Environmental energy harvesting circuit and control method thereof

Abstract

The present invention discloses an environmental energy collection circuit and a control method thereof, belonging to the field of micro energy collection technology. The circuit includes: a cold start module, a first capacitor, a second capacitor, a main energy collection module, a switch module and a voltage detection module; the main energy collection module includes a control unit, a first power conversion component and a second power conversion component; the switch module includes a first switch and a second switch; the voltage detection module is used to generate a first control signal according to the voltage at the output end of the cold start module, generate a second control signal according to the voltage at the power supply end of the main energy collection module, and generate a third control signal according to the voltage at the power supply output end, the first switch is turned on and off according to the first control signal, the control unit controls whether the first power conversion component and the second power conversion component are started according to the second control signal, and the second switch is turned on and off according to the third control signal. The present invention can reduce the startup threshold of the environmental energy collection circuit and improve the startup speed and reliability of the circuit.

Description

Technical Field

[0001] The present invention relates to the technical field of micro energy collection, and in particular to an environmental energy collection circuit and a control method thereof. Background Art

[0002] At present, a lot of research on ambient energy harvesting circuits has been carried out in academia and industry. Considering the application requirements of ambient energy harvesting circuits, such as reliable optimal power point tracking (MPPT), the collected energy needs to be further managed, so a certain scale of digital and / or auxiliary analog circuits need to be added to the circuit. For collecting energy from extremely low ambient energy and waking up other circuits, there is a cold start process, see Figure 1 , the process is to collect the weak electric energy of the environmental energy source 05 to the energy storage device C01 through the cold start circuit 01. When the voltage detection device 03 detects that the voltage on the energy storage device C01 reaches a certain value, the switch S is turned on, and the voltage on the energy storage device C01 is used to wake up the main energy collection circuit 02, so that the main energy collection circuit 02 starts to collect environmental energy more efficiently. The main energy collection circuit 02 contains circuits such as digital control, and the circuit structure is often complex, and an off-chip capacitor C02 is required to stabilize its operating voltage. The energy storage device C01 used for cold start is often implemented with a relatively small on-chip capacitor. When this energy storage device C01 is connected to the main energy collection circuit 02, due to the charge sharing effect of the large off-chip capacitor C02, the voltage on the on-chip capacitor will quickly drop to a very low value, causing the main energy collection circuit 02 to lose power, resulting in the failure of the conversion from cold start to hot start.

[0003] To avoid the above-mentioned problem of rapid drop in on-chip capacitor voltage, see Figure 2 , the related art provides a solution to connect the output of the cold start circuit 01 directly in parallel with the output of the main energy collection circuit 02. Instead of using a small on-chip capacitor, the weak ambient energy is directly injected into the off-chip capacitor after passing through the cold start circuit 01. When the voltage detection device 04 detects that the voltage on the off-chip capacitor C02 reaches a certain value, the main energy collection circuit 02 is started; but since the input energy is very weak and the off-chip capacitor C02 is large, it takes a long charging time to wake up and start the main energy collection circuit 02. In addition, since the other circuits connected to the main energy collection circuit 02 and the off-chip capacitor C02 are a large load for the cold start circuit 01, the cold start voltage threshold is high. Summary of the invention

[0004] The present invention provides an environmental energy harvesting circuit and a control method thereof, so as to reduce a startup threshold of the environmental energy harvesting circuit and improve the startup speed and reliability of the circuit.

[0005] In a first aspect, an embodiment of the present invention provides an environmental energy harvesting circuit, including:

[0006] A cold start module, wherein an input end of the cold start module is connected to an energy input end of the ambient energy collection circuit, and the energy input end is connected to an ambient energy source;

[0007] A first capacitor connected between the output terminal of the cold start module and ground;

[0008] a second capacitor connected between a power supply output terminal of the environmental energy collection circuit and ground; the capacitance of the second capacitor is greater than the capacitance of the first capacitor;

[0009] The main energy collection module comprises: a control unit, a first power conversion component connected between the energy input end and the power supply end of the main energy collection module, and a second power conversion component connected between the energy input end and the power supply output end; the control unit is respectively connected to the control end of the first power conversion component and the control end of the second power conversion component;

[0010] A switch module, comprising: a first switch connected between the output end of the cold start module and the power supply end, and a second switch connected between the power supply end and the power supply output end;

[0011] a voltage detection module, configured to generate a first control signal according to a voltage at an output end of the cold start module, generate a second control signal according to a voltage at the power supply end, and generate a third control signal according to a voltage at the power supply output end;

[0012] Among them, the first switch is used to turn on or off according to the first control signal; the control unit is used to control whether the first power conversion component and the second power conversion component are started according to the second control signal; the second switch is used to turn on or off according to the third control signal.

[0013] Optionally, the environmental energy collection circuit further includes: an energy storage module connected to the energy storage power supply end of the environmental energy collection circuit;

[0014] The main energy collection module also includes: a third power conversion component connected between the energy input end and the energy storage power supply end; the control unit is also connected to the control end of the third power conversion component, and the control unit is also used to control whether the third power conversion component is started according to the second control signal and the third control signal.

[0015] Optionally, the voltage detection module includes:

[0016] a first voltage detection unit, connected to the output end of the cold start module and the control end of the first switch, respectively, and configured to generate the first control signal according to the voltage at the output end of the cold start module;

[0017] a second voltage detection unit, connected to the power supply end and the control unit, respectively, and configured to generate the second control signal according to the voltage of the power supply end;

[0018] a third voltage detection unit, connected to the power supply output terminal and the control terminal of the second switch, respectively, and configured to generate the third control signal according to the voltage of the power supply output terminal;

[0019] And / or, the environmental energy collection circuit further includes: an electrostatic protection module connected to the power supply output terminal.

[0020] Optionally, the control unit comprises:

[0021] a third switch, wherein an output end of the third switch is connected to a control end of the first power conversion component;

[0022] a fourth switch, wherein an output end of the fourth switch is connected to a control end of the second power conversion component;

[0023] a switch control subunit, receiving the second control signal and connected to a control end of the third switch and a control end of the fourth switch respectively;

[0024] A control subunit, wherein the input end of the control subunit is connected to the power supply end, and the output end of the control subunit is connected to the input end of the third switch and the input end of the fourth switch; the control subunit is used to generate and output a driving signal according to the voltage of the power supply end.

[0025] Optionally, the switch control subunit includes:

[0026] A first inverter, wherein an input end of the first inverter is connected to the second control signal, and an output end of the first inverter is connected to a control end of the third switch;

[0027] A second inverter, wherein an input end of the second inverter is connected to an output end of the first inverter, and an output end of the second inverter is connected to a control end of the fourth switch.

[0028] Optionally, the switch control subunit further includes: a first AND gate, a third inverter and a multiplexer;

[0029] The input end of the third inverter is connected to the third control signal; the two input ends of the first AND gate are respectively connected to the output end of the first inverter and the output end of the third inverter, and the output end of the first AND gate is connected to the control end of the third switch; the first input end of the multiplexer is connected to the output end of the second inverter, the second input end of the multiplexer is connected to the output end of the first inverter, the selection end of the multiplexer is connected to the output end of the third inverter, and the output end of the multiplexer is connected to the control end of the fourth switch.

[0030] Optionally, the environmental energy collection circuit further includes: an energy storage component connected between the energy storage power supply terminal of the environmental energy collection circuit and the ground; the main energy collection module further includes: a third power conversion component connected between the energy input terminal and the energy storage power supply terminal;

[0031] The control unit further comprises: a fifth switch, the output end of the fifth switch being connected to the control end of the third power conversion component, and the output end of the control subunit being also connected to the input end of the fifth switch;

[0032] The switch control subunit also includes: a second AND gate, a first input end of the second AND gate is connected to the second control signal or the output end of the second inverter, a second input end of the second AND gate is connected to the third control signal, and an output end of the second AND gate is connected to the control end of the fifth switch.

