Mobile phone adapter insertion surge current suppression method based on distance detection

Abstract

The invention relates to the technical field of mobile phone adapters, in particular to a mobile phone adapter insertion surge current suppression method based on distance detection, and the method is applied to a mobile phone adapter with a built-in distance detection module, a current limiting module, a driving module and a rectification filtering module. According to the mobile phone adapter insertion surge current suppression method based on distance detection, the insertion depth is sensed in real time through the distance detection module, the on resistance of the current limiting module is dynamically adjusted, precise suppression of surge current in the insertion process is achieved, and electric sparks are completely eliminated; meanwhile, when the adapter normally works, the current-limiting module is conducted in a low-resistance mode, no extra power consumption exists, the defects that an existing NTC thermistor scheme is large in power consumption and a relay scheme is slow in response are overcome, the safety, reliability and energy-saving performance of the adapter are remarkably improved, and the adapter is suitable for different voltage input scenes and high in practicability.

Description

Technical Field

[0001] This invention relates to the field of mobile phone adapter technology, and in particular to a method for suppressing surge current during mobile phone adapter insertion based on distance detection. Background Technology

[0002] With the widespread use of mobile devices such as smartphones, the safety and reliability of mobile phone adapters, as essential charging accessories, have become increasingly important. Traditional mobile phone adapters typically use large-capacity electrolytic capacitors in their input filtering circuits to smooth pulsating voltage after rectification and ensure stable DC output. However, when the adapter plug is inserted into the socket, the initial charging current of the input capacitor can reach tens of amperes (according to the formula I = C·dV / dt), causing electrical sparks between the plug's metal contacts and the socket's metal contacts. This not only poses safety hazards (such as igniting dust around the socket or damaging metal contacts) but also shortens the lifespan of both the adapter and the socket.

[0003] To address the aforementioned issues, existing technologies have proposed several surge current suppression solutions: 1. Connecting an NTC thermistor in series in the input circuit, utilizing the thermistor's high resistance at low temperatures and low resistance at high temperatures to suppress initial surge current. However, this solution requires continuous heating to maintain a low resistance state, resulting in significant additional power consumption (typically ≥0.5W) during normal adapter operation, which does not meet energy-saving requirements; 2. Using a relay delay switching circuit to close the short-circuit current-limiting resistor through relay contacts. However, the relay response speed is slow (seconds), unable to match the insertion process in real time, and the mechanical contacts are prone to wear, leading to low reliability; 3. Designing a voltage detection switching circuit to control the current-limiting element by detecting changes in input voltage. However, this solution cannot distinguish between the adapter insertion process and abnormal short-circuit conditions, easily leading to false triggering and current-limiting failure. Therefore, we introduce a distance-based method for suppressing surge current during mobile phone adapter insertion. Summary of the Invention

[0004] The main objective of this invention is to provide a method for suppressing surge current when inserting a mobile phone adapter based on distance detection, which can effectively solve the problems in the background art.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for suppressing surge current in a mobile phone adapter based on distance detection, the method being applied to a mobile phone adapter with a built-in distance detection module, current limiting module, driving module, and rectifier filter module, the method comprising the following steps:

[0007] S1. When the mobile phone adapter is not plugged into an external socket, the distance detection module, the drive module and the current limiting module do not receive power, the current limiting module is in the off state, and the filter capacitor of the rectifier filter module remains uncharged.

[0008] S2. Align the AC pin of the mobile phone adapter with the socket of the external socket and begin to insert it. When the AC pin makes initial contact with the metal conductive piece of the external socket, the external socket supplies power to the mobile phone adapter through the AC pin, and the distance detection module, drive module and current limiting module are simultaneously powered on and started.

[0009] S3. The distance detection module collects the initial distance h0 between the lower surface of the mobile phone adapter housing and the surface of the external socket in real time, and transmits the initial distance signal to the drive module.

[0010] After receiving the initial distance signal, the drive module outputs a preset first drive voltage V1 to the current limiting module, so that the on-resistance of the current limiting module is maintained at a preset high resistance R1. After the external AC current is limited by the current limiting module, it is input to the rectifier and filter module to slowly charge the filter capacitor and avoid the charging current from exceeding the preset surge threshold.

[0011] S4. Continue to push the mobile phone adapter so that the AC plug is gradually inserted into the external socket hole. The distance detection module continuously collects the real-time distance h. When it is detected that the real-time distance h gradually decreases with the increase of insertion depth (h < h0), the distance detection module continuously transmits the real-time distance signal to the drive module.

