JP6023486B2 - Power management circuit, electronic device and wireless sensor - Google Patents

Description

  The present invention relates to a technique for using an energy harvesting element.

  Wireless sensors are used to monitor the status of various places including high places, remote places, and the human body. For example, a wireless sensor for temperature measurement includes a temperature sensor that measures temperature, and a wireless unit that transmits temperature data measured by the temperature sensor to the outside. In order to operate the wireless unit, a power supply is required. However, if a battery is used as the power supply, maintenance such as battery replacement is required, so the wireless sensor uses an energy harvesting element as a power source. There is.

JP 2012-019675 A

  The energy harvesting element is also referred to as an energy harvesting element, and generates electricity by converting light, heat, vibration, and the like into an electric power signal. However, the amount of power generated by the energy harvesting element changes from moment to moment according to the surrounding conditions. Therefore, the conventional wireless sensor has a problem that the power is depleted if the energy harvesting element cannot generate power for a long time.

  Such a problem can occur not only in a wireless sensor but also in various devices using an energy harvesting element.

  SUMMARY An advantage of some aspects of the invention is to provide a power management circuit capable of suppressing power depletion.

  One embodiment of the present invention relates to a power management circuit. The power management circuit is connected to different types of energy harvesting elements, receives a plurality of input terminals to which power signals from the corresponding energy harvesting elements are input, and a power signal input to each of the plurality of input terminals, A power signal selection unit that selects a power signal from one energy harvesting element, a power supply circuit that stabilizes the power signal output from the power signal selection unit, and a detection circuit that detects the power generation amount of each of the plurality of energy harvesting elements And comprising. The power signal selection unit selects a power signal from one energy harvesting element based on the power generation amount of each energy harvesting element detected by the detection circuit.

  According to this aspect, even if the power generation amount of a certain energy harvesting element is reduced, power can be supplied to the load by a power signal from another energy harvesting element, and depletion of power can be suppressed.

  The power signal selection unit selects a power signal from the primary energy harvesting element to be prioritized among a plurality of energy harvesting elements during normal operation, and when the power generation amount of the primary energy harvesting element decreases, another secondary energy is selected. The power generation amount of the harvesting element is measured, and when the power generation amount of the secondary energy harvesting element is larger, the power signal from the secondary energy harvesting element may be selected.

  The power signal selection unit measures the power generation amount of the primary energy harvesting element for each predetermined cycle in a state where the power signal from the secondary energy harvesting element is selected, and when the power generation amount of the primary energy harvesting element is larger, A power signal from the primary energy harvesting element may be selected.

  The power signal selection unit receives a power signal input to each of the plurality of input terminals, selects one, a storage unit that stores data indicating the power generation amount measured by the detection circuit, and is stored in the storage unit And a logic unit that controls the selector based on the data indicating the power generation amount of the plurality of energy harvesting elements.

  The primary energy harvesting element may convert light into electrical power. The secondary energy harvesting element may convert heat into electric power. The secondary energy harvesting element may convert vibration into electric power.

The detection circuit may detect a power generation amount of each energy harvesting element based on a power signal from each energy harvesting element input to the power signal selection unit.
The detection circuit may detect the power generation amount of the energy harvesting element selected by the power signal selection unit based on the power signal input to the power supply circuit.
The detection circuit may detect the power generation amount of the energy harvesting element selected by the power signal selection unit based on the power signal output from the power supply circuit.
The detection circuit may detect the power generation amount of the energy harvesting element selected by the power signal selection unit at that time based on the output current of the power supply circuit.

  Another embodiment of the present invention is also a power management circuit. This power management circuit is provided with a plurality of input terminals to which different types of energy harvesting elements are connected and power signals from the corresponding energy harvesting elements are input, and each energy harvesting element is provided with a corresponding energy harvesting element. Multiple power supply circuits that stabilize the power signal from the harvesting element, a detection circuit that detects the amount of power generated by each of the multiple energy harvesting elements, and a power signal that is output from each of the multiple power supply circuits, and detected by the detection circuit A power signal selection unit that selects a power signal from a power supply circuit corresponding to one energy harvesting element based on the power generation amount of each energy harvesting element.

