DEVICE AND METHODS FOR EFFICIENT ENERGY HARVESTING - Patent application

Abstract

The present disclosure relates to a power management device including a voltage converter, a power point tracker for determining an optimal operating voltage for extracting power, and a controller, the device comprising a sensing device configured to: i) monitor an energy harvesting signal indicative of a presence of harvestable power from an energy source, ii) compare the energy harvesting signal to a first threshold, and iii) generate a first trigger signal when the energy harvesting signal increases from a value below the first threshold to a value above the first threshold. The controller is configured to perform a first energy harvesting unless the sensing device generates a trigger signal, the first energy harvesting including periodically operating the power point tracker to determine a first target voltage and operating and regulating the voltage converter at the first target voltage, and if the sensing device generates the first trigger signal, the controller is configured to perform a second energy harvesting including operating the power point tracker and determining a second target voltage in response to generation of the first trigger signal by the sensing device and operating and regulating the voltage converter at the second target voltage when the power point tracker has completed determining the second target voltage.

Description

[Technical field]

[0001] The present invention relates to a power management device for managing energy received from an energy source, and more particularly to a power management device including a voltage converter and a power point tracker configured to determine an optimal operating voltage for extracting power from the energy source. [Background technology]

[0002] The use of power management devices including voltage converters to extract energy from an energy source is well known in the art. (See, for example, EP-A1-3474407) The extracted energy may be used to charge a rechargeable energy storage device and / or power an application load, which may be any type of application (e.g., a portable device, a sensor, an external circuit, a wireless transmitter, etc.).

[0003] A power management device for managing energy is usually implemented as an integrated circuit and is also called a power management integrated circuit (PMIC). An example of a PMIC available from the applicant of the present patent application is known under the reference number AEM10941.

[0004] A variety of energy sources can be used to harvest energy, such as, for example, photovoltaics (PV), thermoelectric generators (TEG), piezoelectric energy generators, and electromagnetic energy sources.

[0005] Generally, the input voltage of a voltage converter is regulated to efficiently extract power from an energy source. The input voltage is either regulated to a predetermined reference voltage value, or alternatively, the PMIC includes a power point tracker (PPT) for determining an optimal operating voltage, for example, based on sensing an open circuit voltage. Generally, the optimal operating voltage is a voltage defined to extract maximum power from the energy source, and thus the PPT is also called a maximum power point tracker (MPPT).

[0006] When the voltage converter is operational and extracts energy from the energy source, the voltage converter regulates its input voltage to be equal to an optimal operating voltage, either determined via a predetermined reference value or determined by the PPT.

[0007] A drawback of using a predetermined reference value as the optimum operating voltage is that the predetermined reference value is a fixed value and therefore does not necessarily correspond to the actual energy source configuration. Furthermore, the optimum operating voltage, for example for extracting maximum power from the energy source, may vary over time.

[0008] An advantage of using a PMIC with a power point tracker is that the optimum voltage can be determined periodically (e.g., every tens of milliseconds to a few seconds). In some embodiments, the PMIC typically includes a clock generator configured to periodically trigger operation of the PPT during discrete periods to periodically determine the optimum operating voltage.

[0009] Generally, during operation of the PPT, the voltage converter is not operational, in other words, the voltage converter and the power point tracker are operable in a mutually exclusive manner, i.e., either the voltage converter is operational or the PPT is operational, but not both simultaneously.

[0010] One example of the method applied by the PPT to determine the optimum operating voltage is based on measuring the open circuit voltage of the energy source, and a certain ratio of the measured open circuit voltage is defined as the optimum operating voltage.

[0011] However, one problem with current PMICs is that they are not well suited for situations where they receive energy from intermittent energy sources (e.g., sources that behave as on-off sources). These types of intermittent energy sources provide large amounts of energy (e.g., in the range of tens of milliwatts to a few watts) for short periods of time (e.g., periods in the range of hundreds of milliseconds to a few seconds).

[0012] An example of an energy source that behaves as an on-off source is an RF or light emitter in a card reader for reading an access card. The access card sees the energy source as an on-off source because it is only receiving energy from the card reader when it is placed on the card reader. Another example would be a piezoelectric element embedded in a tire that provides energy only when close to the ground as the wheel rotates.

[0013] Because the PPT is only triggered periodically, energy is wasted unless the PPT is triggered.

[0014] A further drawback with intermittent energy sources and current PMICs is the delay before the PMIC can begin to operate efficiently, which can be a serious problem for applications where the period during which energy is available is short and / or where a fast response is required (e.g., in the case of access cards).

[0015] Thus, there is room for improvement in power management devices for energy harvesting. Summary of the Invention

[0016] It is an object of the present invention to provide a power management device for managing energy received from an energy source in an efficient manner without the drawbacks of prior art power management devices that are not suitable for intermittent energy sources as discussed above.

[0017] The invention is defined in the accompanying independent claims. The dependent claims define advantageous embodiments.

[0018] According to a first aspect of the present invention, there is provided a power management device for managing energy from an energy source.

[0019] The power management device includes a voltage converter configured to regulate an input voltage of the voltage converter to a target voltage, a power point tracker configured to determine the target voltage as an optimal operating voltage for extracting power from the energy source, and a controller for controlling operation of the voltage converter and the power point tracker. The power management device further includes a sensing device configured to i) monitor an energy harvesting signal indicative of harvestable power from the energy source, ii) compare the energy harvesting signal to a first threshold, and iii) generate a first trigger signal when the energy harvesting signal increases from a value below the first threshold to a value above the first threshold.

[0020] A controller of a power management device according to the present disclosure is configured to perform a first energy harvesting unless the sensing device generates a first trigger signal, where performing the first energy harvesting includes a) periodically operating a power point tracker to determine a first target voltage, and b) operating and regulating a voltage converter at the first target voltage.

[0021] The controller is further configured to switch from performing the first energy harvesting to performing a second energy harvesting when the sensing device generates a first trigger signal, where performing the second energy harvesting includes: a) operating the power point tracker and determining a second target voltage in response to generation of the first trigger signal by the sensing device; and b) operating and regulating the voltage converter at the second target voltage when the power point tracker completes determining the second target voltage.

[0022] In addition, the sensing device includes a signal output for outputting the first trigger signal, and the signal output of the sensing device is electrically connected to a signal input of the power point tracker, and the power point tracker is configured to initiate a first determination of the second target voltage upon receiving the first trigger signal.

[0023] Advantageously, by using a sensing device to sense the energy harvesting signal and trigger the power point tracker to begin operation and determine a target voltage when power (e.g., from an intermittent energy source) rises above a threshold, the voltage converter will immediately begin operating at an optimal input voltage to efficiently extract power from the energy source, and thus there will be no period of time in which energy is extracted in an inefficient manner, as is the case with prior art power management devices.

[0024] Advantageously, the power point tracking cycle is synchronized with the energy supply cycle of, for example, an intermittent energy source, by using a sensing device to trigger the power point tracker if the power rises above a threshold.

[0025] In some embodiments, the controller is configured to receive a trigger signal from the sensing device and thereafter generate a first start signal for the power point tracker, the power point tracker being configured to receive the first start signal and to initiate a first determination of the target voltage upon receiving the first start signal.

[0026] In some embodiments, performing the second energy harvesting further includes periodically operating the power point tracker to periodically repeat the determination of the second target voltage after the second target voltage is determined by the sensing device for the first time in response to generation of the first trigger signal.

[0027] In some embodiments, the controller is configured to operate the power management device in an energy harvesting mode and a reduced power consumption sleep mode, and the first energy harvest and the second energy harvest occur when in the energy harvesting mode. The controller is further configured to generate a sleep signal to switch the power management device from the energy harvesting mode to the reduced power consumption sleep mode when the energy harvesting signal drops from a value above a third threshold that is lower than the first threshold to a value below the third threshold.

