ENERGY HARVESTING AND CONTROL FOR SENSOR NODE

• US 20150035378A1
• Filed: 02/15/2013
• Published: 02/05/2015
• Est. Priority Date: 02/17/2012
• Status: Active Grant

• Current Assignee: University of Virginia Patent Foundation (University of Virginia)
• Original Assignee: University of Virginia Patent Foundation (University of Virginia), University of Washington
• Inventors: Calhoun, Benton H., Otis, Brian
• Granted Patent: US 9,882,428 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: A61B 2560/0214 of power generation or supply
• CPC Class Codes: A61B 2560/0219 of externally powered implanted units
• CPC Class Codes: A61B 5/30 Input circuits therefor
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/369 Electroencephalography [EEG] devices for psychotechnics A61B5/16
• CPC Class Codes: A61B 5/389 Electromyography [EMG]
• CPC Class Codes: A61N 1/3785 generated by biological activity or substance, e.g. body movement
• CPC Class Codes: A61N 1/3787 from an external energy source
• CPC Class Codes: G05F 1/613 using semiconductor devices in parallel with the load as final control devices G05F1/461 takes precedence
• CPC Class Codes: G06F 1/3287 by switching off individual functional units in the computer system
• CPC Class Codes: H02J 2310/23 The load being a medical device, a medical implant, or a life supporting device
• CPC Class Codes: H02J 50/00 Circuit arrangements or systems for wireless supply or distribution of electric power
• CPC Class Codes: H02J 50/001 Energy harvesting or scavenging
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

An integrated circuit, such as included as a portion of a sensor node, can include a regulator circuit having an input coupleable to an energy harvesting transducer. The integrated circuit can include a wireless receiver circuit coupled to the regulator circuit and configured to wirelessly receive at least enough operating energy to establish operation of the sensor node without requiring the energy harvesting transducer. The integrated circuit can include a digital processor circuit coupled to the regulator circuit and a power management processor circuit. The digital processor circuit or one or more other circuits can include a subthreshold operational mode established by the power management processor circuit based on the selected energy consumption level. For example, establishing the subthreshold operational mode can include adjusting or selecting a supply voltage so as to establish subthreshold operation of a field effect transistor (FET) in the digital processor circuit or other circuits.

Claims

1. A sensor node, comprising:

a regulator circuit including an input coupleable to an energy harvesting transducer;

a wireless receiver circuit coupled to the regulator circuit and configured to wirelessly receive at least enough operating energy to establish operation of the sensor node without requiring the energy harvesting transducer;

a digital processor circuit coupled to the regulator circuit; and

a power management processor circuit configured to select an energy consumption level of the sensor node based on an input to the regulator circuit;

wherein the digital processor circuit includes a subthreshold operational mode established by the power management processor circuit based on the selected energy consumption level; and

wherein establishing the subthreshold operational mode includes adjusting or selecting a supply voltage provided by the regulator circuit so as to establish subthreshold operation of a field effect transistor (FET) in the digital processor circuit.

2. The sensor node of claim 1, further comprising the energy harvesting transducer coupled to the regulator circuit;

wherein the regulator circuit is configured to provide sufficient operating energy for the sensor node to operate continuously when coupled to the energy harvesting transducer and without requiring a primary or rechargeable battery.

3. The sensor node of claim 2, wherein the wireless receiver circuit is configured to wirelessly receive at least enough operating energy to establish operation of the sensor node initially;

and

wherein the regulator circuit and energy harvesting transducer are configured to provide sustained operating energy for the sensor node in the absence of further wirelessly-received operating energy.

4. The sensor node of claim 2, wherein the energy harvesting transducer includes a thermoelectric generator (TEG).

5. The sensor node of claim 1, wherein the power management processor circuit is configured to select the energy consumption level of the sensor node at least in part to inhibit a reset or to inhibit an extinction of operation of the sensor node.

