Micro energy collection boost charging circuit based on periodic sampling MPPT

Abstract

The application discloses a micro-energy collection voltage-boosting charging circuit based on period sampling MPPT, which comprises an energy collection circuit, wherein the energy collection circuit comprises a front end energy taking and control module, a piezoelectric energy taking module, a DCDC voltage reduction module, an energy storage and output management module and an external load system, one end of the piezoelectric energy taking module is connected with one end of the front end energy taking and control module, the other end of the front end energy taking and control module is connected with one end of the DCDC voltage reduction module, and the other end of the DCDC voltage reduction module is connected with one end of the energy storage and output management module, the period oscillator 555 timer is arranged to generate a period clock CLK_MPP, and the working mode of the period timer interrupt sampling and non-sampling period sleep power-off is used to completely solve the problem of high sampling power consumption of the traditional MPPT circuit, the overall static power consumption of the circuit is greatly reduced and is far lower than the micro-energy collection power, the weak environmental energy is effectively stored, and the energy collection efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of electronic engineering technology, specifically to a micro-energy harvesting boost charging circuit based on periodic sampling MPPT. Background Technology

[0002] With the rapid development of passive Internet of Things, smart sensors, wearable devices and micro smart home terminals, the demand for self-powered and passive power supply for micro electronic devices is increasing. Weak distributed energy sources such as photovoltaic micro energy, temperature difference micro energy, and mechanical vibration micro energy are widely present in the environment. These types of energy have the characteristics of low output voltage, small power, unstable output, and strong random fluctuation, making them ideal power sources for micro passive devices.

[0003] However, traditional energy harvesting has the following drawbacks: Traditional energy harvesting circuits for micro-energy harvesting abandon MPPT tracking function and directly perform boost charging, which greatly wastes the limited environmental micro-energy. Some circuits that use conventional MPPT algorithms have excessively high static power consumption due to continuous sampling and continuous calculation, making them completely unsuitable for micro-energy scenarios. Summary of the Invention

[0004] The purpose of this invention is to provide a micro-energy harvesting boost charging circuit based on periodic sampling MPPT, in order to solve the problems mentioned in the background art, where traditional energy harvesting circuits abandon MPPT tracking function and directly perform boost charging, resulting in a great waste of limited environmental micro-energy; and circuits that use conventional MPPT algorithms have excessively high static power consumption due to continuous sampling and continuous calculation, making them completely unsuitable for micro-energy scenarios.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a micro-energy harvesting boost charging circuit based on periodic sampling MPPT, comprising an energy harvesting circuit, The energy harvesting circuit includes a front-end energy harvesting and control module, a piezoelectric energy harvesting module, a DC-DC step-down module, an energy storage and output management module, and an external load system. One end of the piezoelectric energy harvesting module is connected to one end of the front-end energy harvesting and control module, and the other end of the front-end energy harvesting and control module is connected to one end of the DC-DC step-down module. The other end of the DC-DC step-down module is connected to one end of the energy storage and output management module, and the other end of the energy storage and output management module is connected to one end of the external load system. The front-end energy harvesting and control module includes a rectification and front-end energy storage module, a cold start circuit, and a control power supply module. The control power supply module includes a periodic signal generation module, a sampling window generation module, an MPPT sampling module, a sample-and-hold and MPPT judgment module, and an output switch control module. The energy storage and output management module includes a supercapacitor battery and a voltage detection module. The rectifier and front-end energy storage module includes an interface J1, a rectifier bridge DB1, a diode D5, a capacitor C1, and a diode D2. The cold start circuit includes resistors R8, R9, and R12, capacitor C3, transistor U10, transistor U7, and capacitor C2. The periodic signal generation module includes an integrated circuit U8, capacitors C4 and C6, resistors R10, R13, and R14, and capacitor C7. The sampling window generation module includes integrated circuit U9, capacitor C5, resistor R11 and capacitor C8; The MPPT sampling module includes resistor R20, resistor R18, transistor U14, transistor U11, and resistor R17. The sample-and-hold and MPPT determination module includes resistor R15, resistor R16, transistor U12, capacitor C9, resistor R19, resistor R21, transistor U13, and resistor R22. The output switch control module includes resistor R1, resistor R2, transistor U1, transistor U4, transistor U6, and transistor U5; The DC-DC step-down module includes an integrated circuit U2, an inductor L1, a diode D1, a resistor R5, and a resistor R7; The supercapacitor battery contains a battery BAT1, one end of which is grounded. The voltage detection module includes resistors R4, R6, and R3, and transistor U3.

