DTU power failure holding circuit based on super capacitor and control method

Abstract

The invention relates to a DTU power failure holding circuit based on a super capacitor and a control method, the DTU power failure holding circuit comprises a 5V system power supply and a post-stage circuit, and the 5V system power supply is connected with the input end of a switching circuit; the first output end of the switching circuit is connected with the post-stage circuit; the second output end of the switching circuit is connected with the input end of the super-capacitor circuit; the output end of the super capacitor is connected with the input end of the DC-DC booster circuit; and the output end of the DC-DC booster circuit is connected with a subsequent circuit. By integrating the super capacitor and the synchronous boost conversion circuit, an efficient and stable electric power guarantee scheme is provided, when a main power supply of DTU equipment is powered down, the system can provide required electric power through the super capacitor circuit in the shortest time, continuous operation of the equipment is ensured, necessary data storage, fault detection and alarm functions are completed, and the system is safe and reliable. Therefore, the reliability and the data security of the distribution network automation terminal are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated automation of distribution networks, and in particular to a hardware circuit for a distribution network automation terminal that can continuously operate and maintain data storage when a system power supply fails. Background Art

[0002] As a key device in the distribution network, the distribution automation terminal (DTU) is mainly responsible for real-time monitoring of line voltage, current and other operation and fault information; completing remote signaling, remote control and telemetry functions; realizing line fault detection; and having internal data management and data interaction capabilities. In addition, DTU is also compatible with a variety of communication interfaces and standard communication protocols, integrating measurement and control, protection and communication functions. With the acceleration of the intelligentization and automation of power systems, the role of DTU equipment in distribution networks has become increasingly important. However, during operation, DTU may cause power supply fluctuations or interruptions due to occasional power outages or necessary power outage inspections. If the equipment lacks a power-off retention design, it may cause historical data to be lost, which in turn affects the monitoring and control of distribution network automation. Therefore, DTU equipment needs to have a strong power guarantee capability to ensure the safe storage of data in the event of a power outage.

[0003] At present, power-off retention design has been widely used in many fields, and diversified technical solutions have emerged to meet the needs of different fields. In the field of industrial automation, the invention patent with publication number CN116382561A proposes a flexible and reliable data power-off retention method, which can effectively obtain the power-off data of the industrial control system, solving the problem of insufficient flexibility and reliability of the traditional power-off retention solution; another invention patent with publication number CN117785561A designs a power-off retention circuit for motion controllers, which improves the operating reliability of motion controllers in power-off situations. In the field of medical equipment, the invention patent with publication number CN117498528B proposes an optimized power-off data retention circuit design, which solves the problem of high transportation and manufacturing costs caused by using batteries as backup power supplies in medical equipment, and improves the economy and practicality of power-off protection of medical equipment. In the field of smart grids, the invention patent with publication number CN201336565Y integrates the power-off retention circuit into the underground low-voltage feeder switch integrated protector, which not only simplifies the external circuit design, but also improves the reliability of the microcomputer protection function. In the field of aerospace, the invention patent with publication number CN112003464A has designed a power-off holding circuit that meets the requirements of Class B DC power supply equipment under the RTCA-DO-160 standard, ensuring the stable performance of avionics equipment in the event of a power outage. In the field of automotive electronics, the invention patent with publication number CN105553079A has proposed a precise power-off control design, which effectively avoids a series of problems caused by the complexity of traditional circuit maintenance and capacitor failure.

[0004] Although the power-off holding circuit design has shown high practicality in various fields, its actual application in distribution network automation terminal equipment is relatively limited. Although some DTU devices try to combine supercapacitors with switching circuit designs, there is a high energy loss in the power conversion process, which makes it difficult for the equipment to achieve efficient and stable operation in the event of a power failure.

[0005] There is still significant room for optimization in the application of existing power-off retention design solutions in DTU equipment, and more efficient technologies are needed to meet the unique needs of distribution network automation terminals.