[0033] In a second aspect, an embodiment of the present invention further provides a control method for an ambient energy harvesting circuit, which is applied to the ambient energy harvesting circuit provided by any embodiment of the present invention; the control method for the ambient energy harvesting circuit includes:

[0034] The cold start module charges the first capacitor using energy provided by the ambient energy source;

[0035] When the voltage detection module detects that the voltage at the output end of the cold start module reaches a first voltage threshold, the voltage detection module controls the first control signal to be a turn-on voltage of the first switch, so that the first switch is turned on;

[0036] Repeat the first energy distribution step until the voltage at the power supply output terminal reaches a fourth voltage threshold; the first energy distribution step includes: the voltage detection module controls the second control signal to be a first voltage when detecting that the voltage at the power supply terminal is lower than a second voltage threshold, and the control unit controls the first power conversion component to start and controls the second power conversion component to shut down according to the first voltage, so that the environmental energy source charges the first capacitor; the voltage detection module controls the second control signal to be a second voltage when detecting that the voltage at the power supply terminal is higher than a third voltage threshold, and the control unit controls the first power conversion component to shut down and controls the second power conversion component to start according to the second voltage, so that the environmental energy source charges the second capacitor; the first voltage is different from the second voltage, the second voltage threshold is higher than the first voltage threshold, the third voltage threshold is higher than or equal to the second voltage threshold, and the fourth voltage threshold is lower than the second voltage threshold;

[0037] When the voltage detection module detects that the voltage at the power supply output terminal reaches a fourth voltage threshold, the voltage detection module controls the third control signal to be a turn-on voltage of the second switch to turn on the second switch.

[0038] Optionally, when the voltage detection module detects that the voltage at the power supply output terminal reaches a fourth voltage threshold, the control method of the ambient energy collection circuit further includes:

[0039] The control unit controls the first power conversion component to be turned off according to the third control signal having the turn-on voltage of the second switch.

[0040] Optionally, the environmental energy collection circuit further includes: an energy storage module connected between the energy storage power supply terminal of the environmental energy collection circuit and the ground; the main energy collection module further includes: a third power conversion component connected between the energy input terminal and the energy storage power supply terminal;

[0041] Before the voltage detection module detects that the voltage at the power supply output terminal reaches a fourth voltage threshold, the control method of the ambient energy collection circuit further includes:

[0042] The voltage detection module controls the third control signal to be the cut-off voltage of the second switch, so that the second switch is turned off, and the control unit controls the third power conversion component to be turned off according to the third control signal having the cut-off voltage of the second switch;

[0043] After the voltage detection module detects that the voltage at the power supply output terminal reaches a fourth voltage threshold, the control method of the ambient energy collection circuit further includes:

[0044] Repeat the second energy distribution step until the energy storage module is fully charged; the second energy distribution step includes: when the voltage detection module detects that the voltage at the power supply end is lower than the second voltage threshold, the voltage detection module controls the second control signal to be the first voltage, and the control unit controls the second power conversion component to start and controls the third power conversion component to be turned off according to the first voltage, so that the environmental energy source charges the second capacitor; when the voltage detection module detects that the voltage at the power supply end is higher than the third voltage threshold, the voltage detection module controls the second control signal to be the second voltage, and the control unit controls the second power conversion component to be turned off and controls the third power conversion component to start according to the second voltage, so that the environmental energy source charges the energy storage module.

[0045] In the environmental energy collection circuit provided by the embodiment of the present invention, according to the detection results of the voltage detection module on the voltages of the key nodes such as the output end of the cold start module, the power supply end of the main energy collection module and the power supply output end, the on-off state of the first switch and the second switch in the switch module can be controlled, as well as the start-stop state of the first power conversion component and the second power conversion component in the main energy collection module can be controlled to achieve the hierarchical conversion from cold start to hot start. Specifically, the first switch can be controlled to be turned off during the cold start process, so that the cold start module can be quickly started based on a small amount of micro energy; in the conversion process from cold start to hot start, the start and stop of the first power conversion component and the second power conversion component can be controlled according to the voltage of the power supply end of the main energy collection module, so as to control whether the micro energy provided by the environmental energy source is charged to the first capacitor or the second capacitor, so as to ensure that the voltage of the power supply end is sufficient to maintain the operation of the main energy collection module. On the basis of making the voltage of the second capacitor steadily rise; until the voltage of the second capacitor rises to near the power supply voltage of the main energy collection module, the second switch can be controlled to be turned on, so that the first capacitor and the second capacitor are connected and merged, and the hot start is successfully achieved. With this arrangement, the starting voltage of the cold start module can be used as the starting voltage of the ambient energy collection circuit, effectively reducing the starting threshold of the ambient energy collection circuit; and charging the second capacitor through the main energy collection module with higher energy collection efficiency can effectively improve the starting speed of the ambient energy collection circuit compared to charging only with the cold start module; and, in the process of converting from cold start to hot start, by controlling the start and stop of the first power conversion component and the second power conversion component, it can be ensured that the power supply end voltage of the main energy collection module will not drop to the level where the main energy collection module loses power, thereby improving circuit reliability.

[0046] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0048] Figure 1 It is a structural schematic diagram of an ambient energy harvesting circuit in the related art;

[0049] Figure 2 It is a structural schematic diagram of another ambient energy harvesting circuit in the related art;

[0050] Figure 3 is a structural schematic diagram of an environmental energy harvesting circuit provided by an embodiment of the present invention;

[0051] Figure 4 is a schematic structural diagram of another environmental energy harvesting circuit provided by an embodiment of the present invention;

[0052] Figure 5 It is a flow chart of a control method of an environmental energy harvesting circuit provided by an embodiment of the present invention;

[0053] Figure 6 is a structural schematic diagram of a switch control subunit provided by an embodiment of the present invention;

[0054] Figure 7 is a schematic structural diagram of another switch control subunit provided by an embodiment of the present invention;

[0055] Figure 8 is a structural schematic diagram of another environmental energy harvesting circuit provided by an embodiment of the present invention;

[0056] Fig. 9 is a flow chart of another control method of an environmental energy harvesting circuit provided by an embodiment of the present invention;

[0057] Fig.10 is a structural schematic diagram of another switch control subunit provided by an embodiment of the present invention;

[0058] Fig.11 It is a flow chart of another control method of an environmental energy harvesting circuit provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0059] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0060] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0061] An embodiment of the present invention provides an ambient energy harvesting circuit, which can achieve hierarchical cold start to hot start conversion through the cooperation of various switches and various power conversion components, thereby quickly and reliably starting the ambient energy harvesting circuit with a lower starting threshold. Figure 3 is a schematic diagram of the structure of an environmental energy collection circuit provided by an embodiment of the present invention. Figure 3 The environmental energy collection circuit 100 includes: a cold start module 10, a first capacitor C1, a second capacitor C2, a main energy collection module 20, a switch module 30 and a voltage detection module 40.

[0062] The input end of the cold start module 10 is connected to the energy input end EIN of the environmental energy collection circuit, and the energy input end EIN is connected to the environmental energy source 200. The first capacitor C1 is connected between the output end of the cold start module 10 and the ground. The second capacitor C2 is connected between the power supply output end EOUT of the environmental energy collection circuit 100 and the ground; the capacitance of the second capacitor C2 is greater than the capacitance of the first capacitor C1. The main energy collection module 20 includes: a control unit 24, a first power conversion component 21 connected between the energy input end EIN and the power supply end of the main energy collection module 20, and a second power conversion component 22 connected between the energy input end EIN and the power supply output end EOUT; the control unit 24 is respectively connected to the control end of the first power conversion component 21 and the control end of the second power conversion component 22. The switch module 30 includes: a first switch S1 connected between the output end of the cold start module 10 and the power supply end of the main energy collection module 20, and a second switch S2 connected between the power supply end of the main energy collection module 20 and the power supply output end EOUT. The voltage detection module 40 is used to generate a first control signal SW1 according to the voltage at the output end of the cold start module 10, generate a second control signal SW2 according to the voltage at the power supply end, and generate a third control signal SW3 according to the voltage at the power supply output end EOUT. Among them, the first switch S1 is used to turn on or off according to the first control signal SW1; the control unit 24 is used to control whether the first power conversion component 21 and the second power conversion component 22 are started according to the second control signal SW2; the second switch S2 is used to turn on or off according to the second control signal SW3.

