of the TVS diode and the PWM main control chip through forced convection, solving the temperature rise problem under high power density. The symmetrical support arms evenly distribute the weight of the PCB.

Description

Technical Field

[0001] This utility model relates to the technical field of circuit board structure, specifically to an overvoltage protection structure for a fast charging PCBA board. Background Technology

[0002] Fast charging PCBA boards are electronic modules used to realize fast charging functions. They integrate core components such as power management, protocol identification, and protection circuits. They can convert input AC or DC power into high-efficiency DC output that conforms to the fast charging protocols USBPD and QC, enabling fast charging of devices such as mobile phones and laptops.

[0003] Existing PCBA boards lack corresponding overvoltage protection structures. Overvoltage can cause short circuits or overcurrents in components, and the local temperature rise can exceed the heat resistance rating of the PCB and circuit board casing. At the same time, when TVS is missing, the energy of lightning surges can be directly converted into heat and burn the copper foil. Furthermore, when charging mobile phones, computers, or tablets under overvoltage conditions, it can damage the USB controller connected to the PCB circuit board, thereby preventing the mobile phone or computer / tablet from charging or transmitting data. Utility Model Content

[0004] The purpose of this invention is to provide an overvoltage protection structure for a fast-charging PCBA board to solve the above-mentioned defects caused by the prior art.

[0005] An overvoltage protection structure for a fast-charging PCBA board includes a PCB board, a TVS diode, a PWM main control chip, and a bottom support arm. The PCB board has rectangularly distributed positioning holes on its outer side. The PWM main control chip is soldered to the outer side of the PCB board. A protection mechanism is provided on the outer side of the PCB board to prevent abnormal increases in input and output voltage that could damage the device. This mechanism cuts off or clamps the high voltage in a very short time. An outer shielding cover is provided at the bottom of the PCB board. A heat dissipation mechanism is provided inside the PCB board. This heat dissipation mechanism cools the TVS diode, preventing it from being damaged by overheating due to the instantaneous large current generated when clamping high voltage, which could cause a sudden rise in junction temperature.

[0006] Preferably, the protection mechanism includes a TVS diode, a USB output terminal, a resettable fuse, and a filter capacitor. A PCB board is soldered to the outside of the USB output terminal, a filter capacitor is soldered to the surface of the PCB board, the TVS diode is soldered to the surface of the PCB board, and the resettable fuse is connected to the output terminal of the PWM main control chip.

[0007] Preferably, the USB output terminal is connected in series with a unidirectional TVS diode via a VBUS pin.

[0008] Preferably, the heat dissipation mechanism includes a bottom support arm, a rubber pad, an alloy mesh plate, an air inlet, a vortex fan, and a threaded rod. The bottom support arms are symmetrically arranged on both sides of the PCB board. Rubber pads are symmetrically arranged at the top of the bottom support arms. Threaded rods are connected through the outer side of the rubber pads. The air inlet is provided with a bottom support arm. An outer shield is connected to the outer side of the two sets of bottom support arms. A vortex fan is connected to the inner end of the outer shield. Alloy mesh plates are connected to both sides of the outer shield. The alloy mesh plates are arranged parallel to the air inlet.

[0009] Preferably, the bottom support arm is connected to the PCB board through a threaded rod at its top, and the rubber pad at the top of the bottom support arm is in contact with the PCB board.

[0010] Preferably, the bottom support arm is connected to the outside of the positioning hole via symmetrically arranged threaded rods.

[0011] Compared with the prior art, the present invention has the following advantages:

[0012] 1. During the installation of the fast charging PCB board, the bottom-mounted vortex fan significantly improves the heat dissipation efficiency of the TVS diode and PWM main control chip through forced convection, solving the temperature rise problem under high power density. The symmetrical support arms can evenly distribute the weight of the PCB, avoiding stress concentration on one side and deformation. The support arms separate the high heat-generating components from the outer shell, preventing heat from being conducted back to the temperature-sensitive area through the metal shell.

[0013] 2. The support arm uses symmetrically arranged threaded rods to position the PCB board, enabling quick disassembly and positioning of the PCB board. The symmetrical layout disperses stress and avoids unilateral overload that could cause the PCB to bend. At the same time, the outer shield at the top of the outer side of the support arm covers the solder joints at the bottom of the PCB board, preventing exposed solder joints, high-voltage capacitors, etc. from short circuits caused by falling metal objects. The shield can physically isolate such risks. Attached Figure Description

[0014] Figure 1 This is a three-dimensional structural diagram of the present invention.

[0015] Figure 2 This is a side sectional view of the outer shielding cover in this utility model.

[0016] Figure 3 This is a schematic diagram of the structure of the bottom support arm in this utility model.

[0017] Figure 4 This is a top view schematic diagram of the overall structure of this utility model.

[0018] Figure 5This is a schematic diagram of the front section structure of the outer shielding cover in this utility model.