[0028] In some embodiments, the power point tracker is configured to begin determining the target voltage within less than 250 milliseconds, preferably less than 10 milliseconds, and more preferably less than 1 millisecond following generation of the trigger signal by the sensing device. In other words, in view of this fast response time in the millisecond range of the power point tracker to the trigger signal, the response of the power point tracker to the trigger signal can be considered to be nearly instantaneous.

[0029] In some embodiments, the controller of the power management device is configured to delay determining the second target voltage responsive to generating the first trigger signal by a delay period.

[0030] In some embodiments, a power management device according to the present disclosure is further configured to receive an external trigger signal, and the controller is further configured to initiate performing the second energy harvesting when the external trigger signal is received.

[0031] The present disclosure also relates to a system including a power management device as claimed in claim 1, an energy source coupled to a power input terminal of the power management device and a rechargeable storage device or load coupled to a power output terminal of the power management device. The energy source is, for example, an intermittent energy source.

[0032] According to a second aspect of the present invention, there is provided a method of managing energy from an energy source using a power management device including: i) a voltage converter configured to regulate an input voltage to a target voltage; and ii) a power point tracker configured to determine the target voltage as an optimal operating voltage for extracting power from the energy source.

[0033] A method according to the present disclosure includes monitoring an energy harvesting signal indicative of harvestable power from an energy source, comparing the energy harvesting signal to a first threshold, and generating a first trigger signal when the energy harvesting signal increases from a value below the first threshold to a value above the first threshold. The method includes performing a first energy harvest unless the first trigger signal is generated, the first energy harvesting including a) periodically operating a power point tracker to determine a first target voltage, and b) operating and regulating a voltage converter at the first target voltage, and switching from performing the first energy harvesting to performing a second energy harvesting if the first trigger signal is generated, the second energy harvesting including a) initiating operating the power point tracker and determining a second target voltage with the power point tracker in response to generation of the first trigger signal, and b) initiating operating and regulating the voltage converter at the second target voltage when the power point tracker has completed determining the second target voltage. When the second trigger signal is generated, switching from performing the second energy harvesting to performing the first energy harvesting is performed only at the time when the power point tracker is operable for target voltage determination.

[0034] In an embodiment, the power management device is configured to operate the power point tracker and to operate the voltage converter in a mutually exclusive manner. [Brief description of the drawings]

[0035] These and further aspects of the invention will now be described in more detail, by way of example only, and with reference to the accompanying drawings, in which:

[0036] [Figure 1] FIG. 1 is a block diagram that illustrates generally a first embodiment of a power management device according to the present disclosure. [Diagram 2] FIG. 2 is a block diagram that illustrates generally a second embodiment of a power management device according to the present disclosure. [Figure 3a] FIG. 3a shows a schematic example of a timing diagram illustrating the on- and off-periods of a power point tracker and a voltage converter. [Figure 3b]FIG. 3b shows a further example of a time diagram illustrating a first energy harvesting period EH-1 and a second energy harvesting period EH-2. [Figure 3c] FIG. 3c shows a further example of a time diagram illustrating a first energy harvesting period EH-1 and a second energy harvesting period EH-2. [Figure 3d] FIG. 3d shows a further example of a time diagram illustrating a first energy harvesting period EH-1 and a second energy harvesting period EH-2. [Figure 3e] FIG. 3e shows a further example of a time diagram illustrating a first energy harvesting period EH-1 and a second energy harvesting period EH-2. [Figure 3f] FIG. 3f shows a further example of a time diagram illustrating a first energy harvesting period EH-1 and a second energy harvesting period EH-2. [Figure 4] FIG. 4 shows a further example of a timing diagram illustrating the on- and off-periods of a power point tracker and a voltage converter. [Diagram 5] FIG. 5 is a block diagram that illustrates generally a third embodiment of a power management device according to the present disclosure. [Figure 6] FIG. 6 illustrates a further embodiment of a power management device according to the present disclosure. [Figure 7] FIG. 7 illustrates a schematic of an embodiment of a power point tracker. [Figure 8] FIG. 8 illustrates an example of an energy harvesting system according to the present disclosure. [Figure 9] FIG. 9 illustrates an example of an energy harvesting system in which the energy source is an RF energy source. [Figure 10] FIG. 10 is a block diagram that illustrates generally a fourth embodiment of a power management device according to the present disclosure. [Figure 11] FIG. 11 illustrates a schematic of an example embodiment of a voltage converter.

[0037] The depictions in the accompanying drawings are not drawn to scale or to scale, and generally, identical parts are designated by the same reference numerals in the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] The present disclosure is described in terms of specific embodiments that are illustrative of the present disclosure and therefore are not to be construed as limiting. It is understood by those skilled in the art that the present disclosure is not limited by what has been specifically shown and / or described, and alternative or modified embodiments may be developed in light of the entire teachings of the present disclosure. The accompanying drawings described are merely schematic and therefore are not limiting.

[0039] The use of the verb "comprise" and its respective conjugations does not exclude the presence of elements other than those stated. The use of the article "a", "an" or "the" preceding an element does not exclude the presence of a plurality of such elements.

[0040] Moreover, the terms "first," "second," etc., in this specification and claims are used to distinguish between similar elements, and thus are not necessarily used to describe a sequence either temporally, spatially, sequentially, or in any other manner. The terms so used are interchangeable under appropriate circumstances, and it should be understood that the embodiments of the disclosure described herein are capable of operating in sequences other than those described or illustrated herein.

[0041] References throughout this specification to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in one or more embodiments of the present disclosure. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification may, but do not necessarily all refer to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

[0042] Use of the term "controller" should be interpreted in the broadest sense as being an electronic digital circuit that typically includes combinatorial logic.

[0043] General power management devices Example embodiments of power management devices according to the present disclosure are illustrated generally in FIGS.

[0044] A power management device 1 for managing energy from an energy source is connected to an input voltage V in The output voltage V out During energy harvesting, the voltage converter 10 converts an input voltage to a target voltage V T The target voltage V T is the optimum voltage for extracting, for example, maximum power from the energy source.

[0045] Input voltage V at the target voltage by the voltage converter in The regulation of the input voltage V in to the target voltage V T and reducing the input voltage when the input voltage is above the target voltage and increasing the input voltage when the input voltage is below the target voltage.

[0046] In some embodiments, the voltage converter 10 is a DC-DC voltage converter. in A boost converter circuit for increasing the input voltage V in or a buck-boost converter circuit for both reducing and increasing the input voltage. These DC-DC voltage converter circuits are known in the art.

[0047] The power management device sets a target voltage V as the optimal operating voltage for extracting power from the energy source. TThe power point tracker PPT20 further includes a power point tracker configured to determine: Example embodiments of the power point tracker are discussed further below.

[0048] In general, the power management device is configured to operate the voltage converter and the power point tracker in a mutually exclusive manner, i.e., when the power point tracker is operable to determine a target voltage, the voltage converter is not operable, and vice versa. Thus, in these embodiments, no energy can be harvested during the operation of the power point tracker. This is, for example, shown diagrammatically in Figures 3a and 4, where the two top panels represent example time diagrams showing several on-periods of the power point tracker (PPT-ON) and several on-periods of the voltage converter (VC-ON). The periods during which the power point tracker is on are also called sampling periods, and the periods during which the voltage converter is on are also called regulation periods or energy harvesting periods.

[0049] The controller 40 is configured to control the operation of the voltage converter 10 and the operation of the power point tracker 20 .

[0050] A power management device according to the present disclosure is adapted to: i) monitor an energy harvesting signal; ii) compare the energy harvesting signal to a first threshold; and ii) generate a first trigger signal T when the energy harvesting signal increases from a value below the first threshold to a value above the first threshold. PPT The energy harvesting signal is a signal indicative of the presence of energy harvestable power from the energy source.

[0051] Harvestable power may be available from various types of energy sources, and the harvestable energy may vary over time. For example, an on / off source may be switched on, thereby increasing the harvestable power. Another example is an energy source that emits power in a direction, which when directed toward the power management device increases the harvestable power by the power management device.