[0006] As a further technical solution of the present invention, pin 1 and pin 2 of interface J1 are both connected to one end of rectifier bridge DB1, the other end of rectifier bridge DB1 is connected to one end of diode D5, one end of capacitor C1 and one end of diode D2, and the other end of diode D5, the other end of capacitor C1 and the grounding pin of rectifier bridge DB1 are all grounded.

[0007] As a further technical solution of the present invention, the drain of transistor U10 is connected to one end of resistor R8 and the gate of transistor U7, the drain of transistor U7 is connected to one end of capacitor C3 and one end of capacitor C2, the gate of transistor U10 is connected to one end of resistor R12 and one end of resistor R9, the other end of resistor R12, the source of transistor U10, the other end of capacitor C3 and the other end of capacitor C2 are all grounded, and the other ends of resistor R8 and resistor R9 are both connected to the source of transistor U7.

[0008] As a further technical solution of the present invention, pin 7 of the integrated circuit U8 is connected to one end of resistor R13 and one end of resistor R14; pin 2 and pin 6 of the integrated circuit U8 and the other end of resistor R14 are all connected to one end of capacitor C7; pin 5 of the integrated circuit U8 is connected to one end of capacitor C4; pin 3 of the integrated circuit U8 is connected to one end of capacitor C6; pin 4 of the integrated circuit U8 is connected to one end of resistor R10; and pin 1 of the integrated circuit U8, the other end of capacitor C7, and the other end of capacitor C4 are all grounded.

[0009] As a further technical solution of the present invention, pins 8 and 4 of the integrated circuit U9 are both connected to one end of resistor R11, pin 5 of the integrated circuit U9 is connected to one end of capacitor C5, pins 7 and 6 of the integrated circuit U9 and the other end of resistor R11 are all connected to one end of capacitor C8, and the other end of capacitor C8, pin 1 of integrated circuit U9 and the other end of capacitor C5 are all grounded.

[0010] As a further technical solution of the present invention, the source of transistor U11 is connected to one end of resistor R17, the other end of resistor R17 and the gate of transistor U11 are both connected to the drain of transistor U14, the gate of transistor U14 is connected to one end of resistor R18 and one end of resistor R20, and the source of transistor U14 and the other end of resistor R20 are both grounded.

[0011] As a further technical solution of the present invention, the drain of transistor U12 is connected to one end of resistor R15 and one end of resistor R16, the source of transistor U12 is connected to one end of capacitor C9 and the source of transistor U13, the gate of transistor U13 is connected to one end of resistor R19 and one end of resistor R21, the drain of transistor U13 is connected to one end of resistor R22, and the other ends of resistor R16, capacitor C9, resistor R21 and resistor R22 are all grounded.

[0012] As a further technical solution of the present invention, the drain of transistor U5 and the drain of transistor U6 are both connected to one end of resistor R1 and the gate of transistor U4, the drain of transistor U4 is connected to one end of resistor R2 and the gate of transistor U1, and the source of transistor U5, the source of transistor U6 and the source of transistor U4 are all grounded.

[0013] As a further technical solution of the present invention, pin 4 of the integrated circuit U2 is connected to one end of the inductor L1, the other end of the inductor L1 is connected to one end of the resistor R5, the other end of the resistor R5 is connected to pin 2 of the integrated circuit U2 and one end of the resistor R7, pin 5 of the integrated circuit U2 is connected to one end of the diode D1, and pin 3 of the integrated circuit U2 and the other end of the resistor R7 are both grounded.

[0014] As a further technical solution of the present invention, the gate of the transistor U3 is connected to one end of the resistor R4 and one end of the resistor R6, the drain of the transistor U3 is connected to one end of the resistor R3, and the source of the transistor U3 and the other end of the resistor R6 are both grounded.

