Rapid discharging circuit and power supply circuit for gateway equipment

Abstract

The utility model relates to the technical field of electronic circuits, and provides a quick discharge circuit and a power supply circuit for gateway equipment, which comprise a power adapter, a DC-DC power module, a main control chip and a quick discharge circuit, the rapid discharge circuit comprises a follow current module, a voltage drop detection module, a discharge module and a protection circuit, the discharge module is connected into the follow current module, the discharge time of the capacitor is effectively shortened, and the capacitor voltage can be ensured to be completely dropped to be close to 0V during next power-on, so that the gateway equipment is ensured to be powered on and started from a zero-voltage state, and the safety of the gateway equipment is ensured. Correct power-on time sequence of the system is ensured, so that the system stability is improved; a voltage drop detection module is arranged to accurately detect whether the power supply voltage drops to a discharge threshold, so that accurate discharge is realized; meanwhile, a protection circuit is connected to the discharge module, so that circuit burnout caused by rear-end short circuit is avoided, and the system safety is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic circuits, and in particular to a fast discharge circuit and a power supply circuit for gateway equipment. Background Art

[0002] Figure 1 This is a common power supply diagram for gateway devices. Since gateway devices usually have optical communication modules, they must have the function of detecting power failures so that the main control SOC can send an offline notification signal to the OLT device through the optical communication module before power failure. The main control SOC implements power failure detection in the following way:

[0003] The 12V DC power adapter supplies power to the DC / DC power module through the diode D1 and the large-capacitance aluminum electrolytic capacitor C1. The DC / DC power module converts the 12V voltage into a corresponding low voltage and supplies it to the main control SOC. Due to the unidirectional conductivity of the diode D1, the current at the positive pole of the DC power adapter can only flow from the positive pole of the diode to the negative pole, and is supplied to the large-capacitance aluminum electrolytic capacitor C1 and the back-end DC / DC power module. The capacitance of capacitor C1 is usually large, generally above 1000uF. Since the main control SOC has a GPIO port (this GPIO port is also called the dying gasp pin) connected to the positive pole of the diode (or the output positive pole of the DC power adapter) through a lead, when the 12V DC power adapter is powered off, the voltage of the dying gasp pin of the main control SOC drops to 0V. At this time, the main control recognizes that the power is off and executes the instruction to send the offline notification signal.

[0004] Since the capacitance of capacitor C1 is very large, even if the DC power adapter is powered off, capacitor C1 continues to supply power to the back-end DC / DC power module to ensure that the main control SOC works for a short period of time, and the presence of diode D1 ensures that capacitor C1 can only supply power to the back-end DC / DC power module. When the capacitor releases all its charges, the entire gateway system is completely powered off, because the time for capacitor C1 to release its charges is longer than the time for the main control SOC to send an offline notification signal, thereby ensuring that the main control SOC has enough time to send an offline notification signal to the OLT device after detecting that the adapter is powered off.

[0005] However, when the DC power adapter is powered off, capacitor C1 will supply power to the back-end DC / DC power module. After the capacitor continues to discharge for a period of time, its voltage will drop to a certain voltage value. At this voltage value, the DC / DC power module stops running due to insufficient input voltage. After the DC / DC power module stops working, the capacitor C1 lacks load discharge, so the voltage of capacitor C1 remains almost unchanged or slowly decreases, which leads to a very long time required for capacitor C1 to completely discharge. When the capacitor voltage has not completely dropped to close to 0V, the main control SOC power-on timing may be incorrect when powering the gateway device. Summary of the invention

[0006] The utility model provides a fast discharge circuit and a power supply circuit for a gateway device, which solves the technical problem that the existing freewheeling capacitor takes a long time to completely discharge, cannot adapt to the fast on and off of the device input power supply, and thus has incorrect power-on timing of the main control SOC.

