Method and apparatus for high efficiency AC/DC conversion of low voltage input
First Claim
1. An AC/DC converter, comprising:
- a first active diode;
a second active diode;
a first energy storage element; and
a second energy storage element;
wherein the converter is adapted to connect to an input AC voltage source such that the first active diode is in series between the input AC voltage source and the first energy storage element and the second active diode is in series between the input AC voltage source and the second energy storage element, such that when a voltage of the input AC voltage source is below a voltage of the first energy storage element, the first active diode turns on and current flows from the first energy storage element to the input AC voltage source, and when the voltage of the input AC voltage source is higher than a voltage of the second energy storage element, current flows from the input AC voltage source to the second energy storage element;
wherein the first active diode comprises a first comparator and a first switch,wherein the second active diode comprises a second comparator and a second switchwherein the first comparator comprises a first positive input port, a first negative input port, at least one first bias port, and a first output port;
wherein the first switch comprises a first transistor, where the first transistor has a first gate, a first drain, and a first source;
wherein the second comparator comprises a second positive input port, a second negative input port, at least one second bias port, and a second output port;
wherein the second switch comprises a second transistor, wherein the second transistor comprises a second gate, a second drain, and a second source,wherein the converter further comprises;
at least one first bias voltage supply; and
at least one second bias voltage supply;
wherein the at least one first bias voltage supply is connected to the at least one first bias port so as to provide a first bias voltage to the first comparator, wherein the first output port is connected to the first gate, wherein one of the first positive input port and the first negative input port is connected to the first energy storage element, wherein the other of the first positive input port and the first negative input port is adapted to connect to the input AC voltage source, wherein one of the first drain and the first source is adapted to connect to the input AC voltage source and the other of the first drain and first source is connected with the first energy storage element such that the first transistor is in series between the input AC voltage source and the first energy storage element, wherein when the voltage of the input AC voltage source is below the voltage of the first energy storage element a voltage of the first output port turns on the first transistor and current flows from the first energy storage element to the input AC voltage source,wherein the at least one second bias voltage supply is connected to the at least one second bias port so as to provide a second bias voltage to the second comparator, wherein the second output port is connected to the second gate, wherein one of the second positive input port and the second negative input port is connected to the second energy storage element, wherein the other of the second positive input port and the second negative input port is adapted to connect to the input AC voltage source, wherein one of the second drain and the second source is adapted to connect to the input AC voltage source and the other of the second drain and the second source is connected to the second energy storage element such that the second transistor is in series between the input AC voltage source and the second energy storage element, wherein when the voltage of the input AC voltage source is above the voltage of the second energy storage element the second output port voltage turns on the second transistor and current flows from the input AC voltage source to the second energy storage element.
1 Assignment
0 Petitions
Accused Products
Abstract
Embodiments of the subject invention relate to a method and apparatus for providing a low-power AC/DC converter designed to operate with very low input voltage amplitudes. Specific embodiments can operate with input voltages less than or equal to 1 V, less than or equal to 200 mV, and as low as 20 mV, respectively. Embodiments of the subject low-power AC/DC converter can be utilized in magnetic induction energy harvester systems. With reference to a specific embodiment, a maximum efficiency of 92% was achieved for a 1 V input, and efficiencies exceeding 70% were achieved for a 200 mV input. A specific embodiment functioned properly when connected to a magnetic energy harvester device operating below 200 mV input.