[0019] in:

[0020] 1. PCB board; 2. Positioning holes; 3. TVS diode; 4. USB output terminal; 5. Protection mechanism; 6. PWM main control chip; 7. Self-resetting fuse; 8. Heat dissipation mechanism; 9. Outer shielding cover; 10. Bottom support arm; 11. Rubber pad; 12. Alloy mesh plate; 13. Air inlet; 14. Scroll fan; 15. Threaded rod; 16. Filter capacitor. Detailed Implementation

[0021] To make the technical means, creative features, objectives and effects of this utility model easier to understand, the present utility model will be further described below in conjunction with specific embodiments.

[0022] like Figures 1 to 5 As shown, an overvoltage protection structure for a fast-charging PCBA board includes a PCB board 1, a TVS diode 3, a PWM main control chip 6, and a bottom support arm 10. The outer side of the PCB board 1 has rectangularly distributed positioning holes 2. The PWM main control chip 6 is soldered to the outer side of the PCB board 1. A protection mechanism 5 is provided on the outer side of the PCB board 1. The protection mechanism 5 prevents abnormal increases in input and output voltage from causing equipment damage and cuts off or clamps high voltage in a very short time. An outer shielding cover 9 is provided at the bottom of the PCB board 1. A heat dissipation mechanism 8 is provided inside the PCB board 1. The heat dissipation mechanism 8 dissipates heat from the TVS diode 3 when a large instantaneous current is generated during high voltage clamping, causing a sudden rise in junction temperature, thus preventing the TVS diode 3 from being damaged due to overheating.

[0023] In this embodiment, the protection mechanism 5 includes a TVS diode 3, a USB output terminal 4, a resettable fuse 7, and a filter capacitor 16. A PCB board 1 is soldered to the outside of the USB output terminal 4, and a filter capacitor 16 is soldered to the surface of the PCB board 1. The TVS diode 3 is soldered to the surface of the PCB board 1. The resettable fuse 7 is connected to the output terminal of the PWM main control chip 6. The TVS diode 3 effectively discharges ESD energy within a nanosecond-level response. The filter capacitor 16 is used to reduce the AC ripple coefficient to improve the efficient and smooth DC output, while maintaining the signal integrity of the USB output terminal 4.

[0024] In this embodiment, the USB output terminal 4 is connected in series with the unidirectional TVS diode 3 through the VBUS pin. The TVS diode 3 is connected in series between the rectifier bridge and the primary switching transistor to suppress the surge current impact on the PWM main control chip 6.

[0025] In this embodiment, the heat dissipation mechanism 8 includes a bottom support arm 10, a rubber pad 11, an alloy mesh plate 12, an air inlet 13, a vortex fan 14, and a threaded rod 15. The bottom support arms 10 are symmetrically arranged on both sides of the PCB board 1. The top of the bottom support arm 10 is symmetrically provided with a rubber pad 11. The outer side of the rubber pad 11 is connected to the threaded rod 15. The air inlet 13 is provided through the bottom support arm 10. The outer sides of the two sets of bottom support arms 10 are connected to an outer shield 9. The inner end of the outer shield 9 is connected to the vortex fan 14. The two sides of the outer shield 9 are connected to the alloy mesh plate 12. The alloy mesh plate 12 is arranged parallel to the air inlet 13. The bottom support arms 10 are used to position the two sides of the outer shield 9, and the vortex fan 14 is used to circulate and cool the bottom of the PCB board 1.

[0026] In this embodiment, the bottom support arm 10 is connected to the PCB board 1 through a threaded rod 15 at the top end. The rubber pad 11 at the top end of the bottom support arm 10 is in contact with the PCB board 1, and the bottom rubber pad 11 of the bottom support arm 10 makes flexible contact with the PCB board 1.

[0027] In this embodiment, the bottom support arm 10 is connected to the outside of the positioning hole 2 through symmetrically arranged threaded rods 15. The bottom end of the PCB board 1 is positioned by the rectangularly distributed threaded rods 15, which facilitates the positioning of the top end of the outer shielding cover 9.

[0028] In practical applications, the overvoltage protection structure of this fast-charging PCBA board includes the following functions:

[0029] Step 1: During use, align the threaded rod 15 at the top of the bottom support arm 10 with the bottom of the PCB board 1, so that the threaded rod 15 is inserted into the positioning hole 2, and the rubber pad 11 at the bottom of the threaded rod 15 positions the bottom of the PCB board 1. The threaded rod 15 can be threaded and locked with a plastic nut to lock the PCB board 1 and the threaded rod 15, so that the bottom of the PCB board 1 is suspended, reducing the corrosion of the PCB board solder joints by moisture.

