Footwear flame retardation tester power supply module

Abstract

The utility model discloses a power supply module of a shoe flame retardation tester. The power supply module comprises a battery input end; the P-channel high-side switch is arranged at the input end of the battery; the N-channel control switch is connected with the grid electrode of the P-channel high-side switch; a control resistor; the first magnetic bead and the second magnetic bead are respectively connected with the drain electrode of the P-channel high-side switch to form two independent filtering paths; the first low-noise linear voltage regulator and the second low-noise linear voltage regulator are respectively connected with the first magnetic bead and the second magnetic bead and respectively output an analog power supply and a digital power supply; and the battery voltage monitoring circuit is arranged at the input end of the battery, comprises a first divider resistor, a second divider resistor and a filter capacitor, and is used for transmitting a battery voltage signal to the input end of the analog-to-digital converter of the microcontroller. The power supply module of the shoe flame-retardant tester has the characteristics of high safety, low noise, high stability and battery monitoring function.

Description

Technical Field

[0001] This utility model relates to a power module for a footwear flame retardant tester. Background Technology

[0002] During flame retardant testing of footwear, the testing instrument needs to simultaneously process weak flame photoelectric signals and temperature signals. The operation of high-power equipment such as igniters, solenoid valves, and fans generates significant electromagnetic interference, affecting measurement accuracy. Existing testing instrument power supply designs typically lack effective filtering and isolation structures, leading to unstable measurements and an inability to quickly and safely shut down in abnormal conditions, posing certain safety hazards and impacting the reliability and repeatability of test results. Utility Model Content

[0003] The purpose of this invention is to provide a power module for a footwear flame retardant tester. This power module features high safety, low noise, high stability, and battery monitoring capabilities.

[0004] The above-mentioned technical objective of this utility model is achieved through the following technical solution:

[0005] A power module for a footwear flame retardant tester includes: a battery input terminal (BAT); a P-channel MOSFET high-side switch (Q1) disposed at the battery input terminal, the source of the P-channel MOSFET high-side switch (Q1) being connected to the battery input terminal and the drain serving as the output terminal; an N-channel MOSFET control switch (Q2) connected to the gate of the P-channel MOSFET high-side switch (Q1) for controlling the switching state of the P-channel MOSFET high-side switch (Q1); a control resistor (R4), one end of which is connected to the system control signal (VDD_on), and the other end of which is connected to the gate of the N-channel MOSFET control switch (Q2); and a dual diode (D2), the cathode of which is connected to the gate of the N-channel MOSFET control switch (Q2). The two anodes are connected to the safety signals (ok, ok1) respectively; the first ferrite bead (L1) and the second ferrite bead (L2) are connected to the drain of the high-side switch (Q1) of the P-channel MOSFET respectively, forming two independent filtering paths; the first low-noise linear regulator (U5) and the second low-noise linear regulator (U6) are connected to the first ferrite bead (L1) and the second ferrite bead (L2) respectively, and output analog power (VDDA) and digital power (VDD) respectively; the battery voltage monitoring circuit is set at the battery input terminal, which includes a first voltage divider resistor (R5), a second voltage divider resistor (R6) and a filter capacitor (C7), and is used to transmit the battery voltage signal to the analog-to-digital converter input terminal (BAT_ADC) of the microcontroller.

[0006] The present invention is further configured to include a large-capacity input capacitor (C4), which is disposed between the drain of the P-channel MOSFET high-side switch (Q1) and ground, for suppressing power-on surges and load steps.

[0007] The present invention is further configured to include a first filter capacitor (C5) and a second filter capacitor (C3), which are respectively disposed between the output terminals of the first ferrite bead (L1) and the second ferrite bead (L2) and ground, and together with the first ferrite bead (L1) and the second ferrite bead (L2), form a π-type filter network.

[0008] The present invention is further configured to include a gate pull-up resistor (R3), which is connected between the gate and the source of the P-channel MOSFET high-side switch (Q1) to ensure that the P-channel MOSFET high-side switch (Q1) is turned off by default when the system is powered off.

[0009] The present invention is further configured such that the enable pin (EN) of the first low-noise linear regulator (U5) and the second low-noise linear regulator (U6) are respectively connected to their input pin (VIN) and grounded through pull-down resistors (R7, R8).

[0010] The present invention is further configured such that the noise reduction bypass pins (BP) of the first low-noise linear regulator (U5) and the second low-noise linear regulator (U6) are grounded through bypass capacitors (C8, C11) to reduce output noise.