[0007] In order to solve the above technical problems, the utility model provides a fast discharge circuit for a gateway device, including a freewheeling module, a voltage drop detection module, a discharge module and a protection circuit, wherein the freewheeling module is connected in series to a power supply output circuit; the input end of the discharge module is connected to the freewheeling module, and the control end is electrically connected to the voltage drop detection module and the protection circuit; the input end of the voltage drop detection module is connected to the freewheeling module, and the output end is electrically connected to the discharge module and the protection circuit; one end of the protection circuit is connected to the input end of the freewheeling module, and the other end is electrically connected to the voltage drop detection module and the discharge module.

[0008] This basic solution connects a discharge module to the freewheeling module to effectively shorten the discharge time of the freewheeling capacitor, so that the capacitor voltage can be ensured to have completely dropped to close to 0V when it is powered on next time, thereby ensuring that the gateway device is powered on and started from a zero-voltage state, ensuring the correct power-on timing of the system, and effectively improving system stability; a voltage drop detection module is set to accurately detect whether the power supply voltage drops to the discharge threshold, thereby achieving precise discharge; at the same time, a protection circuit is connected to the discharge module to avoid short circuits at the back end that may cause the circuit itself to burn out, thereby improving system safety.

[0009] In a further implementation scheme, the freewheeling module includes a first diode and a first capacitor, the positive electrode of the first diode is connected to the power input terminal, and the negative electrode is connected to the positive electrode of the first capacitor; the negative electrode of the first capacitor is grounded; the negative electrode of the first diode is also electrically connected to the input terminal of the voltage drop detection module and the input terminal of the discharge module.

[0010] This solution is set to connect the first capacitor to the input end of the DC-DC power supply module, and continue to supply power to the rear-end DC / DC power supply module after power failure, so as to ensure that the main control SOC can also work for a short time after the power adapter is powered off; the first diode is set to ensure that the first capacitor can only supply power to the rear-end DC / DC power supply module to avoid current backflow.

[0011] In a further embodiment, the voltage drop detection module includes a voltage divider component and a first switch component, the first switch component includes a first switch tube, the control end of the first switch tube is connected to the voltage divider component, the first end is electrically connected to the discharge module and the protection circuit, and the second end is connected to the negative electrode of the first diode.

[0012] In a further embodiment, the voltage divider component includes a first resistor and a second resistor; one end of the first resistor is connected to the cathode of the first diode and the anode of the first capacitor, and the other end is grounded through the second resistor; the control end of the first switch tube is connected between the first resistor and the second resistor.

[0013] In this solution, resistors connected in series are arranged to form a voltage divider circuit to set a discharge voltage threshold. After the voltage of the first capacitor is lower than the discharge voltage threshold, the first switch tube is triggered to close to drive the discharge circuit to start working to provide a fast discharge path for the first capacitor, thereby accelerating the discharge speed.

[0014] In a further embodiment, the discharge module includes a second switch tube, a third switch tube and a third resistor;

[0015] The control end of the second switch tube is connected to the output end of the voltage drop detection module and the protection circuit, the first end is connected to the control end of the third switch tube, and the second end is connected to the freewheeling module;

[0016] The first end of the third switch tube is connected to the freewheeling module, and the second end is grounded;

[0017] One end of the third resistor is connected to the control end of the second switch tube, and the other end is grounded.

[0018] In this solution, a pull-down resistor (third resistor), a second switch tube, and a third switch tube are set to form a flow path for the discharge charge. The pull-down resistor is used to adjust the current of the capacitor discharge (the smaller the resistance value of the third resistor, the larger the discharge current of the capacitor C1, and the faster the discharge speed). Therefore, according to the energy storage capacity and the operating voltage, the component parameters can be flexibly selected to discharge the capacitor within the required time.

[0019] In a further embodiment, the protection circuit includes a fourth switch tube, a control end and a first end of the fourth switch tube are connected to the input end of the freewheeling module, and a second end is electrically connected to the control end of the discharge module.

[0020] In a further embodiment, the fourth switch tube is a triode or a MOS tube.