[0015] Compared with the prior art, the beneficial effects of the present invention are: By setting a 555 timer to generate the periodic clock CLK_MPP, and by using a timed sampling and sleep-off mode during non-sampling periods, the problem of excessive power consumption in traditional MPPT circuits is completely solved. The overall static power consumption of the circuit is greatly reduced, far below the power of micro-energy harvesting, ensuring that energy in weak environments is effectively stored and improving energy harvesting efficiency. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the architecture of the present invention; Figure 2 This is a circuit diagram of the present invention; Figure 3 This is a circuit diagram of the rectifier and front-end energy storage module of the present invention; Figure 4 This is a circuit diagram of the cold start circuit of the present invention; Figure 5 This is a circuit diagram of the periodic signal generation module of the present invention; Figure 6 This is a circuit diagram of the sampling window generation module of the present invention; Figure 7 This is a circuit diagram of the MPPT sampling module of the present invention; Figure 8 This is a circuit diagram of the sample-and-hold and MPPT determination module of the present invention; Figure 9 This is a circuit diagram of the output switch control module of the present invention; Figure 10 This is a circuit diagram of the DC-DC step-down module of the present invention; Figure 11 This is a circuit diagram of the supercapacitor battery of the present invention; Figure 12 This is a circuit diagram of the voltage detection module of the present invention. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0018] Please see Figure 1-12 This invention provides a micro-energy harvesting boost charging circuit based on periodic sampling MPPT, including an energy harvesting circuit. The energy harvesting circuit includes a front-end energy harvesting and control module, a piezoelectric energy harvesting module, a DC-DC step-down module, an energy storage and output management module, and an external load system. One end of the piezoelectric energy harvesting module is connected to one end of the front-end energy harvesting and control module, the other end of the front-end energy harvesting and control module is connected to one end of the DC-DC step-down module, the other end of the DC-DC step-down module is connected to one end of the energy storage and output management module, and the other end of the energy storage and output management module is connected to one end of the external load system. The front-end energy harvesting and control module contains a rectification and front-end energy storage module, a cold start circuit, and a control power supply module. The control power supply module contains a periodic signal generation module, a sampling window generation module, an MPPT sampling module, a sample-and-hold and MPPT judgment module, and an output switch control module. The energy storage and output management module contains a supercapacitor battery and a voltage detection module. The rectifier and front-end energy storage module includes an interface J1, a rectifier bridge DB1, a diode D5, a capacitor C1, and a diode D2. The cold start circuit includes resistors R8, R9, and R12, capacitor C3, transistor U10, transistor U7, and capacitor C2. The periodic signal generation module includes integrated circuit U8, capacitor C4, capacitor C6, resistor R10, resistor R13, resistor R14 and capacitor C7; The sampling window generation module includes integrated circuit U9, capacitor C5, resistor R11, and capacitor C8; The MPPT sampling module contains resistor R20, resistor R18, transistor U14, transistor U11, and resistor R17. The sample-and-hold and MPPT determination module includes resistor R15, resistor R16, transistor U12, capacitor C9, resistor R19, resistor R21, transistor U13, and resistor R22; The output switch control module includes resistor R1, resistor R2, transistor U1, transistor U4, transistor U6, and transistor U5; The DC-DC step-down module includes integrated circuit U2, inductor L1, diode D1, resistor R5, and resistor R7; The supercapacitor contains a battery BAT1, one end of which is grounded. The voltage detection module includes resistors R4, R6, and R3, and transistor U3.

[0019] Pin 1 and pin 2 of interface J1 are both connected to one end of rectifier bridge DB1. The other end of rectifier bridge DB1 is connected to one end of diode D5, one end of capacitor C1 and one end of diode D2. The other end of diode D5, the other end of capacitor C1 and the grounding pin of rectifier bridge DB1 are all grounded.

[0020] The drain of transistor U10 is connected to one end of resistor R8 and the gate of transistor U7. The drain of transistor U7 is connected to one end of capacitor C3 and one end of capacitor C2. The gate of transistor U10 is connected to one end of resistor R12 and one end of resistor R9. The other end of resistor R12, the source of transistor U10, the other end of capacitor C3, and the other end of capacitor C2 are all grounded. The other ends of resistor R8 and resistor R9 are both connected to the source of transistor U7.

[0021] Pin 7 of integrated circuit U8 is connected to one end of resistor R13 and one end of resistor R14. Pin 2 and pin 6 of integrated circuit U8 and the other end of resistor R14 are all connected to one end of capacitor C7. Pin 5 of integrated circuit U8 is connected to one end of capacitor C4. Pin 3 of integrated circuit U8 is connected to one end of capacitor C6. Pin 4 of integrated circuit U8 is connected to one end of resistor R10. Pin 1 of integrated circuit U8, the other end of capacitor C7, and the other end of capacitor C4 are all grounded.

[0022] Pins 8 and 4 of integrated circuit U9 are connected to one end of resistor R11. Pin 5 of integrated circuit U9 is connected to one end of capacitor C5. Pins 7 and 6 of integrated circuit U9 and the other end of resistor R11 are connected to one end of capacitor C8. The other end of capacitor C8, pin 1 of integrated circuit U9, and the other end of capacitor C5 are all grounded.