[0011] The present invention is further configured such that: the output terminals of the first low-noise linear regulator (U5) and the second low-noise linear regulator (U6) are respectively provided with output stabilizing capacitors (C9, C10), which are connected between the output terminals and ground.

[0012] The present invention is further configured such that the first voltage divider resistor (R5) and the second voltage divider resistor (R6) have the same resistance value, forming a 1:1 voltage division ratio, and the filter capacitor (C7) and the parallel equivalent resistance of the first voltage divider resistor (R5) and the second voltage divider resistor (R6) form a low-pass filter circuit.

[0013] The present invention is further configured such that the impedance of the first magnetic bead (L1) and the second magnetic bead (L2) is 1kΩ@100MHz, which is used to suppress high-frequency electromagnetic interference.

[0014] The present invention is further configured such that the analog ground and digital ground of the first low-noise linear regulator (U5) and the second low-noise linear regulator (U6) are connected at a single point to reduce ground loop interference.

[0015] In summary, this utility model has the following beneficial effects:

[0016] High-safety design: This invention adopts a single-point controlled + interlocked safety power supply architecture. Through a combination of a P-channel MOSFET high-side switch (Q1), an N-channel MOSFET control switch (Q2), a control resistor (R4), and dual diodes (D2), multiple safety signals (ok, ok1) and power-on control signals (VDD_on) are unified onto a single controlled high-side switch. When any safety signal fails, the dual diodes (D2) immediately affect the gate voltage of the N-channel MOSFET control switch (Q2), causing the P-channel MOSFET high-side switch (Q1) to turn off rapidly, cutting off the power to the entire system within milliseconds. This design is more reliable and has a faster response time than traditional multi-point control, significantly reducing safety risks in gas, ignition, and high-temperature scenarios. Simultaneously, the body diode structure of the P-channel MOSFET high-side switch (Q1) provides inherent reverse connection protection, preventing damage to downstream circuitry when the battery is connected incorrectly.

[0017] Dual-channel low-noise power supply design: This invention employs a fully physically isolated dual power supply path design. The output from the P-channel MOSFET high-side switch (Q1) is split into two paths, passing through independent first and second ferrite beads (L1) and their corresponding filter capacitors, and then connected to the first low-noise linear regulator (U5) and the second low-noise linear regulator (U6) respectively, outputting analog power (VDDA) and digital power (VDD). This design completely physically isolates the power supplies of sensitive analog and digital circuits, preventing switching noise from the digital circuits from being transmitted to the sensitive analog circuits through the power lines. Tests show that this design reduces digital noise coupling, ensuring stable signal acquisition even when high-power equipment such as igniters, solenoid valves, and fans are operating, significantly improving the accuracy of flame detection and the precision of temperature measurement.

[0018] Strong EMI suppression capability: This invention employs a π-type filter structure, consisting of a large-capacity input capacitor (C4), a first ferrite bead (L1) / a second ferrite bead (L2), and a first filter capacitor (C5) / a second filter capacitor (C3). The large-capacity input capacitor (C4) suppresses low-frequency ripple, the ferrite beads (L1 / L2) block mid-to-high-frequency noise, and the filter capacitors (C5 / C3) filter out the remaining high-frequency components. This three-stage filtering can attenuate the several-volt pulse interference generated by the igniter to below tens of millivolts, ensuring the stability of the measurement system in strong interference environments. Compared to traditional simple filtering schemes, this design provides a wide-bandwidth filtering effect and is simple in structure, low in cost, and easy to implement.

[0019] Battery health monitoring function: This utility model integrates a dedicated battery voltage monitoring circuit, consisting of a first voltage divider resistor (R5), a second voltage divider resistor (R6), and a filter capacitor (C7). The first voltage divider resistor (R5) and the second voltage divider resistor (R6) form a 1:1 voltage division ratio, reducing the battery voltage to half of its original value to match the range of the microcontroller's analog-to-digital converter. The filter capacitor (C7) and the voltage divider resistors form a low-pass filter circuit with a cutoff frequency of approximately 3.18Hz, effectively filtering out high-frequency noise while preserving the slow change trend of the battery voltage. This design allows the system to record the power state changes throughout the entire testing process. When a test fails, the power curve can be analyzed to determine whether it was caused by power fluctuations, significantly reducing misjudgments and retesting, and improving the reliability and traceability of test results.

