Supercapacitor assisted energy autonomous sensor platform

Abstract

The embodiment of the invention relates to an energy autonomous sensor platform assisted by a super capacitor. An energy autonomous system is disclosed that includes a transducer, a first capacitor, a second capacitor having a greater capacitance than the first capacitor, and a microprocessor. The microprocessor includes a first terminal electrically coupled to the transducer and the first capacitor; a second terminal electrically coupled to the second capacitor; a switch in a conductive state in which the switch electrically couples the first terminal and the second terminal together, or in a non-conductive state in which the switch does not electrically couple the first terminal and the second terminal together; a voltage detector that detects a voltage at the first terminal; and a processor coupled to the voltage detector and the switch. The processor controls charging of the second capacitor by controlling the switch to be in a conductive state or a non-conductive state based on the voltage at the first terminal detected by the voltage detector.

Description

Technical Field

[0001] The present disclosure relates generally to energy autonomous sensor platforms, and more particularly to energy autonomous sensor platforms assisted by supercapacitors that continue to operate when a transducer acting as a primary energy source is not producing energy. Background Art

[0002] Traditionally, systems use a power management integrated circuit (PMIC) to charge an energy storage device (e.g., a battery) based on the output from a transducer (e.g., a photovoltaic cell). Such a PMIC consumes some of the energy output from the transducer that cannot be stored in the energy storage device. In addition, the PMIC increases the material cost of such a system. Summary of the invention

[0003] According to the present disclosure, an energy autonomous system includes a first capacitor that stores energy generated by a transducer and provides energy to a microprocessor that controls the operation of the energy autonomous system. Thus, the energy autonomous system remains operational as long as the transducer generates energy. The microprocessor controls the charging of a second capacitor (e.g., a supercapacitor) that provides energy to the microprocessor during time periods when the transducer is unable to generate energy. Advantageously, the energy autonomous system does not include a PMIC because the microprocessor is used to control the charging of the second capacitor, which reduces the cost of the energy autonomous system.

[0004] For example, the transducer includes a photovoltaic unit, which generates energy as long as a sufficient amount of light shines on the photovoltaic unit. Therefore, the photovoltaic unit can usually supply power to the first capacitor to operate the energy autonomous system during the day, but cannot supply power to the first capacitor to operate the energy autonomous system at night. The energy stored by the second capacitor is supplied to the microprocessor at night to keep the energy autonomous system running at night.

[0005] Because the system according to the present disclosure is energy autonomous and requires minimal or no maintenance, the energy autonomous system according to the present disclosure is suitable for so-called set-and-forget devices. In addition, the energy autonomous system according to the present disclosure can be produced at very low cost. Therefore, the energy autonomous system according to the present disclosure is particularly suitable for Internet of Things (IoT) applications in which a large number of systems are used.

[0006] The system according to the present disclosure may be characterized by including: a transducer; a first capacitor; a second capacitor having a capacitance greater than that of the first capacitor; and a microprocessor including: a first terminal electrically coupled to the transducer and the first capacitor; a second terminal electrically coupled to the second capacitor; a switch, the switch being in a conductive state in which the switch electrically couples the first terminal and the second terminal together or in a non-conductive state in which the switch does not electrically couple the first terminal and the second terminal together; a voltage detector in operation to detect a voltage at the first terminal; and a processor coupled to the voltage detector and the switch. The processor controls the charging of the second capacitor by controlling the switch in a conductive state and a non-conductive state based on the voltage at the first terminal detected by the voltage detector.