[0021] In this solution, the control end of the second switch tube is connected to the second end of the fourth switch tube, and the control end and the first end of the fourth switch tube are connected to the power input end (i.e., the input end of the freewheeling module); on the one hand, when the circuit is short-circuited and the current is too large, the fourth switch tube is turned on to raise the control end voltage of the second switch tube, so that the second switch tube and the third switch tube are cut off, which effectively prevents the discharge circuit from causing a short circuit to the power adapter when the equipment is powered on or when a short circuit is caused by an artificial back-end.

[0022] The utility model also provides a power supply circuit for a gateway device, including a power adapter, a DC-DC power module, a main control chip and a fast discharge circuit; the fast discharge circuit is the above-mentioned fast discharge circuit for a gateway device, including a freewheeling module, a voltage drop detection module, a discharge module and a protection circuit, and the freewheeling module includes a first diode and a first capacitor; the output end of the power adapter is electrically connected to the positive electrode of the first diode, the GPIO port of the main control chip and the protection circuit, and the negative electrode of the first diode is electrically connected to the voltage drop detection module and the discharge module; the input end of the DC-DC power module is connected to the voltage drop detection module and the positive electrode of the first capacitor, and the output end is electrically connected to the main control chip.

[0023] This solution uses the voltage drop detection module to determine the discharge threshold value of the voltage drop, and then forms the discharge charge flow path through the discharge module (pull-down resistor (i.e., the third resistor), the second switch tube, and the third switch tube); and a protection circuit is set between the output end of the power adapter and the discharge module to prevent the discharge circuit from causing a short circuit to the power adapter when the device is powered on or when the back end is short-circuited artificially. The circuit structure is simple, not only realizing the rapid discharge function, but also having the short-circuit protection function, improving the stability and safety of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of power supply for a gateway device in the prior art provided by an embodiment of the utility model;

[0025] Figure 2 It is a schematic diagram of a power supply circuit for a gateway device provided by an embodiment of the utility model;

[0026] Figure 3It is a hardware circuit diagram of a fast discharge circuit for a gateway device provided by an embodiment of the utility model;

[0027] Figure 4 The utility model embodiment provides Figure 1 A schematic diagram of the voltage drop process of the capacitor C1 without a discharge circuit in the prior art;

[0028] Figure 5 The utility model embodiment provides Figure 2 A schematic diagram of a voltage drop process of the first capacitor;

[0029] Among them: a first diode D1, a first capacitor C1, a first resistor R1, a second resistor R2, a third resistor R3, a first switch tube Q1, a second switch tube Q2, a third switch tube Q3, and a fourth switch tube Q4. DETAILED DESCRIPTION

[0030] The following is a detailed explanation of the implementation mode of the present invention in conjunction with the accompanying drawings. The embodiments are provided for illustrative purposes only and cannot be understood as limitations on the present invention. The accompanying drawings are provided for reference and illustration only and do not constitute limitations on the scope of patent protection of the present invention, because many changes can be made to the present invention without departing from the spirit and scope of the present invention.

[0031] Example 1

[0032] The utility model embodiment provides a fast discharge circuit for a gateway device, such as Figure 2 , Figure 3 As shown, in this embodiment, it includes a freewheeling module, a voltage drop detection module, a discharge module and a protection circuit. The freewheeling module is connected in series on the power supply output loop; the input end of the discharge module is connected to the freewheeling module, and the control end is electrically connected to the voltage drop detection module and the protection circuit; the input end of the voltage drop detection module is connected to the freewheeling module, and the output end is electrically connected to the discharge module and the protection circuit; one end of the protection circuit is connected to the input end of the freewheeling module, and the other end is electrically connected to the voltage drop detection module and the discharge module.

[0033] In this embodiment, the freewheeling module includes a first diode D1 and a first capacitor C1, the positive electrode of the first diode D1 is connected to the power input end (i.e., the output end of the power adapter), and the negative electrode is connected to the positive electrode of the first capacitor C1 (i.e., the positive electrode of the first capacitor C1 is connected between the negative electrode of the first diode D1 and the input end of the DC-DC power module); the negative electrode of the first capacitor C1 is grounded; the negative electrode of the first diode D1 is also electrically connected to the input end of the voltage drop detection module and the input end of the discharge module.