[0006] Therefore, how to quickly, stably and efficiently provide backup power to DTU devices when the power is disconnected has become a key issue in the power-off retention design of distribution network automation terminal equipment. Summary of the invention

[0007] In view of the deficiencies in the above-mentioned prior art, the present invention provides a DTU power-off retention circuit design based on a supercapacitor, which solves the problem in the prior art that the DTU device has a power failure or power fluctuation, ensures that the DTU device continues to operate stably in the event of a power failure, avoids the loss of historical data, and thereby improves the reliability and data security of the distribution network automation system.

[0008] The technical solution adopted by the present invention is: A DTU power-off holding circuit based on a supercapacitor comprises: a 5V system power supply and a subsequent circuit, characterized in that: the 5V system power supply is connected to an input end of a switch circuit; a first output end of the switch circuit is connected to the subsequent circuit; a second output end of the switch circuit is connected to an input end of a supercapacitor circuit; an output end of the supercapacitor is connected to an input end of a DC-DC boost circuit; and an output end of the DC-DC boost circuit is connected to a subsequent circuit.

[0009] Preferably, the switch circuit comprises a transistor Q1, a field effect transistor Q2, and resistors R1, R2, and R3; The drain of the field effect transistor Q2 is connected to the 5V system power input terminal, the source is connected to the 5V load terminal, and a resistor R3 is connected in parallel between the gate and the drain; the base of the transistor Q1 is connected to the 5V system power input terminal through the current limiting resistor R1, which serves as the control signal of the field effect transistor. The emitter is grounded, and a resistor R2 is connected in parallel between the emitter and the base to prevent leakage current from causing the transistor to leave the cut-off region and enter the erroneous conduction state. The collector is connected to the gate of the field effect transistor Q2.

[0010] Preferably, the supercapacitor circuit includes supercapacitors C1, C2, resistors R3, R4, capacitor C3 and other components; Two supercapacitors C1 and C2 are connected in series, with the negative pole grounded and the positive pole leading to two ports. One port is connected to the 5V system power supply through a current limiting resistor formed by resistors R4 and R5 in parallel, and the other port is connected to the input end of the DC-DC boost chip, and capacitor C3 is connected in parallel on this path; the negative pole of capacitor C3 is grounded.

[0011] Preferably, the DC-DC boost circuit comprises: a DC-DC boost converter U1, a transistor Q3, resistors R6, R7, R8, R9, R10, R11, capacitors C4, C5, and an inductor L1; The base of transistor Q3 is connected to the 5V system power supply through the current limiting resistor R7 as its control signal, the emitter is grounded, and the resistor R8 is connected in parallel between the emitter and the base to prevent the leakage current from causing the transistor to leave the cut-off region and enter the wrong conduction state. The resistor R9 is connected in parallel between the collector and the emitter to stabilize the current; The DC-DC boost converter adopts a typical application circuit connection method, in which the power input terminal VIN is connected to the 5V system power supply through the filter capacitor C3, and is connected to the SW pin through the inductor L1; the enable terminal EN is connected to the 5V system power supply through the current limiting resistor R6, and is connected in parallel to the collector of the transistor Q3 as its control switch; the feedback pin FB and the boost output pin VOUT are connected in parallel through the resistor R11, and the feedback pin FB is grounded through the resistor R10, and the capacitors C4 and C5 are connected in parallel between the boost output pin VOUT and the ground for filtering, and power is supplied to the subsequent circuit through the diode D1, and the reverse current is effectively prevented; the GND pin is grounded.