[0007] In response to the voltage detector detecting that the voltage at the first terminal is less than or equal to the first voltage threshold, the processor may control the switch to be in a non-conducting state, and in response to the voltage detector detecting that the voltage at the first terminal is greater than or equal to a second voltage threshold, the processor may control the switch to be in a conducting state, the second voltage threshold being greater than the first voltage threshold. In response to determining that the voltage of the second capacitor is greater than or equal to the first voltage threshold, the processor may control the switch to be in a conducting state. The microprocessor may operate in a first power consumption mode in which the microprocessor consumes a first amount of power and in a second power consumption mode in which the processor consumes a second amount of power, the second amount of power being greater than the first amount of power, and in response to determining that the voltage of the second capacitor is greater than or equal to the first voltage threshold, the processor may control the switch to be in a conducting state and cause the microprocessor to change from operating in the second power consumption mode to operating in the first power consumption mode. The microprocessor may charge the second capacitor in a discontinuous charging mode and a continuous charging mode in operation, in which the processor may control the switch to change from being in a conducting state to being in a non-conducting state and from being in a non-conducting state to being in a conducting state, and in a continuous charging mode, the processor may control the switch to be in a conducting state. When the microprocessor charges the second capacitor in a continuous charging mode, the processor may control the microprocessor to operate in a first power consumption mode, and when the microprocessor charges the second capacitor in a discontinuous charging mode, the processor may control the microprocessor to operate in a second power consumption mode. In response to determining that the voltage of the second capacitor is greater than the first voltage threshold, the processor may cause the microprocessor to change from charging the second capacitor in a discontinuous charging mode to charging the second capacitor in a continuous charging mode in operation. The microprocessor may include a transmitter that sends a signal in operation, and when the microprocessor charges the second capacitor in a discontinuous charging mode, the processor may cause the transmitter to send a signal, and when the microprocessor charges the second capacitor in a continuous charging mode, the processor may not cause the transmitter to send a signal. The microprocessor may include a sensor that provides an output to the processor in operation, and the signal sent by the transmitter may be based on the output of the sensor.

[0008] The method according to the present disclosure may be characterized by including: coupling a transducer to a first terminal of a microprocessor; coupling a first capacitor to the first terminal of the microprocessor; coupling a second capacitor having a capacitance greater than that of the first capacitor to a second terminal of the microprocessor; detecting a voltage at the first terminal; and controlling the charging of the second capacitor by controlling a switch included in the microprocessor to a conducting state and a non-conducting state based on the voltage at the first terminal. In the conducting state, the switch electrically couples the first terminal and the second terminal together, and in the non-conducting state, the switch does not electrically couple the first terminal and the second terminal together.

[0009] The method may also include controlling the switch to be in a non-conducting state in response to the voltage at the first terminal being less than or equal to a first voltage threshold, and controlling the switch to be in a conducting state in response to the voltage at the first terminal being greater than or equal to a second voltage threshold, the second voltage threshold being greater than the first voltage threshold. The method may also include controlling the switch to be in a conducting state in response to determining that the voltage of the second capacitor is greater than or equal to the first voltage threshold. The microprocessor may operate in a first power consumption mode in which the microprocessor consumes a first amount of power and in a second power consumption mode in which the microprocessor consumes a second amount of power, the second amount of power being greater than the first amount of power, and the method may also include controlling the switch to change from being in a conducting state and controlling the microprocessor to change from operating in the second power consumption mode to operating in the first power consumption mode in response to determining that the voltage of the second capacitor is greater than or equal to the first voltage threshold. The method may also include charging the second capacitor in a discontinuous charging mode by controlling the switch to change from being in a conducting state to being in a non-conducting state and from being in a non-conducting state to being in a conducting state; and charging the second capacitor in a continuous charging mode by controlling the switch to be in a conducting state. The method may also include controlling the microprocessor to operate in a first power consumption mode when the microprocessor charges the second capacitor in a continuous charging mode, and controlling the microprocessor to operate in a second power consumption mode when the microprocessor charges the second capacitor in a discontinuous charging mode. The method may also include controlling the microprocessor to change from charging the second capacitor in a discontinuous charging mode to charging the second capacitor in a continuous charging mode in response to determining that the voltage of the second capacitor is greater than a first voltage threshold. The method may also include controlling a transmitter included in the microprocessor to send a signal when the microprocessor charges the second capacitor in a discontinuous charging mode, wherein the transmitter is not controlled to send a signal when the microprocessor charges the second capacitor in a continuous charging mode. The signal sent by the transmitter may be based on an output of a sensor included in the microprocessor.

[0010] The system according to the present disclosure may be characterized by including: a transducer; a first capacitor; a battery; and a microprocessor, the microprocessor including: a first terminal electrically coupled to the transducer and the first capacitor; a second terminal electrically coupled to the battery; a switch, the switch being in a conductive state in which the switch electrically couples the first terminal and the second terminal together, or in a non-conductive state in which the switch does not electrically couple the first terminal and the second terminal together; a voltage detector in operation to detect a voltage at the first terminal; and a processor coupled to the voltage detector and the switch. The processor controls the charging of the battery by controlling the switch in a conductive state and a non-conductive state based on the voltage at the first terminal detected by the voltage detector.