[0052] In a power management device according to the present disclosure, the power point tracker 20 is configured to detect a target voltage V in response to generation of a first trigger signal by the sensing device. T In other words, the sensing device 30 triggers operation of the power point tracker 20 when the detected power exceeds a first threshold. This is in contrast to prior art power management devices that do not include such a sensing device 30 that triggers the power point tracker to begin operation. Instead, prior art power management devices typically utilize a clock generator configured to periodically trigger operation of the PPT 20 during discrete periods to periodically determine the optimal operating voltage.

[0053] In some embodiments, the target voltage V T The determination of is initiated upon receipt of a first trigger signal T PPT is generated within less than 250 ms, preferably less than 10 ms, and more preferably less than 1 ms.

[0054] The generation of the first trigger signal and the operation of the power point tracker and the voltage converter are shown diagrammatically in Fig. 3a with several time diagrams. The bottom panel shows diagrammatically an example of an energy harvesting signal E, for example of an on / off type energy source. As shown in the two bottom panels of Fig. 3a, the energy harvesting signal E is generated when the first threshold E T From values ​​less than the first threshold E T When the sensing device detects that the voltage Vcc has increased to a value exceeding PPT A first trigger signal T PPT In response to the generation of , the power point tracker is triggered and set on and begins to determine a target voltage for operating the voltage converter. As shown in Figure 3a, once the target voltage determination is completed, the power point tracker is set off and the voltage converter is set on to harvest energy while regulating the input voltage at the target voltage determined by the power point tracker.

[0055] The power management device of the present disclosure receives a first trigger signal T PPT Energy can be harvested even if the first trigger signal is not triggered. In fact, the first trigger signal is generated only when the available harvestable power exceeds the first threshold, but this does not mean that no harvestable power is available below the first threshold.

[0056] The controller is configured to operate the power management device to perform a first energy harvest EH-1 and a second energy harvest EH-2, the second energy harvest EH-2 being defined as occurring when the energy harvesting signal rises above a first threshold, while the first energy harvest EH-1 is defined as occurring when the energy harvesting signal falls below the first threshold.

[0057] The implementation of the first energy harvest EH-1 and the second energy harvest EH-2 is, for example, shown diagrammatically in FIG. 3b. The bottom panel shows an example of an energy harvesting signal E varying as a function of time. As discussed above, the sensing device detects when the energy harvesting signal E exceeds a first threshold E T1 From values ​​less than the first threshold E T1 If the first trigger signal T PPT , T1. As shown in FIG. 3b, unless the sensing device generates the first trigger signal T1, the controller triggers the first target voltage V T1 periodically operating the power point tracker 20 to determine a first target voltage V T1 In this example, the periodic operation of the power point tracker to determine the first target voltage is performed during a first period P1. C On the other hand, if the sensing device is generating the first trigger signal T1, the controller switches from performing the first energy harvest EH-1 to performing the second energy harvest EH-2, which in response to the generation of the first trigger signal T1 by the sensing device 30 operates the power point tracker 20 and generates the second target voltage VT2 starting to determine and, when the power point tracker has completed determining the second target voltage V T2 starting to operate and regulate the voltage converter at the second target voltage V T2 including.

[0058] In some embodiments, as schematically shown in FIG. 3b, performing the second energy harvesting EH-2 starts to determine the second target voltage V only in response to the generation of the first trigger signal T1 by the sensing device 30. After the determination of, the power point tracker 20 is further periodically operated to periodically repeat the determination of the second target voltage V. In this example, as schematically shown in FIG. 3b, the periodic repetition of the determination of the second target voltage is performed every second period P2. T2 After the determination of, the power point tracker 20 is further periodically operated to periodically repeat the determination of the second target voltage V. T2 In this example, as schematically shown in FIG. 3b, the periodic repetition of the determination of the second target voltage is performed every second period P2. C each time.

[0059] In some embodiments, the periodic operation of the power point tracker 20 for determining the first target voltage V is repeated at a first frequency, and the periodic operation of the power point tracker 20 for determining the second target voltage V is repeated at a second frequency, where F1 > F2, or F1 < F2, or F1 = F2, and F1 and F2 are the first and second frequencies, respectively. The repetition frequency is the reciprocal of the periodic period shown in FIG. 3b, so F1 = 1 / P1 T1 and F2 = 1 / P2 T2 and P1 C and P2 C are the first and second periods for periodically repeating the determination of the first and second target voltages, respectively. C and P2 C are the first and second periods for periodically repeating the determination of the first and second target voltages, respectively.

[0060] As further schematically shown in FIG. 3b, the determination of the first target voltage V T1 and the determination of the second target voltage V T2 are performed during the first tracking period TP1 and the second tracking period TP2, respectively. In some embodiments, the first tracking period TP1 is different from the second tracking period TP2. In other embodiments, the first tracking period TP1 is equal to the second tracking period TP2.

[0061] To switch from the second energy harvest EH-2 to the first energy harvest EH-1, various options are possible, as discussed below.

[0062] In some embodiments, as further shown in FIG. 3b and FIG. 3d, the sensing device 30 detects whether the energy harvesting signal E exceeds a first threshold E T1 From a value exceeding the first threshold, a second threshold E T2 The controller 40 is further configured to switch from performing the second energy harvesting to performing the first energy harvesting when the sensing device generates the second trigger signal T2. In the embodiment shown in FIG. 3b, the second threshold is equal to the first threshold, while in the embodiment shown in FIG. 3d, the second threshold E T2 is the first threshold E T1 Lower.

[0063] In some embodiments, as shown in FIG. 3b, when a second trigger signal T2 is generated, the controller responds to the second trigger signal by immediately stopping operating the voltage converter and switching from performing the second energy harvesting to performing the first energy harvesting, for example by starting operating the power point tracker to make a new target voltage determination.

[0064] In other embodiments, the switch from performing the first energy harvest to performing the second energy harvest is performed only at the time when the power point tracker is operable for target voltage determination (e.g., when a new periodic target voltage determination starts or is in progress). Thus, in these embodiments, when the second trigger signal T2 is generated, the controller is configured to perform the switch from the second energy harvest to the first energy harvest only at the time when the power point tracker is operable for target voltage determination. In other words, in these embodiments, there are two conditions for switching from the second energy harvest to the first energy harvest: the power point tracker is operable and the second trigger signal is generated.

[0065] In a further embodiment, performing the second energy harvest EH-2 includes: T2 to a target threshold. In these embodiments, the controller 40 is further configured to switch from performing the second energy harvest EH-2 to performing the energy harvest EH-1 if, during operation of the power tracker, the determined second target voltage is less than the target threshold. Thus, in these embodiments, the switch from the second energy harvest to the first energy harvest occurs only at a time when the power point tracker is operable for target voltage determination. The target threshold may be a predetermined value that defines a voltage condition for switching from the second energy harvest back to the first energy harvest.

[0066] For embodiments in which the switch from the second energy harvest to the first energy harvest occurs at a time when the power point tracker is operable for target voltage determination, the target voltage determination made by the power point tracker between operating the voltage converter during the second energy harvest and operating the voltage converter again during the first energy harvest is made only once.

[0067] In another embodiment, when performing the second energy harvest EH-2, as shown generally in FIGS. 3c and 3e, the controller 40 may select a first generation of the first trigger signal T1 followed by a predetermined period T2 without a second generation of the first trigger signal T1. lap is configured to switch from performing the second energy harvest EH-2 to performing the first energy harvest EH-1 if the time t1 has elapsed.

[0068] The switch from the second energy harvest EH-2 to the first energy harvest EH-1 occurs for a predetermined period T lap In some embodiments based on the progression of the second target value V, the power point tracker may set the second target value V, as shown in FIG. 3c and FIG. 3e. T2 The determination of is performed when the energy harvesting signal E exceeds a first threshold E T1 From values ​​less than the first threshold E T1 In the example of Figures 3c and 3e, the first trigger signal T1 is shown as being triggered three times.