[0012] Preferably, the switch circuit includes components such as transistors, field effect transistors and resistors, which are used to monitor the power supply status of the power supply, switch the power supply source according to the power supply change, and prevent current backflow during the supercapacitor discharge stage; When the 5V system power supply maintains normal power supply, the switch circuit connects the power supply to the subsequent circuit, the entire system works normally, and the super capacitor is in a charging state. When the 5V system power supply is powered off, the super capacitor starts to discharge, and the field effect tube is in a cut-off state at this time, preventing current backflow, and completing the power supply switching; The supercapacitor circuit includes a supercapacitor, a resistor, and a capacitor, and is used to quickly respond to the load power demand when the 5V system power supply is powered off, and to meet the system's power demand in a short period of time by releasing the stored electric energy; The DC-DC boost circuit is composed of a DC-DC boost converter, a resistor, a capacitor and other components, and is used to boost the low voltage provided by the supercapacitor to a stable 5V output; The DC-DC boost circuit is in an idle state when the 5V system power supply is working normally, because the EN pin of the DC-DC boost converter is at a low level. When the 5V system power supply is powered off, the EN pin of the DC-DC boost converter is at a high level. At this time, the DC-DC boost circuit starts to work and boosts the low voltage provided by the supercapacitor to a stable 5V output to meet the working voltage for normal operation of the system.

[0013] A control method for a DTU power-off holding circuit based on a supercapacitor comprises the following steps: When the 5V system power supply is normally supplied, the transistor Q1 is turned on, the gate level of the field effect tube is pulled down, Q2 is completely turned on, and the 5V system power supply supplies power to the subsequent circuit. At this time, the voltage drop on Q2 is extremely small; the supercapacitors C1 and C2 are in a charging state, and the transistor Q3 belonging to the DC-DC boost conversion circuit is also in a conducting state. The enable terminal EN of the DC-DC boost chip is at a low level, causing the DC-DC boost converter to be in a shutdown state, the DC-DC boost converter stops working, and the conversion circuit is in an idle state; When the 5V system power is off, transistor Q1 and field effect transistor Q2 are both in the off state; transistor Q3 is also in the off state, so that the enable terminal (EN) of the DC-DC boost chip remains at a high level; at this time, the DC-DC boost chip starts to work, the boost conversion circuit starts and performs the boost function; in this process, the super capacitor starts to discharge to provide power support; through the DC-DC boost converter U1, the voltage is boosted to a stable 5V; providing a reliable power supply guarantee for the continuous operation of the core unit. Further, transistor Q3 controls the start and stop of the DC-DC boost converter U1, and starts the boost function when the 5V system power is disconnected; the base of transistor Q3 is connected to the 5V system power through the current limiting resistor R7 as the control signal of the DC-DC boost conversion circuit; resistor R8 is used to prevent transistor Q3 from entering the wrong conduction state due to leakage current after power failure.

[0014] The beneficial effects of the present invention compared with the prior art are as follows: The present invention provides an efficient and stable power guarantee solution by integrating supercapacitors and synchronous boost conversion circuits. When the main power supply of the DTU device fails, the system can provide the required power through the supercapacitor circuit in the shortest time, ensuring the continuous operation of the equipment and completing the necessary data storage, fault detection and alarm functions, avoiding the loss of historical data, thereby improving the reliability and data security of the distribution network automation terminal.

[0015] The present invention ensures continuous operation of the system by integrating supercapacitors and synchronous boost conversion circuits: the present invention can effectively deal with problems such as power outages and fluctuations, and provide power support for at least 2 seconds when the power is lost, ensuring that the DTU can continue to work and avoiding data loss.

[0016] The present invention integrates a supercapacitor and a synchronous boost conversion circuit to quickly respond to power changes: through the combination of a switching circuit and a supercapacitor circuit, the power path can be quickly switched when the power state changes, providing sufficient power response to ensure that the DTU continues to operate within 2 seconds of a system power failure.

[0017] The present invention integrates a supercapacitor and a synchronous boost conversion circuit to achieve efficient power conversion: the DC-DC boost circuit can efficiently boost the low voltage provided by the supercapacitor to the operating voltage required by the DTU device, ensuring stable operation of the system while reducing energy loss and improving power conversion efficiency.