[0023] The source of transistor U11 is connected to one end of resistor R17. The other end of resistor R17 and the gate of transistor U11 are both connected to the drain of transistor U14. The gate of transistor U14 is connected to one end of resistor R18 and one end of resistor R20. The source of transistor U14 and the other end of resistor R20 are both grounded.

[0024] The drain of transistor U12 is connected to one end of resistor R15 and one end of resistor R16. The source of transistor U12 is connected to one end of capacitor C9 and the source of transistor U13. The gate of transistor U13 is connected to one end of resistor R19 and one end of resistor R21. The drain of transistor U13 is connected to one end of resistor R22. The other ends of resistor R16, capacitor C9, resistor R21, and resistor R22 are all grounded.

[0025] The drains of transistors U5 and U6 are connected to one end of resistor R1 and the gate of transistor U4. The drain of transistor U4 is connected to one end of resistor R2 and the gate of transistor U1. The sources of transistors U5, U6, and U4 are all grounded.

[0026] Pin 4 of integrated circuit U2 is connected to one end of inductor L1, the other end of inductor L1 is connected to one end of resistor R5, the other end of resistor R5 is connected to pin 2 of integrated circuit U2 and one end of resistor R7, pin 5 of integrated circuit U2 is connected to one end of diode D1, and pin 3 of integrated circuit U2 and the other end of resistor R7 are both grounded.

[0027] The gate of transistor U3 is connected to one end of resistor R4 and one end of resistor R6, the drain of transistor U3 is connected to one end of resistor R3, and the source of transistor U3 and the other end of resistor R6 are both grounded.

[0028] In this invention, the input terminal of the circuit is used to connect to an external energy harvesting device, such as a piezoelectric element, a thermoelectric generator, or a small photovoltaic panel. Since the output of these energy harvesting devices is usually unstable, including AC pulses, low-voltage DC, or voltages that vary with the environment, the input signal first enters the rectification and front-end energy storage section. The rectifier bridge DB1 converts the AC or pulse input into a DC input voltage VIN_RECT. The input capacitor CIN temporarily stores the energy provided by the energy harvesting device at the front end, so that the subsequent circuit does not directly extract energy instantaneously from the high-impedance energy harvesting device, but intermittently extracts energy from the input capacitor. At the same time, a TVS diode is set at the input terminal to limit the high open-circuit voltage generated by the piezoelectric element, and a discharge resistor is used to release the residual charge at the input terminal to prevent the front-end node from floating for a long time. During the cold start phase, the energy harvesting device initially charges only the front-end input capacitor CIN. At this time, due to the low VIN_RECT voltage, the control power switch remains off, VCTRL is not powered, and the two 555 timers, MPPT sampling circuit, and DC-DC input control circuit are all inactive. The DC-DC converter is also not prematurely connected to the input terminal to prevent the control circuit and DC-DC converter from prematurely consuming the front-end energy before CIN has accumulated sufficient energy, thus preventing the system from getting stuck in a startup state. As VIN_RECT gradually rises to the set startup voltage, the startup detection circuit, composed of a resistor divider and a MOSFET, turns on the control power switch, allowing VIN_RECT to supply power to VCTRL through the control power branch. The circuit begins operation. This cold start control process ensures that the front-end input capacitor has a certain amount of energy before the system enters MPPT sampling and boost power extraction. In the control section, the first 555 timer is a periodic oscillator used to generate the periodic clock CLK_MPP. This signal determines how often the system performs maximum power point sampling. The second 555 timer is used to generate the periodic sampling window signal SAMPLE. This signal determines the duration of each sampling. The purpose of using two timers is to separate the "sampling period" and the "sampling time," so that the system does not need to sample continuously, but instead samples briefly at intervals, with the remaining time used for power extraction. The control power module obtains a small amount of energy from VIN_RECT. The voltage regulator VCTRL is used to power the timer, sampling control circuit, and switch drive circuit. This module only powers the control circuit and does not participate in the maximum power point voltage sampling. When SAMPLE is active, the circuit enters the MPPT sampling stage. At this time, the input switch control circuit closes the input path of the boost DC-DC converter, temporarily stopping the DC-DC converter from drawing energy from VIN_RECT. This restores the front-end input voltage to a state close to the open-circuit voltage of the energy harvesting device. Simultaneously, the MPPT sampling module connects to a proportional voltage divider network to perform voltage division sampling on VIN_RECT. The divided voltage is then stored on the holding capacitor through the sampling switch to form the maximum power point reference voltage VM. After sampling, the voltage divider network... When the sampling switch is disconnected, the holding capacitor continues to store VM as the MPPT reference voltage for this cycle. During the non-sampling phase, the circuit begins to extract power normally. At this time, whether the DC-DC converter is connected to the input terminal is not determined by the DC-DC converter itself, but by the MPPT judgment of the front stage and the control of the input switch. The circuit compares the current input state with the holding voltage VM through the MOS threshold judgment method: if the current VIN_RECT is still higher than the maximum power point reference range represented by VM, it means that the power extraction device has not been pulled too hard, MPPT_OK remains valid, the input PMOS switch is turned on, VIN_RECT is connected to the input terminal of the ordinary boost DC-DC converter, and the DC-DC converter begins to extract power from the front input capacitor and boost the voltage.As the DC-DC converter operates, the energy on CIN is consumed, and VIN_RECT decreases. When it drops below the MPPT reference point, MPPT_OK is canceled, the input switch is turned off, the DC-DC converter stops harvesting energy, and the harvesting device recharges CIN. It waits for VIN_RECT to recover before entering the next round of energy harvesting. In this way, the DC-DC converter actually operates in an intermittent manner, with the input voltage varying around the sampled maximum power point reference value. Thus, the MPPT function is achieved using a regular DC-DC converter and external MOS control. The DC-DC output forms the back-end energy storage node VS, which is used to charge supercapacitors or batteries. If the back-end is a supercapacitor, the DC-DC output is connected to the supercapacitor through an anti-reverse-feed diode or a current-limiting element to prevent reverse discharge of the supercapacitor when the DC-DC stops and to limit the initial charging surge. If the back-end is a battery, current limiting or charging protection needs to be added depending on the battery type. The energy storage voltage detection section samples from VS and drives the MOS detection transistor through a resistor divider. When VS is low, the MOS is not turned on, and the output remains in an unready state. When VS rises to a set threshold, the voltage after voltage division is sufficient to turn on the MOS, outputting a BAT_OK or low-active BAT_OK_N signal to notify the external system that the energy storage voltage has reached a usable level and to start the load. The core idea of ​​the entire circuit is: the front end first accumulates a small amount of energy, the timer periodically disconnects the DC-DC and samples the open-circuit voltage, the capacitor keeps the MPPT reference value, and during the non-sampling phase, the MOS determines whether the input voltage is lower than the reference value and controls the DC-DC input switch accordingly. Finally, the DC-DC sends the energy to the back-end energy storage device, and then notifies the external system through the energy storage voltage detection signal.

