RF power converter

• US 9,041,364 B2
• Filed: 11/30/2012
• Issued: 05/26/2015
• 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: Khlat, Nadim
• Primary Examiner(s): Laxton, Gary L
• Assistant Examiner(s): DEMISSE, AFEWORK S
• Application Number:
  US13/690,187
• Publication Number:
  US 20130141062A1
• Time in Patent Office: 907 Days
• Field of Search: 323/268, 323/273, 323/282, 363/59, 363/60, 363/61, 327551-559
• US Class Current: 323/268
• CPC Class Codes: G05F 1/59 including plural semiconductor devices as final control devices for a single load
• 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 1/10 Arrangements incorporating converting means for enabling loads to be operated at will from different kinds of power supplies, e.g. from ac or dc
• 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) power 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;

a switching controller operable to be activated and deactivated, wherein the switching controller is configured to switch the switching circuit so that the switching circuit generates the pulsed output voltage when the switching controller is activated;

a low-drop out (LDO) regulation circuit operable to be activated and deactivated, the LDO regulation circuit being configured to generate a supply voltage when the LDO regulation circuit is activated; and

an RF filter coupled to receive the pulsed output voltage from the switching circuit and the supply voltage from the LDO regulation circuit, the RF filter being operable to alternate between a first RF filter topology and a second RF filter topology, wherein the first RF filter topology is configured to convert the pulsed output voltage from the switching circuit into the supply voltage and 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.

2. The RF power converter of claim 1 further comprising a charge pump configured to generate a charge pump voltage from the power source voltage, wherein the LDO regulation circuit is configured to generate the supply voltage from the charge pump voltage when the LDO regulation circuit is activated.

3. The RF power converter of claim 1 further comprising an operational mode controller operable to set the RF power converter in a first operational mode and in a second operational mode, wherein the operational mode controller is configured to:

provide the switching controller such that the switching controller is activated in the first operational mode and such that the switching controller is deactivated in the second operational mode;

provide the LDO regulation circuit such that the LDO regulation circuit is deactivated in the first operational mode and such that the LDO regulation circuit is activated in the second operational mode; and

provide the RF filter such that the RF filter has the first RF filter topology in the first operational mode and such that the RF filter has the second RF filter topology in the second operational mode.

4. The RF power converter of claim 3 wherein the operational mode controller is configured to obtain a target average power output parameter that identifies a target average power output value, the operational mode controller being configured to select between the first operational mode and the second operational mode based on the target average power output parameter.

5. The RF power converter of claim 4 wherein the operational mode controller is configured to select the first operational mode when the target average power output value identified by the target average power output parameter is above a threshold value.

6. The RF power converter of claim 4 wherein the operational mode controller is configured to select the second operational mode when the target average power output value identified by the target average power output parameter is below a threshold value.

7. The RF power converter of claim 4 wherein the operational mode controller is configured to:

select the first operational mode when the target average power output value identified by the target average power output parameter is above a first threshold value; and

select the second operational mode when the target average power output value identified by the target average power output parameter is below a second threshold value that is less than the first threshold value.

8. The RF power converter of claim 1 further comprising:

a charge pump configured to generate a charge pump voltage from the power source voltage, the charge pump being operable to provide an adjustable voltage ratio, such that an average DC voltage level of the charge pump voltage has the adjustable voltage ratio with respect to a power source voltage level of the power source voltage, and wherein the LDO regulation circuit is configured to generate the supply voltage from the charge pump voltage when the LDO regulation circuit is activated; and

an operational mode controller operable to set the RF power converter in a first operational mode and a second operational mode, wherein the operational mode controller is configured to;

provide the switching controller such that the switching controller is activated in the first operational mode and such that the switching controller is deactivated in the second operational mode;

provide the LDO regulation circuit such that the LDO regulation circuit is deactivated in the first operational mode and such that the LDO regulation circuit is activated in the second operational mode;

provide the RF filter in the first RF filter topology in the first operational mode and in the second RF filter topology in the second operational mode; and

set the adjustable voltage ratio to be less than one (1) in the second operational mode.

9. The RF power converter of claim 8 wherein the operational mode controller is further configured to:

obtain a target average power output parameter that identifies a target average power output value, the operational mode controller being configured to select between the first operational mode and the second operational mode based on the target average power output parameter;

select the first operational mode when the target average power output value identified by the target average power output parameter is above a first threshold value; and

select the second operational mode when the target average power output value identified by the target average power output parameter is below a second threshold value that is less than the first threshold value.

10. The RF power converter of claim 1 wherein the RF filter includes a decoupling capacitor and a switchable ground path configured to be opened and closed and wherein:

the decoupling capacitor is coupled to receive the supply voltage;

the switchable ground path coupled in shunt with respect to the decoupling capacitor;

the switchable ground path is open in the first RF filter topology of the RF filter; and

the switchable ground path is closed in the second RF filter topology of the RF filter.