[0012] S5. The driving module gradually increases the output driving voltage according to a preset ratio based on the decrease in real-time distance h, so that the driving voltage gradually increases from the first driving voltage V1.

[0013] The on-resistance of the current limiting module decreases synchronously as the driving voltage increases, thereby gradually increasing the current input to the rectifier and filter module and achieving a soft current transition.

[0014] S6. When the distance detection module detects that the real-time distance h is less than the preset full insertion threshold h1, it determines that the mobile phone adapter has been fully inserted into the external socket.

[0015] The driving module immediately outputs the maximum driving voltage Vmax to the current limiting module, causing the current limiting module to switch to a low-resistance conduction state, and the conduction resistance drops to a preset low resistance R2.

[0016] S7. External AC current is directly input to the rectifier and filter module through a low-resistance current limiting module. The rectifier and filter module first converts the AC power into DC voltage, and then adjusts it to a stable DC voltage required by the mobile phone through a voltage regulation circuit. Then, it provides charging voltage to the mobile phone through the DC output interface of the mobile phone adapter, and the mobile phone adapter enters the normal power supply mode.

[0017] Preferably, in S3, the preset high resistance R1 satisfies R1≥Vin_peak / Imax, where Vin_peak is the peak value of the AC input voltage of the external socket, and Imax is the maximum inrush current allowed by the mobile phone adapter.

[0018] Preferably, in S3, the first driving voltage V1 ranges from 0.8 to 2.5V, the preset high resistance R1 ranges from 600 to 1200Ω, and the initial charging current of the filter capacitor is ≤0.5A.

[0019] Preferably, in S4, the detection frequency of the distance detection module is 15-50Hz, the distance error of each detection is ≤0.2mm, and the detection direction of the distance detection module is parallel to the insertion direction of the AC pin.

[0020] Preferably, in S5, the ratio of the increase in driving voltage by the driving module is linearly positively correlated with the decrease in real-time distance h. When the real-time distance h decreases to (h0-h1) / 2, the driving voltage output by the driving module increases to (V1+Vmax) / 2, and the on-resistance of the current limiting module decreases to (R1+R2) / 2.

[0021] Preferably, in S6, the value of the full insertion threshold h1 is 1 / 4 to 1 / 2 of the length of the AC pin of the mobile phone adapter, the value of the maximum driving voltage Vmax is 18-25V, and the value of the preset low resistance R2 is ≤15mΩ.

[0022] Preferably, the method further includes S8: when it is necessary to unplug the mobile phone adapter from the external socket, pull the mobile phone adapter to gradually disconnect the AC plug from the external socket, the distance detection module detects that the real-time distance h gradually increases, and transmits the increased real-time distance signal to the drive module;

[0023] The driving module gradually reduces the output driving voltage according to the increase in real-time distance h, thereby gradually increasing the on-resistance of the current limiting module until the AC pin is completely separated from the metal conductive plate of the external socket, and the current limiting module returns to the off state.

[0024] Preferably, in S8, the rate at which the driving module decreases the driving voltage is consistent with the rate at which the real-time distance h increases. When the real-time distance h increases to the initial distance h0, the driving voltage output by the driving module drops to the first driving voltage V1.

[0025] When the real-time distance h continues to increase to h0+5mm, the drive module stops outputting the drive voltage.

[0026] Preferably, in S3 to S6, during the charging process of the filter capacitor of the rectifier filter module, no electric spark is generated between the AC pin of the mobile phone adapter and the metal conductive plate of the external socket, and the duration of the charging process is 0.5-2s.

[0027] Preferably, the distance detection module is an infrared distance sensor, the current limiting module is an N-channel enhancement-mode MOSFET, the driving module is a voltage driving circuit, and the rectification and filtering module includes a bridge rectifier circuit and an electrolytic capacitor.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] In this invention, the insertion depth is sensed in real time by a distance detection module, and the on-resistance of the current limiting module is dynamically adjusted to achieve precise suppression of surge current during insertion and completely eliminate the generation of electrical sparks. At the same time, the current limiting module conducts with low resistance during normal operation of the adapter, with no additional power consumption. This solves the defects of existing NTC thermistor solutions, such as high power consumption and slow response of relay solutions, significantly improving the safety, reliability and energy efficiency of the adapter. It is adaptable to different voltage input scenarios and has strong practicality. Attached Figure Description

[0030] Figure 1 This is a flowchart of a method for suppressing surge current when inserting a mobile phone adapter based on distance detection, according to the present invention. Detailed Implementation

[0031] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0032] Example 1: Mobile phone adapter compatible with 220V AC input

[0033] A method for suppressing surge current during mobile phone adapter insertion based on distance detection, see [reference]. Figure 1 The method is applied to a mobile phone adapter with a built-in distance detection module, current limiting module, driving module, and rectification and filtering module. The method includes the following steps:

[0034] S1. When the mobile phone adapter is not plugged into an external socket, the distance detection module, the drive module and the current limiting module do not receive power, the current limiting module is in the off state, and the filter capacitor of the rectifier filter module remains uncharged.