17 Citations
52 Claims
-
1. An AC/DC converter, comprising:
-
a first active diode; a second active diode; a first energy storage element; and a second energy storage element; wherein the converter is adapted to connect to an input AC voltage source such that the first active diode is in series between the input AC voltage source and the first energy storage element and the second active diode is in series between the input AC voltage source and the second energy storage element, such that when a voltage of the input AC voltage source is below a voltage of the first energy storage element, the first active diode turns on and current flows from the first energy storage element to the input AC voltage source, and when the voltage of the input AC voltage source is higher than a voltage of the second energy storage element, current flows from the input AC voltage source to the second energy storage element; wherein the first active diode comprises a first comparator and a first switch, wherein the second active diode comprises a second comparator and a second switch wherein the first comparator comprises a first positive input port, a first negative input port, at least one first bias port, and a first output port; wherein the first switch comprises a first transistor, where the first transistor has a first gate, a first drain, and a first source; wherein the second comparator comprises a second positive input port, a second negative input port, at least one second bias port, and a second output port; wherein the second switch comprises a second transistor, wherein the second transistor comprises a second gate, a second drain, and a second source, wherein the converter further comprises; at least one first bias voltage supply; and at least one second bias voltage supply; wherein the at least one first bias voltage supply is connected to the at least one first bias port so as to provide a first bias voltage to the first comparator, wherein the first output port is connected to the first gate, wherein one of the first positive input port and the first negative input port is connected to the first energy storage element, wherein the other of the first positive input port and the first negative input port is adapted to connect to the input AC voltage source, wherein one of the first drain and the first source is adapted to connect to the input AC voltage source and the other of the first drain and first source is connected with the first energy storage element such that the first transistor is in series between the input AC voltage source and the first energy storage element, wherein when the voltage of the input AC voltage source is below the voltage of the first energy storage element a voltage of the first output port turns on the first transistor and current flows from the first energy storage element to the input AC voltage source, wherein the at least one second bias voltage supply is connected to the at least one second bias port so as to provide a second bias voltage to the second comparator, wherein the second output port is connected to the second gate, wherein one of the second positive input port and the second negative input port is connected to the second energy storage element, wherein the other of the second positive input port and the second negative input port is adapted to connect to the input AC voltage source, wherein one of the second drain and the second source is adapted to connect to the input AC voltage source and the other of the second drain and the second source is connected to the second energy storage element such that the second transistor is in series between the input AC voltage source and the second energy storage element, wherein when the voltage of the input AC voltage source is above the voltage of the second energy storage element the second output port voltage turns on the second transistor and current flows from the input AC voltage source to the second energy storage element.
-
-
2. The converter according to claim 1,
wherein the at least one first bias voltage supply comprises a first positive bias voltage supply and a first negative bias voltage supply, wherein the first positive bias voltage supply is connected to the first positive bias port, wherein the first negative bias voltage supply is connected to the first negative bias port, wherein the at least one second bias voltage supply comprises a second positive bias voltage supply and a second negative bias voltage supply, wherein the second positive bias voltage supply is connected to the second positive bias port, wherein the second negative bias voltage supply is connected to the second negative bias port.
-
3. The converter according to claim 1, wherein the first positive input port is connected to the first energy storage element, wherein the first negative input port is adapted to connect to the input AC voltage source.
-
4. The converter according to claim 1, wherein the first negative input port is connected to the first energy storage element, wherein the first positive input port is adapted to connect to the input AC voltage source.
-
5. The converter according to claim 1, wherein the first drain is adapted to connect to the input AC voltage source, wherein the first source is connected to the first energy storage element.
-
6. The converter according to claim 1, wherein the first source is adapted to connect to the input AC voltage source, wherein the first drain is connected to the first energy storage element.
-
7. The converter according to claim 1, wherein the second positive input port is connected to the second energy storage element, wherein the second negative input port is adapted to connect to the input AC voltage source.
-
8. The converter according to claim 1, wherein the second negative input port is connected to the second energy storage element, wherein the second positive input port is adapted to connect to the input AC voltage source.
-
9. The converter according to claim 1, wherein the second drain is adapted to connect to the input AC voltage source, wherein the second source is connected to the second energy storage element.
-
10. The converter according to claim 1, wherein the second source is adapted to connect to the input AC voltage source, wherein the second drain is connected to the second energy storage element.
-
11. The converter according to claim 1, wherein the converter operates with an input AC voltage source of less than or equal to 1 V.
-
12. The converter according to claim 1, wherein the first switch is a first transistor, wherein the second switch is a second transistor.