  According to this aspect, even if the power generation amount of a certain energy harvesting element is reduced, power can be supplied to the load by a power signal from another energy harvesting element, and depletion of power can be suppressed.

  The power signal selection unit selects a power signal from the power supply circuit corresponding to the primary energy harvesting element to be prioritized among a plurality of energy harvesting elements during normal operation, and the power generation amount of the primary energy harvesting element decreases. The power generation amount of another secondary energy harvesting element may be measured, and when the power generation amount of the secondary energy harvesting element is larger, the power signal from the power supply circuit corresponding to the secondary energy harvesting element may be selected.

  The power signal selection unit measures the power generation amount of the primary energy harvesting element for each predetermined period in a state where the power signal from the power supply circuit corresponding to the secondary energy harvesting element is selected, and determines the power generation amount of the primary energy harvesting element. If it is greater, the power signal from the power supply circuit corresponding to the primary energy harvesting element may be selected.

  The power signal selection unit receives a power signal input to each of the plurality of input terminals, selects one, a storage unit that stores data indicating the power generation amount measured by the detection circuit, and is stored in the storage unit And a logic unit that controls the selector based on the data indicating the power generation amount of the plurality of energy harvesting elements.

  The primary energy harvesting element may convert light into electrical power. The secondary energy harvesting element may convert heat into electric power. The secondary energy harvesting element may convert vibration into electric power.

The detection circuit may detect the power generation amount of each energy harvesting element based on a power signal input to each power supply circuit.
The detection circuit may detect the power generation amount of each energy harvesting element based on a power signal output from each power supply circuit.
The detection circuit may detect the power generation amount of the energy harvesting element selected by the power signal selection unit based on the power signal output from the power signal selection unit.

  The power management circuit may be integrated on a single semiconductor substrate. “Integrated integration” includes the case where all of the circuit components are formed on a semiconductor substrate and the case where the main components of the circuit are integrated. A resistor, a capacitor, or the like may be provided outside the semiconductor substrate. By integrating the control circuit as one IC, the circuit area can be reduced and the characteristics of the circuit elements can be kept uniform.

  Another embodiment of the present invention relates to an electronic device. The electronic device may include a plurality of energy harvesting elements, a load circuit, and any one of the power management circuits described above that receives power signals from the plurality of energy harvesting elements and supplies the power signals to the load circuit.

  Another aspect of the present invention relates to a wireless sensor. The wireless sensor includes a plurality of energy harvesting elements, a sensor element, a wireless unit that transmits the output of the sensor element to the outside, and a power signal received from the plurality of energy harvesting elements and supplied to the wireless unit. A power management circuit.

  Note that any combination of the above-described constituent elements and the constituent elements and expressions of the present invention replaced with each other among methods, apparatuses, systems, and the like are also effective as an aspect of the present invention.

  According to an aspect of the present invention, power depletion can be suppressed.

1 is a circuit diagram showing a configuration of a power management circuit according to a first embodiment. FIG. It is a wave form diagram which shows operation | movement of the power management circuit of FIG. It is a circuit diagram which shows the structure of the power management circuit which concerns on 2nd Embodiment. FIGS. 4A and 4B are a block diagram illustrating an electronic device including a power management circuit and a diagram illustrating a usage mode thereof. FIGS. 5A and 5B are a block diagram illustrating a wireless sensor including a power management circuit and a diagram illustrating a usage mode thereof.

  The present invention will be described below based on preferred embodiments with reference to the drawings. The same or equivalent components, members, and processes shown in the drawings are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate. The embodiments do not limit the invention but are exemplifications, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

In this specification, “the state in which the member A is connected to the member B” means that the member A and the member B are electrically connected in addition to the case where the member A and the member B are physically directly connected. It includes the case of being indirectly connected through another member that does not affect the connection state.
Similarly, “the state in which the member C is provided between the member A and the member B” refers to the case where the member A and the member C or the member B and the member C are directly connected, as well as an electrical condition. It includes the case of being indirectly connected through another member that does not affect the connection state.

(First embodiment)
FIG. 1 is a circuit diagram showing a configuration of a power management circuit 100 according to the first embodiment.
The power management circuit 100 includes a plurality (N) of input terminals P1 to PN, a power signal selection unit 110, a power circuit 120, and a detection circuit 130, and is integrated on a single semiconductor substrate.

