DUAL PARALLEL AMPLIFIER BASED DC-DC CONVERTER

• US 20130176075A1
• Filed: 03/01/2013
• Published: 07/11/2013
• Est. Priority Date: 10/26/2011
• Status: Active Grant

• Current Assignee: Qorvo US, Inc. (Qorvo, Inc.)
• Original Assignee: RF Micro Devices Incorporated (Qorvo, Inc.)
• Inventors: Kay, Michael R., Folkmann, Andrew F., Khlat, Nadim, Gorisse, Philippe
• Granted Patent: US 9,024,688 B2
• Time in Patent Office: Days
• US Class Current: 330/127
• CPC Class Codes: G05F 1/46 wherein the variable actually regulated by the final control device is dc G05F1/625 takes precedence
• CPC Class Codes: H03F 1/02 Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation
• CPC Class Codes: H03F 1/0266 by using a signal derived from the input signal
• CPC Class Codes: H03F 2200/432 Two or more amplifiers of different type are coupled in parallel at the input or output, e.g. a class D and a linear amplifier, a class B and a class A amplifier
• CPC Class Codes: H03F 2200/555 A voltage generating circuit being realised for biasing different circuit elements
• CPC Class Codes: H03F 3/195 in integrated circuits
• CPC Class Codes: H03F 3/24 of transmitter output stages

Abstract

A direct current (DC)-DC converter, which includes switching circuitry, a first parallel amplifier, and a second parallel amplifier, is disclosed. The switching circuitry has a switching circuitry output. The first parallel amplifier has a first feedback input and a first parallel amplifier output. The second parallel amplifier has a second feedback input and a second parallel amplifier output. A first inductive element is coupled between the switching circuitry output and the first feedback input. A second inductive element is coupled between the first feedback input and the second feedback input.

Claims

1. Circuitry comprising:

switching circuitry having a switching circuitry output;

a first parallel amplifier having a first feedback input and a first parallel amplifier output, such that a first inductive element is coupled between the switching circuitry output and the first feedback input; and

a second parallel amplifier having a second feedback input and a second parallel amplifier output, such that a second inductive element is coupled between the first feedback input and the second feedback input.

2. The circuitry of claim 1 further comprising the first inductive element and the second inductive element.

3. The circuitry of claim 1 wherein the first feedback input is coupled to the first parallel amplifier output and the second feedback input is coupled to the second parallel amplifier output.

4. The circuitry of claim 1 wherein:

the first parallel amplifier is adapted to partially provide a first power supply output signal via the first parallel amplifier output and the second inductive element based on a voltage setpoint;

the second parallel amplifier is adapted to partially provide the first power supply output signal via the second parallel amplifier output based on the voltage setpoint; and

the switching circuitry is adapted to partially provide the first power supply output signal via the first inductive element and the second inductive element.

5. The circuitry of claim 4 wherein a maximum output current from the first parallel amplifier is at least ten times greater than a maximum output current from the second parallel amplifier.

6. The circuitry of claim 4 wherein the voltage setpoint is based on a power supply control signal.

7. The circuitry of claim 4 wherein:

the first parallel amplifier is further adapted to partially regulate a voltage of the first power supply output signal based on the voltage setpoint;

the second parallel amplifier is further adapted to partially regulate the voltage of the first power supply output signal based on the voltage setpoint; and

the switching circuitry is further adapted to regulate the first power supply output signal to about minimize an output current from the first parallel amplifier.

8. The circuitry of claim 4 further comprising a radio frequency (RF) power amplifier (PA), wherein:

the first power supply output signal is a first envelope power supply signal; and

the RF PA is adapted to receive and amplify an RF input signal to provide an RF transmit signal using the first envelope power supply signal.

9. The circuitry of claim 8 wherein the first envelope power supply signal provides power for amplification to the RF PA.

10. The circuitry of claim 8 wherein the RF PA comprises a final stage adapted to provide the RF transmit signal using the first envelope power supply signal.