-
13. The converter according to claim 12, wherein the first and second transistors are junction gate field-effect transistor (JFET).
-
14. The converter according to claim 12, wherein the first and second transistors are MOS transistors.
-
15. The converter according to claim 14, further comprising a first low pass filter in parallel with the first energy storage element.
-
16. The converter according to claim 12, wherein the second transistor is an NMOS transistor and the first transistor is a PMOS transistor.
-
17. The converter according to claim 16, wherein the second comparator comprises a second positive input port connected to a source of the NMOS transistor.
-
18. The converter according to claim 17, wherein the second comparator comprises a second negative input port connected to a drain of the NMOS transistor.
-
19. The converter according to claim 16, wherein the first comparator comprises a first positive input port connected to a drain of the PMOS transistor.
-
20. The converter according to claim 19, wherein the first comparator comprises a first negative input port connected to a source of the PMOS transistor.
-
21. The converter according to claim 1, further comprising a first resistor in series with the first active diode between the input AC power source and the first energy storage element.
-
22. The converter according to claim 1, further comprising a shunt capacitor connected across output terminals of the input AC power source.
-
23. The converter according to claim 1, further comprising a linear or switching regulator connected to an output of the converter.
-
24. The converter according to claim 1, wherein the converter operates with an input AC power source of less than or equal to 200 mV.
-
25. The converter according to claim 24, wherein the converter has an efficiency greater than 70%.
-
26. The converter according to claim 1, wherein the converter operates with an input AC power source of less than or equal to 20 mV.
-
27. A magnetic induction energy harvester system, comprising an AC/DC converter, wherein the AC/DC converter comprises:
-
a first active diode; a second active diode; a first energy storage element; and a second energy storage element; wherein the converter is adapted to connect to an input AC voltage source such that the first active diode is in series between the input AC voltage source and the first energy storage element and the second active diode is in series between the input AC voltage source and the second energy storage element, such that when a voltage of the input AC voltage source is below a voltage of the first energy storage element, the first active diode turns on and current flows from the first energy storage element to the input AC voltage source, and when the voltage of the input AC voltage source is higher than a voltage of the second energy storage element, current flows from the input AC voltage source to the second energy storage element, wherein the first active diode comprises a first comparator and a first switch, wherein the second active diode comprises a second comparator and a second switch, wherein the first comparator comprises a first positive input port, a first negative input port, at least one first bias port, and a first output port; wherein the first switch comprises a first transistor, where the first transistor has a first gate, a first drain, and a first source; wherein the second comparator comprises a second positive input port, a second negative input port, at least one second bias port, and a second output port; wherein the second switch comprises a second transistor, wherein the second transistor comprises a second gate, a second drain, and a second source, wherein the converter further comprises; at least one first bias voltage supply; and at least one second bias voltage supply; wherein the at least one first bias voltage supply is connected to the at least one first bias port so as to provide a first bias voltage to the first comparator, wherein the first output port is connected to the first gate, wherein one of the first positive input port and the first negative input port is connected to the first energy storage element, wherein the other of the first positive input port and the first negative input port is adapted to connect to the input AC voltage source, wherein one of the first drain and the first source is adapted to connect to the input AC voltage source and the other of the first drain and first source is connected with the first energy storage element such that the first transistor is in series between the input AC voltage source and the first energy storage element, wherein when the voltage of the input AC voltage source is below the voltage of the first energy storage element a voltage of the first output port turns on the first transistor and current flows from the first energy storage element to the input AC voltage source, wherein the at least one second bias voltage supply is connected to the at least one second bias port so as to provide a second bias voltage to the second comparator, wherein the second output port is connected to the second gate, wherein one of the second positive input port and the second negative input port is connected to the second energy storage element, wherein the other of the second positive input port and the second negative input port is adapted to connect to the input AC voltage source, wherein one of the second drain and the second source is adapted to connect to the input AC voltage source and the other of the second drain and the second source is connected to the second energy storage element such that the second transistor is in series between the input AC voltage source and the second energy storage element, wherein when the voltage of the input AC voltage source is above the voltage of the second energy storage element the second output port voltage turns on the second transistor and current flows from the input AC voltage source to the second energy storage element.