[0069] In the embodiment shown diagrammatically in FIG. 1, the sensing device 30 receives a trigger signal T PPT , which signal output of the sensing device 30 is electrically connected to the signal input of the power point tracker 20. Thus, in this embodiment, the PPT receives the trigger signal directly from the sensing device.

[0070] In other embodiments, the trigger signal from the sensing device is first transmitted to the controller 40, which then subsequently triggers the power point tracker 20. For example, in the embodiment shown in FIG. 2, the controller 40 first transmits the trigger signal T generated by the sensing device 30 to the controller 40, which then subsequently triggers the power point tracker 20. PPT The device is configured to receive

[0071] In some embodiments, the controller 40 is configured to generate a first start signal S1 for the power point tracker when the first trigger signal T1 is generated. The power point tracker includes an input for receiving this first start signal S1. The power point tracker 20 is further configured to initiate a first determination of the target voltage upon receiving the first start signal S1.

[0072] As discussed above, the controller 40 for controlling the power point tracker and for controlling the voltage converter may be a dedicated controller or the controller may be the main controller 60 of the power management device or part thereof. In some embodiments, the sub-controller 40a (part of the controller 40) is configured to receive a trigger signal from the sensing device 30 and generate a start signal S1 for the power point tracker, as shown generally in FIG.

[0073] The trigger signal T generated by the sensing device PPT is, for example, a voltage signal or a current-based signal, and the first start signal S1 is, for example, a binary signal (eg, a high voltage level or a low voltage level).

[0074] In some embodiments, the controller 40 is configured to delay the first start signal S1 by a delay period ΔT relative to the first trigger signal T1 generated by the sensing device 30. In this way, errors resulting from transient effects are avoided, i.e. the delay allows the energy source to reach a steady state, thus avoiding the PPT from determining a malfunction point.

[0075] In FIG. 4, an example of an embodiment is shown, where the start signal S1 is a trigger signal T generated by a sensing device. PPT is delayed by a time delay period ΔT.

[0076] In some embodiments, the controller 40 is configured to generate a second start signal S2 following the generation of the first start signal S1, the second start signal S2 being generated after a first time period T1 has elapsed since the generation of the first start signal S1. In response to the second start signal S2, the power point tracker is triggered at a second time to repeat the determination of the target voltage. The generation of the first start signal S1 and then the second start signal S2 is another solution to the transient problem.

[0077] In some embodiments, as discussed above, the controller is configured to switch from performing the second energy harvest EH-2 to performing the first energy harvest EH-1 when the energy harvesting signal falls below a second threshold. In these embodiments, the controller 40 is configured to generate a third start signal S3 when the second trigger signal T2 is generated, and the power point tracker 20, upon receiving the third start signal S3, starts the first target voltage V T1 The method is configured to initiate determining

[0078] In some embodiments, as discussed above, the controller may be configured to wait a predetermined period T without a second generation of the first trigger signal T1. lap The controller 40 is configured to switch from performing the second energy harvest EH-2 to performing the first energy harvest EH-1 after a predetermined period T lap The power point tracker is configured to generate a fourth start signal S4 if the first power point tracker 10 has elapsed, and the power point tracker is configured to start determining the target voltage upon receiving the fourth start signal S4. This allows the voltage converter to efficiently extract energy when there is continuous ambient low power energy available, e.g., possibly from another energy source other than the primary on / off energy source. The other energy source could be, e.g., an ambient RF energy source.

[0079] In some embodiments, a power management device for managing energy from an energy source is implemented as an integrated circuit (i.e., a microchip that includes electronic circuitry and a large number of input / output pins (also called terminals, or connectors, or leads). Typically, an integrated circuit may have between 12 and 48 terminals.

[0080] In some embodiments, as shown in FIGS. 1 and 2, a power management device 1 implemented as an integrated circuit receives an input voltage V in at least a power input terminal 11 for receiving power from an energy source at out and a power output terminal 12 for outputting power in the power supply 10.

[0081] In some embodiments, the power management device is further configured to receive an external trigger signal, and the controller 40 is further configured to initiate performing the second energy harvest EH-2 in response to receiving the external trigger signal. For example, if the power management device receives the external trigger signal while performing the first energy harvest, the power management device switches from performing the first energy harvest EH-1 to performing the second energy harvest EH-2. Similarly, if the power management device receives the external trigger signal while in a sleep mode, the power management device switches from the sleep mode to performing the second energy harvest EH-2.

[0082] In some embodiments, the power management device includes a signal detector for detecting the external trigger signal.

[0083] In another embodiment, the power management device includes a trigger input for receiving an external trigger signal.

[0084] In some embodiments, the external trigger signal is a wireless external trigger signal. In these embodiments, the signal detector includes, for example, an antenna.

[0085] In some embodiments, the controller 40 is configured to generate a further start signal S-EXT for the power point tracker 20 when an external trigger signal is received, and the power point tracker 20 receives the further start signal S-EXT, and upon receiving the further start signal S-EXT, generates a second target voltage V T2 The method is configured to initiate determining

[0086] In some embodiments, similar to the generation of the first trigger signal by the sensing device and when an external trigger signal is received, the controller 40 is configured to delay starting to operate the power point tracker by a delay period ΔT relative to the external trigger signal. Thus, in FIG. 4, the four upper panels (i.e., trigger T PPT , start signal, PPT-ON and VC-ON) are the trigger signal T PPT It is also applicable when t is an external trigger signal received by the power management device.

[0087] Sensing Device In some embodiments, the sensing device 30 includes a signal input for receiving the energy harvesting signal. In some embodiments where the energy harvesting signal is an input voltage, the signal input of the sensing device is electrically connected to a power input terminal 11 of the power management device for sensing an input voltage Vin at the power input terminal 11, as shown diagrammatically in Figures 1 and 2.

[0088] For example, if the input voltage rises above a predetermined threshold voltage, this indicates that the energy provided by the energy source has suddenly increased beyond the energy that can be transferred by the voltage converter 10 (e.g., a DC-DC voltage converter) when regulating to a target voltage level corresponding to low-energy energy harvest EH1.

[0089] In some embodiments, the sensing device 30 includes a signal comparator for comparing the energy harvesting signal to a first threshold value.

[0090] The signal comparator can be either an analog signal comparator or a digital signal comparator as known in the art. The comparator can be based on an operational amplifier. In embodiments where a digital signal comparator is used, the generally analog energy harvesting signal acquired by the sensing device is first digitized by using an ADC (analog-to-digital converter).

[0091] The first threshold may be generated, for example, by a bandgap reference voltage generator, or the first threshold may be generated by passing a reference current through a resistor. Alternatively, the threshold may be communicated over a communication bus.

[0092] The sensing device 30 of the present disclosure is not limited to sensors based on monitoring an input voltage and comparing the input voltage to a threshold value. Other implementations of a sensor device for monitoring an energy harvesting signal indicative of harvestable power may be envisioned.

[0093] In some embodiments, the sensing device 30 is, for example, a device configured to monitor the energy being transferred by the voltage converter 10 (e.g., a DC-DC voltage converter) over a fixed time reference (e.g., 1-250 milliseconds). This may be achieved, for example, by counting the number of pulses being transferred over that reference time window. If the number of pulses increases beyond a predefined pulse threshold, this means that the power generated by the energy harvester has suddenly increased. Thus, in these embodiments, the energy harvesting signal E corresponds to the number of pulses counted over the fixed time reference.

[0094] In some embodiments, the threshold against which the energy harvesting signal is compared may be a dynamically adjustable threshold, for example, if the energy harvesting signal E corresponds to a number of pulses counted over a fixed time base, the pulse threshold may be a function of the input and output voltages (e.g., using a look-up table).

[0095] In some embodiments where the energy harvesting signal E corresponds to the number of pulses counted over a fixed time base, it is evaluated whether the number of pulses has increased significantly compared to the previous count, for example by a factor of more than 5 to 1000. Thus, in these embodiments, the threshold corresponds to the previous number of counts and is dynamically adjusted accordingly.