[0018] The present invention enhances the reliability of the equipment by integrating a supercapacitor and a synchronous boost conversion circuit: The present invention enhances the reliability and stability of the DTU equipment in the distribution network automation system by effectively solving the impact of power failure or fluctuation, which helps to improve the operating efficiency and fault response capabilities in the fields of distribution network automation and smart grid.

[0019] The present invention is applicable to a wide range of application fields by integrating a supercapacitor and a synchronous boost conversion circuit: the present invention is not only applicable to distribution network automation terminals (DTUs), but can also be widely used in smart grids, energy management, remote monitoring and other fields, especially in equipment with high requirements for power supply and continuous data recording. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of a DTU power-off holding circuit based on a supercapacitor of the present invention; Figure 2 It is a circuit schematic diagram of a DTU power-off retention circuit based on a supercapacitor of the present invention. DETAILED DESCRIPTION

[0021] The present invention is described in detail below with reference to the accompanying drawings and embodiments: Attached Figure 1 and 2 It can be seen that a DTU power-off retention circuit based on a supercapacitor includes: a 5V system power supply and a subsequent circuit, characterized in that: the 5V system power supply is connected to the input end of the switch circuit; the first output end of the switch circuit is connected to the subsequent circuit; the second output end of the switch circuit is connected to the input end of the supercapacitor circuit; the output end of the supercapacitor is connected to the input end of the DC-DC boost circuit; and the output end of the DC-DC boost circuit is connected to the subsequent circuit.

[0022] Switching circuit, super capacitor circuit and DC-DC boost circuit; when the 5V system power is off, the integrated super capacitor and synchronous boost conversion circuit provide sufficient power guarantee to ensure that the DTU main control system maintains a certain working state and completes the data recording work before the power failure.

[0023] Preferably, the switch circuit comprises a transistor Q1, a field effect transistor Q2, and resistors R1, R2, and R3; The drain of the field effect transistor Q2 is connected to the 5V system power input terminal, the source is connected to the 5V load terminal, and a resistor R3 is connected in parallel between the gate and the drain; the base of the transistor Q1 is connected to the 5V system power input terminal through the current limiting resistor R1, which serves as the control signal of the field effect transistor. The emitter is grounded, and a resistor R2 is connected in parallel between the emitter and the base to prevent leakage current from causing the transistor to leave the cut-off region and enter the erroneous conduction state. The collector is connected to the gate of the field effect transistor Q2.

[0024] Preferably, the supercapacitor circuit includes supercapacitors C1, C2, resistors R3, R4, capacitor C3 and other components; Two supercapacitors C1 and C2 are connected in series, with the negative pole grounded and the positive pole leading to two ports. One port is connected to the 5V system power supply through a current limiting resistor formed by resistors R4 and R5 in parallel, and the other port is connected to the input end of the DC-DC boost chip, and capacitor C3 is connected in parallel on this path; the negative pole of capacitor C3 is grounded to reduce circuit impedance and improve power supply quality.

[0025] Preferably, the DC-DC boost circuit comprises: a DC-DC boost converter U1, a transistor Q3, resistors R6, R7, R8, R9, R10, R11, capacitors C4, C5, and an inductor L1; The base of transistor Q3 is connected to the 5V system power supply through the current limiting resistor R7 as its control signal, the emitter is grounded, and the resistor R8 is connected in parallel between the emitter and the base to prevent the leakage current from causing the transistor to leave the cut-off region and enter the wrong conduction state. The resistor R9 is connected in parallel between the collector and the emitter to stabilize the current; The DC-DC boost converter adopts a typical application circuit connection method, in which the power input terminal VIN is connected to the 5V system power supply through the filter capacitor C3, and is connected to the SW pin through the inductor L1; the enable terminal EN is connected to the 5V system power supply through the current limiting resistor R6, and is connected in parallel to the collector of the transistor Q3 as its control switch; the feedback pin FB and the boost output pin VOUT are connected in parallel through the resistor R11, and the feedback pin FB is grounded through the resistor R10, and the capacitors C4 and C5 are connected in parallel between the boost output pin VOUT and the ground for filtering, and power is supplied to the subsequent circuit through the diode D1, and the reverse current is effectively prevented; the GND pin is grounded.