  Different types of energy harvesting elements EH1 to EHN are connected to the plurality of input terminals P1 to PN, and the i-th (1 ≦ i ≦ N) input terminal Pi receives a power signal from the corresponding energy harvesting element EHi. Entered. In this embodiment, the case of N = 2 is shown, but the present invention is not limited to this, and N is arbitrary. The types of the plurality of energy harvesting elements EH1 and EH2 are not particularly limited, but it is preferable that the environments in which they can generate power have a complementary relationship.

  As the energy harvesting elements EH1 and EH2, a solar cell that converts light into an electric signal, a Peltier element that converts heat into an electric signal, a piezoelectric element (piezoelectric element) that converts vibration into an electric signal, and the like can be used. Priorities are determined for the plurality of energy harvesting elements EH1 and EH2 based on the expected power generation amount. The element EH1 having the highest priority is also referred to as a primary element, and the remaining EH2 is also referred to as a secondary element. In the present embodiment, primary element EH1 is a solar cell with a large maximum power generation amount, and other elements are selected as secondary element EH2.

  Since the secondary element EH2 is mainly used when the power generation amount of the primary element EH1 is reduced, it is preferable that the power generation possible state has a complementary relationship with the primary element EH1.

  The power signal selection unit 110 receives a power signal input to each of the plurality of input terminals P1 to PN and selects one.

  The power supply circuit 120 stabilizes the power signal output from the power signal selection unit 110. A power storage means 150 such as a secondary battery or a capacitor is connected to the output terminal of the power supply circuit 120. The power supply circuit 120 is a DC / DC converter that boosts the power signal from the power signal selection unit 110 and charges the storage means.

The detection circuit 130 detects the power generation amount of each of the plurality of energy harvesting elements EH1 and EH2. Although the detection method of the electric power generation amount by the detection circuit 130 is not specifically limited, Several preferable methods are demonstrated.
Method 1. The detection circuit 130 in FIG. 1 detects the power generation amount of each energy harvesting element EH1, EH2 based on the power signal from each energy harvesting element EH1, EH2 input to the power signal selection unit 110. According to this method, the power generation amount of any energy harvesting element EH can be measured regardless of the selection state of the power signal selection unit 110.
In addition, when the detection circuit 130 is provided for each energy harvesting element EH, it becomes possible to simultaneously measure the power generation amount of the plurality of energy harvesting elements EH.

  Method 2. The detection circuit 130 determines the power generation amount of the energy harvesting element EH selected by the power signal selection unit 110 based on the power signal input to the power supply circuit 120, that is, the power signal output from the power signal selection unit 110. It may be detected.

Method 3. Based on the power signal output from the power supply circuit 120, the detection circuit 130 may detect the power generation amount of the energy harvesting element EH selected by the power signal selection unit 110 at that time.
Since the efficiency of the power supply circuit 120 varies depending on the range of the input voltage, even if the power generation amount of the energy harvesting element EH alone is large, if the efficiency of the power supply circuit 120 is low, the overall power may be small. is there. According to the method 3, the energy harvesting element EH that can supply the maximum power to the power storage unit 150 and / or the load (not shown) can be selected in consideration of the power generation amount of the energy harvesting element EH and the efficiency of the power supply circuit 120. .

Method 4. The detection circuit 130 may detect the power generation amount of the energy harvesting element EH selected by the power signal selection unit 110 at that time based on the output current of the power supply circuit 120.
When the power supply circuit 120 is a switching regulator or the like and its output voltage is maintained at a predetermined level, since the voltage is known, detecting the current is equivalent to detecting power. According to the scheme 4, the configuration of the detection circuit 130 can be simplified.

  The power signal selection unit 110 selects a power signal from one energy harvesting element based on the power generation amount of each of the energy harvesting elements EH1 and EH2 detected by the detection circuit 130.

  Specifically, the power signal selection unit 110 selects a power signal from the primary element EH1 among the plurality of energy harvesting elements during normal operation. When the power generation amount of the primary element EH1 decreases, the detection circuit 130 measures the power generation amount of another secondary element EH2. When the power generation amount of the secondary element EH2 is larger, the power signal selection unit 110 selects a power signal from the secondary element EH2.