[0011] In response to the voltage detector detecting that the voltage at the first terminal is less than or equal to a first voltage threshold, the processor can control the switch to be in a non-conducting state, and in response to the voltage detector detecting that the voltage at the first terminal is greater than or equal to a second voltage threshold, the processor can control the switch to be in a conducting state, and the second voltage threshold is greater than the first voltage threshold. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Non-limiting and non-exhaustive embodiments are described with reference to the following drawings.In the drawings, like reference numerals refer to like parts throughout the various views unless otherwise specified.

[0013] For a better understanding of the present disclosure, reference will be made to the following detailed description which will be read in conjunction with the accompanying drawings:

[0014] Figure 1 A block diagram of an energy autonomous system according to an embodiment of the present disclosure is shown;

[0015] Figure 2A , Figure 2B , Figure 2C and Figure 2D Shown for explanation Figure 1 A diagram of the operation of the energy autonomous system shown;

[0016] Figure 3 Shown for explanation Figure 1 Another diagram of the operation of the energy autonomous system shown; and

[0017] Figure 4 The switching between discontinuous charging mode and continuous charging mode is shown. Figure 1 An example of energy being charged from a second capacitor of the autonomous system is shown. DETAILED DESCRIPTION

[0018] The system according to an embodiment of the present disclosure implements a wireless sensor platform with minimal bill of materials (BOM) (ie, cost) and power consumption. In addition to sensing, computing, and radio transmission activities, the system also uses a single microcontroller unit (MCU) for energy management.

[0019] The system uses two capacitors to store the energy generated by the energy harvester. The first small value capacitor (uF to mF) provides flexibility to the system and allows it to operate during the time when the energy source can be generated. The second high value capacitor (i.e., supercapacitor (farad)) stores energy during the period when the sensor is idle and the energy source can generate energy at the same time. The energy stored by the supercapacitor is used as a backup by the system to operate during the period when the energy source cannot supply energy.

[0020] Embodiments according to the present disclosure include a transducer for charging a first capacitor and a second capacitor. When the transducer generates energy, the transducer and / or the first capacitor provide energy to a microprocessor, and when the transducer does not generate energy, the second capacitor provides energy to the microprocessor. In one or more implementations, the first capacitor is a normal capacitor and the second capacitor is a supercapacitor.

[0021] Figure 1 A block diagram of an energy autonomous system 100 according to an embodiment of the present disclosure is shown. The energy autonomous system 100 includes a transducer 102, a microprocessor 104, a first capacitor C1 and a second capacitor C2.

[0022] In one or more implementations, the transducer 102 includes a photovoltaic cell or panel. Table 1 shows examples of different photovoltaic cells available from Panasonic Battery that can be used as the transducer 102. Other types of transducers (e.g., piezoelectric transducers, thermocouples, wind turbines, etc.) can be used as the transducer 102 within the scope of the present disclosure.

[0023]

[0024] Table 1

[0025] In one or more implementations, the microprocessor 104 is a STM32WL5x model microcontroller unit (MCU) available from STMicroelectronics. Other microprocessors may be used as the microprocessor 104 within the scope of the present disclosure.

[0026] The microprocessor 104 includes a processor 106 and a memory 108 that stores instructions that, when executed by the processor 106, cause the microprocessor 104 to perform the functions described herein. The microprocessor 104 also includes a sensor 110, such as a temperature sensor, a light sensor, a humidity sensor, etc. In addition, the microprocessor 104 includes a communication circuit system 112, which may include a transmitter and a receiver that send and receive signals according to one or more communication standards (e.g., Bluetooth or the IEEE 802.11 family of communication standards). For example, the sensor 110 periodically measures the temperature and provides a corresponding output, and the transmitter included in the communication circuit system 112 periodically sends a signal including data based on the output of the sensor 110.

[0027] In addition, the microprocessor 104 includes a plurality of terminals for connecting to external devices. Figure 1Only two of the terminals of the microprocessor 104 are shown in FIG. More specifically, the microprocessor 104 includes a terminal Vdd to which a power supply voltage is supplied in order to power the microprocessor 104 so that it can operate. In addition, the microprocessor 104 includes a general purpose input / output (GPIO) interface including a terminal GPIO.