[0063] Among them, the environmental energy source 200 can be understood as an energy source that can collect tiny energy in the environment and convert it into electrical energy. For example, it can convert light energy, heat energy or vibration energy in the environment into usable electrical energy through energy conversion materials such as piezoelectric materials, thermoelectric materials or photovoltaic materials and related technologies, and enable low-power electronic devices to work normally by capturing environmental micro-energy. The environmental energy source 200 can, for example, provide micro-energy at the microwatt level, which can be embodied in the form of a voltage source or a current source. It is exemplarily shown here in the form of a voltage source, but it is not intended to limit the present invention.

[0064] In the environmental energy collection circuit 100, the first capacitor C1 is, for example, a nanofarad capacitor, and the second capacitor C1 is, for example, a microfarad capacitor. The second capacitor C2 can be a discrete capacitor device; except for the second capacitor C2, other functional modules can be integrated into an environmental energy collection chip, and the first capacitor C1 is, for example, a capacitor on a chip formed by relevant wiring in the environmental energy collection chip. The cold start module 10 is an energy conversion circuit that can start and work at a very low voltage / current, so that the cold start module 10 can use the micro energy provided by the environmental energy source 200 to charge the first capacitor C1. The cold start module 10 includes, for example, devices such as a nanowatt oscillator. The starting voltage of the cold start module 10 is, for example, tens or hundreds of millivolts.

[0065] In the main energy collection module 20, each power conversion component can be a power output switch group composed of multiple power switching devices, specifically a DCDC conversion circuit, which can more efficiently collect the micro energy provided by the environmental energy source 200 and charge the first capacitor C1 and / or the second capacitor C2 compared to the cold start module 10. The control unit 24 may include a controller of any structure, and the control unit 24 may control whether the power conversion component is started by controlling whether a drive signal is provided to the power conversion component; and the control unit 24 may also control the working state of the power conversion component after startup by controlling the frequency and duty cycle of the drive signal. The power supply end of the main energy collection module 20 is used to provide its working voltage to each functional unit in the main energy collection module 40. After the main energy collection module 20 is awakened and started, the power supply end needs to provide a relatively stable power supply voltage so that the main energy collection module 20 can efficiently use the micro energy provided by the environmental energy source 200 to charge the first capacitor C1 and / or the second capacitor C2. The power supply end of the main energy collection module 20 is connected to the first node N1, that is, to the connection node between the first switch S1 and the second switch S2. The voltage of the first node N1 is the voltage of the power supply end.

[0066] Exemplarily, the input end of the first power conversion component 21 is connected to the energy input end EIN, the output end is connected to the first node N1, the control end is connected to the first output end of the control unit 24, and the power supply end (not shown in the figure) is connected to the power supply end. The input end of the second power conversion component 22 is connected to the energy input end EIN, the output end is connected to the power supply output end EOUT, the control end is connected to the second output end of the control unit 24, and the power supply end (not shown in the figure) is connected to the power supply end. The power supply end (not shown in the figure) of the control unit 24 is also connected to the power supply end. In other words, the power supply ends of all components in the main energy collection module 20 that need to be supplied with working voltage to support their work can be connected to the power supply end of the main energy collection module 20, and power is taken from the first node N1; each power conversion component is used to charge the first capacitor C1 and / or the second capacitor C2 with the micro energy provided by the environmental energy source 200 when starting.

[0067] In the switch module 30 , each switch can be composed of a transistor, a relay or other controllable switch devices.

[0068] The voltage detection module 40 may include a plurality of voltage detection units, which are respectively used to detect the voltage at the output end of the cold start module 10, the voltage at the power supply end, and the voltage at the power supply output end EOUT, and generate corresponding control signals according to the voltages of the above-mentioned key nodes to control the working state of each switch and each power conversion component. Among them, the voltage at the output end of the cold start module 10 is the voltage on the first capacitor C1, and the voltage at the power supply output end EOUT is the voltage on the second capacitor C2. When the first switch S1 is turned on, the voltage at the power supply end is equal to the voltage on the first capacitor C1. When both the first switch S1 and the second switch S2 are turned on, the voltage at the power supply end is equal to the voltage on the first capacitor C1, and is also equal to the voltage on the second capacitor C2.

[0069] According to the above analysis, after the main energy collection module 20 is awakened and started, the power supply end needs to provide a relatively stable power supply voltage, that is, the voltage of the first node N1 needs to be relatively stable to provide a relatively stable power supply voltage, so that the hot start based on the main energy collection module 20 is successful. In the conversion process between cold start and hot start, based on the voltage change of each key node, the working state of each switch and each power conversion component is controlled, so that the voltage of the first node N1 is always within the allowable range, and the voltage on the second capacitor C2 steadily rises to the power supply voltage required by the power supply end.

[0070] Specifically, the cold start can be understood as the process of the cold start module 10 starting and charging the first capacitor C1. The starting voltage of the environmental energy collection circuit 100 is the voltage of the cold start module 10. The starting voltage threshold is extremely low and can be as low as tens of millivolts. At the beginning of the cold start, the first switch S1 is turned off until the voltage on the first capacitor C1 reaches the first voltage threshold, and the first switch S1 can be controlled to be turned on; at this time, the power supply end of the main energy collection module 20 begins to be powered, the main energy collection module 20 is awakened, and the conversion from cold start to hot start begins. During the conversion process from cold start to hot start, the control unit 24 controls the start and stop of the first power conversion component 21 and the second power conversion component 22, so that the voltage clock of the first node N1 remains above the first voltage threshold, thereby avoiding the problem of power failure of the main energy collection module 20 causing the hot start to fail. Specifically, in the conversion process from cold start to hot start, when the voltage of the first node N1 is low, the first power conversion component 21 is controlled to be turned on, and the second power conversion component 22 is turned off, so that the environmental energy source 200 charges the first capacitor C1, ensuring that the voltage of the first node N1 will not drop below the first voltage threshold; when the voltage of the first node N1 is high, the first power conversion component 21 is controlled to be turned off, and the second power conversion component 22 is turned on, so that the environmental energy source 200 charges the second capacitor C2, so that the voltage of the second capacitor C2 rises steadily; due to the large capacitance of the second capacitor C2, the above control process will be repeated many times. At the beginning of the conversion process from cold start to hot start, the second switch S2 is turned off until the voltage on the second capacitor reaches the fourth voltage threshold, and the second switch S2 can be controlled to be turned on, indicating that the conversion from cold start to hot start is successful, that is, the environmental energy collection circuit 100 is successfully started, and the voltage of the first node N1 can be stabilized by the larger second capacitor C2. Among them, the first voltage threshold and the fourth voltage threshold are both close to or equal to the rated supply voltage of the main energy collection module 20 (for example, 1V).