  The power signal selection unit 110 measures the power generation amount of the primary element EH1 and the secondary element EH2 for each predetermined period in a state where the power signal from the secondary element EH2 is selected. When the power generation amount of the primary element EH1 is larger, the power signal from the primary element EH1 is selected. When the power generation amount of the secondary element EH2 is larger, the power signal selection unit 110 continues to select the power signal from the secondary element EH2.

The power signal selection unit 110 includes a storage unit 112, a logic unit 114, and a selector 116.
The selector 116 receives a power signal input to each of the plurality of input terminals P1 and P2, and selects one. The storage unit 112 is a memory, a register, or the like, and stores data indicating the power generation amount of each of the plurality of energy harvesting elements EH measured by the detection circuit 130. The logic unit 114 controls the selector 116 based on data indicating the power generation amount of the plurality of energy harvesting elements EH stored in the storage unit 112.

The above is the configuration of the power management circuit 100. Next, the operation will be described.
FIG. 2 is a waveform diagram showing the operation of the power management circuit 100 of FIG. The upper part of FIG. 2 shows the power generation amount of each of the energy harvesting elements EH1 and EH2, the middle part shows the energy harvesting element EH selected by the power signal selection unit 110, and the lower part shows the timing of power detection by the detection circuit 130.

  Between times t1 and t2, the energy harvesting element (primary element) EH1 generates sufficiently large power, and the power signal selection unit 110 selects the primary element EH1. During this time, the detection circuit 130 measures the power generation amount of the primary element EH1 every predetermined period τ1, and the logic unit 114 compares the power generation amount of the primary element EH1 with a predetermined threshold value.

At time t2, the power generation amount of the primary element EH1 decreases. When the logic unit 114 detects that the power generation amount of the primary element EH1 is lower than the threshold value at the next power measurement timing t3, the power generation amount of the secondary element EH2 is measured.
As a result, when it is determined that the power generation amount of the secondary element EH2 is large, the power signal selection unit 110 selects the power signal from the secondary element EH2 at time t4.

  While the power signal selection unit 110 selects the secondary element EH2, the detection circuit 130 measures the power generation amount of the energy harvesting elements EH1 and EH2 for each predetermined period τ2. The period τ2 may be the same as or different from the period τ1.

  At the detection timing t5, the power generation amounts of the primary element EH1 and the secondary element EH2 are measured. At this time, since the power generation amount of the primary element EH1 is smaller, the power signal selection unit 110 continues to select the secondary element EH2. At the next detection timing t6, the power signal selection unit 110 selects the primary element EH1 because the power generation amount of the primary element EH1 is larger.

The above is the operation of the power management circuit 100.
According to the power management circuit 100, even if the power generation amount of a certain energy harvesting element is reduced, power can be supplied to the load by a power signal from another energy harvesting element, and depletion of power can be suppressed.

  In addition, priorities are assigned to the plurality of energy harvesting elements EH based on the expected power generation amount. When the power generation amount of the primary element EH1 is sufficiently large, the primary element EH1 is preferentially used. When the power generation amount decreases, the power generation amount of the power management circuit 100 as a whole can be increased by using the secondary element EH2.

  When the power generation amount is measured by operating the detection circuit 130, the detection circuit 130 consumes power. According to the power management circuit 100 according to the embodiment, when the sufficient power generation amount is obtained from the primary element EH1, the power generation amount of the secondary element EH2 is not measured, so that the power consumption of the detection circuit 130 can be suppressed. There are also advantages.

  In addition, since the single power supply circuit 120 is shared and used for the plurality of energy harvesting elements EH, the overall size of the power management circuit 100 can be made compact.

(Second Embodiment)
FIG. 3 is a circuit diagram showing a configuration of the power management circuit 100a according to the second embodiment.
The power management circuit 100a includes a plurality of power supply circuits 120_1 and 120_2, a power signal selection unit 110a, and a detection circuit 130.
The plurality of power supply circuits 120_1 and 120_2 are provided for the energy harvesting elements EH1 and EH2, respectively, and stabilize the power signal from the corresponding energy harvesting element.