[0020] Low power consumption and long lifespan design: The P-channel MOSFET high-side switch (Q1) of this invention, in conjunction with the gate pull-up resistor (R3), ensures that the system is turned off by default when no valid control signal is received. This reduces the system's quiescent current, significantly extending battery standby time. Simultaneously, the low on-resistance of the P-channel MOSFET high-side switch (Q1) during system operation reduces power loss and improves battery efficiency. The large-capacity input capacitor (C4) not only filters ripple but also provides soft-start characteristics, limiting initial inrush current, protecting the battery and subsequent circuitry, and extending system lifespan. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall circuit structure of this utility model. Detailed Implementation

[0022] In the description of this utility model, it should be noted that directional terms such as "up", "down", "front", "back", "left", and "right" are only for the convenience of describing and understanding this utility model, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0023] like Figure 1 As shown, this utility model provides a power supply module for a footwear flame retardant tester. Located on the overall control board, this module converts battery (BAT) power into analog (VDDA) and digital (VDD) power respectively after controlled power-on and EMI filtering. The battery voltage is then fed into the analog-to-digital converter input (BAT_ADC) of the microcontroller for monitoring. The module can be divided into four main functional blocks: power input and controlled switching area, power distribution and EMI filtering area, low-noise voltage regulation area, and battery voltage sampling area.

[0024] The power input and controlled switch area includes the battery input terminal (BAT), a P-channel MOSFET high-side switch (Q1), an N-channel MOSFET control switch (Q2), a control resistor (R4), two diodes (D2), and a gate pull-up resistor (R3). The P-channel MOSFET high-side switch (Q1) is an AO3401A model, operating with its source connected to the battery and its drain connected to the load. Q1 conducts when its gate is pulled low, providing low-dropout power; its body diode direction ensures reverse connection protection. The N-channel MOSFET control switch (Q2) is an AO3400 model, with its drain connected to the gate of Q1 and its source grounded. The gate is connected to the system control signal (VDD_on) through the control resistor (R4) (2.7kΩ). When the controller allows power-on, the VDD_on signal turns on Q2 through R4, pulling the gate of Q1 to ground, thus turning on Q1.

[0025] The cathode of the dual diode (D2) is connected to the gate of Q2, and the two anodes are connected to the safety signals (ok, ok1) respectively. When either safety signal fails, D2 can quickly clamp down, pulling down the gate of Q2 or directly raising the gate potential of Q1, thus turning off Q1 and forming a lockout. The gate pull-up resistor (R3) (10kΩ) is connected between the gate and source of Q1 to ensure that Q1 is turned off by default when the system is powered off.

[0026] The power distribution and EMI filtering area includes a large-capacity input capacitor (C4), a first ferrite bead (L1), a second ferrite bead (L2), a first filter capacitor (C5), and a second filter capacitor (C3). The large-capacity input capacitor (C4) (47μF) is located at the rear end of Q1, connected between the drain of Q1 and ground, and is used to suppress power-on surges and load steps. The output from Q1 is split into two paths, forming independent analog power channels and digital power channels via the first ferrite bead (L1) and the second ferrite bead (L2). The impedances of L1 and L2 are both 1kΩ@100MHz, used to suppress common-mode or differential-mode high-frequency currents. The first filter capacitor (C5) and the second filter capacitor (C3) (each 1μF) are respectively placed between the output terminals of L1 and L2 and ground, forming a π-type filter (C4--L1 / L2--C5 / C3) with the large-capacity input capacitor (C4) and the ferrite bead, thus achieving wideband decoupling.

[0027] The low-noise voltage regulation section includes a first low-noise linear regulator (U5) and a second low-noise linear regulator (U6), both using the RT9193-30GB model. U5 and U6 have the same pin functions: the input pin (VIN) (pin 1) is connected to the output terminals of L1 and L2 respectively; the ground pin (GND) (pin 2) is grounded; the enable pin (EN) (pin 3) is connected to its respective VIN pin and grounded through pull-down resistors (R7 / R8) (100kΩ) to ensure it is turned off when there is no input; the noise reduction bypass pin (BP) (pin 4) is grounded through bypass capacitors (C8 / C11) (22nF) to reduce output noise; and the output pin (VOUT) (pin 5) is connected to output stabilizing capacitors (C9 / C10) (1μF), with C9 / C10 connected between the output terminal and ground. U5 outputs analog power (VDDA) to supply analog front-end components (flame photoelectric amplifier, thermocouple cold junction compensation, ADC reference, etc.); U6 outputs digital power (VDD) to supply microcontrollers, logic and communication modules.

