Circuit and method for measuring turn-off time of cabin wireless access point

Abstract

The invention relates to a circuit and method for measuring the turn-off time of a cabin wireless access point, and the circuit comprises a switch branch which comprises a first transistor, one end close to the drain of the first transistor is connected with an external power supply, one end close to the grid of the first transistor is connected with a control branch, and one end close to the source of the first transistor is connected with the first end of a circuit to be measured; the detection branch comprises a second transistor, one end close to the drain electrode of the second transistor is connected with the second end of the circuit to be detected, one end close to the source electrode is connected with the third end of the circuit to be detected, and one end close to the grid electrode is connected with the control branch; the control branch comprises a controller used for sending a control instruction to the switch branch and the detection branch to measure the turn-off time of the to-be-detected circuit; the to-be-tested circuit comprises a to-be-tested transistor, the first end of the to-be-tested circuit is close to the drain electrode of the to-be-tested circuit, the second end of the to-be-tested circuit is close to the grid electrode of the to-be-tested circuit, and the third end of the to-be-tested circuit is close to the source electrode of the to-be-tested circuit. Based on the scheme, the turn-off time of the cabin wireless access point can be accurately measured.

Description

Technical Field

[0001] The present application relates to the field of aircraft, and particularly to a circuit and method for measuring the turn-off time of a cabin wireless access point. Background Art

[0002] With the rapid development of the air transportation industry, the number of flights and flight routes is increasing rapidly. Through the existing air-ground data communication network, the information communication efficiency and ability between aircraft pilots and ground controllers need to be improved. A cabin wireless access point (WAP) is one of the key devices on modern aircraft to provide Internet connection services. It is used to provide WiFi coverage for the cabin, enabling two-way communication between portable electronic devices and flight data service units through an Ethernet connection.

[0003] Generally, a cabin wireless access point is equipped with a circuit for suppressing abnormal surge voltage and implementing input soft start. To ensure the normal operation of this circuit, it needs to be tested. In current test tasks, an oscilloscope's current probe and voltage probe are generally used to test the voltage and current waveforms when the circuit is turned off. However, it has been found through testing that when using the oscilloscope's current probe for testing, the input current waveform shows an excessive inrush current; when using the oscilloscope's voltage probe for testing, the voltage waveform shows that it has dropped to the target value within a preset time (such as 400 ms), that is, the two test results are inconsistent. Therefore, incorrect results will be measured when measuring this circuit with an oscilloscope. If power is reapplied when the circuit is not completely turned off, it will cause an excessive inrush current in the circuit, thereby triggering the overcurrent protection of its own device and the risk of power failure of other power supply devices in the same branch. Summary of the Invention

[0004] In view of the above problems in the prior art, the present application provides a circuit and method for measuring the turn-off time of a cabin wireless access point, which can correctly measure the turn-off time of the cabin wireless access point circuit, thereby avoiding the risk of overcurrent protection of its own device and power failure of other power supply devices in the same branch.

[0005] To achieve the above object, a first aspect of the present application provides a circuit for measuring the turn-off time of a wireless access point in a cabin. The circuit includes: a switch branch, a detection branch, and a control branch; the first end of the switch branch is the input end of the circuit for connecting an external power supply, the second end of the switch branch is for connecting the control branch, and the third end of the switch branch is for connecting the first end of the circuit under test; wherein, the switch branch at least includes a first transistor, the first end of the switch branch is the end close to the drain of the first transistor, the second end of the switch branch is the end close to the gate of the first transistor, and the third end of the switch branch is the end close to the source of the first transistor; the first end of the detection branch is for connecting the second end of the circuit under test, the second end of the detection branch is for connecting the third end of the circuit under test, and the third end of the detection branch is for connecting the control branch; wherein, the detection branch at least includes a voltage detection branch and a second transistor, the first end of the detection branch is the end close to the drain of the second transistor, the second end of the detection branch is the end close to the source of the second transistor, and the third end of the detection branch is the end close to the gate of the second transistor; the control branch at least includes a controller for sending control instructions to the switch branch and the detection branch to measure the turn-off time of the circuit under test; the circuit under test is the circuit of the wireless access point in the cabin; the circuit under test at least includes a transistor under test, the first end of the circuit under test is the end close to the drain of the transistor under test, the second end of the circuit under test is the end close to the gate of the transistor under test, and the third end of the circuit under test is the end close to the source of the transistor under test.

[0006] As above, by using the above circuit to measure the turn-off time of the wireless access point in the cabin instead of an oscilloscope, the correct turn-off time can be obtained, thereby avoiding the risk of overcurrent protection of its own equipment and power-off of other power supply equipment in the same branch.

[0007] As an implementation manner of this aspect, the switch branch further includes: a first driving branch; the drain of the first transistor is used as the first end of the switch branch, the source of the first transistor is used as the third end of the switch branch, the gate of the first transistor is connected to one end of the first driving branch, and the other end of the first driving branch is used as the second end of the switch branch.

[0008] As above, signal amplification can be achieved through the first driving branch.

[0009] As an implementation of this aspect, the detection branch further includes: a second drive branch, a first resistor, a second resistor, and the voltage detection branch; the drain of the second transistor serves as the first end of the detection branch, the gate of the second transistor is connected to one end of the second drive branch, the other end of the second drive branch serves as the third end of the detection branch, the source of the second transistor is sequentially connected to the first resistor and the second resistor, and the end of the second resistor far from the first resistor serves as the second end of the detection branch and is connected to the third end of the circuit under test; the voltage detection branch is connected in parallel across the second resistor.

[0010] From the above, the voltage value of the device under test in the circuit under test can be measured through this detection branch.