[0034] In this embodiment, a first capacitor C1 is connected to the input end of the DC-DC power supply module to continue to supply power to the rear-end DC / DC power supply module after power failure, so as to ensure that the main control SOC can work for a short time even after the power adapter is powered off; a first diode D1 is provided to ensure that the first capacitor C1 can only supply power to the rear-end DC / DC power supply module to avoid current backflow.

[0035] In this embodiment, the voltage drop detection module includes a voltage divider component and a first switch component. The first switch component includes a first switch tube Q1. The control end of the first switch tube Q1 is connected to the voltage divider component, the first end is electrically connected to the discharge module and the protection circuit, and the second end is connected to the cathode of the first diode D1.

[0036] In this embodiment, the voltage divider component includes a first resistor R1 and a second resistor R2; one end of the first resistor R1 is connected to the cathode of the first diode D1 and the anode of the first capacitor C1, and the other end is grounded through the second resistor R2; the control end of the first switch tube Q1 is connected between the first resistor R1 and the second resistor R2.

[0037] Taking the first switch tube Q1 and the second switch tube Q2 as PNP transistors and the third switch tube Q3 as NPN transistors as an example, specifically:

[0038] Set the discharge voltage threshold U gate The calculation formula is

[0039]

[0040] The calculation formula of discharge current is:

[0041]

[0042] U be-Q1 is the turn-on voltage of PNP transistor Q1, which is a negative value;

[0043] U C1 is the voltage across capacitor C1;

[0044] U be-Q2 is the turn-on voltage of PNP transistor Q2, which is a negative value;

[0045] β Q2 is the current amplification factor of the PNP transistor Q2;

[0046] β Q3 is the current amplification factor of NPN transistor Q3;

[0047] Since the voltage across the first capacitor decreases gradually during the discharge process, the discharge current of the first capacitor C1 decreases synchronously during the discharge process. gateIt can be set according to the minimum operating voltage of the back-end DC / DC power module. gate The setting is entirely based on circuit design requirements and is not limited in this embodiment.

[0048] In this embodiment, a series resistor is arranged to form a voltage divider circuit to set a discharge voltage threshold. After the voltage of the first capacitor C1 is lower than the discharge voltage threshold, the first switch tube Q1 is triggered to close to drive the discharge circuit to start working to provide a fast discharge path for the first capacitor C1, thereby accelerating the discharge speed.

[0049] In this embodiment, the discharge module includes a second switch tube Q2, a third switch tube Q3 and a third resistor R3;

[0050] The control end of the second switch tube Q2 is connected to the output end of the voltage drop detection module and the protection circuit, the first end is connected to the control end of the third switch tube Q3, and the second end is connected to the freewheeling module;

[0051] A first end of the third switch tube Q3 is connected to the freewheeling module, and a second end is grounded;

[0052] One end of the third resistor R3 is connected to the control end of the second switch tube Q2, and the other end is grounded.

[0053] In this embodiment, a pull-down resistor (third resistor R3), a second switch tube Q2, and a third switch tube Q3 are arranged to form a flow path for discharging charge. The pull-down resistor is used to adjust the current of capacitor discharge (the smaller the resistance value of the third resistor R3, the larger the discharge current of the capacitor C1, and the faster the discharge speed). Therefore, according to the energy storage capacity and the operating voltage, the component parameters can be flexibly selected to discharge the capacitor within the required time.

[0054] In this embodiment, the protection circuit includes a fourth switch tube Q4, a control end and a first end of the fourth switch tube Q4 are connected to the input end of the freewheeling module, and a second end is electrically connected to the control end of the discharge module.

[0055] In this embodiment, the first switch tube Q1 to the fourth switch tube Q4 can be selected as triodes or MOS tubes according to requirements.