[0071] Exemplarily, the first voltage threshold may be set equal to the fourth voltage threshold. Alternatively, the first voltage threshold may be set greater than the fourth voltage threshold. Specifically, below the upper limit of the power supply voltage allowed by the energy collection module 20, the first voltage threshold may be set slightly higher than the rated power supply voltage of the main energy collection module 20. Since the capacitance of the first capacitor C1 is small, its voltage maintenance capability is weak. By setting the first voltage threshold slightly higher, power failure caused by the large load connected to the energy collection module 20 when the first switch S1 is turned on can be avoided; and, above the lower limit of the power supply voltage allowed by the energy collection module 20, the fourth voltage threshold may be set slightly lower than the rated power supply voltage of the main energy collection module 20. Since the capacitance of the second capacitor C2 is large, its voltage maintenance capability is strong. Even if the fourth voltage threshold is set slightly lower, it will not cause the main energy collection module 20 to lose power when the second switch S2 is turned on. Since the capacitance of the second capacitor C2 is large, the energy provided by the environmental energy source 200 is relatively weak, so that the charging time of the second capacitor C2 is long. By setting the fourth voltage threshold slightly lower, the startup time of the environmental energy collection circuit 100 can be effectively shortened.

[0072] In the environmental energy collection circuit provided by the embodiment of the present invention, according to the detection results of the voltage detection module 40 on the voltages of key nodes such as the output end of the cold start module 10, the power supply end of the main energy collection module 20 and the power supply output end EOUT, the on-off state of the first switch S1 and the second switch S2 in the switch module 30 can be controlled, as well as the start-stop state of the first power conversion component 21 and the second power conversion component 22 in the main energy collection module 20, to achieve hierarchical conversion from cold start to hot start. Specifically, the first switch S1 can be controlled to be turned off during the cold start process, so that the cold start module 10 can be quickly started based on a smaller micro-energy; in the process of converting from cold start to hot start, the start and stop of the first power conversion component 21 and the second power conversion component 22 can be controlled according to the power supply end voltage of the main energy collection module 20, so as to control whether the micro-energy provided by the environmental energy source 200 is charged to the first capacitor C1 or the second capacitor C2, so as to ensure that the power supply end voltage is sufficient to maintain the operation of the main energy collection module 20, so that the voltage of the second capacitor C2 steadily increases; until the voltage of the second capacitor C2 rises to near the power supply voltage of the main energy collection module 20, the second switch S2 can be controlled to be turned on, so that the first capacitor C1 and the second capacitor C2 are connected and merged, and the hot start is successfully achieved. In this way, the starting voltage of the cold start module 10 can be used as the starting voltage of the ambient energy collection circuit 100, effectively reducing the starting threshold of the ambient energy collection circuit 100; and the second capacitor C2 is charged by the main energy collection module 20 with higher energy collection efficiency, which can effectively improve the starting speed of the ambient energy collection circuit 100 compared with only charging with the cold start module 10; and, in the process of converting from cold start to hot start, by controlling the start and stop of the first power conversion component 21 and the second power conversion component 22, it can be ensured that the power supply end voltage of the main energy collection module 20 will not drop to the extent that the main energy collection module 20 loses power, thereby improving the circuit reliability.

[0073] The following is an exemplary description of the specific structure that each functional module in the ambient energy harvesting circuit may have, but it is not intended to limit the present invention.

[0074] Figure 4 is a schematic diagram of the structure of another environmental energy collection circuit provided by an embodiment of the present invention. Figure 4On the basis of the above embodiments, the voltage detection module 40 optionally includes: a first voltage detection unit 41, a second voltage detection unit 42 and a third voltage detection unit 43. The first voltage detection unit 41 is connected to the output end of the cold start module 10 and the control end of the first switch S1, respectively, and is used to generate a first control signal SW1 according to the voltage of the output end of the cold start module 10; for example, the sampling end of the first voltage detection unit 41 is connected to the output end of the cold start module 10, and the output end is connected to the control end of the first switch S1; wherein the power supply end required for the first voltage detection unit 41 to work itself can be connected to the output end of the cold start module 10. The second voltage detection unit 42 is connected to the power supply end (i.e., connected to the first node N1) and the control unit 24, respectively, and is used to generate a second control signal SW2 according to the voltage of the power supply end; for example, the sampling end of the second voltage detection unit 42 is connected to the first node N1, and the output end is connected to the control unit 24; wherein the power supply end required for the second voltage detection unit 42 to work itself can be connected to the first node N1. The third voltage detection unit 43 is connected to the power supply output terminal EOUT and the control terminal of the second switch S2 respectively, and the third voltage detection unit 43 is used to generate a third control signal SW3 according to the voltage of the power supply output terminal EOUT; for example, the sampling terminal of the third voltage detection unit 43 is connected to the power supply output terminal EOUT, and the output terminal is connected to the control terminal of the second switch S2; wherein the power supply terminal required for the third voltage detection unit 43 to work itself can be connected to the first node N1. Each voltage detection unit can adopt any existing voltage detection device, which will not be repeated here.

[0075] Based on the above embodiments, optionally, the environmental energy harvesting circuit 100 further includes: an electrostatic protection module 50 connected to the power output terminal EOUT to implement electrostatic protection of the power output terminal EOUT. Exemplarily, the electrostatic protection module 50 may include an ESD device connected between the power output terminal EOUT and the ground.

[0076] Figure 5 1 is a flow chart of a control method of an environmental energy collection circuit provided by an embodiment of the present invention. Figure 4 and Figure 5 , the driving process of the ambient energy harvesting circuit may include:

[0077] S101: A cold start module charges a first capacitor.

[0078] When the voltage provided by the environmental energy source 200 to the energy input terminal EIN reaches the start threshold of the cold start module 10, the cold start module 10 starts to run and charges the first capacitor C1. In this process, the first voltage detection unit 41 connected to the first capacitor C1 detects the voltage on the first capacitor C1, that is, detects the voltage at the output terminal of the cold start module 10.

[0079] S102. Is VC1>Vth1 determined? If yes, execute S103; if no, return to execute S101.

[0080] Wherein, VC1 is the voltage on the first capacitor C1, and Vth1 is the first voltage threshold.

[0081] S103 , the first voltage detection unit controls the first switch to be turned on.

[0082] When the voltage on the first capacitor C1 exceeds the first voltage threshold Vth1, the first switch S1 is controlled to be turned on, and the main energy collection module 20 supplies power to the first capacitor C1, but the second switch S2 is not turned on, so the first capacitor C1 and the second capacitor C2 are not connected together. After the first switch S1 is turned on, the second voltage detection unit 42 detects the voltage of the first node N1 as the voltage of the power supply end of the main energy collection module 20; the third voltage detection unit 43 detects the voltage of the power supply output end EOUT as the voltage on the second capacitor C2.

[0083] S104: Determine whether VN1 is less than Vlow. If yes, execute S105; if no, execute S106.

[0084] Wherein, VN1 is the voltage of the first node N1; Vlow is the second voltage threshold. Since the capacitance value of the first capacitor C1 is limited and the power consumption of the main energy collection module 20 is relatively large, the first capacitor C1 must be supplemented with energy to maintain the power supply to the main energy collection module 20. When VN1<Vlow, the first capacitor C1 needs to be charged through the first power conversion component 21. The second voltage threshold Vlow is greater than the first voltage threshold Vth1, so that when the voltage VN1 of the first node N1 is lower than the second voltage threshold Vlow, it is still higher than the first voltage threshold Vth1, ensuring that the first switch S1 is not turned off.

[0085] S105. The control unit controls the first power conversion component to start, and controls the second power conversion component to shut down.

[0086] Compared with the cold start module 10 , the main energy collection module 20 has a higher conversion efficiency and can more effectively convert the energy of the ambient energy source 200 to the first capacitor C1 .

[0087] S106. Determine whether VN1>Vhigh? If yes, execute S107; if no, execute S108.

[0088] Wherein, Vhigh is the third voltage threshold, and the third voltage threshold Vhigh is greater than or equal to the second voltage threshold Vlow, preferably greater than, so as to realize hysteresis control, avoid the start and stop state of the power conversion component from switching at high speed near the voltage threshold, and improve circuit stability. Here, the third voltage threshold Vhigh is greater than the second voltage threshold Vlow as an example for explanation.