[0028] The microprocessor 104 also includes a voltage detector 114 coupled to the terminal Vdd and the processor 106. In one or more implementations, the voltage detector 114 is a programmable voltage detector (PVD).

[0029] For example, the voltage detector 114 includes a comparator having a power supply terminal, a non-inverting input terminal, and an inverting input terminal. The power supply terminal of the comparator is coupled to a terminal Vdd, which supplies power to the comparator so that it can operate. The voltage detector 114 also includes a resistor having a first terminal coupled to the terminal Vdd of the microprocessor 104 and a second terminal coupled to the non-inverting input terminal of the comparator. In addition, the voltage detector 114 includes a variable resistor having a first terminal coupled to the non-inverting input terminal of the comparator and a second terminal grounded. In addition, the voltage detector 114 includes a reference voltage source that provides a reference voltage to the inverting input terminal of the comparator. The processor 106 controls the resistance of the variable resistor and / or the magnitude of the reference voltage to set different threshold voltage levels of the voltage detector 114. If the voltage at the terminal Vdd is greater than a specific threshold voltage level set by the processor 106, the voltage detector 114 outputs a signal to the processor 106, which controls the switch 116 based on the output of the voltage detector 114.

[0030] The switch 116 has a terminal electrically coupled to the terminal Vdd and a terminal electrically coupled to the terminal GPIO. Depending on the characteristics (e.g., voltage level) of the control signal provided to the switch 116 by the processor 106, the switch 116 is in a conducting state or a non-conducting state. When the switch 116 is in the conducting state, the switch 116 electrically couples the terminal Vdd and the terminal GPIO to each other. When the switch 116 is in the non-conducting state, the switch 116 does not electrically couple the terminal Vdd and the terminal GPIO to each other.

[0031] The processor 106 also sets a power consumption mode of the microprocessor 104 based on the output of the voltage detector 114. The microprocessor 104 operates in a first power consumption mode (e.g., a sleep mode or a stop mode) in which the microprocessor 104 consumes a first amount of power and in a second power consumption mode (e.g., a normal mode or a run mode) in which the microprocessor 104 consumes a second amount of power, the second amount of power being greater than the first amount of power. For example, the processor 106 outputs a signal having a specific characteristic (e.g., a voltage level) or changes a value stored in a register to set the power consumption mode of the microprocessor 104.

[0032] When the microprocessor 104 is operating in the second power consumption mode, in response to the voltage detector 114 detecting that the voltage at the terminal Vdd is less than or equal to the first voltage threshold (e.g., 2V), the processor 106 causes the microprocessor 104 to change to operate in the first power consumption mode. In addition, when the microprocessor 104 is operating in the first power consumption mode, in response to the voltage detector 114 detecting that the voltage at the terminal Vdd is greater than or equal to the first voltage threshold, the processor 106 causes the microprocessor 104 to change to operate in the second power consumption mode.

[0033] As described above, the energy autonomous system 100 includes a first capacitor C1 and a second capacitor C2. The first capacitor C1 is a common capacitor, which may also be referred to as a single layer capacitor because it forms a single layer of charge between two plates. The first capacitor C1 includes a first terminal electrically coupled to a terminal Vdd of the microprocessor 104 and a second terminal electrically coupled to a reference potential (such as a ground potential). In one or more implementations, the capacitance of the first capacitor C1 is 470 microfarads (μF). In one or more implementations, the energy autonomous system 100 includes two first capacitors C1 arranged in parallel, wherein the capacitance of each of the capacitors C1 is 470 μF.

[0034] The second capacitor C2 is a supercapacitor, which may also be referred to as an ultracapacitor or a double-layer capacitor, which can store more energy than an ordinary capacitor by generating a double-layer charge between two plates. The second capacitor C2 includes a first terminal electrically coupled to a GPIO terminal of the microprocessor 104 and a second terminal electrically coupled to a reference potential (such as a ground potential). In one or more implementations, the second capacitor C2 has a capacitance of at least 1 farad (F). Therefore, the capacitance of the second capacitor C2 is much greater than the capacitance of the first capacitor C1.