[0035] S2. Align the AC pin of the mobile phone adapter with the socket of the external socket and begin to insert it. When the AC pin makes initial contact with the metal conductive piece of the external socket, the external socket supplies power to the mobile phone adapter through the AC pin, and the distance detection module, drive module and current limiting module are simultaneously powered on and started.

[0036] S3. The distance detection module collects the initial distance h0 between the lower surface of the mobile phone adapter housing and the surface of the external socket in real time, and transmits the initial distance signal to the drive module.

[0037] After receiving the initial distance signal, the drive module outputs a preset first drive voltage V1 to the current limiting module, so that the on-resistance of the current limiting module is maintained at a preset high resistance R1. After the external AC current is limited by the current limiting module, it is input to the rectifier and filter module to slowly charge the filter capacitor and avoid the charging current from exceeding the preset surge threshold.

[0038] S4. Continue to push the mobile phone adapter so that the AC plug is gradually inserted into the external socket hole. The distance detection module continuously collects the real-time distance h. When it is detected that the real-time distance h gradually decreases with the increase of insertion depth (h < h0), the distance detection module continuously transmits the real-time distance signal to the drive module.

[0039] S5. The driving module gradually increases the output driving voltage according to a preset ratio based on the decrease in real-time distance h, so that the driving voltage gradually increases from the first driving voltage V1.

[0040] The on-resistance of the current limiting module decreases synchronously as the driving voltage increases, thereby gradually increasing the current input to the rectifier and filter module and achieving a soft current transition.

[0041] S6. When the distance detection module detects that the real-time distance h is less than the preset full insertion threshold h1, it determines that the mobile phone adapter has been fully inserted into the external socket.

[0042] The driving module immediately outputs the maximum driving voltage Vmax to the current limiting module, causing the current limiting module to switch to a low-resistance conduction state, and the conduction resistance drops to a preset low resistance R2.

[0043] S7. External AC current is directly input to the rectifier and filter module through a low-resistance current limiting module. The rectifier and filter module first converts the AC power into DC voltage, and then adjusts it to a stable DC voltage required by the mobile phone through a voltage regulation circuit. Then, it provides charging voltage to the mobile phone through the DC output interface of the mobile phone adapter, and the mobile phone adapter enters the normal power supply mode.

[0044] In S3, the preset high resistance R1 satisfies R1≥Vin_peak / Imax, where Vin_peak is the peak value of the AC input voltage of the external socket, and Imax is the maximum inrush current allowed by the mobile phone adapter;

[0045] In S3, the first driving voltage V1 ranges from 0.8 to 2.5V, the preset high resistance R1 ranges from 600 to 1200Ω, and the initial charging current of the filter capacitor is ≤0.5A.

[0046] In S4, the detection frequency of the distance detection module is 15-50Hz, the distance error of each detection is ≤0.2mm, and the detection direction of the distance detection module is parallel to the insertion direction of the AC pin.

[0047] In S5, the ratio of the increase in driving voltage by the driving module is linearly positively correlated with the decrease in real-time distance h. When the real-time distance h decreases to (h0-h1) / 2, the driving voltage output by the driving module increases to (V1+Vmax) / 2, and the on-resistance of the current limiting module decreases to (R1+R2) / 2.

[0048] In S6, the value of the full insertion threshold h1 is 1 / 4 to 1 / 2 of the length of the AC plug of the mobile phone adapter, the value of the maximum driving voltage Vmax is 18-25V, and the value of the preset low resistance R2 is ≤15mΩ.

[0049] The method further includes S8: when it is necessary to unplug the mobile phone adapter from the external socket, pull the mobile phone adapter to gradually disconnect the AC plug from the external socket, the distance detection module detects that the real-time distance h gradually increases, and transmits the increased real-time distance signal to the drive module;

[0050] The driving module gradually reduces the output driving voltage according to the increase of the real-time distance h, so that the on-resistance of the current limiting module gradually increases until the AC pin is completely separated from the metal conductive plate of the external socket, and the current limiting module returns to the off state.

