Power management system and method of use thereof

Patent metadata

Field	Value
Publication number	US-9627967-B2
Application number	US-201414222430-A
Country	US
Kind code	B2
Filing date	Mar 21, 2014
Priority date	Mar 21, 2014
Publication date	Apr 18, 2017
Grant date	Apr 18, 2017

Abstract

One embodiment of a power management system includes a reservoir configured to collect energy. The system also includes a voltage regulator coupled to the reservoir via an input terminal and configured to convert the energy to an output voltage via an output terminal when enabled. A threshold detector is coupled to the reservoir and is configured to sense the energy and enable the voltage regulator when the energy exceeds a threshold. The system further includes a feedback circuit coupled between the output terminal and the threshold detector, and configured to feedback the output voltage to the threshold detector to compensate for a voltage drop across the threshold detector due to an output current drawn by the load.

First claim

What is claimed is:

1. A power management system, comprising:
a reservoir configured to collect energy;
a voltage regulator coupled to the reservoir and configured to convert the energy to an output voltage, the voltage regulator including an enable input;
a threshold detector coupled to the reservoir and the enable input of the voltage regulator, the threshold detector configured to sense the energy and enable the voltage regulator when the energy exceeds a threshold; and
a feedback circuit comprising a diode and coupled between an output of the voltage regulator and the enable input of the voltage regulator, the feedback circuit configured to feed back the output voltage to override threshold detector when the voltage regulator is operating.

2. The power management system of claim 1 , wherein the reservoir comprises a super capacitor.

3. The power management system of claim 1 , wherein the voltage regulator comprises a step-up voltage converter circuit.

4. The power management system of claim 1 , wherein the threshold is determined according to a load coupled to the output of the voltage regulator.

5. The power management system of claim 1 , further comprising an energy harvesting unit coupled to the reservoir.

6. The power management system of claim 1 , further comprising a control circuit coupled to the enable input of the voltage regulator to selectively disable the voltage regulator.

7. The power management system of claim 1 , further comprising a control circuit coupled to the reservoir and configured to monitor the energy in the reservoir.

8. The power management system of claim 1 , wherein the threshold detector comprises:
a voltage divider circuit coupled between the reservoir and a ground terminal; and
a comparator with an input coupled to the voltage divider circuit and an output coupled to the enable input of the voltage regulator.

9. The power management system of claim 1 , wherein the feedback circuit further comprises a resistor serially coupled to the diode, the diode having an anode terminal coupled to the output of the voltage regulator and a cathode coupled to the enable input.

10. A wireless component comprising:
an energy harvesting circuit;
a capacitor coupled to the energy harvesting circuit;
a voltage divider coupled in parallel with the capacitor;
a comparator with an input coupled to an intermediate node of the voltage divider;
a voltage regulator having a power input coupled to the capacitor and an enable input coupled to an output of the comparator;
a feedback circuit comprising a diode and coupled between a power output of the voltage regulator and the input of the comparator; and
a load coupled to the power output of the voltage regulator.

11. The component of claim 10 , wherein wireless component comprises an electronic shelf label and wherein the load comprises a display.

12. The component of claim 11 , wherein the load further comprises a microcontroller unit coupled to the display.

13. The component of claim 10 , wherein the feedback circuit comprises a serially coupled diode and resistor coupled between the power output of the voltage regulator and the input of the comparator.

14. A system, comprising:
an energy harvesting subsystem configured to capture energy from an environment source;
a load associated with a power threshold; and
a power management subsystem coupled between the energy harvesting subsystem and the load, the power management subsystem comprising:
a reservoir coupled to the energy harvesting subsystem and configured to collect the energy captured by the energy harvesting subsystem;
a voltage regulator coupled to the reservoir and configured to convert the energy to an output voltage, the voltage regulator including an enable input;
a threshold detector coupled to the reservoir and the enable input of the voltage regulator, the threshold detector configured to sense the energy and enable the voltage regulator when the energy exceeds a threshold; and
a feedback circuit comprising a diode and coupled between an output of the voltage regulator the enable input of the voltage regulator, the feedback circuit configured to feed back the output voltage to override threshold detector when the voltage regulator is operating.

15. The system of claim 14 , wherein the load has a periodic power demand.

16. The system of claim 14 , wherein the load comprises an electronic paper display.

17. The system of claim 14 , wherein the reservoir comprises a super capacitor.

18. The system of claim 14 , wherein the voltage regulator comprises a step-up voltage converter circuit.

19. The system of claim 14 , wherein the voltage regulator is coupled so as to remain enabled until the reservoir is discharged.

20. The system of claim 14 , wherein the load comprises a microcontroller unit coupled to the feedback circuit and configured to selectively disable the voltage regulator.

21. The system of claim 20 , wherein the microcontroller unit is configured to monitor the energy in the reservoir.

22. The system of claim 14 , wherein the threshold detector comprises:
a voltage divider circuit coupled between the reservoir and a ground terminal; and
a comparator coupled between an intermediate node of the voltage divider circuit and the enable input of the voltage regulator.

23. A power management system, comprising:
means for collecting energy in a reservoir;
means for converting the energy to an output voltage;
means for sensing the energy and enabling the means for converting when the energy exceeds a threshold; and
means for feeding the output voltage back through a diode to the means for sensing to override the means for sensing when the means for converting is operating.

24. The power management system of claim 23 , wherein the threshold is determined according to a load coupled to the output of the means for converting.

25. The power management system of claim 23 , further comprising means for harvesting the energy to be collected.

26. The power management system of claim 25 , wherein the means for harvesting comprises means for harvesting radio frequency (RF) energy.

27. The power management system of claim 23 , further comprising means for monitoring the energy in the reservoir.

28. The power management system of claim 23 , wherein the means for collecting energy comprises a super capacitor;
wherein the means for converting comprises a step-up voltage converter circuit; and
wherein the means for feeding the output voltage back comprises a serially coupled diode and resistor.

29. The power management system of claim 23 , wherein the means for converting comprises:
a voltage divider circuit coupled between the reservoir and a ground terminal; and
a comparator with an input coupled to the voltage divider circuit and an output coupled to an enable input of a voltage regulator.

Assignees

• St Microelectronics Int Nv

Inventors

• Mallik Ranajay
• Jain Jitendra

Classifications

• Y10T307/406

  Cross-Sectional Technologies · mapped topic

• H02M2001/0025

  Electricity · mapped topic

• H02M3/156 Primary

  with automatic control of output voltage or current, e.g. switching regulators · CPC title

• H02M1/0025

  Arrangements for modifying reference values, feedback values or error values in the control loop of a converter · CPC title