[0029] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A micro-energy harvesting boost charging circuit based on periodic sampling MPPT, comprising an energy harvesting circuit, Its features are: The energy harvesting circuit includes a front-end energy harvesting and control module, a piezoelectric energy harvesting module, a DC-DC step-down module, an energy storage and output management module, and an external load system. One end of the piezoelectric energy harvesting module is connected to one end of the front-end energy harvesting and control module, and the other end of the front-end energy harvesting and control module is connected to one end of the DC-DC step-down module. The other end of the DC-DC step-down module is connected to one end of the energy storage and output management module, and the other end of the energy storage and output management module is connected to one end of the external load system. The front-end energy harvesting and control module includes a rectification and front-end energy storage module, a cold start circuit, and a control power supply module. The control power supply module includes a periodic signal generation module, a sampling window generation module, an MPPT sampling module, a sample-and-hold and MPPT judgment module, and an output switch control module. The energy storage and output management module includes a supercapacitor battery and a voltage detection module. The rectifier and front-end energy storage module includes an interface J1, a rectifier bridge DB1, a diode D5, a capacitor C1, and a diode D2. The cold start circuit includes resistors R8, R9, and R12, capacitor C3, transistor U10, transistor U7, and capacitor C2. The periodic signal generation module includes an integrated circuit U8, capacitors C4 and C6, resistors R10, R13, and R14, and capacitor C7. The sampling window generation module includes integrated circuit U9, capacitor C5, resistor R11 and capacitor C8; The MPPT sampling module includes resistor R20, resistor R18, transistor U14, transistor U11, and resistor R17. The sample-and-hold and MPPT determination module includes resistor R15, resistor R16, transistor U12, capacitor C9, resistor R19, resistor R21, transistor U13, and resistor R22. The output switch control module includes resistor R1, resistor R2, transistor U1, transistor U4, transistor U6, and transistor U5; The DC-DC step-down module includes an integrated circuit U2, an inductor L1, a diode D1, a resistor R5, and a resistor R7; The supercapacitor battery contains a battery BAT1, one end of which is grounded. The voltage detection module includes resistors R4, R6, and R3, and transistor U3.