  The detection circuit 130 detects the power generation amount of each of the plurality of energy harvesting elements EH1 and EH2. The detection circuit 130 is the same as that in the first embodiment. That is, the detection circuit 130 may monitor the inputs of the power supply circuits 120_1 and 120_2, may monitor the outputs of the power supply circuits 120_1 and 120_2, or may monitor the output of the power signal selection unit 110a.

  The power signal selection unit 110a receives a power signal output from each of the plurality of power supply circuits 120_1 and 120_2, and from one energy harvesting element based on the amount of power generated by each of the energy harvesting elements EH1 and EH2 detected by the detection circuit 130. Select the power signal. The configuration of the power signal selection unit 110a is the same as that of the power signal selection unit 110 of FIG.

The above is the configuration of the power management circuit 100a according to the second embodiment.
The same effect as that of the first embodiment can also be obtained by the power management circuit 100a.

  Since the power management circuit 100a is provided with the power circuit 120 for each energy harvesting element EH, the power management circuit 100a is more disadvantageous than the power management circuit 100 in terms of circuit area. However, since each of the power supply circuits 120_1 and 120_2 can be optimized and designed according to the output voltage-output current characteristics of each of the energy harvesting elements EH1 and EH2, a single power supply circuit is provided between the plurality of energy harvesting elements EH. Compared to the case of sharing 120, it is advantageous in terms of efficiency.

Finally, the application of the power management circuit according to the first and second embodiments will be described.
FIGS. 4A and 4B are a block diagram illustrating an electronic device including the power management circuit 100 and a diagram illustrating a usage mode thereof.

  4A includes a plurality of energy harvesting elements EH1 and EH2, a load circuit 502, and a power management circuit that receives power signals from the plurality of energy harvesting elements EH1 and EH2 and supplies the power signal to the load circuit 502. 100.

  As shown in FIG. 4B, the electronic device 500 may be, for example, a medical device embedded in a human body 510, such as a pacemaker. The load 502 is an electrical stimulation generator that applies stimulation to the heart 512. As the energy harvesting elements EH1 and EH2, an element that converts heat into an electric signal and an element that converts vibration into an electric signal can be used. According to this configuration, power depletion can be suppressed, and electronic device 500 can be operated stably.

FIGS. 5A and 5B are a block diagram illustrating a wireless sensor 600 including the power management circuit 100 and a diagram illustrating how the wireless sensor 600 is used.
The wireless sensor 600 of FIG. 5A includes a plurality of energy harvesting elements EH1 and EH2, a sensor element 602, a microcontroller 604, a wireless unit 606, and a power management circuit 100.

The wireless sensor 600 monitors a surrounding state of a place where the wireless sensor 600 is installed, for example, temperature, power consumption, pressure, vibration, displacement, acceleration, and the like, and transmits the monitoring result to a remotely disposed management device. The wireless sensor 600 can be used in a building management system (BEMS) as shown in FIG. In this case, a plurality of wireless sensors 600 are arranged for each room or floor of the building 650.
The wireless sensor 600 in FIG. 5A is used in a factory energy management system, a crustal movement detection system, an earthquake prediction system, a road and bridge sensor, a human body, or a health monitor in an animal body. Is available.

  The sensor element 602 measures characteristics to be sensed by the wireless sensor 600, that is, temperature, power consumption, pressure, vibration, displacement, acceleration, and the like. The microcontroller 604 receives the measurement value of the sensor element 602, performs signal processing as necessary, and transmits it to the wireless unit 606. The wireless unit 606 transmits an RF signal corresponding to the measurement value.

  In such a wireless sensor 600, the power management circuit 100 supplies power to the sensor element 602, the microcontroller 604, and the wireless unit 606. For example, the energy harvesting element EH1 is an element that converts light into an electrical signal, and the energy harvesting element EH2 is an element that converts heat and vibration into an electrical signal.

  According to this configuration, power depletion can be suppressed, and the wireless sensor 600 can be stably operated.

  Although the present invention has been described using specific terms based on the embodiments, the embodiments only illustrate the principles and applications of the present invention, and the embodiments are defined in the claims. Many modifications and arrangements can be made without departing from the spirit of the present invention.