[0051] In S8, the rate at which the driving module reduces the driving voltage is consistent with the rate at which the real-time distance h increases. When the real-time distance h increases to the initial distance h0, the driving voltage output by the driving module drops to the first driving voltage V1.

[0052] When the real-time distance h continues to increase to h0+5mm, the drive module stops outputting the drive voltage;

[0053] In S3 to S6, during the charging process of the filter capacitor of the rectifier filter module, no electric spark is generated between the AC pin of the mobile phone adapter and the metal conductive plate of the external socket, and the duration of the charging process is 0.5-2s.

[0054] The distance detection module is an infrared distance sensor, the current limiting module is an N-channel enhancement-mode MOSFET, the driving module is a voltage driving circuit, and the rectification and filtering module includes a bridge rectifier circuit and an electrolytic capacitor.

[0055] In this embodiment, the mobile phone adapter is compatible with 220V / 50Hz AC input and has a DC output specification of 5V / 2A. The built-in distance detection module is an infrared distance sensor, the current limiting module is an N-channel MOSFET, the driving module is a voltage driving circuit, and the rectification and filtering module includes a bridge rectifier circuit composed of four 1N4007 diodes and a 220μF / 400V electrolytic capacitor (filter capacitor).

[0056] Unplugged state (S1): When the mobile phone adapter is not plugged into the socket, the AC plug is not powered, the distance detection module, the drive module, and the current limiting module are all in a power-off state, the MOSFET is turned off, the filter capacitor has no charge storage, and the adapter has no output.

[0057] Initial insertion (S2-S3): Align the AC plug with the 220V socket and insert it. When the AC plug contacts the metal contacts of the socket, 220V AC power is input to the adapter through the AC plug, and all modules are powered on and started. The distance detection module collects the initial distance h0 = 15mm between the lower surface of the adapter housing and the surface of the socket and transmits the signal to the drive module. The drive module outputs the first drive voltage V1 = 1.5V, and the on-resistance of the MOSFET is maintained at the preset high resistance R1 = 800Ω (satisfying R1 ≥ 311V / 0.5A = 622Ω, where 311V is the peak value of the 220V AC voltage and 0.5A is the maximum inrush current). At this time, the external current is input to the rectifier and filter module through the 800Ω current-limiting resistor. The initial charging current of the filter capacitor is ≈ 0.39A (311V / 800Ω), which is less than the maximum inrush current of 0.5A, and no electric spark is generated.

[0058] Deep insertion (S4-S5): Continue pushing the adapter, the AC pins are deeply inserted into the socket, and the distance detection module collects the real-time distance h at a frequency of 30Hz: When h = 10mm (decreased by 5mm), the drive module increases the drive voltage to (1.5V + 20V) / 2 = 10.75V (maximum drive voltage Vmax = 20V), the on-resistance of the MOSFET decreases to (800Ω + 10mΩ) / 2 ≈ 400Ω, and the input current ≈ 0.78A; when h = 5mm (decreased by another 5mm), the drive voltage increases to 15.25V, the on-resistance decreases to 200Ω, and the input current ≈ 1.56A, achieving a soft transition of current from 0.39A to 1.56A;

[0059] Full Insertion (S6-S7): When the distance detection module detects h = 3mm (AC pin length is 12mm, h1 = 3mm = 12mm × 1 / 4, meeting the full insertion threshold), it determines that the adapter is fully inserted. The drive module immediately outputs the maximum 20V drive voltage, the MOSFET's on-resistance drops to 10mΩ, and the external current is input to the rectifier and filter module through the low-resistance MOSFET. Since the current-limiting MOSFET is located at the front end of the rectifier and filter module, the voltage is close to the AC input peak value (approximately 311V), and the current is small (approximately 0.5A for the MOSFET when the adapter outputs 80W). The additional power consumption of the MOSFET is approximately (0.5A). 2 ×10mΩ=0.0025W, which is negligible. After rectification and filtering, it outputs 5V / 2A DC power to charge the mobile phone, and the adapter enters the normal power supply mode.

[0060] Unplugging process (S8): Pull the adapter out. The distance detection module detects that h gradually increases: when h = 5mm, the drive voltage drops to 15.25V and the on-resistance rises to 200Ω; when h = 10mm, the drive voltage drops to 10.75V and the on-resistance rises to 400Ω; when h = 15mm, the drive voltage drops to 1.5V; when h = 20mm, the drive module stops outputting voltage, the MOSFET turns off, and the AC pin is completely disconnected from the socket. There is no sudden change in current during the unplugging process.