[0011] The second aspect of the present application provides a method for measuring the turn-off time of an in-cabin wireless access point based on the circuit according to any one of the above first aspects. The method includes: S310: Control the switch branch to conduct for a first preset duration Tc and then turn off the switch branch, and start timing to obtain a first timing time T1; S320: After the first timing time T1, control the detection branch to conduct, and measure and obtain a first voltage VGS between the gate and the source of the transistor under test through the detection branch; S330: Determine the magnitude relationship between the first voltage VGS and a preset turn-off voltage threshold VGS(th), and determine the turn-off time according to the magnitude relationship; where the first timing time is a preset value.

[0012] As an implementation of this aspect, the judging the first voltage V GS and the preset turn-off voltage threshold V GS(th) and determining the turn-off time according to the magnitude relationship includes: if the first voltage V GS is not less than the preset turn-off voltage threshold V GS(th) , then return to step S310; after N1 times of judgment in step S330, if the first voltage V GS is still not less than the preset turn-off voltage threshold V GS(th) , then exit the operation, and determine that the circuit under test of the in-cabin wireless access point is unqualified; where N1*T1 = T 1 , let T 1 ≤Ts; in the above formula, N1 is the first preset calculation times threshold, T1 is the first timing time, T 1 is the total duration after N1 times of calculation, and Ts is the threshold of the circuit turn-off duration.

[0013] As an implementation of this aspect, the judging the first voltage V GS and the preset turn-off voltage threshold V GS(th)The magnitude relationship between them, and determining the turn-off time according to the magnitude relationship, includes: If the first voltage V GS is less than the preset turn-off voltage threshold V GS(th) , then perform the following operations: S410: Control the switch branch to conduct for a first preset duration T c , then disconnect the switch branch and start timing to obtain a second timing time T2; S420: After the second timing time T2, control the detection branch to conduct, and measure and obtain a first voltage V between the gate and source of the transistor under test through the detection branch GS ; S430: Determine the magnitude relationship between the first voltage V GS and the preset turn-off voltage threshold V GS(th) , and determine the turn-off time according to the magnitude relationship; wherein, the second timing time T2 is determined according to the first timing time T1 and the second preset calculation times threshold N2, and the first preset calculation times threshold N1 is not less than the second preset calculation times threshold N2.

[0014] As an implementation manner of this aspect, the second timing time T2 is determined according to the following formula:

[0015] T2 = (n1 - 1)×T1 + T1÷N2×n2

[0016] In the above formula, T1 represents the first timing time, n1 ∈ N1, n2 ∈ N2, N1 represents the first calculation times threshold, N2 represents the second calculation times threshold, n1 represents the n1th calculation, and n2 represents the n2th calculation.

[0017] As an implementation manner of this aspect, determining the magnitude relationship between the first voltage V GS and the preset turn-off voltage threshold V GS(th) , and determining the turn-off time according to the magnitude relationship, includes: When it is executed that the first voltage V GS is less than the preset turn-off voltage threshold V GS(th) , perform the following operations: S510: Control the switch branch to conduct for a first preset duration T c , then disconnect the switch branch and start timing to obtain a third timing time T3; S520: After the third timing time T3, control the detection branch to conduct, and measure and obtain a first voltage V between the gate and source of the transistor under test through the detection branch GS ; S530: Determine the magnitude relationship between the first voltage V GS and the preset turn-off voltage threshold V GS(th)The magnitude relationship therebetween is determined, and the turn-off time is determined according to the magnitude relationship; wherein, the third timing time T3 is determined according to the first timing time T1, the second preset calculation times threshold N2 and the third preset calculation times threshold N3, and the second preset calculation times threshold N2 is not less than the third preset calculation times threshold N3.

[0018] As an implementation manner of this aspect, the third timing time T3 is determined according to the following formula:

[0019] T3 = (n1 - 1) × T1 + (n2 - 1) × T1 ÷ N2 + T1 ÷ (N2 × N3) × n3

[0020] In the above formula, T1 represents the first timing time, n1 ∈ N1, n2 ∈ N2, n3 ∈ N3, N1 represents the first preset calculation times threshold, N2 represents the second preset calculation times threshold, N3 represents the third preset calculation times threshold, n1 represents the n1th calculation, n2 represents the n2th calculation, and n3 represents the n3th calculation.

[0021] As an implementation manner of this aspect, the judgment of the first voltage V GS and the preset turn-off voltage threshold V GS(th) The magnitude relationship therebetween is determined, and the turn-off time is determined according to the magnitude relationship, including: when it is executed to the first voltage V GS is less than the preset turn-off voltage threshold V GS(th) output the turn-off time T;

[0022] Wherein, the turn-off time T is determined according to the following formula:

[0023] T = n3 * T3

[0024] In the above formula, n3 ∈ N3, n3 represents the n3th calculation, N3 represents the third preset calculation times threshold, and T3 represents the third timing time.

[0025] Thus, this aspect provides a measurement method based on the circuit of the first aspect above, that is, provides the control logic in the above circuit control branch. Through the above control logic, the turn-off time of the cabin wireless access point can be measured, and the correct turn-off time can be obtained, thereby avoiding the risk of overcurrent protection of its own equipment and power-off of other power supply equipment in the same branch.

[0026] The third aspect of the present application provides a computing device, including: at least one processor; and at least one memory, which is connected to the processor and stores program instructions, and when the program instructions are executed by the at least one processor, the at least one processor executes the method for measuring the turn-off time of the cabin wireless access point described in any item of the second aspect above.

[0027] The beneficial effects of this aspect can also be seen from the descriptions of the beneficial effects of each part of the above first aspect or second aspect.