[0026] Preferably, the switch circuit includes components such as transistors, field effect transistors and resistors, which are used to monitor the power supply status of the power supply, switch the power supply source according to the power supply change, and prevent current backflow during the supercapacitor discharge stage; When the 5V system power supply maintains normal power supply, the switch circuit connects the power supply to the subsequent circuit, the entire system works normally, and the super capacitor is in a charging state. When the 5V system power supply is powered off, the super capacitor starts to discharge, and the field effect tube is in a cut-off state at this time, preventing current backflow, and completing the power supply switching; The supercapacitor circuit includes a supercapacitor, a resistor, and a capacitor, and is used to quickly respond to the load power demand when the 5V system power supply is powered off, and to meet the system's power demand in a short period of time by releasing the stored electric energy; The DC-DC boost circuit is composed of a DC-DC boost converter, a resistor, a capacitor and other components, and is used to boost the low voltage provided by the supercapacitor to a stable 5V output; The DC-DC boost circuit is in an idle state when the 5V system power supply is working normally, because the EN pin of the DC-DC boost converter is at a low level. When the 5V system power supply is powered off, the EN pin of the DC-DC boost converter is at a high level. At this time, the DC-DC boost circuit starts to work and boosts the low voltage provided by the supercapacitor to a stable 5V output to meet the working voltage for normal operation of the system.

[0027] The circuit can ensure that the DTU core unit is provided with power support for more than 2 seconds after the 5V system power is disconnected, meeting the time requirement for the DTU core unit to write historical data.

[0028] The circuit completes automatic switching after the 5V system power is restored, and recharges the super capacitor to provide backup power when the 5V system power is lost next time.

[0029] The circuit is suitable for distribution network automation, smart grid, energy management and remote monitoring, and is particularly suitable for power monitoring equipment such as distribution network automation terminal (DTU).

[0030] A control method for a DTU power-off holding circuit based on a supercapacitor comprises the following steps: When the 5V system power supply is normally supplied, the transistor Q1 is turned on, the gate level of the field effect tube is pulled down, Q2 is completely turned on, and the 5V system power supply supplies power to the subsequent circuit. At this time, the voltage drop on Q2 is extremely small; the supercapacitors C1 and C2 are in a charging state, and the transistor Q3 belonging to the DC-DC boost conversion circuit is also in a conducting state. The enable terminal EN of the DC-DC boost chip is at a low level, causing the DC-DC boost converter to be in a shutdown state, the DC-DC boost converter stops working, and the conversion circuit is in an idle state; When the 5V system power is off, transistor Q1 and field effect transistor Q2 are both in the off state; transistor Q3 is also in the off state, so that the enable terminal (EN) of the DC-DC boost chip remains at a high level; at this time, the DC-DC boost chip starts to work, the boost conversion circuit starts and performs the boost function; in this process, the super capacitor starts to discharge to provide power support; through the DC-DC boost converter U1, the voltage is boosted to a stable 5V; providing a reliable power supply guarantee for the continuous operation of the core unit. Further, transistor Q3 controls the start and stop of the DC-DC boost converter U1, and starts the boost function when the 5V system power is disconnected; the base of transistor Q3 is connected to the 5V system power through the current limiting resistor R7 as the control signal of the DC-DC boost conversion circuit; resistor R8 is used to prevent transistor Q3 from entering the wrong conduction state due to leakage current after power failure.

[0031] The present invention provides an efficient and stable power guarantee solution by integrating supercapacitors and synchronous boost conversion circuits. When the main power supply of the DTU device fails, the system can provide the required power through the supercapacitor circuit in the shortest time, ensuring the continuous operation of the equipment and completing the necessary data storage, fault detection and alarm functions, avoiding the loss of historical data, thereby improving the reliability and data security of the distribution network automation terminal.