[0096] Power Point Tracker In some embodiments, the power point tracker 20 includes a voltage tracking input, and the power point tracker is configured to sample a voltage sensed at the voltage tracking input. Typically, the power point tracker converts the sampled voltage, or a percentage of the sampled voltage, into a target voltage V for regulating the voltage converter. T Sampling the input voltage should be interpreted as capturing or measuring the input voltage.

[0097] In some embodiments, the voltage tracked at the voltage tracking input is the open circuit voltage, and thus the target voltage V T is defined as a percentage of the open circuit voltage.

[0098] The percentage value depends on the type of energy source, for example if the energy source is a photovoltaic cell then the percentage value is typically 70% to 85% of the open circuit voltage of the energy source, if the energy being harvested is from an RF energy source then the percentage is typically set to 50% of the open circuit voltage.

[0099] In some embodiments, the power point tracker 20 detects a target voltage V T The input may be configured to use a predetermined voltage or a percentage of a predetermined voltage as the input.

[0100] 6, the power management device 1 includes a buffer capacitor terminal 13 for connecting a buffer capacitor 85. This buffer capacitor terminal 13 is electrically connected to the input terminal 11. The buffer capacitor is charged during operation of the voltage converter, when energy is transferred from an energy source to a storage device or load connected to the power output terminal 12. This buffer capacitor 85 prevents the input node from collapsing when the inductor of the voltage converter is boosting current.

[0101] In some embodiments, as further shown in Fig. 6, the power management device includes a switch SW configured such that the buffer capacitor terminal 13 is electrically disconnected from the input terminal 11 when the power point tracker 20 is operational, and the buffer capacitor terminal 13 is electrically connected to the input terminal 11 when the voltage converter 10 is operational. In other words, during operation of the power point tracker 30, the switch SW is open, and during operation of the voltage converter 10, the switch SW is closed. In this way, transient effects are reduced when starting to operate the power point tracker. The switch SW is typically controlled by a main controller of the power management device.

[0102] Power point trackers are known in the art and an exemplary embodiment is shown diagrammatically in FIG. 7, where the power point tracker 20 is implemented, for example, by an analog-to-digital converter (ADC) based on a successive approximation register (SAR) architecture. As diagrammatically shown in FIG. 7 and FIG. 10, the power point tracker 20 typically includes a PPT electronic circuit 20a and a PPT controller 20b that controls the PPT electronic circuit. In this example, the PPT electronic circuit 20a includes a resistor ladder 22, a series of switches 25 that select the output of the resistor ladder, a capacitor ladder 23, switches SC_1 and SC_2 that reset the capacitor ladder, and a voltage comparator 21. By closing the switches SC_1 and SC_2 shown in FIG. 7, the capacitor ladder 23 can be discharged. The PPT controller 20b can be a dedicated controller or a controller that is part of a main controller 60 as diagrammatically shown in FIG. 10.

[0103] The power point tracker receives a trigger signal T from the sensing device 30. PPT When subsequently operated, a number of sequential steps occur: In a first step, the voltage converter 20 is disabled and the input voltage at the power input terminals is stabilized at the open circuit voltage.

[0104] In a second step, a predetermined percentage of the voltage at the power point tracker input is used at the positive input of the voltage comparator 21. The predetermined percentage can be 100% or a lower percentage value. For example, for open circuit voltage evaluation, the percentage can be set to, for example, 80% or, for example, 50%. The percentage is determined through the use of a capacitor divider 23. When the percentage is 100%, the capacitor divider 23 is an optional component.

[0105] In the third step, a percentage of a known voltage is used at the negative input of comparator 21. Different percentages of this known voltage can be selected via different switches 25 placed at different positions in the resistor ladder.

[0106] In the fourth step, the PPT controller 20b uses successive approximations to determine the proportion of a known voltage that best matches the voltage at the capacitor divider output. Finally, once the best match is found, this matching voltage on the resistive divider is set to the target value V for regulating the input voltage of the voltage converter. T This becomes the new optimum operating voltage to be used as the optimum operating voltage. In this way, the optimum operating voltage is stored via the resistor divider matching setting. Alternatively, the PPT controller may digitally store the matching voltage as the optimum operating voltage by taking the successive comparator output value.

[0107] In some embodiments, the power point tracker can be configured to define two or more values ​​for the percentage of the sampled voltage. In some embodiments, the power management device may, for example, determine the voltage V sensed at the power input terminals during the period that needs to be taken as the optimal operating voltage. in The power point tracker 20 may include a configuration terminal coupled to the power point tracker 20 for providing a configuration signal to the power point tracker that allows defining what fraction or percentage of the open circuit voltage. The configuration signal may have, for example, three defined levels indicating whether the power point tracker should take 50%, 80% or 100% of the open circuit voltage. The configuration signal may consist of multiple signals (e.g., a bus signal that transfers the configuration information).

[0108] In an alternative embodiment, the PPT does not include a capacitor divider, and in step 2 the open circuit voltage is measured, and in step 4 the PPT controller takes a percentage of the matched voltage as the target voltage.

[0109] In some embodiments, the percentage of the open circuit voltage to be taken is hard coded, while in other embodiments, a configuration signal is transferred to the power point tracker that allows defining what percentage or percentage of the open circuit voltage needs to be taken as the optimal operating voltage. The configuration signal may have, for example, four defined levels indicating whether the power point tracker needs to take 50%, 70%, 80% or 100% of the open circuit voltage. The configuration signal may consist of multiple signals (e.g., bus signals) for transferring the configuration information. In some embodiments, the PMIC includes two or more configuration terminals for providing the configuration signals or bus signals.

[0110] Sleep and Reset Modes In some embodiments, the controller 40 is configured to switch the power management device between an energy harvesting mode EH-M and a reduced power consumption sleep mode SLP-M. The first energy harvest EH-1 and the second energy harvest EH-2 are performed when in the energy harvesting mode. The energy harvesting mode may also be referred to as an active mode.

[0111] In some embodiments, as shown generally in FIGS. 3d-3f, the sensing device 30 detects whether the energy harvesting signal E exceeds a first threshold E T1 Less than a third threshold E T3 From values ​​exceeding the third threshold E T3 In these embodiments, the controller 40 is configured to generate a sleep signal SLP for switching the power management device 1 from the energy harvesting mode EH-M to a reduced power consumption sleep mode SLP-M when the third trigger signal T3 is generated.

[0112] In this manner, by switching from energy harvesting mode EH-M to sleep mode SLP-M, power consumption is reduced when the power management device is not active to harvest energy. In some embodiments, during sleep mode, the clock frequency is reduced and parts of the voltage converter are typically off to reduce the PMIC quiescent current.

[0113] In some embodiments, as further shown in FIGS. 3d-3f, the sensing device 30 detects whether the energy harvesting signal E exceeds a third threshold E T3 From values ​​less than the third threshold E T3 3d and 3e, the controller 40 is configured to generate a fourth trigger signal T4 if the fourth trigger signal T4 increases to a value greater than 0. In these embodiments, the controller 40 is configured to switch from the sleep mode SLP-M to the energy harvesting mode EH-M when the fourth trigger signal T4 is generated. In the embodiment shown in FIG. 3d and 3e, there is a switch from the sleep mode SLP-M to the first energy harvesting mode EH-1.

[0114] For the particular case shown diagrammatically in FIG. 3f, when in sleep mode SLP-M, the energy harvesting signal E is increasing rapidly and first crosses the third threshold E T3 When the first threshold E rises above the fourth trigger signal T4, a fourth trigger signal T5 is generated, followed by a second trigger signal T6. T1 Further increase above V leads to generation of a first trigger signal T1. The voltage converter is then operational and starts harvesting energy, and drives the input voltage to the second target voltage V T2 Thus, in this example, there is a switch from the sleep mode SLP-M to directly engaging the second energy harvester EH-2. Even in response to the fourth trigger signal T4, the power point tracker regulates the first target voltage V T1 3f, this determination of the first target voltage is interrupted by a first trigger signal T1 and a new determination of the target voltage is started.