[0028] The fourth aspect of the present application provides a computer-readable storage medium, on which program instructions are stored, and when the program instructions are executed by a computer, the computer is caused to execute the method for measuring the turn-off time of the cabin wireless access point described in any one of the above second aspects.

[0029] The beneficial effects of this aspect can also be seen from the descriptions of the beneficial effects of each part of the above first aspect or second aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The following further describes the various technical features of the present application and the relationships between them with reference to the drawings. The drawings are exemplary. Some technical features are not shown in actual proportions, and some conventional technical features in the technical field to which the present application belongs and which are not essential for understanding and implementing the present application may be omitted in some of the drawings, or some technical features that are not essential for understanding and implementing the present application may be additionally shown. That is, the combination of the various technical features shown in the drawings is not used to limit the present application. In addition, throughout the present application, the content referred to by the same reference numerals is the same. The specific description of the drawings is as follows:

[0031] Figure 1 It is a structural diagram of a circuit for realizing abnormal surge voltage suppression and soft start for a cabin wireless access point provided by an embodiment of the present application;

[0032] Figure 2 It is a circuit structural diagram for measuring the turn-off time of a cabin wireless access point provided by an embodiment of the present application;

[0033] Figure 3 It is a flowchart of a method for measuring the turn-off time of a cabin wireless access point provided by an embodiment of the present application;

[0034] Figure 4 It is a schematic structural diagram of a computing device provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The following further illustrates the technical solutions provided by the present application by way of examples in conjunction with the drawings. It should be understood that the system structure and service scenarios provided in the embodiments of the present application are mainly for illustrating possible implementation manners of the technical solutions of the present application, and should not be construed as the only limitation of the technical solutions of the present application. Those of ordinary skill in the art will know that with the evolution of the system structure and the emergence of new service scenarios, the technical solutions provided by the present application are equally applicable to similar technical problems.

[0036] It should be understood that the embodiments of the present application provide a solution for measuring the turn-off time of a wireless access point in an aircraft cabin (i.e., an aircraft cockpit or flight deck). Since the principles of these technical solutions for solving problems are the same or similar, in the following introduction of specific embodiments, some repetitions may not be elaborated again, but it should be regarded that there are mutual references between these specific embodiments and they can be combined with each other.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. In case of inconsistency, it shall be based on the meaning described in this specification or the meaning derived from the content recorded in this specification. In addition, the terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0038] The embodiments of the present application will be described in detail below with reference to the accompanying drawings. First, the application scenario of the solution for measuring the turn-off time of the wireless access point in the aircraft cabin provided by the embodiments of the present application will be introduced.

[0039] As Figure 1 shown, it is an example of a circuit for realizing abnormal surge voltage suppression and input soft start in a wireless access point of an aircraft cabin. In this embodiment, the Figure 1 circuit shown will be used as the circuit under test 10 to introduce the solution of the present application. It should be understood that the circuit under test 10 is only an exemplary description. Among them, the present application mainly measures Figure 1 the turn-off time of the transistor M1 therein. Next, the circuit under test 10 in this example will be introduced first.

[0040] As Figure 1 shown, the circuit under test 10 includes an abnormal surge voltage suppression and input soft start control chip LTC4366-2 (control chip). The GATE pin of this chip is connected to the gate (G pole) of the transistor (or MOSFET) M1 through a resistor R G ; the V DD pin of this chip is connected to the drain (D pole) of the transistor M1 through a resistor R IN and serves as the input terminal V IN of the circuit under test 10 to be connected to an external power supply; the OUT pin of this chip is connected to the source (S pole) of the transistor M1 and serves as the output terminal V OUT of the circuit under test 10 to be connected to an external load; the SD pole of this chip is connected to the collector (c pole) of the triode Q11 through a resistor R11. The emitter (e pole) of the triode Q11 is grounded, and the base (b pole) of the triode Q11 is connected to an external SD terminal through a resistor R22; the FB pin of this chip is connected to the source of the transistor M1 through a resistor R FB1 , and the FB pin of this chip is also connected to the source of the transistor M1 through a resistor R FB2Connected to the ground terminal; the BASE pin of the chip is connected to the source of the transistor M1 through a capacitor C1; the V SS pin of the chip is connected to the ground through a resistor R SS ; the TIMER pin of the chip is connected to the resistor R T through a capacitor C SS near one end of the chip V SS pin.

[0041] In the LTC4366-2 chip, the functions of each pin are as follows:

[0042] 1) BASE pin: Used for the base driver output of the PNP shunt regulator. This pin is connected to the anode of an internal 6.2V Zener diode (whose cathode is connected to the OUT pin). When a lower quiescent current is desired but a large V SS resistor is not used, connect the base of an external PNP to this pin (the collector of this PNP is grounded, and the emitter is connected to V SS ). Connect this pin to V SS when not in use.

[0043] 2) FB pin: Overvoltage regulation amplifier feedback input pin. Connect this pin to an external resistive voltage divider between OUT and ground. The overvoltage regulation amplifier is responsible for controlling the gate of the external N-channel MOSFET to regulate the F B pin voltage 1.23V below OUT. In the case of sending a fast overvoltage, the overvoltage amplifier will activate a 200mA pull-down current source on the GATE pin.

[0044] 3) GATE pin: Used for the gate drive of the external N-channel MOSFET. During startup, an internal 7.5μA current source charges the gate of the external N-channel MOSFET from the V DD pin. When the OUTPUT voltage is 4.75V higher than V SS , the charge pump will complete the charging of GATE (a voltage 12V higher than OUT). In the case of a fast overvoltage, first activate a 200mA pull-down current source between GATE and OUT, and then the overvoltage regulation amplifier regulates the GATE pin voltage.