[0032] The present invention ensures continuous operation of the system by integrating supercapacitors and synchronous boost conversion circuits: the present invention can effectively deal with problems such as power outages and fluctuations, and provide power support for at least 2 seconds when the power is lost, ensuring that the DTU can continue to work and avoiding data loss.

[0033] The present invention integrates a supercapacitor and a synchronous boost conversion circuit to quickly respond to power changes: through the combination of a switching circuit and a supercapacitor circuit, the power path can be quickly switched when the power state changes, providing sufficient power response to ensure that the DTU continues to operate within 2 seconds of a system power failure.

[0034] The present invention integrates a supercapacitor and a synchronous boost conversion circuit to achieve efficient power conversion: the DC-DC boost circuit can efficiently boost the low voltage provided by the supercapacitor to the operating voltage required by the DTU device, ensuring stable operation of the system while reducing energy loss and improving power conversion efficiency.

[0035] The present invention enhances the reliability of the equipment by integrating a supercapacitor and a synchronous boost conversion circuit: The present invention enhances the reliability and stability of the DTU equipment in the distribution network automation system by effectively solving the impact of power failure or fluctuation, which helps to improve the operating efficiency and fault response capabilities in the fields of distribution network automation and smart grid.

[0036] The present invention is applicable to a wide range of application fields by integrating a supercapacitor and a synchronous boost conversion circuit: the present invention is not only applicable to distribution network automation terminals (DTUs), but can also be widely used in smart grids, energy management, remote monitoring and other fields, especially in equipment with high requirements for power supply and continuous data recording.

[0037] The present invention relates to a circuit design based on power-off retention of distribution network automation terminal (DTU). The circuit is designed to provide at least 2 seconds of power support for the DTU core unit when the main power supply is disconnected or fluctuates, to ensure its normal operation and complete the necessary data storage. The invention combines a switch circuit, a supercapacitor circuit and a DC-DC boost conversion circuit to achieve efficient and stable power-off retention capability. The description and specific implementation of each component are as follows.

[0038] Reference Figure 2 When the 5V system power supply is normally supplied, the transistor Q1 is turned on, the gate level of the field effect tube is pulled down, Q2 is completely turned on, and the 5V system power supply supplies power to the subsequent circuit, and the voltage drop on Q2 is extremely small at this time; the supercapacitors C1 and C2 are in a charging state, and because the transistor Q3 belonging to the DC-DC boost conversion circuit is also in a conducting state, the enable terminal EN of the DC-DC boost chip is in a low level, causing the DC-DC boost converter to be in a shutdown state, the DC-DC boost converter stops working, and the conversion circuit is in an idle state.

[0039] Furthermore, in order to reduce the voltage drop on the field effect transistor Q2 and reduce power loss, the gate of Q2 is controlled by the transistor Q1 to ensure a rapid switching process while reducing the voltage drop.

[0040] Furthermore, the resistor R2 is used to prevent Q1 from entering an erroneous conduction state due to leakage current after power failure.

[0041] Furthermore, when the 5V system power supply is normally supplied, the parallel design of the current limiting resistors R4 and R5 controls the charging current to prevent overcurrent from damaging the supercapacitor.

[0042] Furthermore, supercapacitors C1 and C2 are connected in series to provide a higher operating voltage range, ensuring rapid release of energy during discharge.

[0043] Furthermore, the filter capacitor C3 is used to stabilize the voltage and reduce the impact of voltage fluctuations on the subsequent circuit.

[0044] Exemplarily, the transistor Q1 is S9013-E or a similar component; the field effect transistor Q2 is IRF7416TRPBF or an equivalent model; the resistance values ​​of the resistors R1 and R2 are 1 kΩ and 10 kΩ.

[0045] Exemplarily, the capacity of supercapacitors C1 and C2 is 10F / 2.7V; the resistance of current limiting resistors R3 and R4 is 10Ω; and the capacity of filter capacitor C3 is 10µF.

