Average power tracking controller

• US 9,280,163 B2
• Filed: 01/23/2013
• Issued: 03/08/2016
• Est. Priority Date: 12/01/2011
• Status: Active Grant

• Current Assignee: Qorvo US, Inc. (Qorvo, Inc.)
• Original Assignee: RF Micro Devices Incorporated (Qorvo, Inc.)
• Inventors: Kay, Michael R., Khlat, Nadim
• Primary Examiner(s): Berhane, Adolf
• Assistant Examiner(s): Demisse, Afework
• Application Number:
  US13/747,725
• Publication Number:
  US 20130141068A1
• Time in Patent Office: 1,140 Days
• Field of Search: 323282-285, 323/351, 323/286, 323/287, 323/268, 323/273, 363/59, 363/60, 363/61
• US Class Current: 1/1
• 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: H02M 1/0067 Converter structures employing plural converter units, other than for parallel operation of the units on a single load
• CPC Class Codes: H02M 1/14 Arrangements for reducing ripples from dc input or output
• CPC Class Codes: H03F 1/0227 using supply converters
• CPC Class Codes: H03F 1/26 Modifications of amplifiers to reduce influence of noise generated by amplifying elements
• CPC Class Codes: H03F 2200/351 Pulse width modulation being used in an amplifying circuit
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 2200/504 the supply voltage or current being continuously controlled by a controlling signal, e.g. the controlling signal of a transistor implemented as variable resistor in a supply path for, an IC-block showed amplifier
• CPC Class Codes: H03F 3/24 of transmitter output stages
• CPC Class Codes: H04B 15/005 Reducing noise, e.g. humm, from the supply

Abstract

This disclosure relates to radio frequency (RF) power converters and methods of operating the same. In one embodiment, an RF power converter includes an RF switching converter, a low-drop out (LDO) regulation circuit, and an RF filter. The RF filter is coupled to receive a pulsed output voltage from the RF switching converter and a supply voltage from the LDO regulation circuit. The RF filter is operable to alternate between a first RF filter topology and a second RF filter topology. In the first RF filter topology, the RF filter is configured to convert the pulsed output voltage from a switching circuit into the supply voltage. The RF filter in the second RF filter topology is configured to filter the supply voltage from the LDO regulation circuit to reduce a ripple variation in a supply voltage level of the supply voltage. As such, the RF filter provides greater versatility.

Claims

1. A radio frequency (RF) switching converter comprising:

a switching circuit operable to receive a power source voltage, the switching circuit being switchable so as to generate a pulsed output voltage from the power source voltage;

an RF filter coupled to receive the pulsed output voltage from the switching circuit and operable to convert the pulsed output voltage from the switching circuit into a supply voltage having a supply voltage level with a ripple variation;

a bang-bang controller (BBC) operable to receive an Average Power Tracking (APT) signal and configured to switch the switching circuit based on an APT signal level of the APT signal so that the switching circuit generates the pulsed output voltage and so that the supply voltage level of the supply voltage has an average DC supply voltage level set in accordance with a DC offset signal level of the APT signal; and

an APT controller operable to receive a supply control input signal having a supply control input signal level, the APT controller being configured to;

generate the APT signal such that the APT signal level varies from the DC offset signal level of the APT signal in accordance with the ripple variation of the supply voltage level of the supply voltage; and

set the DC offset signal level of the APT signal in accordance with the supply control input signal level of the supply control input signal.

2. The RF switching converter of claim 1 wherein:

the supply control input signal level is indicative of a target DC supply voltage level for the average DC supply voltage level; and

the APT controller is configured to set the DC offset signal level of the APT signal in accordance with the supply control input signal level of the supply control input signal so that the average DC supply voltage level is driven by the BBC to the target DC supply voltage level.

3. The RF switching converter of claim 1 wherein the APT controller is further operable to receive a feedback signal having a feedback signal level that is indicative of the supply voltage level of the supply voltage and is configured to:

generate the APT signal from the feedback signal such that the APT signal level corresponds with the feedback signal level of the feedback signal and the APT signal level is provided at the DC offset signal level when the feedback signal level of the feedback signal is provided at a feedback voltage magnitude; and

set the DC offset signal level of the APT signal by establishing the feedback voltage magnitude in accordance with the supply control input signal level of the supply control input signal.

4. The RF switching converter of claim 3 wherein the APT controller is further configured to establish the feedback voltage magnitude as being equal to the supply control input signal level of the supply control input signal.

5. The RF switching converter of claim 1 wherein the APT controller comprises an amplification circuit having an amplification gain, wherein the amplification circuit is operable to receive the supply control input signal and to receive a feedback signal having a feedback signal level indicative of the supply voltage level of the supply voltage, the amplification circuit being configured to:

set the DC offset signal level of the APT signal in accordance with the supply control input signal level of the supply control input signal by generating an error signal having an error signal level set in accordance with a difference between the feedback signal level and the supply control input signal level; and

generate the APT signal from the error signal by amplifying the error signal level in accordance with the amplification gain.