[0115] In a further embodiment, the controller 40 controls the reset period ΔT Rhas elapsed without receiving a trigger signal from the sensing device, the power management device is configured to reset the power management device 1. The reset mode is a mode in which the power management device is off and therefore no power is consumed.

[0116] In FIG. 5, an embodiment of a power management device is shown, in which a controller 40 receives a trigger signal T PPT is the predetermined reset period ΔT R If not generated by the sensing device 30 for a longer period of time, a reset signal R is output to the voltage converter 10 and the power point tracker 20 .

[0117] In some embodiments, the power management device includes a cold start circuit 50 for starting after a reset.

[0118] The cold start circuit 50 is a start-up circuit for obtaining energy from an energy source and powering the power management device 1. Normally, the voltage converter 10 is not operable unless sufficient supply power is available to power the controller of the PMIC. Indeed, for example, the voltage converter controller operates only when the supply voltage V sup is operational only if Vcc is equal to or greater than the minimum required supply voltage. Once sufficient supply voltage is available to operate the controller, cold-start energy harvesting is stopped, as discussed above, and the power management device then sequentially operates the power point tracker and the voltage converter based on the trigger signal received from the sensing device.

[0119] Voltage Converter A power management device 1 according to the present disclosure includes at least one voltage converter 10. Typically, the voltage converter 10 includes a voltage converter electronic circuit 10a and a voltage converter controller 10b for controlling the voltage converter electronic circuit.

[0120] As discussed above, in some embodiments, the voltage converter may convert, for example, an input voltage V inA boost converter circuit for increasing the input voltage V in or a buck-boost converter circuit for both reducing and increasing the input voltage.

[0121] An example of a boost converter circuit is shown diagrammatically in FIG. 11. Typically, a voltage converter electronic circuit 10a includes an inductor 15 and a first switch SVC_1 and a second switch SVC_2 controlled by a voltage converter controller 10b. In some embodiments, the voltage converter controller 10b may be part of a main controller 60 of a power management device, as shown diagrammatically in FIG. 10. As shown in FIG. 11, when a boost converter is used, the inductor 15 is placed in series with the power input terminal 11. As known in the art, by periodically controlling the first switch SVC_1 and the second switch SVC_2, the magnetic energy stored in the inductor 15 is boosted to a voltage, e.g., a converter input V in Output voltage higher than the voltage at V out The voltage converter output 12 at

[0122] In some embodiments, instead of using an inductive voltage converter as discussed above, a switched capacitor converter is used. Switched capacitor converters are known in the art, and these converters deliver power by means of a charging and discharging capacitor.

[0123] When extracting power from the energy source, the voltage converter operates to obtain a target voltage V T By using it as in is continuously regulated.

[0124] In some embodiments, the stored final target voltage may be the target voltage determined by the power point tracker following a trigger signal generated by the sensing device. However, for some embodiments, the stored final target voltage is not necessarily the target voltage determined following a trigger signal of the sensing device. This is the case when the power point tracker is additionally triggered by another signal other than the trigger signal from the sensing device. For example, as discussed above, in some embodiments, the controller 40 generates a second start signal S2 following the generation of the first start signal S1 and in response to the second start signal S2, and the power point tracker is triggered at a second time and repeats the determination of the target voltage, with the second value determined becoming the final value defined and stored. In other embodiments, after the first trigger of the PPT by the trigger signal from the sensing device, the PPT may be further repeatedly triggered, for example, by an internal clock generator.

[0125] In some embodiments, the voltage converter controller 10b controls the input voltage V in and a sensor for sensing the input voltage to the target voltage V determined by the power point tracker. T and a comparator or amplifier for comparing Vcc / Vcc to Vcc / Vcc. When the voltage at the converter input falls below the target value, the voltage converter is disabled to prevent the voltage at the converter input from going any lower. On the other hand, when the voltage at the voltage converter input rises above the target value, power transfer from the converter input to its output is enabled. In this way, the input voltage is regulated to stay close to the target voltage.

[0126] In some embodiments in which the power management device is implemented as an IC, the inductor 15 is located outside the IC and an additional terminal is provided for coupling the inductor to the IC.

[0127] The voltage converter is disabled by leaving the first switch SVC_1 and the second switch SVC_2 of the voltage converter open. This prevents power from being extracted by the voltage converter. The voltage converter is disabled, for example, during the operation of the power point tracker.

[0128] In some embodiments, as shown in FIG. 4, the voltage converter is VC-ON For example, if the energy source is a repetitive on / off energy source, the energy source is turned on for a given period of time ΔT VC-ON may be selected to correspond to the period during which the on / off energy source is expected to be on.

[0129] In another embodiment, as shown in FIG. 3a, the voltage converter is configured such that the energy harvesting signal is coupled to a trigger signal T PPT The first threshold E used to trigger T 3a, the first threshold and the further threshold are equal. In some embodiments, the further threshold is lower than the first threshold. In other embodiments, the first threshold and the further threshold are equal, as shown in FIG. 3a. In some embodiments, the further threshold is higher than the first threshold.

[0130] Energy Harvesting System In FIG. 8, an example of an energy harvesting system 100 including a power management device 1 according to the present disclosure is shown diagrammatically.

[0131] 8, an energy source 70 is coupled to the power input terminals 11 of the power management device, and a rechargeable storage device 80 is coupled to the power output terminals 12. In other embodiments, a load is coupled to the power output terminals 12. The energy source is, for example, an intermittent energy source.

[0132] 9, a further embodiment of an energy harvesting system 100 including a power management device 1 according to the present disclosure is shown generally. In this example, the energy source is an RF source 70. In this embodiment, the system 100 includes an antenna 75 for capturing RF energy from the RF source 70, and further includes a rectifier 90, the output of which is coupled to the power input terminal 11 of the power management device 1.

[0133] 8 and 9, the controller 40 for controlling the operation of the power point tracker and the voltage converter is not shown. As discussed above, the controller 40 may correspond to the main controller 60 of the power management device, or the controller 40 may be a sub-controller of the main controller 60 of the power management device.

[0134] How to manage energy from your sources The present disclosure provides a method for: i) converting an input voltage into a target voltage V T ii) a target voltage V as an optimal operating voltage for extracting power from the energy source. T The present invention also relates to a method of managing energy from an energy source using a power management device including a power point tracker 20 configured to determine

[0135] A method for managing energy from an energy source includes the steps of: monitoring the energy harvest E indicative of the presence of energy from the energy source; The energy harvesting signal E is set to a first threshold E T1 comparing with The energy harvesting signal exceeds a first threshold E T1 From values ​​less than the first threshold E T1 If the first trigger signal T PPT , T1; First trigger signal T PPT , T1 is not generated, performing a first energy harvest EH-1, the first energy harvest comprising: a) A first target voltage V T1 periodically operating the power point tracker 20 to determine b) a first target voltage V T1 and operating and regulating the voltage converter 10 at A process comprising: First trigger signal T PPT , T1 is generated, switching from performing a first energy harvest EH-1 to performing a second energy harvest EH-2, the second energy harvest being a) A first trigger signal T PPT and operating the power point tracker 20 in response to the generation of a second target voltage V T2 and initiating a process for determining b) The power point tracker detects a second target voltage V T2 Once the determination of the second target voltage V is completed, the voltage converter 10 is set to the second target voltage V T2 To commence operating and regulating the A process including:

[0136] In some embodiments, the method further comprises: The energy harvesting signal E exceeds a first threshold E T1 From the value exceeding the first threshold E T1 A second threshold E that is less than or equal to T2 generating a second trigger signal T2 if the first trigger signal T falls to a value less than Switching from performing the second energy harvesting to performing the first energy harvesting when a second trigger signal T2 is generated.