[0089] S107: The control unit controls the first power conversion component to shut down, and controls the second power conversion component to start up.

[0090] The environmental energy source 200 charges the second capacitor C2 through the second power conversion component 22, so that the voltage on the second capacitor C2 gradually increases. At the same time, the voltage on the first capacitor C1 decreases again, and when the voltage on the first capacitor C1 is lower than the second low voltage threshold Vlow again, it enters S105 again, and so on, until the voltage on the second capacitor C2 reaches the fourth voltage threshold.

[0091] S108. The control unit controls the first power conversion component and the second power conversion component to maintain a state.

[0092] Controlling any power conversion component to maintain its state may specifically be controlling the driving signal transmitted to the control end of the power conversion component to maintain the previous waveform, for example, the frequency, amplitude and pulse width remain unchanged.

[0093] S109. Determine whether VC2>Vth4. If yes, execute S110; if no, return to execute S104.

[0094] Wherein, VC2 is the voltage on the second capacitor C2, Vth4 is the fourth voltage threshold, and the fourth voltage threshold Vth4 is less than the second voltage threshold Vlow, for example, approximately equal to the first voltage threshold Vth1. It can be understood that the first voltage threshold Vth1, the second voltage threshold Vlow, the third voltage threshold Vhigh and the fourth voltage threshold Vth4 are all within the allowable range of the power supply voltage of the main energy collection module 20.

[0095] S110 , the third voltage detection unit controls the second switch to be turned on.

[0096] When the second switch S2 is turned on, the first capacitor C1 is combined with the second capacitor C2.

[0097] S111. A control unit controls the working states of a first power conversion component and a second power conversion component.

[0098] After the first capacitor C1 and the second capacitor C2 are combined, since the two are connected in parallel on a power supply path, the control unit 24 controls at least one of the first power conversion component 21 and the second power conversion component 22 to start, so as to realize the common charging of the first capacitor C1 and the second capacitor C2. When the voltage on the second capacitor C2 is too high, the first power conversion component 21 and the second power conversion component 22 can be controlled to be disabled to prevent the voltage on the second capacitor C2 from exceeding the upper limit allowed by the power supply voltage of the main energy collection module 20.

[0099] The embodiment of the present invention provides a control method for an environmental energy collection circuit based on S101-S111. In the process of starting the environmental energy collection circuit 100 using the control method, the cold start module 10 first charges the first capacitor C1, which is an internal energy storage device of the chip. When the voltage on the first capacitor C1 is sufficient for the main energy collection module 20 to work, that is, when the first voltage threshold Vth1 is reached, the control unit 24 in the main energy collection module 20 will decide whether to charge the first capacitor C1 or the second capacitor C2, which is an external capacitor of the chip, according to whether the power supply voltage of the main energy collection module 20 is sufficient. This mechanism avoids directly short-circuiting the internal energy storage device of the chip and the external capacitor of the chip. While ensuring the high sensitivity and high-speed startup of the internal energy storage device of the chip by the cold start module 10, the external capacitor of the chip can be gradually charged until the internal energy storage device of the chip and the external capacitor of the chip are connected.

[0100] Continue to see Figure 4On the basis of the above embodiments, the control unit 24 optionally includes: a third switch S3, a fourth switch S4, a switch control subunit 241 and a control subunit 242. The input end of the third switch S3 is connected to the drive signal SDR, the output end of the third switch S3 is connected to the control end of the first power conversion component 21, and the third switch S3 is used to turn on or off according to the signal connected to its control end to control whether the drive signal SDR is transmitted to the control end of the first power conversion component 21. The input end of the fourth switch S4 is connected to the drive signal SDR, and the output end is connected to the control end of the second power conversion component 22; the fourth switch S4 is used to turn on or off according to the signal connected to its control end to control whether the drive signal SDR is transmitted to the control end of the second power conversion component 22. The switch control subunit 241 is connected to the second control signal SW2, and the switch control subunit 241 is connected to the control end of the third switch S3 and the control end of the fourth switch S4 respectively; the switch control subunit 241 is used to control the signal transmitted to the control end of the third switch S3 and the signal transmitted to the control end of the fourth switch S4 according to the second control signal SW2. The input end of the control subunit 242 is connected to the power supply end, and the output end is connected to the input end of the third switch S3 and the input end of the fourth switch S4; the control subunit 242 is used to generate a drive signal SDR according to the voltage of the power supply end, and the drive signal SDR is output from the output end of the control subunit 242. Any power conversion component is started when its control end receives the drive signal SDR, and is disabled when its control end does not receive the drive signal SDR. Among them, the control subunit 242 can adjust the frequency, pulse width, amplitude and duty cycle of the output drive signal SDR according to the voltage of the power supply end, thereby controlling the working state of the power conversion component receiving the drive signal SDR.

[0101] Correspondingly, the control unit 24 controls the start-up of the first power conversion component 21 to specifically: the switch control subunit 241 controls the third switch S3 to be turned on, and the control subunit 242 controls the drive signal SDR transmitted to the control end of the first power conversion component 21 according to the voltage of the power supply end, so that the micro energy provided by the environmental energy source 200 is converted and output by the first power conversion component 21. The process of the control unit 24 controlling the start-up of the second power conversion component 22 is similar, and will not be repeated.

[0102] On the basis of the above-mentioned embodiments, optionally, there are multiple implementations of the switch control subunit 241 , several of which are described below, but are not intended to limit the present invention.

[0103] Figure 6 is a schematic diagram of the structure of a switch control subunit provided by an embodiment of the present invention. Figure 6In one embodiment, optionally, the switch control subunit 241 includes: a first inverter INV1 and a second inverter INV2. The input end of the first inverter INV1 is connected to the second control signal SW2, and the output end of the first inverter INV1 is connected to the control end of the third switch S3; the input end of the second inverter INV2 is connected to the output end of the first inverter INV1, and the output end of the second inverter INV2 is connected to the control end of the fourth switch S4. Among them, the output signals of the first inverter INV1 and the second inverter INV2 are the inverted signal and the same phase signal of the second control signal, respectively. In this way, after the second switch S2 is turned on, the switch control subunit 241 can still control the on and off of the third switch S3 and the fourth switch S4 according to the rules before the second switch S2 is turned on, so that the circuit structure is simple and the control logic is simple.

[0104] In the above embodiment, the switch control subunit 241 controls the on-off state of the third switch S3 and the fourth switch S4 according to the second control signal SW2, which is not intended to limit the present invention. In another embodiment, the switch control subunit 241 may also be connected to the third control signal SW3, and the on-off state of the third switch S3 and the fourth switch S4 may be jointly controlled according to the second control signal SW2 and the third control signal SW3.

[0105] Specifically, see Figure 7 , the switch control subunit 241 is removed Figure 6In addition to the first inverter INV1 and the second inverter INV2 shown, the present invention may further include: a first AND gate AND1, a third inverter INV3 and a multiplexer MUX. The input end of the third inverter INV3 is connected to the third control signal SW3; the two input ends of the first AND gate AND1 are respectively connected to the output end of the first inverter INV1 and the output end of the third inverter INV3, and the output end of the first AND gate AND1 is connected to the control end of the third switch S3; the first input end (for example, the 1 input end) of the multiplexer MUX is connected to the output end of the second inverter INV2, the second input end (for example, the 0 input end) of the multiplexer MUX is connected to the output end of the first inverter INV1, the selection end of the multiplexer MUX is connected to the output end of the third inverter INV3, and the output end of the multiplexer MUX is connected to the control end of the fourth switch S4. In this embodiment, the second control signal SW2 and the third control signal SW3 are respectively transmitted to the first AND gate AND1 after passing through the inverter, so that before the third control signal SW3 controls the second switch S2 to be turned on, the switch control subunit 241 controls the on-off state of the third switch S3 according to the second control signal SW2, and after the third control signal SW3 controls the second switch S2 to be turned on, the third switch S3 is forced to be controlled to be turned off, and the switch control subunit 241 maintains the voltage on the second capacitor C2 only by controlling the on-off state of the fourth switch S4. Exemplarily, the on-voltage of each switch is a high voltage (e.g., logic 1), and the off-voltage is a low voltage (e.g., logic 0).

