SINGLE INDUCTOR DC-DC CONVERTER WITH REGULATED OUTPUT AND ENERGY HARVESTING SYSTEM

• US 20160099582A1
• Filed: 10/02/2014
• Published: 04/07/2016
• Est. Priority Date: 10/02/2014
• Status: Active Grant

• Current Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Inventors: Ramorini, Stefano, Gasparini, Alessandro, Cattani, Alberto
• Granted Patent: US 9,680,323 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices
• 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 3/158 including plural semiconductor devices as final control devices for a single load

Abstract

An energy harvesting circuit receives an input voltage from a transducer and uses a single inductor operating in a DC-DC converter charging mode to generate charging current at a first output coupled to an energy storage device where a supply voltage is stored. The energy harvesting circuit further receives the supply voltage from the energy storage device and uses the same single inductor operating in a DC-DC converter regulating mode to generate load current at a second output where a regulated load voltage is provided. The energy harvesting circuit switches between the charging mode and the regulating mode in accordance with a discontinuous mode (DCM) control process.

Claims

1. An energy harvesting circuit, comprising:

an input configured to receive an input voltage from a transducer;

a first output configured to be coupled to an energy storage device;

a second output configured to be coupled to a load circuit; and

a circuit coupled between the input and the first and second outputs, the circuit configured to use a same single inductor element for generating charging current at the first output and generating load current at the second output.

2. The energy harvesting circuit of claim 1, wherein said circuit is configured for operation in a charging mode to generate said charging current from said input voltage in order to store a supply voltage on said energy storage device.

3. The energy harvesting circuit of claim 2, wherein said circuit is further configured for operation in a regulating mode to generate said load current from said supply voltage in order to provide a regulated output voltage to said load circuit.

4. The energy harvesting circuit of claim 1, wherein said circuit comprises a set of switches and a control circuit, wherein said control circuit is configured to actuate said set of switches for selective connection of the single inductor element in a buck-boost mode to charge said energy storage device at the first output to a supply voltage in response to the input voltage.

5. The energy harvesting circuit of claim 4, wherein said control circuit is further configured to actuate said set of switches for selective connection of the single inductor element in a buck mode to regulate voltage at the second output in response to said supply voltage.

6. The energy harvesting circuit of claim 4, wherein said control circuit is further configured to actuate said set of switches for selective connection of the single inductor element in a buck-boost mode to regulate voltage at the second output in response to said supply voltage.

7. The energy harvesting circuit of claim 1, wherein said first output comprises a first energy storage output and a second energy storage output, further comprising a set of switches configured to selectively couple one or more of the first and second energy storage outputs to said single inductor element.

8. The energy harvesting circuit of claim 1, wherein said circuit comprises:

a first switch coupled between said input and a first node configured to be coupled to a first terminal of said single inductor element;

a second switch coupled between said first node and a reference node;

a third switch coupled between a second node configured to be coupled to a second terminal of said single inductor element and the reference node;

a fourth switch coupled between the first node and the first output;

a fifth switch coupled between the second node and the first output; and

a sixth switch coupled between the second node and the second output.

9. The energy harvesting circuit of claim 8, wherein said circuit further comprises a control circuit configured to selectively actuate said first through sixth switches in both a charging mode and in a regulating mode using said single inductor element.

10. The energy harvesting circuit of claim 9, wherein the control circuit, in the charging mode, operates in a first switching phase to actuate the first and third switches and then operates in a second switching phase to actuate the second and fifth switches.

11. The energy harvesting circuit of claim 10, wherein the control circuit, in the regulating mode, operates in a first switching phase to actuate the third and fourth switches and then operates in a second switching phase to actuate the second and sixth switches.

12. The energy harvesting circuit of claim 10, wherein the control circuit, in the regulating mode, operates in a first switching phase to actuate the fourth and sixth switches and then operates in a second switching phase to actuate the second and sixth switches.

13. The energy harvesting circuit of claim 1, wherein said circuit comprises:

a first switch coupled between said input and a first node configured to be coupled to a first terminal of said single inductor element;

a second switch coupled between said first node and a reference node;

a third switch coupled between a second node configured to be coupled to a second terminal of said single inductor element and the reference node;

a fourth switch coupled between the second node and the first output; and

a fifth switch coupled between the first node and the second output.

14. The energy harvesting circuit of claim 13, wherein said circuit further comprises a control circuit configured to selectively actuate said first through fifth switches in both a charging mode and in a regulating mode using said single inductor element.

15. The energy harvesting circuit of claim 14, wherein the control circuit, in the charging mode, operates in a first switching phase to actuate the first and third switches and then operates in a second switching phase to actuate the second and fourth switches.

16. The energy harvesting circuit of claim 15, wherein the control circuit, in the regulating mode, operates in a first switching phase to actuate the fourth and fifth switches and then operates in a second switching phase to actuate the third and fifth switches.

17. The energy harvesting circuit of claim 15, wherein the control circuit, in the regulating mode, operates in a first switching phase to actuate the second and fourth switches and then operates in a second switching phase to actuate the third and fifth switches.

18. The energy harvesting circuit of claim 1, wherein said circuit is configured for operation in a charging mode to generate said charging current from said input voltage in order to store a supply voltage on said energy storage device, wherein said circuit is further configured for operation in a regulating mode to generate said load current from said supply voltage in order to provide a regulated output voltage to said load circuit, and further comprising a control circuit configured to control switching between the charging mode and the regulating mode in accordance with a discontinuous mode (DCM) hysteretic control process.

19. The energy harvesting circuit of claim 1, wherein said circuit is configured for operation in a charging mode to generate said charging current from said input voltage in order to store a supply voltage on said energy storage device, wherein said circuit is further configured for operation in a regulating mode to generate said load current from said supply voltage in order to provide a regulated output voltage to said load circuit, and further comprising a control circuit configured to control switching between the charging mode and the regulating mode in accordance with a discontinuous mode (DCM) pulse frequency modulation control process.

20. A method, comprising:

receiving an input voltage from a transducer;

generating a first output coupled to an energy storage device;

generating a second output coupled to a load circuit;

using a single inductor element in a charging mode to generate charging current at the first output; and

using said single inductor element in a regulating mode to generate load current at the second output.

21. The method of claim 20, further comprising:

storing a supply voltage on said energy storing device in response to the charging current;

wherein using said single inductor element in the regulating mode to generate load current at the second output comprises generating the load current from said supply voltage.

22. The method of claim 20, wherein using the single inductor element in the charging mode to generate charging current at the first output comprises selectively connecting the single inductor element in a buck-boost mode to charge said energy storage device at the first output to a supply voltage in response to the input voltage.

23. The method of claim 22, wherein using said single inductor element in the regulating mode to generate load current at the second output comprises selectively connecting the single inductor element in a buck mode to regulate voltage at the second output in response to said supply voltage.

24. The method of claim 22, wherein using said single inductor element in the regulating mode to generate load current at the second output comprises selectively connecting the single inductor element in a buck-boost mode to regulate voltage at the second output in response to said supply voltage.

25. The method of claim 20, further comprising switching between the charging mode and the regulating mode in accordance with a discontinuous mode (DCM) hysteretic control process.

26. The method of claim 20, further comprising switching between the charging mode and the regulating mode in accordance with a discontinuous mode (DCM) pulse frequency modulation control process.