[0137] In some embodiments, the method includes: In response to the generation of the first trigger signal T1, the second target voltage V T2 After making this determination, the second target voltage V T2 periodically operating the power point tracker 20 to periodically repeat the determination of

[0138] In some embodiments, when the second trigger signal T2 is generated, the switch from performing the second energy harvest EH-2 to performing the first energy harvest EH-1 is performed only at the time when the power point tracker is operable for target voltage determination. In other words, the switch from the first energy harvest to the second energy harvest is not performed while the voltage converter is operable, but only when the periodic operation of the power point tracker has started or is in progress.

[0139] In some embodiments, the method includes: In response to the generation of the first trigger signal (T1), the second target voltage (V T2 ) is determined, the second target voltage (V T2 periodically operating the power point tracker (20) to periodically repeat the determination of Each determined second target voltage (V T2 ) to a target threshold; During operation of the power tracker, switching from performing the second energy harvest (EH-2) to performing the first energy harvest (EH-1) if the determined second target voltage is less than the target threshold.

[0140] In other embodiments, the method includes: Following the first generation of the first trigger signal T1, there is a predetermined period T without a second generation of the first trigger signal T1. lap and switching from performing the second energy harvesting to performing the first energy harvesting if time has elapsed.

[0141] In some embodiments, the method includes: The energy harvesting signal E exceeds a first threshold E T1 A lower third threshold E T3 From values ​​exceeding the third threshold E T3 If it drops below this value, switch to a sleep mode of reduced power consumption.

[0142] In some embodiments, the method includes: Receiving an external trigger signal, and starting to perform a second energy harvesting EH-2 when the external trigger signal is received.

[0143] In some embodiments, the first trigger signal T1,T PPT In response to generating the first target voltage V T The step of initiating the determination occurs within less than 250 ms, preferably within less than 10 ms, and more preferably within less than 1 ms.

[0144] In some embodiments, before starting to operate the voltage converter, the power point tracker is disabled, in other words, the power management device is configured to operate the power point tracker 20 and operate the voltage converter 10 in a mutually exclusive manner.

Claims

1. A power management device (1) for managing energy from an energy source, comprising: A voltage converter (10) for converting an input voltage of the voltage converter to a target voltage (V Ｔ A voltage converter (10) configured to regulate The target voltage (V Ｔ a power point tracker (20) configured to determine A controller (40) for controlling the operation of the voltage converter (10) and the power point tracker (20). Including, A sensing device (30), i) monitoring an energy harvesting signal (E) indicative of harvestable power from an energy source; ii) adjusting the energy harvesting signal (E) to a first threshold (E Ｔ , E Ｔ１ ) and iii) the energy harvesting signal exceeds the first threshold (E Ｔ , E Ｔ１ ) from a value less than the first threshold (E Ｔ , E Ｔ１ ) the first trigger signal (T ＰＰＴ , T １ ) and A sensing device (30) configured to The controller (40) includes: i) the sensing device (30) detects the first trigger signal (T ＰＰＴ , T １ performing a first energy harvest (EH-1) unless a) First target voltage (V Ｔ１ periodically operating the power point tracker (20) to determine b) the first target voltage (V Ｔ１ and operating and regulating the voltage converter (10) at and ii) the sensing device detects the first trigger signal (T １ ), switching from performing a first energy harvest (EH-1) to performing a second energy harvest (EH-2), where performing the second energy harvest includes: a) the first trigger signal (T ＰＰＴ , T １ ) and generating a second target voltage (V Ｔ２ ) determining b) the power point tracker detects the second target voltage (V Ｔ２ ) is completed, the second target voltage (V Ｔ２ and operating and regulating the voltage converter in Including switching and and the sensing device (30) is configured to receive the first trigger signal (T ＰＰＴ , T １ ), the signal output of the sensing device (30) is electrically connected to a signal input of the power point tracker (20), and the power point tracker (20) is adapted to output the first trigger signal (T ＰＰＴ , T １ ), the second target voltage (V Ｔ２ 2. A power management device (1) configured to initiate a first determination of a power consumption.

2. 2. The power management device of claim 1, wherein the sensing device (30) detects the first trigger signal (T ＰＰＴ 11. A power management device comprising: a signal output for outputting a first input of a power supply;

3. In the power management according to claim 1 or 2, the controller (40) is configured to: １ ) is generated, the power point tracker (20) is configured to generate a first start signal (S1) of the power point tracker (20), the power point tracker (20) receives the first start signal (S1), and upon receiving the first start signal (S1), the power point tracker (20) Ｔ２ ) a first determination of a power consumption.

4. 4. The power management device of claim 3, wherein the controller (40) is configured to receive the first trigger signal (T ＰＰＴ , T １ ) by a delay period (ΔT).

5. The power management device of claim 3, wherein the controller (40) is configured to generate a second start signal (S2) after a first period (T1) has elapsed since the generation of the first start signal (S1), and the power point tracker (20) is configured to initiate a second determination of the second target voltage (VT2) upon receiving the second start signal (S2).

6. In the power management device of claim 1 or 2, the sensing device (30) detects whether the energy harvesting signal (E) exceeds the first threshold (E Ｔ１ ) to a second threshold value (E Ｔ２ ) the second trigger signal (T ２ ), the controller (40) being configured to generate iii) the sensing device (30) detects the second trigger signal (T ２ ), switching from performing the second energy harvest (EH-2) to performing the first energy harvest (EH-1). The power management device further configured to:

7. 7. The power management device of claim 6, wherein the controller (40) is configured to receive the second trigger signal (T ２ ) is generated, the power point tracker (20) is configured to generate a third start signal (S3) when the first target voltage (V Ｔ１ ).

8. 7. The power management device of claim 6, wherein the sensing device (30) detects the second trigger signal (T ２ ), the switching from performing the second energy harvest (EH-2) to performing the first energy harvest (EH-1) is performed only at a time when the power point tracker is operable for target voltage determination.

9. The power management device according to claim 1, wherein the controller comprises: iii) the first trigger signal (T １ ) followed by the first generation of the first trigger signal (T １ ) for a predetermined period (T ｌａｐ ) has elapsed, switch from performing the second energy harvest (EH-2) to performing the first energy harvest (EH-1). The power management device further configured to:

10. 10. The power management device of claim 9, wherein the controller (40) is ｌａｐ ) has elapsed, the power point tracker (20) is configured to generate a fourth start signal (S4) when the first target voltage (V Ｔ１ ).

11. In the power management device according to claim 1 or 2, performing the second energy harvest (EH-2) comprises: c) the first trigger signal (T １ ) and only then does the second target voltage (V Ｔ２ After making the determination of the second target voltage (V Ｔ２ and periodically operating said power point tracker (20) to periodically repeat said determination of 23. The power management device according to claim 22, further comprising:

12. In the power management device according to claim 1, performing the second energy harvest (EH-2) comprises: c) the first trigger signal (T １ ) and only then does the second target voltage (V Ｔ２ After making the determination of the second target voltage (V Ｔ２ periodically operating the power point tracker (20) to periodically repeat said determination of d) Each determined second target voltage (V Ｔ２ ) to a target threshold. The controller (40) further comprises: iii) during operation of the power tracker, switching from performing the second energy harvest (EH-2) to performing the first energy harvest (EH-1) if the determined second target voltage is less than the target threshold. The power management device further configured to:

13. The power management device of claim 11, wherein the first target voltage (V Ｔ１ The periodically operating the power point tracker (20) to determine a second target voltage (V Ｔ２ wherein the periodically operating the power point tracker (20) to determine F1 (F2), F1 is repeated at a second frequency, where F1>F2, or F1<F2, or F1=F2, and F1 and F2 are the first and second frequencies, respectively.

14. The power management device of claim 11, wherein the first target voltage (V Ｔ１ ) and the second target voltage (V Ｔ２ ) are determined during a first tracking period (TP1) and a second tracking period (TP2), respectively, wherein the first tracking period (TP1) is different from the second tracking period (TP2) or, alternatively, the first tracking period (TP1) is equal to the second tracking period (TP2).