[0106] The above embodiments exemplarily provide a distribution method of the energy provided by the ambient energy source 200 according to the voltage conditions of each key node when the first capacitor C1 and the second capacitor C2 are provided, but this is not intended to limit the present invention. In other embodiments, optionally, see Figure 8 , the environmental energy collection circuit 100 may further include an energy storage module, and the energy storage module is connected to the energy storage power supply terminal EP of the environmental energy collection circuit 100. Exemplarily, the energy storage module may be a super capacitor C3 or an energy storage battery, which may be connected between the energy storage power supply terminal EP and the ground. The converted electric energy can be stored by the energy storage module for subsequent use. The capacity of the energy storage module is much larger than the second capacitor C2. Correspondingly, the main energy collection module 20 may also include: a third power conversion component 23 connected between the energy input terminal EIN and the energy storage power supply terminal EP. The control unit 24 is also connected to the control end of the third power conversion component 23, and the control unit 24 is also used to control the on-off state of the third power conversion component 23 according to the second control signal SW2 and the third control signal SW3. Among them, the structure and function of the third power conversion component 23 can refer to the description of the first power conversion component 21 and the second power conversion component 22, which will not be repeated here.

[0107] Due to the huge difference in voltage and capacitance between the second capacitor C2 and the energy storage module, the second capacitor C2 and the energy storage module cannot be directly connected, and no switch is set between the second capacitor C2 and the energy storage module. An energy switch and a path for independently controlling C3 can be set in the control unit 24. Specifically, the control unit 24 can also include a fifth switch S5; the input end of the fifth switch S5 is connected to the output end of the control subunit 242, and the drive signal SDR is connected; the output end of the fifth switch S5 is connected to the control end of the third power conversion component 23; the fifth switch S5 is used to turn on or off according to the signal connected to its control end to control whether the drive signal SDR is transmitted to the control end of the first power conversion component 21. The switch control subunit 241 is also connected to the control end of the fifth switch S5 to control the on-off state of the fifth switch S5.

[0108] against Figure 8 The startup process of the ambient energy harvesting circuit 100 with energy storage module is compared with Figure 5 The process shown has some adjustments. After the second switch S2 is controlled to be turned on, a process similar to the process of distributing the micro energy between the first capacitor C1 and the second capacitor C2 can be used to distribute the micro energy between the second capacitor C2 and the energy storage module, so as to achieve the gradual charging of the energy storage module on the basis of ensuring that the voltage on the second capacitor C2 is relatively stable. Fig. 9 , the control method of the environmental energy harvesting circuit includes:

[0109] S201: A cold start module charges a first capacitor.

[0110] S202: Is VC1>Vth1? If yes, execute S203; if no, return to execute S201.

[0111] S203 , the first voltage detection unit controls the first switch to be turned on.

[0112] S204: Determine whether VN1 is less than Vlow. If yes, execute S205; if no, execute S206.

[0113] S205. The control unit controls the first power conversion component to start, and controls the second power conversion component and the third power conversion component to shut down.

[0114] S206. Determine whether VN1>Vhigh? If yes, execute S207; if no, execute S208.

[0115] S207: The control unit controls the first power conversion assembly and the third power conversion assembly to shut down, and controls the second power conversion assembly to start up.

[0116] S208. The control unit controls the first power conversion assembly, the second power conversion assembly, and the third power conversion assembly to maintain a state.

[0117] S209. Determine whether VC2>Vth4. If yes, execute S210; if no, return to execute S204.

[0118] S210, the third voltage detection unit controls the second switch to be turned on, and the control unit controls the first power conversion component to be turned off.

[0119] After the above S201-S210, the successful conversion from cold start to hot start can be achieved, which is equivalent to successfully starting the environmental energy collection circuit 100. The above S201-S210 is basically the same as the steps of S101-S110, except that, since the third power conversion component 23 is provided in the main energy collection module 20, the third power conversion component 23 must be controlled to be turned off (or disabled) before successful startup. And, in S210, the first power conversion component 21 is directly controlled to be turned off, and the subsequent first power conversion component 21 is also kept turned off, so as to simplify the control logic when the micro energy is subsequently distributed between the second capacitor C2 (or the combined structure of the second capacitor C2 and the first capacitor C1) and the energy storage module.

[0120] S211. Determine whether VN1 is less than Vlow. If yes, execute S212; if no, execute S213.

[0121] Among them, when VN1<Vlow, it is necessary to charge the combined structure of the first capacitor C1 and the second capacitor C2 through the second power conversion component 22, so that the voltage VN1 of the first node N1 will not drop too low to cause the main energy collection module 20 to lose power. When VN1≥Vhigh, the environmental energy source 200 charges the energy storage module through the third power conversion component 23, so that the voltage on the energy storage module gradually increases; but at the same time, the voltage on the first node N1 will drop again, and when the voltage VN1 of the first node N1 is lower than the second low voltage threshold Vlow again, it will enter S212 again, and so on, the voltage of the energy storage module gradually increases, and at the same time, the voltage VN1 of the first node N1 can also be maintained within a certain range.

[0122] S212: The control unit controls the second power conversion component to start, and controls the third power conversion component to shut down.

[0123] S213. Determine whether VN1>Vhigh? If yes, execute S214; if no, execute S215.

[0124] S214: The control unit controls the second power conversion component to shut down, and controls the third power conversion component to start up.

[0125] After this step, the process can return to S211 to distribute the micro-energy back and forth until the energy storage module is fully charged.

[0126] S215. The control unit controls the first power conversion assembly, the second power conversion assembly, and the third power conversion assembly to maintain a state.

[0127] The embodiment of the present invention provides a control method for an ambient energy harvesting circuit through S201 - S215 , which can realize low-threshold rapid and reliable startup of the ambient energy harvesting circuit 100 .

[0128] Fig.10 is a schematic diagram of the structure of another switch control subunit provided by an embodiment of the present invention. Fig.10 On the basis of the above embodiments, optionally, to achieve Figure 8 The structure of the switch control subunit 241 of the main energy collection module 20 shown in FIG. 24 may specifically be: Figure 7 On the basis of the structure shown, a second AND gate AND2 is added. Among them, the first input end of the second AND gate AND2 is connected to the output end of the second inverter INV2, the second input end of the second AND gate AND2 is connected to the third control signal SW3, and the output end of the second AND gate AND2 is connected to the control end of the fifth switch S5. The relevant explanations of the devices other than the second AND gate AND2 in the switch control subunit 241 can refer to the explanations in the above-mentioned embodiments, and no further description is given. For the control of the fifth switch S5, when the third control signal S3 controls the second switch S2 to be turned off, the fifth switch S5 is forced to be controlled to be turned off. Since the voltage on the second capacitor C2 has not reached the fourth voltage threshold, it is not enough to provide stable power supply to the main energy collection module 20, and the environmental energy source 200 cannot be used to charge the energy storage module at this time; when the third control signal S3 controls the second switch S2 to be turned on, the switch control subunit 241 can control the fourth switch S4 and the fifth switch S5 to be different in conduction state according to the second control signal SW2, so as to control the transmission of micro energy to the second capacitor C2 or the energy storage module, and realize reasonable energy distribution.

[0129] In the above embodiment, the first input terminal of the second AND gate AND2 is connected to the output terminal of the second inverter INV2, but this is not intended to limit the present invention. In other embodiments, the first input terminal of the second AND gate AND2 may be directly connected to the second control signal SW2. Since the second inverter INV2 outputs the in-phase signal of the second control signal SW2, the first input terminal of the second AND gate AND2 may be directly connected to the second control signal SW2 to obtain the AND gate. Fig.10 Consistent control effect.