[0061] Example 2: Mobile phone adapter adapted to 110V AC input

[0062] Based on Embodiment 1, in this embodiment, the mobile phone adapter is adapted to 110V / 60Hz AC input, and the DC output specification is 5V / 1.5A. The built-in distance detection module is an infrared distance sensor, the current limiting module is an N-channel MOSFET, the driving module is a voltage driving circuit, and the rectification and filtering module includes a bridge rectifier circuit composed of four 1N5408 diodes and a 180μF / 200V electrolytic capacitor (filter capacitor).

[0063] Not inserted state (S1): When the adapter is not inserted into the socket, all modules are powered off, the MOSFETs are turned off, the filter capacitors are not charged, and there is no output;

[0064] Initial insertion (S2-S3): The AC pin is inserted into a 110V socket. When it contacts the metal plate, 110V AC power is input, the module is powered on, the distance detection module acquires the initial distance h0 = 12mm, the drive module outputs the first drive voltage V1 = 1V, the MOSFET on-resistance R1 = 500Ω (satisfying R1 ≥ 155.6V / 0.4A = 389Ω, where 155.6V is the peak value of 110V AC voltage, and 0.4A is the maximum inrush current), the input current ≈ 155.6V / 500Ω ≈ 0.31A, the filter capacitor charges slowly, and there is no electrical spark;

[0065] Deep insertion (S4-S5): The adapter is pushed deeper, and the distance detection module collects h at a frequency of 20Hz: When h = 8mm, the driving voltage rises to (1V + 18V) / 2 = 9.5V (Vmax = 18V), the on-resistance drops to 250Ω, and the current ≈ 0.62A; when h = 4mm, the driving voltage rises to 13.75V, the on-resistance drops to 125Ω, and the current ≈ 1.24A, achieving a soft current transition;

[0066] Fully inserted (S6-S7): When h = 2mm (AC pin length is 8mm, h1 = 2mm = 8mm × 1 / 4), full insertion is determined. The drive module outputs a maximum voltage of 18V, the MOSFET's on-resistance drops to 8mΩ, and the input current passes through a low-impedance input rectifier and filter module, outputting 5V / 1.5A DC power to charge the mobile phone. During normal operation, the MOSFET's additional power consumption is approximately (1.5A). 2 ×8mΩ=0.018W, with no additional energy consumption;

[0067] Pull-out process (S8): When pulling out, h increases: when h = 4mm, the driving voltage drops to 13.75V and the resistance rises to 125Ω; when h = 8mm, the voltage drops to 9.5V and the resistance rises to 250Ω; when h = 12mm, the voltage drops to 1V; when h = 17mm, the driving module is powered off, the MOSFET is turned off, and the pull-out is completed.

[0068] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for suppressing surge current during mobile phone adapter insertion based on distance detection, characterized in that, The method is applied to a mobile phone adapter with a built-in distance detection module, current limiting module, driving module, and rectification and filtering module. The method includes the following steps: S1. When the mobile phone adapter is not plugged into an external socket, the distance detection module, the drive module and the current limiting module do not receive power, the current limiting module is in the off state, and the filter capacitor of the rectifier filter module remains uncharged. S2. Align the AC pin of the mobile phone adapter with the socket of the external socket and begin to insert it. When the AC pin makes initial contact with the metal conductive piece of the external socket, the external socket supplies power to the mobile phone adapter through the AC pin, and the distance detection module, drive module and current limiting module are simultaneously powered on and started. S3. The distance detection module collects the initial distance h0 between the lower surface of the mobile phone adapter housing and the surface of the external socket in real time, and transmits the initial distance signal to the drive module. After receiving the initial distance signal, the drive module outputs a preset first drive voltage V1 to the current limiting module, so that the on-resistance of the current limiting module is maintained at a preset high resistance R1. After the external AC current is limited by the current limiting module, it is input to the rectifier and filter module to slowly charge the filter capacitor and avoid the charging current from exceeding the preset surge threshold. S4. Continue to push the mobile phone adapter so that the AC plug is gradually inserted into the external socket hole. The distance detection module continuously collects the real-time distance h. When it is detected that the real-time distance h gradually decreases with the increase of insertion depth (h < h0), the distance detection module continuously transmits the real-time distance signal to the drive module. S5. The driving module gradually increases the output driving voltage according to a preset ratio based on the decrease in real-time distance h, so that the driving voltage gradually increases from the first driving voltage V1. The on-resistance of the current limiting module decreases synchronously as the driving voltage increases, thereby gradually increasing the current input to the rectifier and filter module and achieving a soft current transition. S6. When the distance detection module detects that the real-time distance h is less than the preset full insertion threshold h1, it determines that the mobile phone adapter has been fully inserted into the external socket. The driving module immediately outputs the maximum driving voltage Vmax to the current limiting module, causing the current limiting module to switch to a low-resistance conduction state, and the conduction resistance drops to a preset low resistance R2. S7. External AC current is directly input to the rectifier and filter module through a low-resistance current limiting module. The rectifier and filter module first converts the AC power into DC voltage, and then adjusts it to a stable DC voltage required by the mobile phone through a voltage regulation circuit. Then, it provides charging voltage to the mobile phone through the DC output interface of the mobile phone adapter, and the mobile phone adapter enters the normal power supply mode.

