HIGH EFFICIENCY VOLTAGE MODE CLASS D TOPOLOGY

• US 20150069855A1
• Filed: 09/09/2014
• Published: 03/12/2015
• Est. Priority Date: 09/10/2013
• Status: Active Grant

• Current Assignee: Efficient Power Conversion Corporation
• Original Assignee: Efficient Power Conversion Corporation
• Inventors: De Rooij, Michael A., Strydom, Johan T., Nair, Bhaskaran R.
• Granted Patent: US 9,887,677 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H03F 1/565 using inductive elements
• CPC Class Codes: H03F 2200/387 A circuit being added at the output of an amplifier to adapt the output impedance of the amplifier
• CPC Class Codes: H03F 2200/541 Transformer coupled at the output of an amplifier
• CPC Class Codes: H03F 3/2171 with field-effect devices H03F3/2173 - H03F3/2178 take precedence
• CPC Class Codes: H03F 3/2173 of the bridge type

Abstract

A high efficiency voltage mode class D amplifier and energy transfer system is provided. The amplifier and system includes a pair of transistors connected in series between a voltage source and a ground connection. Further, a ramp current tank circuit is coupled in parallel with one of the pair of transistors and a resonant tuned load circuit is coupled to the ramp current tank circuit. The ramp current tank circuit can include an inductor that absorbs an output capacitance C_OSS of the pair of transistors and a capacitor the provides DC blocking.

Claims

1. A power amplifier comprising:

a pair of transistors connected in series between a voltage source and a ground connection;

a switch node disposed between a source of a first transistor of the pair of transistors and a drain of a second transistor of the pair of transistors;

a circuit connected between the switch node and the ground connection or supply connection or both, the circuit having an inductor with an inductance that absorbs an output capacitance of the pair of transistors; and

a resonant tuning circuit connected in series between the switch node and a load coupled to the power amplifier.

2. The power amplifier of claim 1, wherein each of the pair of transistors is a GaN transistor.

3. The power amplifier of claim 1, wherein the circuit is a tank circuit comprising the inductor and a capacitor connected in series between the switch node and the ground connection.

4. The power amplifier of claim 3, wherein the capacitor has a capacitance configured to provide DC blocking.

5. The power amplifier of claim 4, wherein the power amplifier is configured to self-commutate the switch-node with a necessary dead-time between gate signals applied to the pair of transistors.

6. The power amplifier of claim 3, wherein the tank circuit enables the power amplifier to operate as a no load buck converter with zero voltage switching.

7. The power amplifier of claim 3, further comprising at least one add-on tank circuit coupled in parallel with the tank circuit.

8. The power amplifier of claim 7, wherein the at least one add-on tank circuit comprises a second inductor and a second capacitor.

9. The power amplifier of claim 8, further comprising another transistor connected in series between the at least one add-on tank circuit and the ground connection.

10. The power amplifier of claim 7, wherein the at least one add-on tank circuit comprises:

a second inductor having a pair of terminals with a first terminal coupled to the switch node; and

another transistor having a source coupled to a node between the inductor and the capacitor of the tank circuit and a drain coupled to a second terminal of the second inductor.

11. The power amplifier of claim 7, wherein the at least one add-on tank circuit comprises:

a second inductor having a pair of terminals with a first terminal coupled to a node between the inductor and the capacitor of the tank circuit; and

another transistor having a source coupled to the ground connection and a drain coupled to a second terminal of the second inductor.

12. A wireless energy transfer system comprising:

a power transmitting device including;

a pair of transistors connected in series between a voltage source and a ground connection;

a switch node disposed between a source of a first of the pair of transistors and a drain of a second of the pair of transistors;

a circuit connected between the switch node and the ground connection, the circuit having an inductor with an inductance that absorbs an output capacitance of the pair of transistors; and

a capacitor and series connected coil coupled in parallel to the tank circuit between the switch node and the ground connection; and

a power receiving device including;

a load;

a rectifier connected in parallel to the load;

a pair of capacitors coupled to the rectifier; and

a receiving coil coupled in parallel to at least one of the pair of capacitors.

13. The wireless energy transfer system of claim 12, wherein when the power receiving device is inductively coupled to the power transmitting device a highly resonant wireless energy transfer coil with matching network is formed.

14. The wireless energy transfer system of claim 12, wherein each of the pair of transistors is a GaN transistor.

15. The wireless energy transfer system of claim 12, wherein the circuit is a tank circuit comprising the inductor and a capacitor connected in series between the switch node and the ground connection.

16. The wireless energy transfer system of claim 15, wherein the capacitor has a capacitance configured to provide DC blocking.

18. The wireless energy transfer system of claim 15, wherein the tank circuit enables the power amplifier to operate as a no load buck converter with zero voltage switching.

19. The wireless energy transfer system of claim 15, further comprising at least one add-on tank circuit coupled in parallel with the tank circuit.

20. The wireless energy transfer system of claim 19, wherein the at least one add-on tank circuit comprises a second inductor and a second capacitor.

21. The wireless energy transfer system of claim 20, further comprising another transistor connected in series between the at least one add-on tank circuit and the ground connection.

22. The wireless energy transfer system of claim 19, wherein the at least one add-on tank circuit comprises:

a second inductor having a pair of terminals with a first terminal coupled to the switch node; and

another transistor having a source coupled to a node between the inductor and the capacitor of the tank circuit and a drain coupled to a second terminal of the second inductor.

23. The wireless energy transfer system of claim 19, wherein the at least one add-on tank circuit comprises:

a second inductor having a pair of terminals with a first terminal coupled to a node between the inductor and the capacitor of the tank circuit, and

another transistor having a source coupled to the ground connection and a drain coupled to a second terminal of the second inductor.

17. The wireless energy transfer system 16, wherein the power amplifier is configured to self-commutate the switch-node with a necessary dead-time between gate signals applied to the pair of transistors.

24. A power amplifier comprising:

a first pair of transistors connected in series between a voltage source and a ground connection;

a second pair of transistors connected in series between a voltage source and a ground connection;

a first switch node disposed between a source of a first transistor of the first pair of transistors and a drain of a second transistor of the first pair of transistors;

a second switch node disposed between a source of a first transistor of the second pair of transistors and a drain of a second transistor of the second pair of transistors;

a first inductor connected between the first switch node and the second switch node; and

a capacitor connected to a load in series and coupled to either the first or the second switch nodes.

25. The power amplifier of claim 24, wherein each of the pair of transistors is a GaN transistor.

26. The power amplifier of claim 24, further comprising a second inductor that forms a resonant tuning circuit with the capacitor.

27. The power amplifier of claim 24, wherein the resonant tuning circuit is coupled in series with the load and between the first switch node and a ground connection.

28. The power amplifier of claim 24, wherein the first inductor and the second pair of transistors form a tank circuit.

29. The power amplifier of claim 24, wherein the capacitor and the load are coupled in parallel to the first inductor.

30. The power amplifier of claim 24, wherein the first pair of transistors form a half bridge voltage inverter and the load is coupled to the half bridge voltage inverter.