[0056] In this embodiment, the control end of the second switch tube Q2 is connected to the second end of the fourth switch tube Q4, and the control end and the first end of the fourth switch tube Q4 are connected to the power input end (that is, the input end of the freewheeling module); on the one hand, when the circuit is short-circuited and the current is too large, the fourth switch tube Q4 is turned on to raise the control end voltage of the second switch tube Q2, so that the second switch tube Q2 and the third switch tube Q3 are turned off, which effectively prevents the discharge circuit from causing a short circuit to the power adapter when the device is powered on or the back end is short-circuited artificially.

[0057] In this embodiment, taking the first switch tube Q1 and the second switch tube Q2 as PNP transistors, and the third switch tube Q3 and the fourth switch tube Q4 as NPN transistors as an example, the working principle of this embodiment is as follows:

[0058] 1. Normal working status

[0059] When the gateway device is working normally, the power adapter outputs normally, the voltage at point E is 11.3V (assuming that the forward tube voltage drop of diode D1 is 0.7V), the voltage at point A is 9.72V, and the U of the first switch tube Q1 is be For U A -U E =-1.58V<-0.7V (assuming that the turn-on voltage of Q4 is -0.7V), at this time, the first switch tube Q1 is saturated and turned on.

[0060] Then, the voltage at point B is pulled up to close to point E, so the second switch tube Q2 is cut off, point C is in a high impedance state and no collector current of the second switch tube Q2 is injected into point C. Since no current is injected into the base of the third switch tube Q3, the third switch tube Q3 is also in a cut-off state.

[0061] Therefore, the discharging module does not work and does not affect the normal operation of the gateway device.

[0062] Due to the saturation conduction of the first switch tube Q1, the voltage at point B is close to point E, and the voltage at point E is lower than point D, so the voltage at point D is higher than point B, so that the fourth switch tube Q4 is turned on, which further ensures that the potential at point B is pulled high, and also ensures that the second switch tube Q2 and the third switch tube Q3 are completely in the cut-off state.

[0063] 2. Power-off and discharge state

[0064] When the power adapter is powered off, the voltage at point D changes from 12V to 0V, and the fourth switch tube Q4 switches to a cut-off state. At this time, the fourth switch tube Q4 has no effect on the circuit.

[0065] Since the first capacitor C1 supplies power to the back-end DC / DC power module, its own charge is constantly consumed, and the voltage across the first capacitor C1 is gradually decreasing. The base-emitter voltage U be When the voltage across the first capacitor C1 drops to the set discharge voltage threshold value U gate When (assuming U gate The voltage is set to be equal to the minimum operating voltage of the DC / DC power module), and at this time, the DC / DC power module at the rear end stops working, and the first capacitor C1 loses the load and consumes the charge, and the first capacitor C1 discharges slowly.

[0066] in U C1 Decreased to slightly less than Ugate When the U of the first switch tube Q1 be The voltage at point C starts to rise, and the collector current of the second switch tube Q2 is injected into the base of the third switch tube Q3, so the third switch tube Q3 is turned on. After the third switch tube Q3 is turned on, a discharge path is provided for the first capacitor C1, and the capacitor C1 is quickly discharged through the third switch tube Q3.

[0067] 3. Short circuit protection

[0068] The existence of the fourth switch tube Q4 effectively prevents the third switch tube Q3 from burning out due to a large current flowing through it for a long time when a short circuit is caused at the rear end by human intervention.

[0069] (1) When the fourth switch tube Q4 does not exist, if the gateway device is in normal operation and the back-end short circuit is caused by human or other factors, the voltage across the first capacitor C1 decreases. C1 Lower than the discharge voltage threshold U gate When the third switch tube Q3 is turned on, the DC power adapter forms a short circuit through the first diode D1 and the third switch tube Q3. Then, a large current flows through the third switch tube Q3 for a long time, causing the components to burn out.