[0035] Figure 2A , Figure 2B , Figure 2C and Figure 2D A diagram for explaining the operation of the energy autonomous system 100 is shown. Figure 2AThe energy autonomous system 100 is shown operating in an energy harvesting mode, for example, when the energy autonomous system 100 is initially deployed. It is assumed that the first capacitor C1 is initially discharged and the transducer 102 is outputting energy. For example, the transducer 102 is a photovoltaic unit illuminated by the sun. The energy output by the transducer 102 is provided to the terminal Vdd of the microprocessor 104 and the first capacitor C1. Therefore, the first capacitor C1 is charged and the microprocessor 104 is able to operate.

[0036] Figure 2B The energy autonomous system 100 is shown operating in a discontinuous charging mode, which may follow operation of the energy autonomous system 100 in an energy harvesting mode. In response to the microprocessor 104 determining that the first capacitor C1 is sufficiently charged so that it can charge the second capacitor C2, the energy autonomous system 100 transitions from the energy harvesting mode to the discontinuous charging mode.

[0037] For example, the processor 106 determines whether the voltage at the terminal Vdd is greater than or equal to a second voltage threshold (e.g., 3V) based on the output from the voltage detector 114. In response to determining that the voltage at the terminal Vdd is greater than or equal to the second voltage threshold, the processor 106 provides a control signal to the switch 116, which causes the switch 116 to be in an on state. Therefore, current flows from the first capacitor C1 to the second capacitor C2 through the terminal Vdd, the switch 116, and the terminal GPIO, which causes the second capacitor C2 to charge.

[0038] Figure 2C An energy autonomous system 100 is shown operating in a continuous charging mode, which follows the operation of the energy autonomous system 100 in a discontinuous charging mode. Before entering the continuous charging mode, the microprocessor 104 determines that the second capacitor C2 is sufficiently charged so that it does not cause the microprocessor 104 to reset. For example, the microprocessor 104 requires that the terminal Vdd be applied with at least 1.7 volts (V) in order for the microprocessor 104 to operate. If a voltage less than 1.7V is applied to the terminal Vdd when the microprocessor 104 is operating, the microprocessor 104 stops operating and resets. A first voltage threshold (e.g., 1.8V or 2.0V) can be established to ensure that the microprocessor 104 will not reset. In addition, when the energy autonomous system 100 operates in the continuous charging mode, the processor 106 causes the microprocessor 104 to operate in a first power consumption mode (e.g., a sleep mode or a stop mode).

[0039] The memory 108 stores instructions that cause the processor 106 to generate a signal based on the energy autonomous system 100 being in a state of Figure 2BThe amount of time that the transducer 102 and / or the first capacitor C1 charges the second capacitor C2 when operating in the discontinuous charging mode shown is used to determine or estimate the amount of charge in the second capacitor C2. For example, the processor 106 determines or estimates the amount of charge in the second capacitor C2 based on a timer set by the processor 106, characteristics of the transducer 102 (e.g., see Table 1), and a specific capacitance of the second capacitor C2. After the processor 106 determines that the second capacitor C2 has been sufficiently charged from operating in the discontinuous charging mode, the processor 106 provides a control signal to the switch 116, which causes the switch 116 to be in a conductive state. As a result, current flows from the transducer 102 through the terminal Vdd, the switch 116, and the terminal GPIO to the second capacitor C2, which causes the second capacitor C2 to charge.

[0040] When the microprocessor 104 is operating in a first power consumption mode (eg, a sleep mode or a stop mode), Figure 2C The charging efficiency of capacitor C2 in the continuous charging mode shown is better than that in Figure 2B The discontinuous charging mode (e.g., normal mode or operating mode) shown is much higher. For example, if the transducer 102 is a photovoltaic unit illuminated with a light intensity of 2600 Lux, and the capacitor C2 has a capacitance of 1 F, then in the continuous charging mode, the capacitor C2 is provided with 0.206 joules per minute, while in the discontinuous charging mode, the capacitor C2 is only provided with 0.022 joules per minute.