[0028] The battery voltage sampling area includes a first voltage divider resistor (R5), a second voltage divider resistor (R6), and a filter capacitor (C7). R5 and R6 are both 100kΩ and are connected in series between the battery input terminal (BAT) and ground, forming a 1:1 voltage divider ratio. This allows the BAT_ADC to obtain half the battery voltage value, matching the range of the microcontroller's analog-to-digital converter. The filter capacitor (C7) (1μF) is connected between the voltage divider point and ground, forming an RC low-pass filter circuit with R5 and R6 (50kΩ). The cutoff frequency is approximately 3.18Hz, effectively filtering out high-frequency noise from ignition or motor switching while retaining the slowly changing battery voltage trend for power estimation and lifespan prediction.

[0029] In addition, the filter capacitors (C8-C11) are used to perform post-filtering on their respective power supplies during output.

[0030] The module operates as follows: When conditions such as casing closure, normal ventilation, and normal airflow are met, the safety signal (ok / ok1) is valid, and the controller simultaneously turns on VDD_on. VDD_on turns on Q2 through R4, pulling the gate of Q1 low, thus turning on Q1. Current flows from the battery through Q1, charging the large-capacity input capacitor (C4) first. Then, the current splits into two paths, passing through L1 / L2 and C5 / C3 respectively for filtering, before entering U5 / U6. U5 and U6 operate synchronously, outputting VDDA and VDD respectively to supply the analog and digital circuits. Simultaneously, the battery voltage is divided by R5 / R6 and filtered by C7 before being sent to BAT_ADC for power display, low-voltage shutdown, and test report archiving. If any safety signal fails, D2 will trigger Q2 to turn off, which in turn turns off Q1, cutting off both power supplies and ensuring test safety.

[0031] During flame retardant testing of footwear, the igniter, ignition coil, fan / solenoid valve, etc., generate a large amount of pulse interference. This module's π-type filter network and dual-path physically isolated low-noise power supply design effectively suppress these interferences, ensuring the stability of the measurement system. Simultaneously, the single-point controlled safety architecture ensures rapid shutdown in abnormal situations, improving system safety. The battery health monitoring function provides traceability of the power status for the test results, reducing misjudgments and retesting.

[0032] Through the above structural design and working process, this utility model realizes a safe, low-noise, and traceable power module, providing a stable and reliable power foundation for the footwear flame retardant tester and improving the accuracy and reliability of the test results.

[0033] This utility model aims to evaluate the technical effectiveness of the power module of a footwear flame retardant tester.

[0034] 1. A comparative testing method was employed to directly compare the power module of this invention with a traditional single-channel LDO solution. The testing equipment included: a high-precision oscilloscope (1GHz bandwidth), a power analyzer (±0.1% accuracy), a programmable electronic load, an EMI receiver, a high-speed camera, and dedicated test fixtures. Test conditions covered standard operating conditions (25°C) and high-temperature conditions (50°C), simulating interference sources from igniters and solenoid valves. A sample of 10 power modules from this invention and 10 conventional power modules was selected, with each test repeated 20 times to ensure data reliability.

[0035] 2. Technical Effect Comparison Table

[0036]

[0037] 3. Verification Conclusion

[0038] Experimental results show that the power module of the footwear flame retardant tester of this invention is significantly better than the traditional solution in terms of key performance indicators.

[0039] In safety testing, traditional solutions require 15-25ms to completely shut down the power supply in simulated emergency situations, while the single-point controlled + interlocking structure of this invention can achieve complete shutdown within 0.8-1.2ms, improving the response speed by 95%. Ignition tests captured by high-speed cameras show that this millisecond-level response capability is sufficient to cut off the system power supply before the danger escalates, significantly improving test safety.

[0040] Noise test results show that the dual-channel physical isolation design of this invention reduces the simulated channel noise level from 2.8-3.5mV in traditional schemes to 0.4-0.6mV, a reduction of 85%. This ultra-low noise environment improves flame detection sensitivity by approximately three times, enabling stable and reliable detection results even under weak flame conditions. Simultaneously, the π-type filter network achieves a suppression rate of 35-40dB for ignition interference, 25dB higher than traditional schemes, ensuring the stability of the measurement system under strong interference environments.

[0041] In practical application testing, the false judgment rate of the test instrument equipped with the power module of this utility model is only 1.2%, far lower than the 8.5% of the traditional solution. This significant improvement is mainly due to the built-in battery health monitoring function and the stable dual power supply design, which enables the system to record the power state changes throughout the test process and eliminate false judgments caused by power fluctuations in subsequent analysis.