[0030] Step 2: The bottom support arms 10 of the two groups are connected to the outer shield 9. The outer shield 9 uses the Faraday cage principle to limit the noise in the sealed space and reduce radiation interference. At the same time, the vortex fan 14 accelerates the air flow speed and the air inlet 13 continuously draws the outside air into the interior of the outer shield 9. The alloy mesh plate 12 filters the drawn-in air, thereby cooling the TVS diode 3 and PWM main control chip 6 at the top of the PCB board 1.

[0031] Step 3: Under normal voltage conditions, TVS diode 3 is in a high-resistance state, which does not affect the circuit operation. When the voltage exceeds the TVS breakdown voltage, TVS instantly enters a low-resistance state, and the impedance drops from the megaohm level to the ohm level. The avalanche effect is activated, clamping the voltage at the clamping voltage. The surge current is directed to GND through TVS diode 3 to prevent high voltage from entering the downstream circuit. If the energy exceeds the rated power of TVS diode 3, TVS diode 3 may be sacrificially damaged, but other components are protected.

[0032] Step 4: After the input voltage is filtered by the input capacitor, it is sent to the VIN pin of the PWM main control chip 6. The MOSFETs inside the PWM main control chip 6 form a synchronous buck circuit. The PWM main control chip 6 integrates protocol functions (such as IP2726) and hands with the device through the CC / D+ / D- lines to switch voltage levels. The current is output through the USB output terminal 4 set on one side of the PCB board 1. When the overcurrent protection of the PWM main control chip 6 fails or the response is insufficient, the current exceeds the holding current of the self-resetting fuse 7, which will cause the self-resetting fuse 7 to heat up. This causes the lattice of the polymer material inside the self-resetting fuse 7 to expand, and the resistance increases sharply from the milliohm level to the megaohm level, limiting the current to the microampere level. After the fault is cleared and cooled down, the resistance returns to normal and the circuit automatically recovers.

[0033] Therefore, the above-disclosed embodiments are merely illustrative in all respects and are not the only ones. All modifications within the scope of this utility model or its equivalents are included in this utility model.

Claims

1. An overvoltage protection structure of a fast-charging PCBA board, characterized in that: The device includes a PCB board (1), a TVS diode (3), a PWM main control chip (6), and a bottom support arm (10). The outer side of the PCB board (1) has rectangular positioning holes (2). The outer side of the PCB board (1) is soldered with a PWM main control chip (6). The outer side of the PCB board (1) is provided with a protection mechanism (5). The protection mechanism (5) prevents abnormal rise in input and output voltage from causing equipment damage and cuts off or clamps high voltage in a very short time. The bottom end of the PCB board (1) is provided with an outer shield (9). The inside of the PCB board (1) is provided with a heat dissipation mechanism (8). The heat dissipation mechanism (8) dissipates heat from the TVS diode (3) when it generates a large instantaneous current that causes a sudden rise in junction temperature during high voltage clamping, thus preventing the TVS diode (3) from being damaged due to overheating.

2. The overvoltage protection structure of a fast-charging PCBA board according to claim 1, characterized in that: The protection mechanism (5) includes a TVS diode (3), a USB output terminal (4), a self-resetting fuse (7), and a filter capacitor (16). A PCB board (1) is soldered to the outside of the USB output terminal (4). A filter capacitor (16) is soldered to the surface of the PCB board (1). The TVS diode (3) is soldered to the surface of the PCB board (1). The self-resetting fuse (7) is connected to the output terminal of the PWM main control chip (6).

3. The overvoltage protection structure of a fast-charging PCBA board according to claim 2, characterized in that: The USB output terminal (4) is connected in series with a unidirectional TVS diode (3) via a VBUS pin.

4. The overvoltage protection structure of a fast-charging PCBA board according to claim 1, characterized in that: The heat dissipation mechanism (8) includes a bottom support arm (10), a rubber pad (11), an alloy mesh plate (12), an air inlet (13), a vortex fan (14), and a threaded rod (15). The bottom support arm (10) is symmetrically arranged on both sides of the PCB board (1). The top of the bottom support arm (10) is symmetrically provided with a rubber pad (11). The outer side of the rubber pad (11) is connected to the threaded rod (15). The air inlet (13) is provided through the bottom support arm (10). The outer sides of the two sets of bottom support arms (10) are connected to an outer shield (9). The inner end of the outer shield (9) is connected to the vortex fan (14). The two sides of the outer shield (9) are connected to alloy mesh plates (12). The alloy mesh plates (12) are arranged parallel to the air inlet (13).

5. The overvoltage protection structure of a fast-charging PCBA board according to claim 4, characterized in that: The bottom support arm (10) is connected to the PCB board (1) through a threaded rod (15) at the top end, and the rubber pad (11) at the top end of the bottom support arm (10) is in contact with the PCB board (1).

6. The overvoltage protection structure for a fast-charging PCBA board according to claim 4, characterized in that: The bottom support arm (10) is connected to the outside of the positioning hole (2) through symmetrically arranged threaded rods (15).

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