[0041] Figure 2DAn energy autonomous system 100 is shown operating in an auxiliary power mode, which follows the operation of the energy autonomous system in a discontinuous charging mode and a continuous charging mode. As described above, based on the characteristics of the transducer 102, the first capacitor C1, and the second capacitor C2, the microprocessor 104 determines or estimates the amount of charge stored in the second capacitor C2 based on the amount of time that the first capacitor C1 and / or the transducer 102 charges the second capacitor C2 when the energy autonomous system 100 operates in the discontinuous charging mode and the amount of time that the transducer 102 charges the second capacitor C2 when the energy autonomous system 100 operates in the continuous charging mode. In addition, the microprocessor 104 determines that the transducer 102 has stopped outputting energy for at least a predetermined amount of time based on the voltage detected by the programmable voltage detector 114. After the microprocessor 104 determines that the second capacitor C2 is fully charged and the transducer 102 has stopped outputting energy for at least a predetermined amount of time, the microprocessor 104 provides a control signal to the switch 116, and the control signal causes the switch 116 to be in a conductive state. Therefore, current flows from the second capacitor C2 through the terminal GPIO and the switch 116 to the terminal Vdd, which enables the microprocessor 104 to operate when the transducer 102 is not outputting energy. For example, if the transducer 102 is a photovoltaic unit, the processor 106 causes the energy autonomous system 100 to operate at night. Figure 2D Auxiliary power mode operation is shown.

[0042] Figure 3 Another diagram for explaining the operation of the energy autonomous system 100 is shown. Figure 3 1 shows the change of the voltage of the first capacitor C1 and the second capacitor C2 over time. Initially, the voltage of the first capacitor C1 is zero, and the energy autonomous system 100 is Figure 2A After the voltage of the first capacitor C1 reaches a first voltage threshold (e.g., 2V), the microprocessor 104 starts to operate in the second power consumption mode. After the voltage of the first capacitor C1 reaches a second voltage threshold (e.g., 3V), the autonomous system 100 starts to operate in the second power consumption mode. Figure 2B The circuit operates in the discontinuous charging mode as shown, and the voltage of the second capacitor C2 begins to increase.

[0043] When the energy autonomous system 100 operates in the second power consumption mode (e.g., normal mode or running mode), the microprocessor 104 periodically performs a sensing function using the sensor 110 (e.g., a temperature sensor) and stores the sensing result in the memory 108. The microprocessor 104 periodically wirelessly transmits data based on the sensing result using the communication circuit system 112, which causes a decrease in the voltage stored by the first capacitor C1.

[0044] Figure 4 Shown in Figure 11 is an example of switching between a discontinuous charging mode (DCM) and a continuous charging mode (CCM) for charging the supercapacitor C2 shown. When operating in the discontinuous charging mode (DCM), the voltage of the first capacitor C1 varies between a first voltage threshold (e.g., 2V) and a second voltage threshold (e.g., 3V). In response to the processor 106 determining that the voltage of the first capacitor C1 has reached the second voltage threshold based on the output from the programmable voltage detector 114, the processor 106 causes the microprocessor 104 to send sensor data using the communication circuit system 112 (e.g., a Bluetooth transmitter), which results in a decrease in the voltage of the first capacitor C1. In addition, the processor 106 outputs a control signal that causes the switch 116 to be in an on state, so that the microprocessor 104 charges the second capacitor C2 using the current provided by the first capacitor C1 in a relatively short period of time, as shown in FIG. Figure 2B When the processor 106 determines that the voltage of the first capacitor C1 has reached the first voltage threshold based on the output from the programmable voltage detector 114, the processor 106 causes the microprocessor 104 to operate in a first power consumption mode (eg, a sleep mode or a stop mode).

[0045] After a predetermined number of transmissions (e.g., 14 times) or a predetermined amount of time (e.g., 40 seconds), the processor 106 determines whether the voltage of the second capacitor C2 is greater than the first voltage threshold. After determining that the voltage of the second capacitor C2 is greater than the first voltage threshold, the processor 106 outputs a control signal that causes the switch 116 to be in an on state and then causes the microprocessor 104 to operate in a first power consumption mode (e.g., a sleep mode or a stop mode), which causes the second capacitor C2 to be charged in a continuous charging mode (CCM).