11. The RF power converter of claim 10 wherein the decoupling capacitor is operable to passively filter the supply voltage from the LDO regulation circuit to reduce the ripple variation in the supply voltage level of the supply voltage when the switchable ground path is closed.

12. The RF power converter of claim 10 wherein the switching controller further comprises a ripple current correction circuit configured to generate a ripple correction current and wherein:

the switchable ground path is coupled in shunt between the ripple current correction circuit and the decoupling capacitor; and

the ripple current correction circuit is coupled so as to inject the ripple correction current into the decoupling capacitor when the switchable ground path is open, wherein the decoupling capacitor is operable to filter the ripple correction current and output the ripple correction current such that the ripple correction current reduces a ripple variation in a supply current level of a supply current resulting from the supply voltage.

13. The RF power converter of claim 10 wherein:

the RF filter further comprises a power inductor configured to receive the pulsed output voltage from the switching circuit in the first RF filter topology;

the switching circuit comprises a P-type field effect transistor (P-FET) operable to receive the power source voltage, and an N-type field effect transistor (N-FET) coupled to ground, wherein when the switching controller is activated, the switching controller is configured to;

switch the P-FET between an on state and an off state, the P-FET being configured to pull the pulsed output voltage toward the power source voltage in the on state; and

switch the N-FET between the on state and the off state, the N-FET being configured to pull the pulsed output voltage toward ground in the on state;

wherein the switching controller is further configured to hold the P-FET in the off state and hold the N-FET in the on state when the switching controller is deactivated such that the switching circuit and the power inductor form a second ground path in the second RF filter topology of the RF filter.

14. The RF power converter of claim 13 wherein the RF filter is operable to be alternated to a third RF filter topology and wherein:

the RF filter is provided in the first RF filter topology when the switchable ground path is open while the switching controller is activated; and

the RF filter is provided in the third RF filter topology when the switchable ground path is closed and while the switching controller is activated.

15. The RF power converter of claim 14 wherein:

the decoupling capacitor is operable to passively filter the supply voltage to reduce the ripple variation in the supply voltage level of the supply voltage when the RF filter is in the second RF filter topology; and

the decoupling capacitor is operable to passively filter the supply voltage converted from the pulsed output voltage generated by the switching circuit when the RF filter is in the third RF filter topology.

16. The RF power converter of claim 15 further comprising a ripple current correction circuit configured to generate a ripple correction current, the ripple current correction circuit being coupled so as to inject the ripple correction current into the decoupling capacitor when the switchable ground path is opened, such that the decoupling capacitor filters the ripple correction current, wherein the decoupling capacitor outputs the ripple correction current such that the ripple correction current reduces a ripple variation in a supply current level of a supply current resulting from the supply voltage.

17. The RF power converter of claim 1 further comprising:

a current sense detector configured to;

generate a current sense signal having a sense signal level set so as to indicate a supply current level of a supply current when the RF filter is in the first RF filter topology; and

adjust the sense signal level of the current sense signal in response to a change in the supply voltage level of the supply voltage when the RF filter is in the first RF filter topology; and

a bang-bang controller (BBC) operable to be activated and deactivated, wherein the BBC is configured to switch the switching circuit based on the sense signal level of the current sense signal so as to generate the pulsed output voltage when the BBC is activated.

18. The RF power converter of claim 17 further comprising a voltage offset loop wherein:

the current sense detector is further configured to generate a supply control output voltage;

the RF filter in the first RF filter topology is operable to apply the supply control output voltage to the supply voltage such that the supply voltage level of the supply voltage is biased by a supply control output voltage level of the supply control output voltage, and the supply control output voltage level and the supply voltage level are displaced by a displacement voltage magnitude;

the BBC is configured to receive an offset voltage having an offset voltage magnitude and is further configured to switch the switching circuit such that the displacement voltage magnitude is set in accordance with the offset voltage magnitude when the BBC is activated; and

the voltage offset loop is configured to;

generate the offset voltage; and

adjust the offset voltage magnitude so that the displacement voltage magnitude is driven to a target displacement voltage magnitude.

19. A method of producing a supply voltage comprising:

providing an RF filter in a first RF filter topology, wherein the RF filter is operable to be alternated between the first RF filter topology and a second RF filter topology;

switching a switching circuit so as to generate a pulsed output voltage from a power source voltage;

converting the pulsed output voltage to the supply voltage using the RF filter in the first RF filter topology;

providing the RF filter in the second RF filter topology;

generating the supply voltage with a low-drop out (LDO) regulation circuit; and

filtering the supply voltage from the LDO regulation circuit with the RF filter in the second RF filter topology to reduce a ripple variation in a supply voltage level of the supply voltage.