2. The micro-energy harvesting boost charging circuit based on periodic sampling MPPT according to claim 1, characterized in that: Pin 1 and pin 2 of interface J1 are both connected to one end of rectifier bridge DB1. The other end of rectifier bridge DB1 is connected to one end of diode D5, one end of capacitor C1 and one end of diode D2. The other end of diode D5, the other end of capacitor C1 and the grounding pin of rectifier bridge DB1 are all grounded.

3. The micro-energy harvesting boost charging circuit based on periodic sampling MPPT according to claim 1, characterized in that: The drain of transistor U10 is connected to one end of resistor R8 and the gate of transistor U7. The drain of transistor U7 is connected to one end of capacitor C3 and one end of capacitor C2. The gate of transistor U10 is connected to one end of resistor R12 and one end of resistor R9. The other end of resistor R12, the source of transistor U10, the other end of capacitor C3, and the other end of capacitor C2 are all grounded. The other ends of resistor R8 and resistor R9 are both connected to the source of transistor U7.

4. The micro-energy harvesting boost charging circuit based on periodic sampling MPPT according to claim 1, characterized in that: Pin 7 of integrated circuit U8 is connected to one end of resistor R13 and one end of resistor R14. Pin 2 and pin 6 of integrated circuit U8 and the other end of resistor R14 are all connected to one end of capacitor C7. Pin 5 of integrated circuit U8 is connected to one end of capacitor C4. Pin 3 of integrated circuit U8 is connected to one end of capacitor C6. Pin 4 of integrated circuit U8 is connected to one end of resistor R10. Pin 1 of integrated circuit U8, the other end of capacitor C7, and the other end of capacitor C4 are all grounded.

5. The micro-energy harvesting boost charging circuit based on periodic sampling MPPT according to claim 1, characterized in that: Pin 8 and pin 4 of integrated circuit U9 are both connected to one end of resistor R11. Pin 5 of integrated circuit U9 is connected to one end of capacitor C5. Pin 7, pin 6 of integrated circuit U9, and the other end of resistor R11 are all connected to one end of capacitor C8. The other end of capacitor C8, pin 1 of integrated circuit U9, and the other end of capacitor C5 are all grounded.

6. The micro-energy harvesting boost charging circuit based on periodic sampling MPPT according to claim 1, characterized in that: The source of transistor U11 is connected to one end of resistor R17. The other end of resistor R17 and the gate of transistor U11 are both connected to the drain of transistor U14. The gate of transistor U14 is connected to one end of resistor R18 and one end of resistor R20. The source of transistor U14 and the other end of resistor R20 are both grounded.

7. The micro-energy harvesting boost charging circuit based on periodic sampling MPPT according to claim 1, characterized in that: The drain of transistor U12 is connected to one end of resistor R15 and one end of resistor R16. The source of transistor U12 is connected to one end of capacitor C9 and the source of transistor U13. The gate of transistor U13 is connected to one end of resistor R19 and one end of resistor R21. The drain of transistor U13 is connected to one end of resistor R22. The other ends of resistor R16, capacitor C9, resistor R21, and resistor R22 are all grounded.

8. The micro-energy harvesting boost charging circuit based on periodic sampling MPPT according to claim 1, characterized in that: The drains of transistors U5 and U6 are connected to one end of resistor R1 and the gate of transistor U4. The drain of transistor U4 is connected to one end of resistor R2 and the gate of transistor U1. The sources of transistors U5, U6, and U4 are all grounded.

9. A micro-energy harvesting boost charging circuit based on periodic sampling MPPT according to claim 1, characterized in that: The fourth pin of the integrated circuit U2 is connected to one end of the inductor L1, the other end of the inductor L1 is connected to one end of the resistor R5, the other end of the resistor R5 is connected to the second pin of the integrated circuit U2 and one end of the resistor R7, the fifth pin of the integrated circuit U2 is connected to one end of the diode D1, and the third pin of the integrated circuit U2 and the other end of the resistor R7 are both grounded.

10. A micro-energy harvesting boost charging circuit based on periodic sampling MPPT according to claim 1, characterized in that: The gate of transistor U3 is connected to one end of resistor R4 and one end of resistor R6, the drain of transistor U3 is connected to one end of resistor R3, and the source of transistor U3 and the other end of resistor R6 are both grounded.

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