[0070] (2) When the fourth switch tube Q4 is present, if a rear short circuit occurs, the voltage U across the first capacitor C1 is C1 Lower than the discharge voltage threshold U gate When the first switch tube Q1 is in the cut-off state, but because the potential at point D is higher than the potential at point B, the fourth switch tube Q4 is in the on state. The conduction of the fourth switch tube Q4 ensures that the potential at point B is raised to be close to or greater than the voltage at point E (the first diode D1 is a power diode, and its tube voltage drop is usually slightly greater than the on-voltage of the fourth switch tube Q4). This makes the second switch tube Q2 still in the cut-off state, and thus the third switch tube Q3 is also in the cut-off state, and the short-circuit current will not flow through the third switch tube Q3 to cause it to be burned out.

[0071] (3) At the same time, the presence of the fourth switch tube Q4 also prevents the short circuit phenomenon triggered when the gateway device is powered on from a zero voltage state. The specific implementation principle is:

[0072] When the gateway device is not powered on, the voltages at points E and B are both 0V.

[0073] When the gateway device is powered on, since the capacitance of the first capacitor C1 is very large, the voltage at point E is still at a relatively low potential at the moment of power-on, while the voltage at point D becomes higher due to the addition of the adapter, and point B maintains a relatively low potential due to the pull-down effect of the third resistor R3. The fourth switch tube Q4 is turned on to pull up the voltage at point B, so that the second switch tube Q2 and the third switch tube Q3 are both in the off state, thereby effectively preventing the short circuit caused by the conduction of the second switch tube Q2 and the third switch tube Q3 due to the excessively low voltage at point E at the moment of power-on.

[0074] In the embodiment of the utility model, a discharge module is connected to the freewheeling module, which effectively shortens the discharge time of the freewheeling capacitor, so that the capacitor voltage can be ensured to have completely dropped to close to 0V when powered on next time, thereby ensuring that the gateway device is powered on and started from a zero-voltage state, ensuring the correct power-on timing of the system, and effectively improving the stability of the system; a voltage drop detection module is provided to accurately detect whether the power supply voltage drops to the discharge threshold, thereby achieving precise discharge; at the same time, a protection circuit is connected to the discharge module to avoid the back-end short circuit causing the circuit itself to burn out, thereby improving the safety of the system.

[0075] Example 2

[0076] The utility model also provides a power supply circuit for a gateway device, including a power adapter, a DC-DC power module, a main control chip and a fast discharge circuit; the fast discharge circuit is the technical solution provided in Example 1, including a freewheeling module, a voltage drop detection module, a discharge module and a protection circuit, the freewheeling module includes a first diode D1 and a first capacitor C1; the output end of the power adapter is connected to the positive electrode of the first diode D1, the GPIO port of the main control chip (such as Figure 2 , Figure 3 The cathode of the first diode D1 is electrically connected to the voltage drop detection module and the discharge module; the input end of the DC-DC power supply module is connected to the voltage drop detection module and the positive electrode of the first capacitor C1, and the output end is electrically connected to the main control chip.

[0077] See also Figure 4 When no discharge circuit is added to the gateway device, the voltage waveform across capacitor C1 is obtained by testing when the power is off. From the measured voltage waveform, it can be seen that the time required for the voltage across capacitor C1 to drop from 11.48V to 1V is 70.8s, of which the time for the natural discharge of the capacitor after the DC / DC power module stops working accounts for the vast majority.

[0078] See also Figure 5After the gateway device is added with the discharge circuit of the present embodiment, the voltage waveform across the first capacitor C1 is obtained by testing when the power is off. From the measured voltage waveform, it can be seen that the time required for the voltage across the first capacitor C1 to drop from 11.48V to 1V is 586ms (i.e., 0.586s), which is only 0.837% of the former, greatly shortening the voltage discharge time of the first capacitor C1, confirming the feasibility of the circuit of the utility model.

[0079] This embodiment uses a voltage drop detection module to determine the discharge threshold value of the voltage drop, and then forms a discharge charge flow path through a discharge module (pull-down resistor (third resistor R3), second switch tube Q2, third switch tube Q3); and a protection circuit is set between the output end of the power adapter and the discharge module to prevent the discharge circuit from causing a short circuit to the power adapter when the device is powered on or when the back end is short-circuited artificially. The circuit structure is simple, not only realizing the rapid discharge function, but also having a short-circuit protection function, improving the stability and safety of the circuit.