6. The sensor node of claim 1, comprising a function-specific processor circuit including a subthreshold operational mode established by the power management processor circuit based on the selected energy consumption level;

wherein the digital processor circuit comprises a general-purpose processor circuit;

wherein the regulator circuit includes an adjustable output configured to provide the supply voltage to one or more of the general-purpose processor circuit or the function-specific processor circuit; and

wherein establishing the subthreshold operational mode includes adjusting the adjustable output so as to establish subthreshold operation of a respective field effect transistor (FET) in one or more of the general-purpose processor circuit or the function-specific processor circuit.

7. The sensor node of claim 1, comprising a function-specific processor circuit including a subthreshold operational mode established by the power management processor circuit based on the selected energy consumption level;

wherein the digital processor circuit comprises a general-purpose processor circuit;

wherein the regulator circuit includes two or more outputs configured to provide different specified supply voltages controllably coupleable to one or more of the general-purpose processor circuit or the function-specific processor circuit; and

wherein the power management circuit is configured to control coupling of the respective outputs of the regulator circuit to one or more of the general-purpose processor circuit or the function-specific processor circuit to establish the subthreshold operational mode.

8. The sensor node of claim 1, comprising a clock generation circuit configured to provide a specified output clock frequency at a clock output;

wherein the power management processor circuit is configured to adjust the output clock frequency provided to the digital processor circuit, or to gate the clock output provided to the digital processor circuit, based on the selected energy consumption level.

9. The sensor node of claim 1, comprising:

an analog input configured to obtain information indicative of a physiologic signal, the analog input controllably coupleable to the digital processor circuit under the control of the power management circuit and based on the selected energy consumption level.

10. The sensor node of claim 9, wherein the analog input includes an analog-to-digital converter;

wherein the power management circuit is configured to obtain information indicative of the input to the regulator circuit using the analog-to-digital converter; and

wherein the power management circuit is configured to adjust the energy consumption level of the sensor node using the obtained information about the input to the regulator circuit.

11. The sensor node of claim 9, comprising a wireless transmitter controllably coupleable to the digital processor circuit or to the analog input, the wireless transmitter configured to transmit one or more of streamed or processed information indicative of the physiologic signal obtained by the analog input under the control of the power management circuit and based on the selected energy consumption level.

12. The sensor node of claim 11, comprising a function-specific processor circuit including a subthreshold operational mode established by the power management processor circuit based on the selected energy consumption level;

wherein the digital processor circuit comprises a general-purpose processor circuit; and

wherein the power management circuit is configured to controllably establish a data path between the analog input and the wireless transmitter to include or exclude one or more of the general-purpose processor circuit or the function-specific accelerator circuit based on the selected energy consumption level.

13. The sensor node of claim 11, wherein the energy consumption levels include at least three levels, including:

a first energy consumption level wherein the general-purpose processor circuit, the application-specific processor circuit, the analog input, and the wireless transmitter are enabled;

a second energy consumption level wherein the wireless transmitter is duty-cycled to consume less energy than the corresponding energy consumption of the wireless transmitter when the first energy consumption level is selected; and

a third energy consumption level wherein;

the wireless transmitter is further duty-cycled or disabled to consume less energy than the corresponding energy consumption of the wireless transmitter when the first or second energy consumption levels are selected, and

wherein one or more of the general-purpose processor circuit, the application-specific processor circuit, or the analog input are inhibited from receiving one or more of a clock signal or a supply voltage.

14. The sensor node of claim 1, comprising a commonly-shared instruction memory circuit coupled to the power management circuit and the digital processor circuit.

15. The sensor node of claim 14, comprising a data memory circuit coupled to one or more of the power management circuit and the digital processor circuit.

16. The sensor node of claim 1, wherein the active portions of the regulator circuit, the wireless receiver circuit, the digital processor circuit, and the power management circuit are co-integrated in a commonly-shared integrated circuit device.

17. The sensor node of claim 16, wherein the integrated circuit device comprises a complementary metal-oxide-semiconductor (CMOS) device.