[0046] For example, the boost chip U1 uses TPS61023DRLT or similar models; the inductor L1 is 1µH; the filter capacitors C4 and C5 have a capacity of 22µF / 16V; the protection diode D1 is SS34-SMB, the transistor uses S9013-E or similar components, and R7, R8, R9, R10, and R11 are 1K, 10K, 6.8K, 787K, and 100K respectively.

[0047] Reference Figure 2 , when the 5V system power is off, both transistor Q1 and field effect transistor Q2 are in the cut-off state. Due to the cut-off of field effect transistor Q2, the current backflow is effectively prevented, protecting the circuit safety. At the same time, transistor Q3 is also in the cut-off state, so that the enable terminal (EN) of the DC-DC boost chip remains at a high level. At this time, the DC-DC boost chip starts to work, and the boost conversion circuit starts and performs the boost function. In this process, the supercapacitor starts to discharge and provide power support. Through U1, the voltage is boosted to a stable 5V, providing a reliable power supply guarantee for the continuous operation of the core unit. Furthermore, Q3 controls the start and stop of U1, and starts the boost function when the 5V system power is disconnected.

[0048] Furthermore, the base of the transistor Q3 is connected to a 5V system power supply via a current limiting resistor R7 as a control signal of the DC-DC boost converter circuit.

[0049] Furthermore, the resistor R8 is used to prevent Q3 from entering an erroneous conduction state due to leakage current after power failure.

[0050] Furthermore, the diode D1 is used to prevent the current from flowing in the opposite direction and protect the circuit; It can be seen from the above technical solutions that the design of the present invention is applicable to the following scenarios: 1. Power-off protection and data storage of distribution network automation terminal (DTU).

[0051] 2. Power supply guarantee for smart grid, energy management and remote monitoring equipment.

[0052] 3. Other electronic devices that need to maintain short-term operation in the event of a power outage, such as industrial controllers, communication equipment, etc.

[0053] Through the implementation of the present invention, the reliability and data security of the distribution network automation terminal in the event of a power outage can be effectively improved, providing a guarantee for the stable operation of the smart grid.

[0054] The above is only a preferred embodiment of the present invention, and does not limit the structure of the present invention in any form. Any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention are within the scope of the technical solution of the present invention.

Claims

1. A DTU power-off retention circuit based on supercapacitor, comprising: A 5V system power supply and a subsequent circuit, characterized in that: the 5V system power supply is connected to the input end of the switch circuit; the first output end of the switch circuit is connected to the subsequent circuit; the second output end of the switch circuit is connected to the input end of the supercapacitor circuit; the output end of the supercapacitor is connected to the input end of the DC-DC boost circuit; and the output end of the DC-DC boost circuit is connected to the subsequent circuit.

2. According to the supercapacitor-based DTU power-off retention circuit of claim 1, it is characterized in that: The switch circuit includes a transistor Q1, a field effect transistor Q2, and resistors R1, R2, and R3; The drain of the field effect tube Q2 is connected to the 5V system power input terminal, the source is connected to the 5V load terminal, and a resistor R3 is connected in parallel between the gate and the drain; the base of the transistor Q1 is connected to the 5V system power input terminal through a current limiting resistor R1 as a control signal of the field effect tube, the emitter is grounded, and a resistor R2 is connected in parallel between the emitter and the base.

3. The DTU power-off retention circuit based on supercapacitor according to claim 1 is characterized in that: The supercapacitor circuit comprises supercapacitors C1 and C2, resistors R3 and R4, and capacitor C3; Two supercapacitors C1 and C2 are connected in series, with the negative pole grounded and the positive pole leading to two ports. One port is connected to the 5V system power supply through a current limiting resistor formed by resistors R4 and R5 in parallel, and the other port is connected to the input end of the DC-DC boost chip, and capacitor C3 is connected in parallel on this path; the negative pole of capacitor C3 is grounded.