[0045] 4) OUT Pin: Power supply voltage for the charge pump and overvoltage regulation amplifier. It is the power input for the floating circuit powered from the MOSFET source. When the OUT voltage is higher than 4.75V (UVL02), the charge pump will turn on and draw power from this pin. When OUT exceeds 2.55V (UVL01), it is used as a power supply and reference input for the overvoltage regulation amplifier. This pin is clamped at 5.7V and requires a 0.22 μF or larger capacitor to bypass to V SS Pin.

[0046] 5) TIMER Pin: Timer input pin. Leave this pin open, the overvoltage regulation time is 1 μs, then fault shutdown occurs. Connect a capacitor between this pin and V SS to set an overvoltage regulation time of 278 ms / μF before the switch turns off. The LTC4366-2 version incorporates a 9s cooling cycle and restarts.

[0047] 6) V DD Pin: Startup power supply. It is the power input for the 7.5 μA startup current source (which is responsible for charging the gate of the external M-channel MOSFET). This pin is also used to power the timer and logic circuits that are operational when the external MOSFET is off. This pin is clamped at V SS +12V. Do not use a capacitor to bypass this pin.

[0048] 7) V SS Pin: Device return line and substrate. The capacitors on the TIMER and OUT pins should be connected back to this pin.

[0049] 8) SD Pin: Provides a way to turn off or enable the chip. Specifically, when the SD pin is pulled low (usually connected to ground GND), the LTC4366-2 enters the shutdown mode. In this mode, the chip consumes very little current and hardly performs any activities, thus saving power. At this time, all input and output ports are in a high-impedance state and no longer transmit data; when the SD pin is pulled high (usually connected to V CC or a logic high voltage level), the LTC4366-2 operates normally and can perform its predetermined level conversion function, enabling normal communication between devices with different voltage levels.

[0050] It should be understood that the above circuit under test 10 is only an exemplary description and does not limit the scope of this application. In other embodiments, the circuit under test 10 can be other circuits of the cabin wireless access point, that is, corresponding to other circuit structures.

[0051] Referring to the accompanying drawings below, the circuit and method for measuring the turn-off time of the wireless access point in the engine room provided by the embodiments of the present application will be introduced in detail. The following embodiments take the circuit to be measured as the above Figure 1 shown circuit 10 as an example for description. Before introducing the circuit 20 for measuring the turn-off time of the wireless access point in the engine room provided by this embodiment, first Figure 1 The connection terminals of the circuit 10 to be measured shown are defined as follows: The circuit 10 to be measured includes a transistor M1 to be measured. One end close to the drain of the transistor M1 to be measured is used as the first end of the circuit 10 to be measured, one end close to the gate of the transistor M1 to be measured is used as the second end of the circuit 10 to be measured, and one end close to the source of the transistor M1 to be measured is used as the third end of the circuit 10 to be measured.

[0052] As Figure 2 shown, the circuit 20 for measuring the turn-off time of the wireless access point in the engine room includes a switch branch 210, a detection branch 220, and a control branch 230. Next, each branch will be introduced separately.

[0053] The switch branch 210 is used to control the on / off of the circuit 20. The switch branch 210 includes a first transistor Q1 and a first drive branch. The drain (D pole) of the first transistor Q1 is used as the first end of the switch branch 210 to connect to an external power source, that is, the first end of the switch branch 210 is the input end of the circuit 20. The gate (G pole) of the first transistor Q1 is used as the second end of the switch branch 210 to connect to the control branch 230. The source (S pole) of the first transistor Q1 is used as the third end of the switch branch 210 to connect to the first end of the circuit 10 to be measured. Among them, in this embodiment, the first end of the circuit 10 to be measured is the drain (D pole) of the transistor M1.

[0054] In some embodiments, the first drive branch in the switch branch is used to receive the control signal of the control branch 230 and amplify the control signal to generate a signal that can drive the first transistor Q1 to act. As an implementation manner, the first drive branch can be implemented by using a single or multiple transistors as drive devices; as another implementation manner, the first drive branch can also be implemented by using a dedicated integrated circuit (such as an IC chip) as a drive device.

[0055] The detection branch 220 is used to detect the voltage between the gate and the source of the transistor to be tested. The detection branch 220 includes a second transistor Q2, a second drive branch, a first resistor R1, a second resistor R2, and a voltage detection branch. The drain of the second transistor Q2 serves as the first end of the detection branch 220 for connecting to the second end of the circuit 10 to be tested, where the second end of the circuit 10 to be tested is the gate (G pole) of the transistor M1. The source of the second transistor Q2 is sequentially connected to the first resistor R1 and the second resistor R2, and the end of the second resistor R2 far from the first resistor R1 is used as the second end of the detection branch 220 to connect to the third end of the circuit 10 to be tested, where the third end of the circuit 10 to be tested is the source of the transistor M1. The gate of the second transistor Q2 is connected to one end of the second drive branch, and the other end of the second drive branch serves as the third end of the detection branch 220 to connect to the control branch 230.

[0056] In some embodiments, the second drive branch in the detection branch 220 is used to receive the control signal of the control branch 230 and amplify the control signal to generate a signal that can drive the second transistor Q2 to act. Similar to the first drive branch, the second drive branch can also achieve the drive function by means of a single or multiple transistors or a dedicated integrated circuit as the drive device.

[0057] Both the first resistor R1 and the second resistor R2 are voltage-dividing resistors. Among them, the resistance values of R1 and R2 can be selected as resistors with resistance values between 1 MΩ and 10 MΩ. As an implementation method, the magnitude relationship between R1 and R2 can satisfy the following formula: R2 / R1 = 6.