15. The power management device of claim 1 or 2, wherein the sensing device (30) detects whether the energy harvesting signal (E) exceeds a third threshold (E Ｔ３ ) from the value exceeding the third threshold value (E Ｔ３ ) the third trigger signal (T ３ ), the controller (40) is configured to switch the power management device between an energy harvesting mode (EH-M) and a reduced power consumption sleep mode (SLP-M), the first energy harvest and the second energy harvest occur when in the energy harvesting mode, and the controller (40) is configured to generate the third trigger signal (T ３ ) is generated, generating a sleep signal (SLP) for switching the power management device (1) from the energy harvesting mode (EH-M) to the sleep mode (SLP-M) of reduced power consumption.

16. 16. The power management device of claim 15, wherein the sensing device (30) detects when the energy harvesting signal (E) exceeds the third threshold (E Ｔ３ ) from a value less than the third threshold (E Ｔ３ ) to a value exceeding the fourth trigger signal (T ４ ), and the controller (40) is configured to generate the fourth trigger signal (T ４ ) is generated,

17. A power management device as described in claim 1 or 2, characterized in that the sensing device (30) includes a comparator for comparing the energy harvesting signal with the first threshold value.

18. A power management device as described in claim 1 or 2, characterized in that the sensing device (30) is configured to monitor the energy transferred by the voltage converter (10) over a fixed time reference by counting the number of energy pulses transferred over the reference time window, and the number of pulses counted over the fixed time reference corresponds to the energy harvesting signal (E).

19. 20. The power management device of claim 18, wherein the fixed time reference is a time value between 1 and 250 milliseconds.

20. In the power management device according to claim 1 or 2, the voltage converter (10) is configured to convert the target voltage (V Ｔ１ , V Ｔ２ ) is completed.

21. The power management device according to claim 1, wherein the second target voltage (V Ｔ２ Operating and regulating the voltage converter (10) for a fixed period (ΔT ＶＣ－ＯＮ . ) during power management.

22. The power management device according to claim 1, wherein the second target voltage (V Ｔ２ ) and regulating the voltage converter (10) at a voltage lower than the first threshold (E Ｔ１ until the sensing device (30) detects that the power supply voltage Vcc has dropped below a further threshold, Vcc being equal to or less than a further threshold.

23. A power management device as described in claim 1 or 2, further configured to receive an external trigger signal, wherein the controller (40) is further configured to start performing a second energy harvest (EH-2) when the external trigger signal is received.

24. 24. The power point tracker of claim 23, wherein the controller (40) is configured to delay initiating operation of the power point tracker by a delay period (ΔT) relative to the external trigger signal.

25. The power management device according to claim 1, - a power input terminal (11) for receiving energy from an energy source; A buffer capacitor terminal (13) for connecting a buffer capacitor; a switch (SW) configured such that, when the switch is open or closed, the buffer capacitor terminal (13) is electrically disconnected from or electrically coupled to the power input terminal (11), respectively; configured to maintain the switch (SW1) in an open state when the power point tracker (20) is operational and to maintain the switch (SW1) in a closed state when the voltage converter (10) is operational.

26. i) Set the input voltage to the target voltage (V Ｔ ii) a voltage converter (10) configured to regulate said target voltage (V) as an optimal operating voltage for extracting power from an energy source. Ｔ and a power point tracker (20) configured to determine a power point distribution (PDS) from the energy source, the method comprising: Monitoring an energy harvesting signal (E) indicative of harvestable power from the energy source; - setting the energy harvesting signal (E) at a first threshold (E Ｔ１ ) compared to The energy harvesting signal is at least one of the first threshold (E Ｔ１ ) from a value less than the first threshold (E Ｔ１ ) the first trigger signal (T ＰＰＴ , T １ ) to generate The first trigger signal (T ＰＰＴ ) is not generated, the first energy harvest (EH-1) is performed, a) First target voltage (V Ｔ１ periodically operating the power point tracker (20) to determine b) the first target voltage (V Ｔ１ and operating and regulating the voltage converter (10) at Including, doing, The first trigger signal (T ＰＰＴ ) is generated, switching from performing a first energy harvest (EH-1) to performing a second energy harvest (EH-2), the second energy harvest (EH-2) being a) the first trigger signal (T ＰＰＴ ) and using the power point tracker to generate a second target voltage (V Ｔ２ and commencing a process to determine b) the power point tracker detects the second target voltage (V Ｔ２ ) is completed, the second target voltage (V Ｔ２ and starting to operate and regulate the voltage converter (10) at Including, switching and the second trigger signal (T ２ ) is generated, the switching from performing the second energy harvest (EH-2) to performing the first energy harvest (EH-1) is performed only at a time when the power point tracker is operable for target voltage determination.

27. 27. The method of claim 26, The energy harvesting signal (E) is greater than or equal to the first threshold (E Ｔ１ ) from a value exceeding the first threshold value (E Ｔ１ A second threshold (E Ｔ２ ) the second trigger signal (T ２ ) and The second trigger signal (T ２ ), switch from performing the second energy harvest (EH-2) to performing the first energy harvest (EH-1); The method according to claim 1, further comprising:

28. 28. The method of claim 27, The first trigger signal (T １ ) and only then does the second target voltage (V Ｔ２ After making the determination of the second target voltage (V Ｔ２ and periodically operating said power point tracker (20) to periodically repeat said determination of The method according to claim 1, further comprising:

29. 27. The method of claim 26, The first trigger signal (T １ ) and only then does the second target voltage (V Ｔ２ After making the determination of the second target voltage (V Ｔ２ periodically operating the power point tracker (20) to periodically repeat the determination of Each determined second target voltage (V Ｔ２ ) to a target threshold; and during operation of the power tracker, switching from performing the second energy harvest (EH-2) to performing the first energy harvest (EH-1) if the determined second target voltage is less than the target threshold; The method according to claim 1, further comprising:

30. 27. The method of claim 26, The first trigger signal (T １ ) followed by the first generation of the first trigger signal (T １ ) for a predetermined period (T ｌａｐ ) has elapsed, switch from performing the second energy harvest (EH-2) to performing the first energy harvest (EH-1). The method according to claim 1, further comprising:

31. 31. The method according to any one of claims 26 to 30, wherein the fixed period (ΔT ＶＣ－ＯＮ ) during the second target voltage (V Ｔ２ ) or alternatively, regulating the voltage converter (10) at the second target voltage (V Ｔ２ ) and regulating the voltage converter (10).

32. The method according to any one of claims 26 to 30, The energy harvesting signal (E) is greater than or equal to the first threshold (E Ｔ１ A third threshold (E Ｔ３ ) from the value exceeding the third threshold value (E Ｔ３ ) to switch to a reduced power consumption sleep mode (SLP-M). The method according to claim 1, further comprising:

33. 33. The method of claim 32, The energy harvesting signal (E) exceeds the third threshold (E Ｔ３ ) from a value less than the third threshold (E Ｔ３ ) to switch from the sleep mode (SLP-M) to the first energy harvesting (EH-1). The method according to claim 1, further comprising:

34. The method according to any one of claims 26 to 30, receiving an external trigger signal and initiating a second energy harvest (EH-2) if said external trigger signal is received; The method according to claim 1, further comprising:

35. A power management device as described in claim 1 or 2, characterized in that the power point tracker (20) includes a voltage tracking input, the power point tracker being configured to sample a voltage sensed at the voltage tracking input and store the sampled voltage or a percentage of the sampled voltage as the target voltage.

36. A power management device as described in claim 1 or 2, characterized in that the power management device (1) is configured to operate the power point tracker (20) and operate the voltage converter (10) in a mutually exclusive manner.

37. The power management device according to claim 1 or 2, wherein the first trigger signal (T ＰＰＴ ) and operating the power point tracker (20) in response to the generation of the second target voltage (V Ｔ２ ) is determined based on the first trigger signal (T １ ) occurring within less than 250 ms, preferably less than 10 ms, more preferably less than 1 ms following said generation of said signal.

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