2. The method for suppressing surge current during insertion of a mobile phone adapter based on distance detection according to claim 1, characterized in that, In S3, the preset high resistance R1 satisfies R1≥Vin_peak / Imax, where Vin_peak is the peak value of the AC input voltage of the external socket, and Imax is the maximum inrush current allowed by the mobile phone adapter.

3. The method for suppressing surge current during mobile phone adapter insertion based on distance detection according to claim 1, characterized in that, In S3, the first driving voltage V1 ranges from 0.8 to 2.5V, the preset high resistance R1 ranges from 600 to 1200Ω, and the initial charging current of the filter capacitor is ≤0.5A.

4. The method for suppressing surge current during insertion of a mobile phone adapter based on distance detection according to claim 1, characterized in that, In S4, the detection frequency of the distance detection module is 15-50Hz, the distance error of each detection is ≤0.2mm, and the detection direction of the distance detection module is parallel to the insertion direction of the AC pin.

5. The method for suppressing surge current during insertion of a mobile phone adapter based on distance detection according to claim 1, characterized in that, In S5, the ratio of the increase in driving voltage by the driving module is linearly positively correlated with the decrease in real-time distance h. When the real-time distance h decreases to (h0-h1) / 2, the driving voltage output by the driving module increases to (V1+Vmax) / 2, and the on-resistance of the current limiting module decreases to (R1+R2) / 2.

6. The method for suppressing surge current during insertion of a mobile phone adapter based on distance detection according to claim 1, characterized in that, In S6, the value of the full insertion threshold h1 is 1 / 4 to 1 / 2 of the length of the AC pin of the mobile phone adapter, the value of the maximum driving voltage Vmax is 18-25V, and the value of the preset low resistance R2 is ≤15mΩ.

7. The method for suppressing surge current during insertion of a mobile phone adapter based on distance detection according to claim 1, characterized in that, The method further includes S8: when it is necessary to unplug the mobile phone adapter from the external socket, pull the mobile phone adapter to gradually disconnect the AC plug from the external socket, the distance detection module detects that the real-time distance h gradually increases, and transmits the increased real-time distance signal to the drive module; The driving module gradually reduces the output driving voltage according to the increase in real-time distance h, thereby gradually increasing the on-resistance of the current limiting module until the AC pin is completely separated from the metal conductive plate of the external socket, and the current limiting module returns to the off state.

8. The method for suppressing surge current during insertion of a mobile phone adapter based on distance detection according to claim 7, characterized in that, In S8, the rate at which the driving module reduces the driving voltage is consistent with the rate at which the real-time distance h increases. When the real-time distance h increases to the initial distance h0, the driving voltage output by the driving module drops to the first driving voltage V1. When the real-time distance h continues to increase to h0+5mm, the drive module stops outputting the drive voltage.

9. A method for suppressing surge current during insertion of a mobile phone adapter based on distance detection according to claim 1, characterized in that, In steps S3 to S6, during the charging process of the filter capacitor of the rectifier filter module, no electric sparks are generated between the AC pin of the mobile phone adapter and the metal conductive plate of the external socket, and the charging process lasts for 0.5-2 seconds.

10. A method for suppressing surge current during insertion of a mobile phone adapter based on distance detection according to claim 1, characterized in that, The distance detection module is an infrared distance sensor, the current limiting module is an N-channel enhancement-mode MOSFET, the driving module is a voltage driving circuit, and the rectification and filtering module includes a bridge rectifier circuit and an electrolytic capacitor.

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