[0046] After a predetermined amount of time (e.g., 2 min), if the voltage at terminal Vdd is greater than the first voltage threshold, processor 106 causes microprocessor 104 to operate in a second power consumption mode (e.g., normal mode or run mode) and causes switch 116 to be in a non-conductive state, which causes second capacitor C2 to be charged in a discontinuous charging mode (DCM). For example, the predetermined amount of time corresponds to a time when microprocessor 104 is scheduled to perform a sensing operation using sensor 110 and / or transmit data using communication circuit system 112.

[0047] Therefore, the energy autonomous system 100 periodically switches between charging the second capacitor C2 in a discontinuous charging mode (DCM) and charging the second capacitor C2 in a continuous charging mode (CCM). This causes the second capacitor C2 to store a sufficient amount of charge so that the second capacitor C2 can be used when the transducer 102 is unable to output energy (for example, at night). Figure 2DThe auxiliary power mode shown provides power to the microprocessor 104 .

[0048] In one or more implementations, when charging the second capacitor C2 in the discontinuous charging mode, the microprocessor 104 increases the first voltage threshold (eg, from 2V to 2.3V), which increases the amount of time the second capacitor C2 is charged in the discontinuous charging mode.

[0049] The various embodiments described above can be combined to provide additional embodiments. All U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications, and non-patent publications mentioned in this specification and / or listed in the application data sheet are all incorporated herein by reference. If necessary, various aspects of the embodiments can be modified to provide additional embodiments using the concepts of various patents, applications, and publications. For example, a rechargeable battery can be used instead of the second capacitor C2.

[0050] These and other changes can be made to the embodiments in light of the above detailed description. In general, in the following claims, the terms used should not be interpreted to limit the claims to the specific embodiments disclosed in the specification and claims, but should be understood to include all possible embodiments and the full range of equivalents to which these claims are entitled. Therefore, the claims are not limited by this disclosure.

Claims

1. A system comprising: Transducer; a first capacitor; a second capacitor, wherein the capacitance of the second capacitor is greater than the capacitance of the first capacitor; as well as Microprocessor, including: a first terminal electrically coupled to the transducer and the first capacitor; a second terminal electrically coupled to the second capacitor; a switch, in operation, in a conducting state wherein the switch electrically couples the first terminal and the second terminal together, or in a non-conducting state wherein the switch does not electrically couple the first terminal and the second terminal together; a voltage detector, in operation to detect a voltage at the first terminal, and a processor, coupled to the voltage detector and the switch, The processor is operable to control charging of the second capacitor by controlling the switch to be in the conducting state and the non-conducting state based on the voltage at the first terminal detected by the voltage detector.

2. The system of claim 1, wherein: In response to the voltage detector detecting that the voltage at the first terminal is less than or equal to a first voltage threshold, the processor controls the switch to be in the non-conducting state, and The processor controls the switch to be in the on state in response to the voltage detector detecting that the voltage at the first terminal is greater than or equal to a second voltage threshold, the second voltage threshold being greater than the first voltage threshold. 3 . The system of claim 2 , wherein the processor controls the switch to be in the on state in response to determining that the voltage of the second capacitor is greater than or equal to the first voltage threshold.

4. The system of claim 2, wherein: the microprocessor operates in a first power consumption mode in which the microprocessor consumes a first amount of power and in a second power consumption mode in which the microprocessor consumes a second amount of power, the second amount of power being greater than the first amount of power, and In response to determining that the voltage of the second capacitor is greater than or equal to the first voltage threshold, the processor controls the switch to be in the on state and causes the microprocessor to change from operating in the second power consumption mode to operating in the first power consumption mode.

5. The system of claim 4, wherein: The microprocessor is operable to charge the second capacitor in a discontinuous charging mode and a continuous charging mode. In the discontinuous charging mode, the processor controls the switch to change from the conducting state to the non-conducting state and from the non-conducting state to the conducting state, and In the continuous charging mode, the processor controls the switch to be in the on state.

6. The system of claim 5, wherein: When the microprocessor charges the second capacitor in the continuous charging mode, the processor controls the microprocessor to operate in the first power consumption mode, and When the microprocessor charges the second capacitor in the discontinuous charging mode, the processor controls the microprocessor to operate in the second power consumption mode.

7. The system of claim 5, wherein in response to determining that the voltage of the second capacitor is greater than the first voltage threshold, the processor causes the microprocessor to change from charging the second capacitor in the discontinuous charging mode to charging the second capacitor in the continuous charging mode during operation.