4. The DTU power-off retention circuit based on supercapacitor according to claim 1 is characterized in that: The DC-DC boost circuit includes: a DC-DC boost converter U1, a transistor Q3, resistors R6, R7, R8, R9, R10, R11, capacitors C4, C5, and an inductor L1; The base of transistor Q3 is connected to the 5V system power supply through the current limiting resistor R7 as its control signal, the emitter is grounded, the resistor R8 is connected in parallel between the emitter and the base, and the resistor R9 is connected in parallel between the collector and the emitter; The power input terminal VIN of the DC-DC boost converter is connected to the 5V system power supply through the filter capacitor C3, and is connected to the SW pin through the inductor L1; the enable terminal EN is connected to the 5V system power supply through the current limiting resistor R6, and is connected in parallel to the collector of the transistor Q3 as its control switch; the feedback pin FB and the boost output pin VOUT are connected in parallel through the resistor R11, and the feedback pin FB is grounded through the resistor R10, and the capacitors C4 and C5 are connected in parallel between the boost output pin VOUT and the ground for filtering, and power is supplied to the subsequent circuit through the diode D1, and the reverse current is effectively prevented; the GND pin is grounded.

5. The DTU power-off retention circuit based on supercapacitor according to claim 1 is characterized in that: The switch circuit includes a transistor, a field effect transistor and a resistor, which are used to monitor the power supply status of the power supply, switch the power supply source according to the power supply change, and prevent current backflow during the supercapacitor discharge stage; When the 5V system power supply is maintained normally, the switch circuit connects the power supply to the subsequent circuit, the entire system works normally, and the supercapacitor is in a charging state. When the 5V system power supply is powered off, the supercapacitor starts to discharge, and the field effect tube is in a cut-off state, completing the power supply switching; The supercapacitor circuit includes supercapacitors, resistors, and capacitors, which are used to quickly respond to the load power demand when the 5V system power supply is powered off, and to meet the system's power demand in a short period of time by releasing the stored electrical energy; The DC-DC boost circuit consists of a DC-DC boost converter, resistors, and capacitors, and is used to boost the low voltage provided by the supercapacitor to a stable 5V output; DC-DC boost circuit, when the 5V system power supply is working normally, the EN pin of the DC-DC boost converter is at a low level, and the DC-DC boost circuit is in an idle state. When the 5V system power supply is powered off, the EN pin of the DC-DC boost converter is at a high level, and the DC-DC boost circuit starts working, boosting the low voltage provided by the supercapacitor to a stable 5V output.

6. The control method of the DTU power-off holding circuit based on supercapacitor according to claims 1 to 4 is characterized in that: The steps include: When the 5V system power supply is normally supplied, the transistor Q1 is turned on, the gate level of the field effect tube is pulled down, Q2 is completely turned on, and the 5V system power supply supplies power to the subsequent circuit. At this time, the voltage drop on the field effect tube Q2 is extremely small; the supercapacitors C1 and C2 are in a charging state, and the transistor Q3 belonging to the DC-DC boost conversion circuit is also in a conducting state. The enable terminal EN of the DC-DC boost chip is at a low level, the DC-DC boost converter is in a shut-off state, the DC-DC boost converter stops working, and the conversion circuit is in an idle state; When the 5V system power is off, transistor Q1 and field effect transistor Q2 are both in the cut-off state; transistor Q3 is also in the cut-off state, so that the enable end of the DC-DC boost chip remains at a high level; the DC-DC boost chip starts to work, and the boost conversion circuit starts and performs the boost function; in this process, the supercapacitor starts to discharge to provide power support; through the DC-DC boost converter U1, the voltage is boosted to a stable 5V; transistor Q3 controls the start and stop of the DC-DC boost converter U1, and when the 5V system power is disconnected, the boost function is started; the base of transistor Q3 is connected to the 5V system power through the current limiting resistor R7 as the control signal of the DC-DC boost conversion circuit; resistor R8 is used to prevent transistor Q3 from entering the erroneous conduction state due to leakage current after power failure.

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