EH ... energy harvesting element, 100 ... power management circuit, 110 ... power signal selection unit, 112 ... storage unit, 114 ... logic unit, 116 ... selector, 120 ... power supply circuit, 130 ... detection circuit, 150 ... power storage means, 500 ... Electronic device 502 ... Load circuit 600 ... Wireless sensor 602 ... Sensor element 604 ... Microcontroller 606 ... Wireless unit

Claims (25)

A plurality of input terminals to which different types of energy harvesting elements are connected and power signals from the corresponding energy harvesting elements are input,
A power signal selection unit that receives a power signal input to each of the plurality of input terminals and selects a power signal from one energy harvesting element;
A power supply circuit for stabilizing the power signal output from the power signal selection unit;
A detection circuit for detecting a power generation amount of each of the plurality of energy harvesting elements;
With
The power signal selection unit selects a power signal from one energy harvesting element based on the power generation amount of each energy harvesting element detected by the detection circuit , and during normal operation, among the plurality of energy harvesting elements When the power signal from the primary energy harvesting element to be prioritized is selected and the power generation amount of the primary energy harvesting element is reduced, the power generation amount of another secondary energy harvesting element is measured, and the power generation of the secondary energy harvesting element is performed. when Write amount is large, the secondary energy harvesting to that power management circuit and selects a power signal from element. The power signal selection unit measures a power generation amount of the primary energy harvesting element at a predetermined cycle in a state where a power signal from the secondary energy harvesting element is selected, and determines a power generation amount of the primary energy harvesting element. is large, the power management circuit of claim 1, wherein the selecting the power signal from the primary energy harvesting device. The power signal selector is
A selector that receives a power signal input to each of the plurality of input terminals and selects one;
Storage means for storing data indicating the amount of power generation measured by the detection circuit;
A logic unit for controlling the selector based on data indicating the power generation amount of the plurality of energy harvesting elements stored in the storage unit;
Power management circuit according to claim 1 or 2, characterized in that it comprises a. Power management circuit according to claim 1 or 2, wherein the primary energy harvesting device and converting light into electricity. Power management circuit according to claim 1 or 2, wherein the secondary energy harvesting device and converting heat into electricity. Power management circuit according to claim 1 or 2, wherein the secondary energy harvesting device and converting the vibration to electric power. The said detection circuit detects the electric power generation amount of each energy harvesting element based on the electric power signal from each energy harvesting element input into the said electric power signal selection part, The any one of Claim 1 to 6 characterized by the above-mentioned. Power management circuit. The detection circuit, based on the power signal input to the power supply circuit, one of claims 1 to 6, characterized in that to detect the power generation amount of the selected energy harvesting device by the time the power signal selector The power management circuit according to the above. The detection circuit, based on the power signal output from the power supply circuit, one of claims 1 to 6, characterized in that to detect the power generation amount of the selected energy harvesting device by the time the power signal selector The power management circuit according to the above. The detection circuit, based on an output current of said power supply circuit, according to claim 1, wherein 6 to detect the power generation amount of the selected energy harvesting device by the time the power signal selector Power management circuit. A plurality of input terminals to which different types of energy harvesting elements are connected and power signals from the corresponding energy harvesting elements are input,
A power signal selection unit that receives a power signal input to each of the plurality of input terminals and selects a power signal from one energy harvesting element;
A power supply circuit for stabilizing the power signal output from the power signal selection unit;
A detection circuit for detecting a power generation amount of each of the plurality of energy harvesting elements;
With
The power signal selection unit selects a power signal from one energy harvesting element based on the power generation amount of each energy harvesting element detected by the detection circuit,
The detection circuit, the based on the power signal to be input to the power supply circuit, that when said power signal to that power management circuit and detecting a power generation amount of energy harvesting device selected by the selection unit. A plurality of input terminals to which different types of energy harvesting elements are connected and power signals from the corresponding energy harvesting elements are input,
A power signal selection unit that receives a power signal input to each of the plurality of input terminals and selects a power signal from one energy harvesting element;
A power supply circuit for stabilizing the power signal output from the power signal selection unit;
A detection circuit for detecting a power generation amount of each of the plurality of energy harvesting elements;
With