[0080] The utility model can be applied not only to gateway devices, but also to set-top boxes, routers, televisions, etc. In addition, the present embodiment can be constructed with discrete components and can also be packaged into a chip through integrated circuit design, thereby further reducing the circuit space.

[0081] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principle of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A fast discharge circuit for a gateway device, characterized in that: It includes a freewheeling module, a voltage drop detection module, a discharge module and a protection circuit. The freewheeling module is connected in series on the power supply output circuit; the input end of the discharge module is connected to the freewheeling module, and the control end is electrically connected to the voltage drop detection module and the protection circuit; the input end of the voltage drop detection module is connected to the freewheeling module, and the output end is electrically connected to the discharge module and the protection circuit; one end of the protection circuit is connected to the input end of the freewheeling module, and the other end is electrically connected to the voltage drop detection module and the discharge module.

2. A fast discharge circuit for a gateway device as claimed in claim 1, characterized in that: The freewheeling module includes a first diode D1 and a first capacitor C1, wherein the positive electrode of the first diode D1 is connected to the power input terminal, and the negative electrode is connected to the positive electrode of the first capacitor C1; the negative electrode of the first capacitor C1 is grounded; the negative electrode of the first diode D1 is also electrically connected to the input terminal of the voltage drop detection module and the input terminal of the discharge module.

3. A fast discharge circuit for a gateway device as claimed in claim 2, characterized in that: The voltage drop detection module includes a voltage divider component and a first switch component. The first switch component includes a first switch tube Q1. The control end of the first switch tube Q1 is connected to the voltage divider component, the first end is electrically connected to the discharge module and the protection circuit, and the second end is connected to the cathode of the first diode D1; the voltage divider component is connected to the cathode of the first diode D1 and the anode of the first capacitor C1.

4. A fast discharge circuit for a gateway device as claimed in claim 3, characterized in that: The voltage divider component includes a first resistor R1 and a second resistor R2; one end of the first resistor R1 is connected to the cathode of the first diode D1 and the anode of the first capacitor C1, and the other end is grounded through the second resistor R2; the control end of the first switch tube Q1 is connected between the first resistor R1 and the second resistor R2.

5. A fast discharge circuit for a gateway device as claimed in claim 4, characterized in that: The discharge module includes a second switch tube Q2, a third switch tube Q3 and a third resistor R3; The control end of the second switch tube Q2 is connected to the output end of the voltage drop detection module and the protection circuit, the first end is connected to the control end of the third switch tube Q3, and the second end is connected to the freewheeling module; A first end of the third switch tube Q3 is connected to the freewheeling module, and a second end is grounded; One end of the third resistor R3 is connected to the control end of the second switch tube Q2, and the other end is grounded.

6. A fast discharge circuit for a gateway device as claimed in claim 1, characterized in that: The protection circuit includes a fourth switch tube Q4, a control end and a first end of the fourth switch tube Q4 are connected to the input end of the freewheeling module, and a second end is electrically connected to the control end of the discharge module.

7. A fast discharge circuit for a gateway device as claimed in claim 6, characterized in that: The fourth switch tube Q4 is a triode or a MOS tube.

8. A power supply circuit for a gateway device, characterized in that: It comprises a power adapter, a DC-DC power module, a main control chip and a fast discharge circuit; the fast discharge circuit is as described in any one of claims 1 to 7, comprising a freewheeling module, a voltage drop detection module, a discharge module and a protection circuit, the freewheeling module comprising a first diode D1 and a first capacitor C1; the output end of the power adapter is electrically connected to the positive electrode of the first diode D1, the GPIO port of the main control chip and the protection circuit, and the negative electrode of the first diode D1 is electrically connected to the voltage drop detection module and the discharge module; the input end of the DC-DC power module is connected to the voltage drop detection module and the positive electrode of the first capacitor C1, and the output end is electrically connected to the main control chip.

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