[0042] Power consumption tests show that the power consumption of this invention in standby mode is only 25-40μA, which is more than 99% lower than the 2.8-3.5mA of the traditional solution. In typical intermittent use scenarios, this low-power design can extend battery life from the traditional 2-3 days to 20-30 days, significantly reducing maintenance frequency and costs.

[0043] In summary, the power module of this utility model comprehensively solves the problems of power stability and safety in footwear flame retardant testing through its safety architecture, dual-path physical isolation design, powerful EMI suppression, and precise battery monitoring function. It provides a foundation for obtaining accurate and reliable test results and has broad application prospects.

Claims

1. A power module for a footwear flame retardant tester, characterized in that, include: Battery input terminal (BAT); A P-channel MOSFET high-side switch (Q1) is provided at the battery input terminal, with its source connected to the battery input terminal and its drain serving as the output terminal. An N-channel MOSFET control switch (Q2) connected to the gate of the P-channel MOSFET high-side switch (Q1) is used to control the switching state of the P-channel MOSFET high-side switch (Q1). The control resistor (R4) has one end connected to the system control signal (VDD_on) and the other end connected to the gate of the N-channel MOSFET control switch (Q2); A dual diode (D2) has its cathode connected to the gate of the N-channel MOSFET control switch (Q2), and its two anodes connected to safety signals (ok, ok1), respectively. The first magnetic bead (L1) and the second magnetic bead (L2) are respectively connected to the drain of the P-channel MOSFET high-side switch (Q1) to form two independent filtering paths; The first low-noise linear regulator (U5) and the second low-noise linear regulator (U6) are connected to the first ferrite bead (L1) and the second ferrite bead (L2) respectively, and output analog power (VDDA) and digital power (VDD) respectively. The battery voltage monitoring circuit, which is located at the battery input terminal, includes a first voltage divider resistor (R5), a second voltage divider resistor (R6), and a filter capacitor (C7), and is used to transmit the battery voltage signal to the analog-to-digital converter input terminal (BAT_ADC) of the microcontroller.

2. The power module of the footwear flame retardant tester according to claim 1, characterized in that, It also includes a large-capacity input capacitor (C4), which is located between the drain of the P-channel MOSFET high-side switch (Q1) and ground to suppress power-on surges and load steps.

3. The power module for the footwear flame retardant tester according to claim 1, characterized in that, It also includes a first filter capacitor (C5) and a second filter capacitor (C3), which are respectively disposed between the output terminals of the first ferrite bead (L1) and the second ferrite bead (L2) and ground, forming a π-type filter network with the first ferrite bead (L1) and the second ferrite bead (L2).

4. The power module of the footwear flame retardant tester according to claim 1, characterized in that, It also includes a gate pull-up resistor (R3), which is connected between the gate and source of the P-channel MOSFET high-side switch (Q1) to ensure that the P-channel MOSFET high-side switch (Q1) is turned off by default when the system is powered off.

5. The power module of the footwear flame retardant tester according to claim 1, characterized in that, The enable pin (EN) of the first low-noise linear regulator (U5) and the second low-noise linear regulator (U6) are connected to their input pins (VIN) and grounded through pull-down resistors (R7, R8).

6. The power module of the footwear flame retardant tester according to claim 1, characterized in that, The noise reduction bypass pins (BP) of the first low-noise linear regulator (U5) and the second low-noise linear regulator (U6) are grounded through bypass capacitors (C8, C11) to reduce output noise.

7. The power module of the footwear flame retardant tester according to claim 1, characterized in that, The output terminals of the first low-noise linear regulator (U5) and the second low-noise linear regulator (U6) are respectively provided with output stabilizing capacitors (C9 and C10), which are connected between the output terminal and ground.

8. The power module of the footwear flame retardant tester according to claim 1, characterized in that, The first voltage divider resistor (R5) and the second voltage divider resistor (R6) have the same resistance value, forming a 1:1 voltage division ratio. The filter capacitor (C7) and the parallel equivalent resistance of the first voltage divider resistor (R5) and the second voltage divider resistor (R6) form a low-pass filter circuit.

9. The power module for the footwear flame retardant tester according to claim 1, characterized in that, The first ferrite bead (L1) and the second ferrite bead (L2) have an impedance of 1kΩ@100MHz and are used to suppress high-frequency electromagnetic interference.

10. The power module of the footwear flame retardant tester according to claim 1, characterized in that, The analog ground and digital ground of the first low-noise linear regulator (U5) and the second low-noise linear regulator (U6) are connected at a single point to reduce ground loop interference.

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