[0130] In summary, the embodiment of the present invention provides a fast and reliable ambient energy harvesting circuit with a low startup threshold. The circuit can be applied to low-power circuit systems such as passive Internet of Things to meet the demand for ambient energy harvesting under lower input voltage and power. Based on the basic principle of the above circuit, after testing, it has Figure 8 The environmental energy harvesting circuit of the structure shown can be specifically: a low threshold fast energy harvesting circuit with a minimum cold start voltage of 120mv and a minimum cold start power of 1uw. Taking the first capacitor C1 as 2nF, the second capacitor C2 as 10uF, and the energy storage module as an ordinary lithium battery as an example, Fig. 9 The hierarchical startup strategy shown, the cold start time (i.e., the time when the voltage on the first capacitor C1 reaches the first voltage threshold Vth1) under the lowest voltage and lowest power is greatly shortened from several minutes in the related art to within 10 seconds. The cold start to hot start conversion time (i.e., the time from the end of the cold start to the voltage on the second capacitor C2 reaching the fourth voltage threshold Vth4) depends on the input power and system efficiency. Under the condition of the lowest input power (1uw) and a conversion efficiency of 40%, the conversion time required from cold start to hot start is within 13 seconds. Therefore, the startup time of the entire circuit is within 25 seconds, which is much less than the startup time of several minutes in the related art. Moreover, the lowest cold start voltage in the related art is above 200mv, and the lowest cold start power is above 1.5uw. The lowest cold start voltage and power of the circuit provided by the embodiment of the present invention are smaller than those in the related art.

[0131] An embodiment of the present invention further provides a control method for an ambient energy harvesting circuit, which is applied to the ambient energy harvesting circuit provided by any embodiment of the present invention and has corresponding beneficial effects. Fig.11 FIG. 1 is a flow chart of another control method of an ambient energy harvesting circuit provided by an embodiment of the present invention. Fig.11 , the control method of the environmental energy harvesting circuit includes:

[0132] S310. The cold start module charges the first capacitor using energy provided by the environmental energy source.

[0133] Give steps for the cold start process

[0134] S320: When the voltage detection module detects that the voltage at the output end of the cold start module reaches a first voltage threshold, the voltage detection module controls the first control signal to be a turn-on voltage of the first switch to turn on the first switch.

[0135] When the voltage at the output end of the cold start module reaches the first voltage threshold, the cold start is completed.

[0136] S330, repeatedly executing the first energy distribution step until the voltage at the power supply output terminal reaches a fourth voltage threshold.

[0137] Among them, the first energy distribution step includes: the voltage detection module controls the second control signal to be the first voltage when it detects that the voltage at the power supply end is lower than the second voltage threshold, and the control unit controls the first power conversion component to start and controls the second power conversion component to shut down according to the first voltage, so that the environmental energy source charges the first capacitor; the voltage detection module controls the second control signal to be the second voltage when it detects that the voltage at the power supply end is higher than the third voltage threshold, and the control unit controls the first power conversion component to shut down and controls the second power conversion component to start according to the second voltage, so that the environmental energy source charges the second capacitor; the first voltage is different from the second voltage, the second voltage threshold is higher than the first voltage threshold, the third voltage threshold is higher than or equal to the second voltage threshold, and the fourth voltage threshold is lower than the second voltage threshold.

[0138] This step is equivalent to the transition process from cold start to hot start.

[0139] S340: When the voltage at the power supply output terminal is detected to reach a fourth voltage threshold, the voltage detection module controls the third control signal to be a turn-on voltage of the second switch to turn on the second switch.

[0140] When the voltage at the power supply output terminal reaches the fourth voltage threshold, it is equivalent to a successful hot start.

[0141] Exemplarily, after the second switch is turned on, the control unit can control the start and stop of the first power conversion component and the second power conversion component according to the second control signal, thereby stabilizing the voltage on the second capacitor within a certain range.

[0142] In the control method of the environmental energy collection circuit provided by the embodiment of the present invention, according to the detection results of the voltage detection module on the voltage of the key nodes such as the output end of the cold start module, the power supply end of the main energy collection module and the power supply output end, the on-off state of the first switch and the second switch can be controlled, as well as the start-stop state of the first power conversion component and the second power conversion component can be controlled to achieve the hierarchical cold start to hot start conversion. Specifically, before the voltage at the output end of the cold start module reaches the first voltage threshold, the first switch is controlled to be turned off, so that the cold start module can be quickly started based on a small micro energy; in the conversion process from cold start to hot start, the start and stop of the first power conversion component and the second power conversion component are controlled according to the power supply end voltage of the main energy collection module, so as to control whether the micro energy provided by the environmental energy source is charged to the first capacitor or the second capacitor, so as to ensure that the power supply end voltage is sufficient to maintain the operation of the main energy collection module. On the basis of making the voltage of the second capacitor (i.e., the voltage of the power supply output end) steadily rise; until the voltage of the second capacitor rises to the fourth voltage threshold, the second switch is controlled to be turned on, so that the first capacitor and the second capacitor are connected and merged, and the hot start is successfully achieved. With this arrangement, the starting voltage of the cold start module can be used as the starting voltage of the ambient energy collection circuit, effectively reducing the starting threshold of the ambient energy collection circuit; and charging the second capacitor through the main energy collection module with higher energy collection efficiency can effectively improve the starting speed of the ambient energy collection circuit compared to charging only with the cold start module; and, in the process of converting from cold start to hot start, by controlling the start and stop of the first power conversion component and the second power conversion component, it can be ensured that the power supply end voltage of the main energy collection module will not drop to the level where the main energy collection module loses power, thereby improving the circuit startup reliability.

[0143] On the basis of the above embodiments, optionally, when the voltage detection module detects that the voltage at the power supply output terminal reaches a fourth voltage threshold, the control method of the environmental energy collection circuit further includes: the control unit controls the first power conversion component to be turned off according to a third control signal having a turn-on voltage of the second switch. In this way, after the second switch is turned on, the control unit can control the start and stop of the second power conversion component according to the second control signal, thereby stabilizing the voltage on the second capacitor within a certain range.

[0144] On the basis of the above-mentioned embodiments, optionally, the environmental energy collection circuit further includes: an energy storage module connected between the energy storage power supply end of the environmental energy collection circuit and the ground; the main energy collection module further includes: a third power conversion component connected between the energy input end and the energy storage power supply end. Accordingly, before the voltage detection module detects that the voltage at the power supply output end reaches the fourth voltage threshold, the control method of the environmental energy collection circuit further includes: the voltage detection module controls the third control signal to be the cut-off voltage of the second switch, so that the second switch is turned off, and the control unit controls the third power conversion component to be turned off according to the third control signal having the cut-off voltage of the second switch;

[0145] After the voltage detection module detects that the voltage at the power supply output terminal reaches the fourth voltage threshold, the control method of the environmental energy collection circuit also includes: repeating the second energy distribution step until the energy storage module is fully charged. Wherein, the second energy distribution step includes: when the voltage detection module detects that the voltage at the power supply terminal is lower than the second voltage threshold, the control unit controls the second control signal to be the first voltage, and controls the second power conversion component to start and the third power conversion component to shut down according to the first voltage, so that the environmental energy source charges the second capacitor; when the voltage detection module detects that the voltage at the power supply terminal is higher than the third voltage threshold, the control unit controls the second control signal to be the second voltage, and controls the second power conversion component to shut down and the third power conversion component to start according to the second voltage, so that the environmental energy source charges the energy storage module.

[0146] It should be noted that, in each embodiment of the above-mentioned ambient energy harvesting circuit, a series of explanations have been given on the control method of the ambient energy harvesting circuit. For the contents not explained in detail here, please refer to the explanations in the above-mentioned embodiments, and no further explanation will be given.