6. The RF switching converter of claim 5 wherein generating the error signal having the error signal level set in accordance with the difference between the feedback signal level and the supply control input signal level provides the DC offset signal level as a quiescent APT signal level of the APT signal when the error signal level is zero.

7. The RF switching converter of claim 5 wherein:

the feedback signal is a feedback voltage and the feedback signal level is a feedback voltage level;

the supply control input signal is a supply control input voltage and the supply control input signal level is a supply control input voltage level;

the error signal is an error voltage and the error signal level is an error voltage level; and

the amplification gain of the amplification circuit is a transconductance gain so that the APT signal is an APT current, the APT signal level is an APT current level, and the DC offset signal level of the APT signal is a DC offset current level.

8. The RF switching converter of claim 7 wherein the difference is from the feedback voltage level to the supply control input voltage level.

12. The RF switching converter of claim 1 wherein the APT controller is further configured to generate the APT signal such that a first change in the supply voltage level of the supply voltage results in a second change in the APT signal level, the second change being negatively proportional to the first change.

13. The RF switching converter of claim 12 wherein:

the switching circuit is switchable so as to provide the pulsed output voltage in a first voltage state, a second voltage state that is higher than the first voltage state, and a third voltage state that is higher than the second voltage state; and

the BBC is operable in a first bang-bang mode and in a second bang-bang mode, the BBC being configured to;

in the first bang-bang mode, switch the switching circuit to change the pulsed output voltage from the first voltage state to the second voltage state in response to the APT signal level of the APT signal being above a first threshold signal level;

in the first bang-bang mode, switch the switching circuit to change the pulsed output voltage from the second voltage state to the first voltage state in response to the APT signal level of the APT signal being below a second threshold signal level that is lower than the first threshold signal level;

in the second bang-bang mode, switch the switching circuit to change the pulsed output voltage from the second voltage state to the third voltage state in response to the APT signal level of the APT signal being above the first threshold signal level; and

in the second bang-bang mode, switch the switching circuit to change the pulsed output voltage from the third voltage state to the second voltage state in response to the APT signal level of the APT signal being below the second threshold signal level.

14. The RF switching converter of claim 1 wherein the BBC is further operable to receive a current sense signal and is further configured to switch the switching circuit based on the current sense signal so that the switching circuit generates the pulsed output voltage.

15. The RF switching converter of claim 14 wherein the BBC is further configured to select between the current sense signal and the APT signal so that the BBC switches the switching circuit based on the APT signal when the APT signal is selected and based on the current sense signal when the current sense signal is selected.

16. The RF switching converter of claim 15 wherein:

the BBC includes a multiplexer operable to receive the APT signal and the current sense signal; and

the multiplexer is configured to select between the APT signal and the current sense signal for the BBC so that the BBC switches the switching circuit based on the APT signal when the APT signal is selected and based on the current sense signal when the current sense signal is selected.

17. The RF switching converter of claim 15 further comprising a current sense detector wherein:

the RF filter comprises a power inductor coupled in series with the switching circuit to produce a power inductor current in response to the pulsed output voltage, such that a power inductor current level of the power inductor current has an other ripple variation;

the current sense detector is configured to generate a current sense signal in response to the power inductor current such that a sense signal level of the current sense signal varies in accordance with the ripple variation of the supply voltage.

18. The RF switching converter of claim 17 wherein the current sense detector is configured to generate the current sense signal such that a first change in the power inductor current level of the power inductor current results in a second change in the sense signal level, the second change being negatively proportional to the first change.

19. The RF switching converter of claim 18 wherein:

the APT controller is further configured to generate the APT signal such that a first change in the supply voltage level of the supply voltage results in a second change in the APT signal level, the second change being negatively proportional to the first change;

the switching circuit is switchable so as to provide the pulsed output voltage in a first voltage state, a second voltage state that is higher than the first voltage state, and a third voltage state that is higher than the second voltage state; and

the BBC is operable in a first bang-bang mode, in a second bang-bang mode, and in a third bang-bang mode, the BBC being configured to;

generate a sense voltage from the APT signal when the APT signal is selected, such that a sense voltage level of the sense voltage is provided in accordance with the APT signal level of the APT signal;

generate the sense voltage from the current sense signal when the current sense signal is selected, such that the sense voltage level of the sense voltage is provided in accordance with the sense signal level of the current sense signal;

generate a first threshold voltage having a first threshold voltage level, a second threshold voltage having a second threshold voltage level that is higher than the first threshold voltage level, and a third threshold voltage having a third threshold voltage level that is higher than the second threshold voltage level;