11. The circuitry of claim 4 wherein:

a DC power source is adapted to provide a DC source signal to the first parallel amplifier, to the second parallel amplifier, and to the switching circuitry;

the first parallel amplifier is further adapted to partially provide the first power supply output signal using the DC source signal;

the second parallel amplifier is further adapted to partially provide the first power supply output signal using the DC source signal; and

the switching circuitry is further adapted to partially provide the first power supply output signal using the DC source signal.

12. The circuitry of claim 11 wherein the DC power source is a battery.

13. The circuitry of claim 11 further comprising the DC power source.

14. The circuitry of claim 4 wherein:

the first inductive element and the second inductive element are coupled to one another at a first connection node; and

the first inductive element and the second inductive element are adapted to provide a second power supply output signal via the first connection node.

15. The circuitry of claim 1 further comprising a first offset capacitive element and a second offset capacitive element wherein:

the first offset capacitive element is coupled between the first feedback input and the first parallel amplifier output; and

the second offset capacitive element is coupled between the second feedback input and the second parallel amplifier output.

16. The circuitry of claim 1 wherein the first inductive element has a first inductance and the second inductive element has a second inductance, such that a magnitude of the first inductance is at least three times greater than a magnitude of the second inductance.

17. The circuitry of claim 1 wherein a third inductive element is coupled between the first parallel amplifier output and the first feedback input.

18. The circuitry of claim 17 wherein:

the first parallel amplifier is adapted to partially provide a first power supply output signal via the first parallel amplifier output based on a voltage setpoint; and

a phase-shift across the third inductive element at least partially compensates for limited open loop gain of the first parallel amplifier at frequencies above a first frequency threshold.

19. The circuitry of claim 17 wherein the first inductive element has a first inductance, the second inductive element has a second inductance, and the third inductive element has a third inductance, such that a magnitude of the first inductance is at least ten times greater than a magnitude of the third inductance.

20. The circuitry of claim 19 wherein the magnitude of the first inductance is at least three times greater than a magnitude of the second inductance.

21. The circuitry of claim 17 wherein a fourth inductive element is coupled between the second parallel amplifier output and the second feedback input.

22. The circuitry of claim 21 wherein:

the first parallel amplifier is adapted to partially provide a first power supply output signal via the first parallel amplifier output based on a voltage setpoint;

the second parallel amplifier is adapted to partially provide the first power supply output signal via the second parallel amplifier output based on the voltage setpoint;

a phase-shift across the third inductive element at least partially compensates for limited open loop gain of the first parallel amplifier at frequencies above a first frequency threshold; and

a phase-shift across the fourth inductive element at least partially compensates for limited open loop gain of the second parallel amplifier at frequencies above a second frequency threshold.

23. The circuitry of claim 21 wherein the first inductive element has a first inductance, the second inductive element has a second inductance, the third inductive element has a third inductance, and the fourth inductive element has a fourth inductance, such that a magnitude of the second inductance is at least ten times greater than a magnitude of the fourth inductance.

24. The circuitry of claim 23 wherein a magnitude of the first inductance is at least three times greater than the magnitude of the second inductance.

25. Circuitry comprising:

switching circuitry having a switching circuitry output;

a first parallel amplifier having a first feedback input and a first parallel amplifier output, such that a first inductive element is coupled between the switching circuitry output and the first feedback input; and

a second parallel amplifier having a second feedback input and a second parallel amplifier output, such that a second inductive element and a third inductive element are coupled in series between the first feedback input and the second feedback input.

26. A method comprising:

partially providing a first power supply output signal via a series combination of a first inductive element and a second inductive element;

partially providing the first power supply output signal via a first parallel amplifier output based on a voltage setpoint and feeding back a voltage to a first feedback input from a first connection node between the first inductive element and the second inductive element; and

partially providing the first power supply output signal via a second parallel amplifier output based on the voltage setpoint and feeding back a voltage to a second feedback input from the second inductive element.