[0058] The voltage detection branch is connected in parallel across the two ends of the second resistor R2, and the voltage across the two ends of the second resistor R2 is measured to characterize the voltage between the source and the gate of the transistor M1 to be tested. As an implementation method, for example, the voltage detection branch can be implemented by means of an amplification and clamping circuit as the detection voltage branch; as another implementation method, the voltage detection branch can also be implemented by means of a dedicated integrated circuit (such as an IC chip) as the detection voltage branch.

[0059] The control branch 230 at least includes a controller, such as only including an MCU. In other embodiments, the control branch may also include circuits with other structures, as long as it can send control logic to the switch branch 210 and the detection branch 220 to measure the turn-off time of the circuit to be tested.

[0060] Next, the control logic in the MCU in the control branch will be introduced in combination with the accompanying drawings, that is, the measurement method based on the above Figure 2 shown circuit 20.

[0061] As Figure 3As shown, the method for measuring the turn-off time of the cabin wireless access point provided in this embodiment includes the following steps S310 - S330, S410 - S430, and S510 - S530. Next, each step will be described in detail.

[0062] Before measurement, the following parameters need to be initialized (predetermined):

[0063] T c : The first preset duration, that is, the duration for the circuit to enter the normal working state after the circuit is turned on; in some embodiments, 1s < T c <30s. In this embodiment, it is preset to 5s.

[0064] T1: The first timing time, that is, the estimated turn-off duration of the circuit; in some embodiments, 50ms < T1 < 500s. In this embodiment, it is preset to 300ms.

[0065] V GS : The first voltage, that is, the voltage value between the gate and source of the transistor under test obtained by real-time measurement.

[0066] V GS(th) : The turn-off voltage threshold, obtained by referring to the transistor specification sheet, that is, the voltage value between the gate and source when it is regarded as turned off. This value is generally less than 3V. In this embodiment, 2V is taken as an example.

[0067] N1: The first preset calculation times threshold, N1 is an integer.

[0068] N2: The second preset calculation times threshold, N2 is an integer.

[0069] N3: The third preset calculation times threshold, N3 is an integer.

[0070] In some embodiments, N1 ≥ N2 ≥ N3. By setting this size relationship, it is possible to avoid abnormal discharge phenomena caused by frequent power-on and power-off of the transistor under test during the calculation process corresponding to N2 and the calculation process corresponding to N3, thereby affecting the measurement result. Generally, N1 is not greater than 30. In this embodiment, N1 is set to 20, N2 is set to 18, and N3 is set to 15.

[0071] T2: The second timing time, determined according to the first timing time T1 and the second preset calculation times threshold N2.

[0072] T3: The third timing time, determined according to the first timing time T1, the second preset calculation times threshold N2, and the third preset calculation times threshold N3.

[0073] Ts: Threshold value of the circuit turn-off duration; in some embodiments, Ts < 30s. It should be understood that in this embodiment, it is preset to 600ms.

[0074] In this embodiment, the product of the first preset calculation times threshold N1 and the first timing time T1 represents the total duration T used for N1 calculations. 1 , that is: N1 * T1 = T 1 , therefore, when presetting the values of N1 and T1, it is necessary to satisfy T 1 ≤ Ts, because if the total duration T 1 is greater than the circuit turn-off duration threshold, it means that the time consumed for the transistor to turn off is too long, which does not meet the requirements for turn-off. Therefore, when assigning values to N1 and T1, attention should be paid to making their product not greater than Ts.

[0075] It should be understood that the specific values of the above parameters can be changed according to actual needs. In addition, this embodiment sets three rounds of calculation processes, namely N1 to N3. If higher precision is desired, the Nth round of calculation times threshold N N can also be set, and through multiple rounds of calculations, the turn-off duration range is subdivided multiple times to obtain higher calculation precision.

[0076] S310: Control the switch branch to conduct for the first preset duration T c and then disconnect the switch branch and start timing to obtain the first timing time T1.

[0077] In some embodiments, the MCU in the control branch 230 controls the first transistor Q1 in the switch branch 210 to conduct for the first preset duration T c (5s in this embodiment), then controls the first transistor Q1 in the switch branch 210 to disconnect. At this time, timing starts and the first timing time T1 is obtained.

[0078] S320: After the first timing time T1, control the detection branch to conduct, and measure and obtain the first voltage V between the gate and source of the transistor to be measured through the detection branch GS .

[0079] In some embodiments, when the first timing time T1 = 300ms, control the second transistor Q2 in the detection branch 220 to conduct, and use the voltage detection branch in the detection branch 220 to detect and obtain the voltage across the second resistor R2, that is, obtain the voltage V between the gate and source of the transistor M1 to be measured GS and then immediately control the second transistor Q2 to disconnect.

[0080] S330: Judge the first voltage V GS and the preset turn-off voltage threshold V GS(th)The magnitude relationship therebetween, and determine the turn-off time according to the magnitude relationship.

[0081] In some embodiments, if V GS ≥V GS(th) , that is, the voltage (the first voltage) between the gate and the source of the transistor under test M1 is greater than or equal to the turn-off voltage threshold, at this time, return to step S310 to re-measure until after N1 measurements (that is, a total of T 1 duration), the first voltage V GS is still not less than the preset turn-off voltage threshold V GS(th) , at this time, it is not necessary to obtain the turn-off time of the circuit under test, and the circuit under test is determined to be unqualified and needs to be redesigned.

[0082] In some embodiments, if V GS <V GS(th) , that is, when the voltage (the first voltage) between the gate and the source of the transistor under test M1 is less than the turn-off voltage threshold: then perform the following operations:

[0083] S410: Control the switch branch to conduct for a first preset duration T c and then disconnect the switch branch, and start timing to obtain a second timing time T2.