in the first bang-bang mode, switch the switching circuit to change the pulsed output voltage from the first voltage state to the second voltage state in response to the sense voltage level of the sense voltage being above the second threshold voltage level;

in the first bang-bang mode, switch the switching circuit to change the pulsed output voltage from the second voltage state to the first voltage state in response to the sense voltage level of the sense voltage being below the first threshold voltage level;

in the first bang-bang mode, switch the switching circuit so as to maintain the pulsed output voltage in the second voltage state when the sense voltage level of the sense voltage is above the third threshold voltage level;

in the second bang-bang mode, switch the switching circuit to change the pulsed output voltage from the second voltage state to the third voltage state in response to the sense voltage level of the sense voltage being above the second threshold voltage level;

in the second bang-bang mode, switch the switching circuit to change the pulsed output voltage from the third voltage state to the second voltage state in response to the sense voltage level of the sense voltage being below the first threshold voltage level;

in the second bang-bang mode, switch the switching circuit so as to maintain the pulsed output voltage in the third voltage state when the sense voltage level of the sense voltage is above the first threshold voltage level;

in the third bang-bang mode, switch the switching circuit to change the pulsed output voltage from the first voltage state to the second voltage state in response to the sense voltage level of the sense voltage being above the second threshold voltage level;

in the third bang-bang mode, switch the switching circuit to change the pulsed output voltage from the second voltage state to the third voltage state in response to the sense voltage level of the sense voltage being above the third threshold voltage level;

in the third bang-bang mode, switch the switching circuit to change the pulsed output voltage from the second voltage state to the first voltage state in response to the sense voltage level of the sense voltage being below the first threshold voltage level; and

in the third bang-bang mode, switch the switching circuit to change the pulsed output voltage from the third voltage state to the first voltage state in response to the sense voltage level of the sense voltage being below the first threshold voltage level.

9. The RF switching converter of 8 wherein the transconductance gain has a negative value.

10. The RF switching converter of claim 9 wherein:

the switching circuit is switchable so as to provide the pulsed output voltage in a first voltage state, a second voltage state that is higher than the first voltage state, and a third voltage state that is higher than the second voltage state; and

the BBC is operable in a first bang-bang mode and in a second bang-bang mode, the BBC being configured to;

generate a sense voltage from the APT current such that a sense voltage level of the sense voltage is directly proportional to the APT signal level of the APT signal;

generate a first threshold voltage having a first threshold voltage level and a second threshold voltage having a second threshold voltage level that is higher than the first threshold voltage level;

in the first bang-bang mode, switch the switching circuit to change the pulsed output voltage from the first voltage state to the second voltage state in response to the sense voltage level being above the second threshold voltage level;

in the first bang-bang mode, switch the switching circuit to change the pulsed output voltage from the second voltage state to the first voltage state in response to the sense voltage level of the sense voltage being below the first threshold voltage level;

in the second bang-bang mode, switch the switching circuit to change the pulsed output voltage from the second voltage state to the third voltage state in response to the sense voltage level being above the second threshold voltage level; and

in the second bang-bang mode, switch the switching circuit to change the pulsed output voltage from the third voltage state to the second voltage state in response to the sense voltage level of the sense voltage being below the first threshold voltage level.

11. The RF switching converter of claim 10 wherein the first voltage state is set near ground, the second voltage state is set near a power source voltage level of the power source voltage, and the third voltage state is set so as to be boosted with respect to the power source voltage level of the power source voltage.

20. A switching controller for a switching circuit comprising:

a bang-bang controller (BBC) operable to receive an Average Power Tracking (APT) signal and configured to switch the switching circuit based on an APT signal level of the APT signal so that the switching circuit generates a pulsed output voltage;

an APT controller operable to receive a supply control input signal having a supply control input signal level and to receive a feedback voltage in response to a supply voltage that is generated from the pulsed output voltage and has a supply voltage level with a ripple variation, the feedback voltage having a feedback signal level that is indicative of the supply voltage level of the supply voltage, the APT controller being configured to;

generate the APT signal from the feedback voltage such that the APT signal level is set in accordance with the feedback signal level of the feedback voltage and varies from a DC offset signal level; and

set the DC offset signal level of the APT signal in accordance with the supply control input signal level of the supply control input signal.

21. A method of converting a power source voltage into a supply voltage that has a supply voltage level with a ripple variation comprising:

receiving a supply control input signal having a supply control input signal level;

generating an Average Power Tracking (APT) signal having an APT signal level that varies from a DC offset signal level in accordance with the ripple variation of the supply voltage level of the supply voltage;

setting the DC offset signal level of the APT signal in accordance with the supply control input signal level;

switching a switching circuit so that the switching circuit generates a pulsed output voltage based on the APT signal level of the APT signal; and

filtering the pulsed output voltage so as to generate the supply voltage from the pulsed output voltage.