8. The system of claim 5, wherein: The microprocessor includes a transmitter that transmits a signal in operation, When the microprocessor charges the second capacitor in the discontinuous charging mode, the processor causes the transmitter to send the signal, and When the microprocessor charges the second capacitor in the continuous charging mode, the processor does not cause the transmitter to send the signal.

9. The system of claim 8, wherein: The microprocessor includes a sensor that provides an output to the processor in operation, and The signal sent by the transmitter is based on the output of the sensor.

10. A method comprising: coupling the transducer to a first terminal of the microprocessor; coupling a first capacitor to the first terminal of the microprocessor; coupling a second capacitor to a second terminal of the microprocessor, wherein the capacitance of the second capacitor is greater than the capacitance of the first capacitor; detecting a voltage at the first terminal; as well as controlling the charging of the second capacitor by controlling a switch included in the microprocessor to be in a conducting state and a non-conducting state based on the voltage at the first terminal, wherein in the on state, the switch electrically couples the first terminal and the second terminal together, and Wherein in the non-conducting state, the switch does not electrically couple the first terminal and the second terminal together.

11. The method according to claim 10, further comprising: in response to the voltage at the first terminal being less than or equal to a first voltage threshold, controlling the switch to be in the non-conducting state, and The switch is controlled to be in the on state in response to the voltage at the first terminal being greater than or equal to a second voltage threshold, the second voltage threshold being greater than the first voltage threshold.

12. The method according to claim 11, further comprising: In response to determining that the voltage of the second capacitor is greater than or equal to the first voltage threshold, the switch is controlled to be in the on state.

13. The method according to claim 11, wherein: the microprocessor operates in a first power consumption mode in which the microprocessor consumes a first amount of power and in a second power consumption mode in which the microprocessor consumes a second amount of power, the second amount of power being greater than the first amount of power, and The method also includes controlling the switch from being in the on state and controlling the microprocessor from operating in the second power consumption mode to operating in the first power consumption mode in response to determining that the voltage of the second capacitor is greater than or equal to the first voltage threshold.

14. The method according to claim 13, further comprising: charging the second capacitor in a discontinuous charging mode by controlling the switch to change from being in the conducting state to being in the non-conducting state and from being in the non-conducting state to being in the conducting state; as well as The second capacitor is charged in a continuous charging mode by controlling the switch to be in the on state.

15. The method according to claim 14, further comprising: When the microprocessor charges the second capacitor in the continuous charging mode, controlling the microprocessor to operate in the first power consumption mode, and When the microprocessor charges the second capacitor in the discontinuous charging mode, the microprocessor is controlled to operate in the second power consumption mode.

16. The method according to claim 15, further comprising: In response to determining that the voltage of the second capacitor is greater than the first voltage threshold, the microprocessor is controlled to change from charging the second capacitor in the discontinuous charging mode to charging the second capacitor in the continuous charging mode.

17. The method according to claim 14, further comprising: When the microprocessor charges the second capacitor in the discontinuous charging mode, controlling a transmitter included in the microprocessor to send a signal, When the microprocessor charges the second capacitor in the continuous charging mode, the transmitter is not controlled to send the signal.

18. The method of claim 17, wherein the signal sent by the transmitter is based on an output of a sensor included in the microprocessor.

19. A system comprising: Transducer; a first capacitor; Battery; as well as Microprocessor, including: a first terminal electrically coupled to the transducer and the first capacitor; a second terminal electrically coupled to the battery; a switch, in operation, in a conducting state wherein the switch electrically couples the first terminal and the second terminal together, or in a non-conducting state wherein the switch does not electrically couple the first terminal and the second terminal together; a voltage detector, in operation to detect a voltage at the first terminal, and a processor, coupled to the voltage detector and the switch, The processor is operable to control charging of the battery by controlling the switch to be in the conducting state and the non-conducting state based on the voltage at the first terminal detected by the voltage detector.

20. The system of claim 19, wherein: In response to the voltage detector detecting that the voltage at the first terminal is less than or equal to a first voltage threshold, the processor controls the switch to be in the non-conducting state, and The processor controls the switch to be in the on state in response to the voltage detector detecting that the voltage at the first terminal is greater than or equal to a second voltage threshold, the second voltage threshold being greater than the first voltage threshold.

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