[0147] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0148] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An ambient energy harvesting circuit, characterized in that: include: A cold start module, wherein an input end of the cold start module is connected to an energy input end of the ambient energy collection circuit, and the energy input end is connected to an ambient energy source; A first capacitor connected between the output terminal of the cold start module and ground; A second capacitor is connected between the power supply output terminal of the environmental energy collection circuit and the ground; The capacitance of the second capacitor is greater than the capacitance of the first capacitor; The main energy collection module comprises: a control unit, a first power conversion component connected between the energy input end and the power supply end of the main energy collection module, and a second power conversion component connected between the energy input end and the power supply output end; the control unit is respectively connected to the control end of the first power conversion component and the control end of the second power conversion component; A switch module, comprising: a first switch connected between the output end of the cold start module and the power supply end, and a second switch connected between the power supply end and the power supply output end; a voltage detection module, configured to generate a first control signal according to a voltage at an output end of the cold start module, generate a second control signal according to a voltage at the power supply end, and generate a third control signal according to a voltage at the power supply output end; Among them, the first switch is used to turn on or off according to the first control signal; the control unit is used to control whether the first power conversion component and the second power conversion component are started according to the second control signal; the second switch is used to turn on or off according to the third control signal.

2. The environmental energy harvesting circuit according to claim 1, characterized in that: Also includes: An energy storage module connected to the energy storage power supply end of the environmental energy collection circuit; The main energy collection module also includes: a third power conversion component connected between the energy input end and the energy storage power supply end; the control unit is also connected to the control end of the third power conversion component, and the control unit is also used to control whether the third power conversion component is started according to the second control signal and the third control signal.

3. The environmental energy harvesting circuit according to claim 1 or 2, characterized in that: The voltage detection module comprises: a first voltage detection unit, connected to the output end of the cold start module and the control end of the first switch, respectively, and configured to generate the first control signal according to the voltage at the output end of the cold start module; a second voltage detection unit, connected to the power supply end and the control unit, respectively, and configured to generate the second control signal according to the voltage of the power supply end; a third voltage detection unit, connected to the power supply output terminal and the control terminal of the second switch, respectively, and configured to generate the third control signal according to the voltage of the power supply output terminal; And / or, the environmental energy collection circuit further includes: an electrostatic protection module connected to the power supply output terminal.

4. The environmental energy harvesting circuit according to claim 1, characterized in that: The control unit comprises: a third switch, wherein an output end of the third switch is connected to a control end of the first power conversion component; a fourth switch, wherein an output end of the fourth switch is connected to a control end of the second power conversion component; a switch control subunit, receiving the second control signal and connected to a control end of the third switch and a control end of the fourth switch respectively; A control subunit, wherein the input end of the control subunit is connected to the power supply end, and the output end of the control subunit is connected to the input end of the third switch and the input end of the fourth switch; the control subunit is used to generate and output a driving signal according to the voltage of the power supply end.

5. The environmental energy harvesting circuit according to claim 4, characterized in that: The switch control subunit comprises: A first inverter, wherein an input end of the first inverter is connected to the second control signal, and an output end of the first inverter is connected to a control end of the third switch; A second inverter, wherein an input end of the second inverter is connected to an output end of the first inverter, and an output end of the second inverter is connected to a control end of the fourth switch.

6. The environmental energy harvesting circuit according to claim 5, characterized in that: The switch control subunit further includes: a first AND gate, a third inverter and a multiplexer; The input end of the third inverter is connected to the third control signal; the two input ends of the first AND gate are respectively connected to the output end of the first inverter and the output end of the third inverter, and the output end of the first AND gate is connected to the control end of the third switch; the first input end of the multiplexer is connected to the output end of the second inverter, the second input end of the multiplexer is connected to the output end of the first inverter, the selection end of the multiplexer is connected to the output end of the third inverter, and the output end of the multiplexer is connected to the control end of the fourth switch.

7. The environmental energy harvesting circuit according to claim 6, characterized in that: The environmental energy collection circuit further includes: an energy storage component connected between the energy storage power supply terminal of the environmental energy collection circuit and the ground; the main energy collection module further includes: a third power conversion component connected between the energy input terminal and the energy storage power supply terminal; The control unit further includes: a fifth switch, the output end of the fifth switch is connected to the control end of the third power conversion component, and the output end of the control subunit is also connected to the input end of the fifth switch; The switch control subunit also includes: a second AND gate, a first input end of the second AND gate is connected to the second control signal or the output end of the second inverter, a second input end of the second AND gate is connected to the third control signal, and an output end of the second AND gate is connected to the control end of the fifth switch.

8. A control method for an ambient energy harvesting circuit, characterized in that: An ambient energy harvesting circuit applied to any one of claims 1-7; The control method of the environmental energy harvesting circuit comprises: The cold start module charges the first capacitor using energy provided by the ambient energy source; When the voltage detection module detects that the voltage at the output end of the cold start module reaches a first voltage threshold, the voltage detection module controls the first control signal to be a turn-on voltage of the first switch, so that the first switch is turned on; Repeat the first energy distribution step until the voltage at the power supply output terminal reaches a fourth voltage threshold; the first energy distribution step includes: the voltage detection module controls the second control signal to be a first voltage when detecting that the voltage at the power supply terminal is lower than a second voltage threshold, and the control unit controls the first power conversion component to start and controls the second power conversion component to shut down according to the first voltage, so that the environmental energy source charges the first capacitor; the voltage detection module controls the second control signal to be a second voltage when detecting that the voltage at the power supply terminal is higher than a third voltage threshold, and the control unit controls the first power conversion component to shut down and controls the second power conversion component to start according to the second voltage, so that the environmental energy source charges the second capacitor; the first voltage is different from the second voltage, the second voltage threshold is higher than the first voltage threshold, the third voltage threshold is higher than or equal to the second voltage threshold, and the fourth voltage threshold is lower than the second voltage threshold; When the voltage detection module detects that the voltage at the power supply output terminal reaches a fourth voltage threshold, the voltage detection module controls the third control signal to be a turn-on voltage of the second switch to turn on the second switch.

9. The control method of the environmental energy harvesting circuit according to claim 8, characterized in that: When the voltage detection module detects that the voltage at the power supply output terminal reaches a fourth voltage threshold, the control method of the ambient energy collection circuit further includes: The control unit controls the first power conversion component to be turned off according to the third control signal having the turn-on voltage of the second switch.

10. The control method of the environmental energy harvesting circuit according to claim 9, characterized in that: The environmental energy collection circuit also includes: an energy storage module connected between the energy storage power supply end of the environmental energy collection circuit and the ground; the main energy collection module also includes: a third power conversion component connected between the energy input end and the energy storage power supply end; Before the voltage detection module detects that the voltage at the power supply output terminal reaches a fourth voltage threshold, the control method of the ambient energy collection circuit further includes: The voltage detection module controls the third control signal to be the cut-off voltage of the second switch, so that the second switch is turned off, and the control unit controls the third power conversion component to be turned off according to the third control signal having the cut-off voltage of the second switch; After the voltage detection module detects that the voltage at the power supply output terminal reaches a fourth voltage threshold, the control method of the ambient energy collection circuit further includes: Repeat the second energy distribution step until the energy storage module is fully charged; the second energy distribution step includes: when the voltage detection module detects that the voltage at the power supply end is lower than the second voltage threshold, the voltage detection module controls the second control signal to be the first voltage, and the control unit controls the second power conversion component to start and controls the third power conversion component to be turned off according to the first voltage, so that the environmental energy source charges the second capacitor; when the voltage detection module detects that the voltage at the power supply end is higher than the third voltage threshold, the voltage detection module controls the second control signal to be the second voltage, and the control unit controls the second power conversion component to be turned off and controls the third power conversion component to start according to the second voltage, so that the environmental energy source charges the energy storage module.

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