18. The sensor node of claim 1, wherein the wireless receiver circuit is configured to receive one or more of inductively-coupled electromagnetic operating energy or radiatively-coupled electromagnetic operating energy.

19. A method of operating a sensor node, comprising:

wirelessly receiving, at a wireless receiver circuit coupled to a regulator circuit coupleable to an energy harvesting transducer, sufficient operating energy to establish operation of a sensor node without requiring operating energy from the energy harvesting transducer;

selecting an energy consumption level of the sensor node based on an input to the regulator circuit; and

establishing a subthreshold operational mode of a digital processor circuit based on the selected energy consumption level, including adjusting or selecting a supply voltage provided by the regulator circuit so as to establish subthreshold operation of a field effect transistor (FET) in the digital processor circuit.

20. The method of claim 19, comprising obtaining sufficient operating energy for the sensor node to operate continuously using the energy harvesting transducer without requiring a primary or rechargeable battery.

21. The method of claim 20, comprising wirelessly receiving, at a wireless receiver circuit enough operating energy to establish operation of the sensor node initially;

and

obtaining sustained operating energy for operation of the sensor node using the energy harvesting transducer in the absence of further wirelessly-received operating energy.

22. The method of claim 20, wherein the energy harvesting transducer includes a thermoelectric generator (TEG).

23. The method of claim 19, comprising selecting the energy consumption level of the sensor node at least in part to inhibit a reset or to inhibit an extinction of operation of the sensor node.

24. The method of claim 19, comprising adjusting an output of the regulator circuit to provide a supply voltage to one or more of a general-purpose processor circuit or a function-specific processor circuit;

wherein establishing the subthreshold operational mode includes adjusting the adjustable output so as to establish subthreshold operation of a respective field effect transistor (FET) in one or more of the general-purpose processor circuit or the function-specific processor circuit.

25. The method of claim 19, comprising controllably coupling respective different outputs of the regulator circuit to one or more of a general-purpose processor circuit or a function-specific processor circuit to establish the subthreshold operational mode.

26. The method of claim 19, comprising generating a specified output clock frequency at a clock output, including adjusting the output clock frequency provided to the digital processor circuit, or gating the clock output provided to the digital processor circuit, based on the selected energy consumption level.

27. The method of claim 19, comprising obtaining information indicative of a physiologic signal using an analog input controllably coupleable to the digital processor circuit based on the selected energy consumption level.

28. The method of claim 27, wherein the physiologic signal includes one or more of an electrocardiogram (ECG), and electroencephalogram (EEG), or an electromyogram (EMG).

29. The method of claim 27, comprising adjusting the energy consumption level of the sensor node using obtained information about the input to the regulator circuit, the information obtained using the analog input.

30. The method of claim 27, comprising wirelessly transmitting one or more of streamed or processed information indicative of the physiologic signal obtained by the analog input based on the selected energy consumption level, using a wireless transmitter.

31. The method of claim 29, comprising controllably establishing a data path between the analog input and the wireless transmitter to include or exclude one or more of a general-purpose processor circuit or a function-specific accelerator circuit based on the selected energy consumption level.

32. The method of claim 29, wherein the energy consumption levels include at least three levels, including:

a first energy consumption level wherein the general-purpose processor circuit, the application-specific processor circuit, the analog input, and the wireless transmitter are enabled;

a second energy consumption level wherein the wireless transmitter is duty-cycled to consume less energy than the corresponding energy consumption of the wireless transmitter when the first energy consumption level is selected; and

a third energy consumption level wherein;

the wireless transmitter is further duty-cycled or disabled to consume less energy than the corresponding energy consumption of the wireless transmitter when the first or second energy consumption levels are selected, and

wherein one or more of the general-purpose processor circuit, the application-specific processor circuit, or the analog input are inhibited from receiving one or more of a clock signal or a supply voltage.

33. A processor-readable medium including instructions that, when executed by at least one processor circuit, cause an apparatus including the at least one processor circuit to perform the method as recited in claim 19.