The power signal selection unit selects a power signal from one energy harvesting element based on the power generation amount of each energy harvesting element detected by the detection circuit,
The detection circuit, the based on the power signal output from the power source circuit, that when said power signal to that power management circuit and detecting a power generation amount of energy harvesting device selected by the selection unit. A plurality of input terminals to which different types of energy harvesting elements are connected and power signals from the corresponding energy harvesting elements are input,
A power signal selection unit that receives a power signal input to each of the plurality of input terminals and selects a power signal from one energy harvesting element;
A power supply circuit for stabilizing the power signal output from the power signal selection unit;
A detection circuit for detecting a power generation amount of each of the plurality of energy harvesting elements;
With
The power signal selection unit selects a power signal from one energy harvesting element based on the power generation amount of each energy harvesting element detected by the detection circuit,
The detection circuit, the power source based on the output current circuit, then the said power signal to that power management circuit and detecting a power generation amount of energy harvesting device selected by the selection unit. A plurality of input terminals to which different types of energy harvesting elements are connected and power signals from the corresponding energy harvesting elements are input,
A plurality of power supply circuits, each provided for each energy harvesting element, for stabilizing the power signal from the corresponding energy harvesting element;
A detection circuit for detecting a power generation amount of each of the plurality of energy harvesting elements;
The power signal output from each of the plurality of power supply circuits is received, and the power signal from the power supply circuit corresponding to one energy harvesting element is selected based on the power generation amount of each of the energy harvesting elements detected by the detection circuit. A power signal selector;
With
The power signal selection unit selects a power signal from a power supply circuit corresponding to a primary energy harvesting element to be prioritized among the plurality of energy harvesting elements during normal operation, and the amount of power generated by the primary energy harvesting element is When the power generation amount of another secondary energy harvesting element is measured when decreasing, and when the power generation amount of the secondary energy harvesting element is larger, selecting a power signal from the power supply circuit corresponding to the secondary energy harvesting element power management circuit characterized. The power signal selection unit measures a power generation amount of the primary energy harvesting element for each predetermined period in a state where a power signal from a power supply circuit corresponding to the secondary energy harvesting element is selected, and the primary energy harvesting element The power management circuit according to claim 14 , wherein a power signal from a power supply circuit corresponding to the primary energy harvesting element is selected when the amount of power generation is larger. The power signal selector is
A selector that receives a power signal input to each of the plurality of input terminals and selects one;
Storage means for storing data indicating the amount of power generation measured by the detection circuit;
A logic unit for controlling the selector based on data indicating the power generation amount of the plurality of energy harvesting elements stored in the storage unit;
The power management circuit according to claim 14 , wherein the power management circuit includes: The power management circuit according to claim 14, wherein the primary energy harvesting element converts light into electric power. The power management circuit according to claim 14, wherein the secondary energy harvesting element converts heat into electric power. The power management circuit according to claim 14, wherein the secondary energy harvesting element converts vibration into electric power. 20. The power management circuit according to claim 14 , wherein the detection circuit detects a power generation amount of each energy harvesting element based on a power signal input to each power supply circuit. 20. The power management circuit according to claim 14 , wherein the detection circuit detects a power generation amount of each energy harvesting element based on a power signal output from each power supply circuit. The detection circuit, the power signal based on the power signal output from the selecting section 19 from claim 14, characterized in that to detect the power generation amount of the selected energy harvesting device by the time the power signal selector The power management circuit according to any one of the above. Power management circuit according to any one of claims 1 22, characterized in that it is integrated on a single semiconductor substrate. Multiple energy harvesting elements;
A load circuit;
The power management circuit according to any one of claims 1 to 23 , which receives power signals from a plurality of the energy harvesting elements and supplies the power signals to the load circuit;
An electronic device comprising: Multiple energy harvesting elements;
A sensor element;
A wireless unit for transmitting the output value of the sensor element to the outside;
The power management circuit according to any one of claims 1 to 23 , which receives power signals from a plurality of the energy harvesting elements and supplies the power signals to the wireless unit.
A wireless sensor comprising:

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