Power management for power constrained devices

• US 8,072,095 B2
• Filed: 05/26/2009
• Issued: 12/06/2011
• Est. Priority Date: 05/26/2009
• Status: Active Grant

• Current Assignee: BAE Systems Information and Electronic Systems Integration Incorporated (BAE Systems Plc)
• Original Assignee: BAE Systems Information and Electronic Systems Integration Incorporated (BAE Systems Plc)
• Inventors: Lawrence, Gary J., Gili, Paul E.
• Primary Examiner(s): RUTLAND WALLIS, MICHAEL
• Application Number:
  US12/472,279
• Publication Number:
  US 20100301669A1
• Time in Patent Office: 924 Days
• Field of Search: 307/55, 307/43, 307/31, 320/166
• US Class Current: 307/31
• CPC Class Codes: H02J 1/14 Balancing the load in a network
• CPC Class Codes: H02J 50/001 Energy harvesting or scavenging
• CPC Class Codes: H02J 50/27 characterised by the type of receiving antennas, e.g. rectennas
• CPC Class Codes: H02M 1/009 having two or more independently controlled outputs for DC-DC converter with intermediate AC H02M3/33561
• CPC Class Codes: H02M 3/1563 without using an external clock H02M3/158 takes precedence

Abstract

Techniques are disclosed for optimizing power consumption in electronic devices that operate on battery-based or scavenged power. The power scavenged or otherwise supplied by such devices may therefore last longer, allowing longer performance on a given charge (whether sourced from scavenged power, battery power, or a combination thereof). An energy distribution circuit can be used in conjunction with a hysteretic switch, wherein the hysteretic switch can be used to switch an energy storage element in-circuit (so that it can provide charge to sub-circuitry or components) when the charge stored on that element exceeds a given charge threshold; otherwise, the hysteretic switch presents as a high resistance or open circuit when the charge stored on the energy storage element drops below a lower recharge threshold. The energy distribution circuit can be configured for adaptively providing different discharge rates for different loads.

Claims

1. A system for optimizing the use of energy consumption by electronics having multiple loads, the system comprising:

a hysteretic switch circuit having an input for coupling to an energy storage circuit and an output coupled to a node, the hysteretic switch circuit for coupling power applied at its input to the node when the power stored by the energy storage circuit reaches a charge threshold; and

an energy distribution circuit having an input coupled to the node, and for controlling operating time during which DC voltage above an operating threshold voltage is presented to each of a plurality of device loads coupled to an output of the energy distribution circuit, wherein at least two of the device loads have different operating times.

2. The system of claim 1 wherein at least two of the device loads have different operating threshold voltage ranges.

3. The system of claim 1 further comprising the energy storage circuit.

4. The system of claim 3 wherein the energy storage circuit includes a capacitor capable of storing potential electrical energy from a DC power source.

5. The system of claim 1 further comprising a DC power source for providing DC electrical power to the system.

6. The system of claim 5 wherein the DC power source includes a battery.

7. The system of claim 5 wherein the DC power source includes an antenna operatively coupled to a rectifier, wherein RF energy scavenged by the antenna is rectified to provide DC power.

8. The system of claim 1 wherein a first device load is coupled to the node.

9. The system of claim 1 wherein the energy distribution circuit comprises at least one diode and one capacitor associated with each of at least two of its outputs, the at least one diode for setting a maximum DC voltage provided by that output, and the at least one capacitor for setting the operating time associated with that output.

10. The system of claim 1 wherein the energy distribution circuit is for controlling an amount of energy that is allotted for each of at least two of the device loads.

11. A system for optimizing the use of energy consumption by electronics having multiple loads, the system comprising:

a DC power source for providing DC electrical power;

an energy storage circuit for storing power produced by the DC power source;

a hysteretic switch circuit having an input coupled to the energy storage circuit and an output coupled to a node, the hysteretic switch circuit for coupling power stored by the energy storage circuit to the node when the power stored by the energy storage circuit is above a charge threshold; and

an energy distribution circuit having an input coupled to the node, and for controlling operating time during which DC voltage above an operating threshold voltage is presented to each of a plurality of device loads coupled to an output of the energy distribution circuit, wherein at least two of the device loads have different operating times.

12. The system of claim 11 wherein at least two of the device loads have different operating threshold voltage ranges.

13. The system of claim 11 further comprising the energy storage circuit, wherein the energy storage circuit includes a capacitor capable of storing potential electrical energy from a DC power source.

14. The system of claim 11 further comprising a DC power source for providing DC electrical power to the system, wherein the DC power source includes at least one of a battery and/or an antenna operatively coupled to a rectifier, wherein RF energy scavenged by the antenna is rectified to provide DC power.

15. The system of claim 11 wherein the energy distribution circuit comprises at least one diode and one capacitor associated with each of at least two of its outputs, the at least one diode for setting a maximum DC voltage provided by that output, and the at least one capacitor for setting the operating time associated with that output.

16. The system of claim 11 wherein the energy distribution circuit is for controlling an amount of energy that is allotted for each of at least two of the device loads.

17. A system for optimizing the use of energy consumption by electronics having multiple loads, the system comprising:

a DC power source for providing DC electrical power to the system, wherein the DC power source includes at least one of a battery and/or an antenna operatively coupled to a rectifier, wherein RF energy scavenged by the antenna is rectified to provide DC power;

a hysteretic switch circuit having an input for coupling to an energy storage circuit and an output coupled to a node, that hysteretic switch circuit for coupling power applied at its input to the node when the power stored by the energy storage circuit reaches a charge threshold; and

an energy distribution circuit having an input coupled to the node, and for controlling operating time during which DC voltage above an operating threshold voltage is presented to each of a plurality of device loads coupled to an output of the energy distribution circuit, wherein the energy distribution circuit comprises at least one diode and one capacitor associated with each of at least two of its outputs, the at least one diode for setting a maximum DC voltage provided by that output, and the at least one capacitor for setting the operating time associated with that output, and wherein at least two of the device loads have different operating times, and wherein at least two of the device loads have different operating threshold voltage ranges.

18. The system of claim 17 further comprising the energy storage circuit, for storing DC power provided by the DC power source.

19. The system of claim 18 wherein the energy storage circuit includes a capacitor capable of storing potential electrical energy from a DC power source.

20. The system of claim 17 wherein the energy distribution circuit is for controlling an amount of energy that is allotted for each of at least two of the device loads.