-
-
28. The magnetic induction energy harvester system according to claim 27, wherein the converter operates with an input AC voltage source of less than or equal to 1 V.
-
29. The magnetic induction energy harvester system according to claim 27,
wherein the at least one first bias voltage supply comprises a first positive bias voltage supply and a first negative bias voltage supply, wherein the first positive bias voltage supply is connected to the first positive bias port, wherein the first negative bias voltage supply is connected to the first negative bias port, wherein the at least one second bias voltage supply comprises a second positive bias voltage supply and a second negative bias voltage supply, wherein the second positive bias voltage supply is connected to the second positive bias port, wherein the second negative bias voltage supply is connected to the second negative bias port.
-
30. The magnetic induction energy harvester system according to claim 27, wherein the first positive input port is connected to the first energy storage element, wherein the first negative input port is adapted to connect to the input AC voltage source.
-
31. The magnetic induction energy harvester system according to claim 27, wherein the first negative input port is connected to the first energy storage element, wherein the first positive input port is adapted to connect to the input AC voltage source.
-
32. The magnetic induction energy harvester system according to claim 27, wherein the first drain is adapted to connect to the input AC voltage source, wherein the first source is connected to the first energy storage element.
-
33. The magnetic induction energy harvester system according to claim 27, wherein the first source is adapted to connect to the input AC voltage source, wherein the first drain is connected to the first energy storage element.
-
34. The magnetic induction energy harvester system according to claim 27, wherein the second positive input port is connected to the second energy storage element, wherein the second negative input port is adapted to connect to the input AC voltage source.
-
35. The magnetic induction energy harvester system according to claim 27, wherein the second negative input port is connected to the second energy storage element, wherein the second positive input port is adapted to connect to the input AC voltage source.
-
36. The magnetic induction energy harvester system according to claim 27, wherein the second drain is adapted to connect to the input AC voltage source, wherein the second source is connected to the second energy storage element.
-
37. The magnetic induction energy harvester system according to claim 27, wherein the second source is adapted to connect to the input AC voltage source, wherein the second drain is connected to the second energy storage element.
-
38. The converter according to claim 27, wherein the first switch is a first transistor, wherein the second switch is a second transistor.
-
39. The converter according to claim 38, wherein the first and second transistors are junction gate field-effect transistor (JFET).
-
40. The converter according to claim 38, wherein the first and second transistors are MOS transistors.
-
41. The converter according to claim 40, further comprising a first low pass filter in parallel with the first energy storage element.
-
42. The converter according to claim 38, wherein the second transistor is an NMOS transistor and the first transistor is a PMOS transistor.
-
43. The converter according to claim 42, wherein the second comparator comprises a second positive input port connected to a source of the NMOS transistor.
-
44. The converter according to claim 43, wherein the second comparator comprises a second negative input port connected to a drain of the NMOS transistor.
-
45. The converter according to claim 42, wherein the first comparator comprises a first positive input port connected to a drain of the PMOS transistor.
-
46. The converter according to claim 45, wherein the first comparator comprises a first negative input port connected to a source of the PMOS transistor.
-
47. The converter according to claim 27, further comprising a first resistor in series with the first active diode between the input AC power source and the first energy storage element.
-
48. The converter according to claim 27, further comprising a shunt capacitor connected across output terminals of the input AC power source.
-
49. The converter according to claim 27, further comprising a linear or switching regulator connected to an output of the converter.
-
50. The converter according to claim 27, wherein the converter operates with an input AC power source of less than or equal to 200 mV.
-
51. The converter according to claim 50, wherein the converter has an efficiency greater than 70%.
-
52. The converter according to claim 27, wherein the converter operates with an input AC power source of less than or equal to 20 mV.
Specification