[0084] In this embodiment, the implementation of this step can refer to step S310. At this time, the first transistor Q1 is powered on again for 5 s and then the first transistor Q1 is disconnected, and then timing is started and the second timing time T2 is obtained.

[0085] Specifically, the second timing time T2 can be determined according to the following formula:

[0086] T2 = (n1 - 1)×T1 + T1÷N2×n2

[0087] In the above formula, T1 represents the first timing time, n1 ∈ N1, n2 ∈ N2, N1 represents the first calculation times threshold, N2 represents the second calculation times threshold, n1 represents the n1th calculation, and n2 represents the n2th calculation.

[0088] S420: After the second timing time T2, control the detection branch to conduct, and measure and obtain the first voltage V between the gate and the source of the transistor under test through the detection branch GS .

[0089] In this embodiment, when the second timing time T2 satisfies the above calculation formula, control the second transistor Q2 in the detection branch 220 to conduct, and use the voltage detection branch in the detection branch 220 to detect and obtain the voltage V between the gate and the source of the transistor under test M1 GS and then immediately control the second transistor Q2 to disconnect.

[0090] S430: Determine the magnitude relationship between the first voltage V GS and a preset turn-off voltage threshold V GS(th) , and determine the turn-off time according to the magnitude relationship.

[0091] If V GS ≥V GS(th) , that is, the voltage (the first voltage) between the gate and source of the transistor M1 to be measured is greater than or equal to the turn-off voltage threshold. At this time, return to step S410 to re-measure.

[0092] It should be noted here that if the execution process of S410 - S420 is entered, then in the corresponding process of S310 - S330, there must be a situation where V GS <V GS(th) (that is, there must be a situation where the judgment in S330 is "no"). Therefore, in the execution process of up to N2 times, there must be a certain time when V GS <V GS(th) .

[0093] Therefore, when it is executed to V GS <V GS(th) , that is, the voltage (the first voltage) between the gate and source of the transistor M1 to be measured is less than the turn-off voltage threshold: the following operations are performed:

[0094] S510: Control the switch branch to conduct for a first preset duration T c , and then disconnect the switch branch and start timing to obtain a third timing time T3.

[0095] The implementation process of this step can refer to the above S310 and S410. Specifically: Re-power on the first transistor Q1 for 5s and then disconnect the first transistor Q1, and then start timing and obtain the third timing time T3.

[0096] Specifically, the third timing time T3 can be determined according to the following formula:

[0097] T3 = (n1 - 1)×T1 + (n2 - 1)×T1÷N2 + T1÷(N2×N3)×n3

[0098] In the above formula, T1 represents the first timing time, n1 ∈ N1, n2 ∈ N2, n3 ∈ N3, N1 represents the first preset calculation times threshold, N2 represents the second preset calculation times threshold, N3 represents the third preset calculation times threshold, n1 represents the n1th calculation, n2 represents the n2th calculation, and n3 represents the n3th calculation.

[0099] S520: After the third timing duration T3, control the detection branch to conduct, and measure the first voltage V between the gate and the source of the transistor under test through the detection branch GS .

[0100] In this embodiment, when the third timing duration T3 satisfies the above calculation formula, control the second transistor Q2 in the detection branch 220 to conduct, and use the voltage detection branch in the detection branch 220 to detect the voltage V between the gate and the source of the transistor under test M1 GS , and immediately control the second transistor Q2 to turn off.

[0101] S530: Determine the magnitude relationship between the first voltage V GS and the preset turn-off voltage threshold V GS(th) , and determine the turn-off time according to the magnitude relationship.

[0102] This step is similar to step S430. Since there must be a situation where V GS < V GS(th) in the process corresponding to steps S310 - S330, when S510 - S530 are executed, it is certain that it can reach V GS < V GS(th) .

[0103] If V GS ≥ V GS(th) , that is, the voltage (the first voltage) between the gate and the source of the transistor under test M1 is greater than or equal to the turn-off voltage threshold. At this time, return to step S510 to measure again.

[0104] It should be noted here that if the execution process of S510 - S530 is entered, then there must be a situation where V GS < V GS(th) in the process corresponding to S310 - S330 (that is, there must be a situation where the judgment in S330 is "no"). Therefore, during the execution process of up to N3 times, there must be a certain time when the turn-off condition V GS < V GS(th) can be reached.

[0105] Therefore, when it reaches V GS < V GS(th) , that is, the voltage (the first voltage) between the gate and the source of the transistor under test M1 is less than the turn-off voltage threshold. At this time, the circuit has been turned off. Therefore, the elapsed time at this time is the turn-off time T. Output this turn-off time T.

[0106] Among them, the turn-off time T (that is, the elapsed time) is: T = n3 * T3;

[0107] In the above formula, n3 ∈ N3, where n3 represents the n3th calculation, N3 represents the third pre-designed calculation times threshold, and T3 represents the third timing time.

[0108] It should be noted here that this embodiment adopts three rounds of calculations (i.e., N1 to N3). In other embodiments, the number of calculation rounds can be increased or decreased according to the required accuracy, and this embodiment does not limit it.

[0109] Based on the circuit and method for measuring the shutdown time of the cabin wireless access point provided by the embodiments of the present application, the shutdown time of the cabin wireless access point can be correctly measured.

[0110] Figure 4 It is a structural schematic diagram of a computing device 900 provided by the embodiments of the present application. This computing device can execute various optional embodiments of the method for measuring the shutdown time of the cabin wireless access point described above. This computing device can be a terminal, or a chip or chip system inside the terminal. As Figure 4 shown, the computing device 900 includes: a processor 910, a memory 920, and a communication interface 930.

[0111] It should be understood that Figure 4 the communication interface 930 in the computing device 900 shown can be used for communication with other devices, and specifically can include one or more transceiver circuits or interface circuits.

[0112] Among them, the processor 910 can be connected to the memory 920. The memory 920 can be used to store the program code and data. Therefore, the memory 920 can be an internal storage unit of the processor 910, or an external storage unit independent of the processor 910, or a component including an internal storage unit of the processor 910 and an external storage unit independent of the processor 910.

[0113] Optionally, the computing device 900 can further include a bus. Among them, the memory 920 and the communication interface 930 can be connected to the processor 910 through the bus. The bus can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For the sake of simplicity of representation, Figure 4 a line without an arrow is used in

[0114] It should be understood that in the embodiments of the present application, the processor 910 may adopt a central processing unit (CPU). The processor may also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc. Alternatively, the processor 910 adopts one or more integrated circuits for executing relevant programs to implement the technical solutions provided by the embodiments of the present application.

[0115] The memory 920 may include a read-only memory and a random access memory, and provide instructions and data to the processor 910. A part of the processor 910 may also include a non-volatile random access memory. For example, the processor 910 may also store information about the device type.

[0116] When the computing device 900 is running, the processor 910 executes the computer-executable instructions in the memory 920 to perform any operation step of the above method and any optional embodiment thereof.

[0117] It should be understood that the computing device 900 according to the embodiments of the present application may correspond to the corresponding subject executing the methods according to the embodiments of the present application, and the above and other operations and / or functions of each module in the computing device 900 respectively implement the corresponding processes of the methods in the present embodiments. For the sake of brevity, they will not be described in detail here.

[0118] Those of ordinary skill in the art can realize that the steps of the circuits and methods of the examples described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present application.

[0119] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the systems, devices, and units described above can refer to the corresponding processes in the foregoing method embodiments and will not be described in detail here.

[0120] When the above-mentioned functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of this application. The aforementioned storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical discs that can store program codes.

[0121] Embodiments of this application also provide a computer-readable storage medium, on which a computer program is stored. When the program is executed by a processor, it is used to execute the above method, and the method includes at least one of the solutions described in the above various embodiments.

[0122] The computer storage medium of the embodiments of this application can adopt any combination of one or more computer-readable media. The computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the above. More specific examples (non-exhaustive list) of the computer-readable storage medium include: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In this document, the computer-readable storage medium can be any tangible medium that contains or stores a program, and this program can be used by or combined with an instruction execution system, apparatus, or device.

[0123] The computer-readable signal medium can include a data signal propagated in a baseband or as part of a carrier wave, which carries the computer-readable program code. Such a propagated data signal can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The computer-readable signal medium can also be any computer-readable medium other than the computer-readable storage medium, and this computer-readable medium can send, propagate, or transmit a program for use by or in combination with an instruction execution system, apparatus, or device.

[0124] The program code contained on a computer-readable medium can be transmitted using any suitable medium, including but not limited to wireless, wire, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

[0125] The computer program code for performing the operations of this application can be written in one or more programming languages or combinations thereof. The programming languages include object-oriented programming languages such as Java, Smalltalk, C++, and also include conventional procedural programming languages such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, executed as an independent software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer can be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computer (for example, by using an Internet service provider to connect through the Internet).

[0126] "Some embodiments" or "embodiments" mentioned in this specification mean that the specific features, structures, or characteristics described in connection with the embodiment are included in at least one embodiment of this application. Thus, the phrases "in some embodiments" or "in an embodiment" that appear throughout this specification do not necessarily all refer to the same embodiment, but may refer to the same embodiment. In addition, in one or more embodiments, the various specific features, structures, or characteristics can be combined in any suitable manner, as will be apparent to those of ordinary skill in the art from this disclosure.

[0127] Note that the above is only the preferred embodiment of this application and the technical principles applied. Those skilled in the art will understand that this application is not limited to the specific embodiments described herein. Various obvious changes, re-adjustments, and substitutions can be made by those skilled in the art without departing from the protection scope of this application. Therefore, although this application has been described in more detail through the above embodiments, this application is not limited to the above embodiments. Without departing from the concept of this application, more other equivalent embodiments can also be included, all of which fall within the protection scope of this application.

Claims

1. A circuit for measuring the turn-off time of a wireless access point in an engine room, characterized in that, The circuit includes: a switch branch, a detection branch, and a control branch; The first end of the switch branch is the input end of the circuit for connecting to an external power supply, the second end of the switch branch is for connecting to the control branch, and the third end of the switch branch is for connecting to the first end of the circuit under test; wherein, the switch branch includes at least a first transistor, the first end of the switch branch is the end close to the drain of the first transistor, the second end of the switch branch is the end close to the gate of the first transistor, and the third end of the switch branch is the end close to the source of the first transistor; The first end of the detection branch is for connecting to the second end of the circuit under test, the second end of the detection branch is for connecting to the third end of the circuit under test, and the third end of the detection branch is for connecting to the control branch; wherein, the detection branch includes at least a voltage detection branch and a second transistor, the first end of the detection branch is the end close to the drain of the second transistor, the second end of the detection branch is the end close to the source of the second transistor, and the third end of the detection branch is the end close to the gate of the second transistor; The control branch includes at least a controller for sending control instructions to the switch branch and the detection branch to measure the turn-off time of the circuit under test; The circuit under test is the circuit of the cabin wireless access point; the circuit under test includes at least a transistor under test, the first end of the circuit under test is the end close to the drain of the transistor under test, the second end of the circuit under test is the end close to the gate of the transistor under test, and the third end of the circuit under test is the end close to the source of the transistor under test.

2. The circuit according to claim 1, wherein The switch branch further includes: a first drive branch; The drain of the first transistor serves as the first end of the switch branch, the source of the first transistor serves as the third end of the switch branch, the gate of the first transistor is connected to one end of the first drive branch, and the other end of the first drive branch serves as the second end of the switch branch.

3. The circuit according to claim 1, characterized in that, The detection branch further includes: a second drive branch, a first resistor, a second resistor, and the voltage detection branch; The drain of the second transistor serves as the first end of the detection branch, the gate of the second transistor is connected to one end of the second drive branch, the other end of the second drive branch serves as the third end of the detection branch, the source of the second transistor is sequentially connected to the first resistor and the second resistor, and the end of the second resistor far from the first resistor serves as the second end of the detection branch and is connected to the third end of the circuit under test; The voltage detection branch is connected in parallel across the two ends of the second resistor.

4. A method for measuring the shutdown time of the wireless access point in the engine room based on the circuit according to any one of claims 1-3, characterized in that, The method includes: S310: Control the switch branch to conduct for a first preset duration T c Then disconnect the switch branch and start timing to obtain a first timing time T1; S320: After the first timing time T1, control the conduction of the detection branch, and measure and obtain the first voltage V between the gate and the source of the transistor to be measured through the detection branch GS ; S330: Determine the magnitude relationship between the first voltage V GS and a preset turn-off voltage threshold V GS(th) , and determine the turn-off time according to the magnitude relationship; Wherein, the first timing time is a preset value.

5. The method according to claim 4, characterized in that, Determining the magnitude relationship between the first voltage V GS and a preset turn-off voltage threshold V GS(th) and determining the turn-off time according to the magnitude relationship, includes: If the first voltage V GS is not less than the preset turn-off voltage threshold V GS(th) , then return to step S310; After the determination in step S330 is performed N1 times, the first voltage V GS is still not less than the preset turn-off voltage threshold V GS(th) , then the operation is exited, and the circuit under test of the cabin wireless access point is determined to be unqualified; Among them, N1 * T1 = T 1 , let T 1 ≤ Ts; In the above formula, N1 is the first pre-designed calculation times threshold, T1 is the first timing time, T 1 is the total duration after N1 calculations, and Ts is the threshold of the circuit turn-off duration.

6. The method according to claim 5, wherein Determining the magnitude relationship between the first voltage V GS and a preset turn-off voltage threshold V GS(th) and determining the turn-off time according to the magnitude relationship, including: If the first voltage V GS is less than the preset turn-off voltage threshold V GS(th) , then perform the following operations: S410: Control the switch branch to conduct for a first preset duration T c Then disconnect the switch branch and start timing to obtain a second timing time T2; S420: After the second timing time T2, control the conduction of the detection branch, and measure and obtain a first voltage V between the gate and the source of the transistor under test through the detection branch GS ; S430: Determine the magnitude relationship between the first voltage V GS and a preset turn-off voltage threshold V GS(th) and determine the turn-off time according to the magnitude relationship; Wherein, the second timing time T2 is determined according to the first timing time T1 and the second preset calculation times threshold N2, and the first preset calculation times threshold N1 is not less than the second preset calculation times threshold N2.

7. The method according to claim 6, characterized in that, The second timing time T2 is determined according to the following formula: T2 = (n1 - 1) × T1 + T1 ÷ N2 × n2 In the above formula, T1 represents the first timing time, n1 ∈ N1, n2 ∈ N2, N1 represents the first calculation times threshold, N2 represents the second calculation times threshold, n1 represents the n1-th calculation, and n2 represents the n2-th calculation.

8. The method according to claim 6, wherein Determining the magnitude relationship between the first voltage V GS and a preset turn-off voltage threshold V GS(th) and determining the turn-off time according to the magnitude relationship, including: When the execution reaches the first voltage V GS less than the preset turn-off voltage threshold V GS(th) the following operations are performed: S510: Control the switch branch to conduct for a first preset duration T c Then disconnect the switch branch and start timing to obtain a third timing time T3; S520: After the third timing time T3, control the detection branch to conduct, and measure and obtain a first voltage V between the gate and the source of the transistor to be measured through the detection branch GS ; S530: Determine the magnitude relationship between the first voltage V GS and the preset turn-off voltage threshold V GS(th) , and determine the turn-off time according to the magnitude relationship; Among them, the third timing time T3 is determined according to the first timing time T1, the second preset calculation times threshold N2, and the third preset calculation times threshold N3, and the second preset calculation times threshold N2 is not less than the third preset calculation times threshold N3.

9. The method according to claim 8, wherein The third timing time T3 is determined according to the following formula: T3 = (n1 - 1) × T1 + (n2 - 1) × T1 ÷ N2 + T1 ÷ (N2 × N3) × n3 In the above formula, T1 represents the first timing time, n1 ∈ N1, n2 ∈ N2, n3 ∈ N3, N1 represents the first preset calculation times threshold, N2 represents the second preset calculation times threshold, N3 represents the third preset calculation times threshold, n1 represents the n1-th calculation, n2 represents the n2-th calculation, and n3 represents the n3-th calculation.

10. The method according to claim 8, characterized in that, Determining the magnitude relationship between the first voltage V GS and a preset turn-off voltage threshold V GS(th) and determining the turn-off time according to the magnitude relationship, including: When reaching the first voltage V GS less than the preset turn-off voltage threshold V GS(th) output the turn-off time T; Among them, the turn-off time T is determined according to the following formula: T = n3 * T3 In the above formula, n3 ∈ N3, n3 represents the n3-th calculation, N3 represents the third preset calculation times threshold, and T3 represents the third timing time.

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