Pseudo-envelope following feedback delay compensation

• US 9,431,974 B2
• Filed: 12/10/2013
• Issued: 08/30/2016
• Est. Priority Date: 04/19/2010
• Status: Active Grant

• Current Assignee: Qorvo US, Inc. (Qorvo, Inc.)
• Original Assignee: Qorvo US, Inc. (Qorvo, Inc.)
• Inventors: Khlat, Nadim, Kay, Michael R., Gorisse, Philippe
• Primary Examiner(s): Nguyen, Patricia T
• Application Number:
  US14/101,770
• Publication Number:
  US 20140097895A1
• Time in Patent Office: 994 Days
• Field of Search: 330/127, 330/297, 455/127.1, 323/222
• US Class Current: 1/1
• CPC Class Codes: H02M 1/0025 Arrangements for modifying reference values, feedback values or error values in the control loop of a converter
• CPC Class Codes: H02M 3/07 using capacitors charged and discharged alternately by semiconductor devices with control electrode , e.g. charge pumps
• CPC Class Codes: H03F 1/0244 Stepped control
• CPC Class Codes: H03F 1/025 by using a signal derived from the input signal
• CPC Class Codes: H03F 1/0277 Selecting one or more amplifiers from a plurality of amplifiers
• CPC Class Codes: H03F 1/42 Modifications of amplifiers to extend the bandwidth
• CPC Class Codes: H03F 2200/102 A non-specified detector of a signal envelope being used in an amplifying circuit
• CPC Class Codes: H03F 2200/204 A hybrid coupler being used at the output of an amplifier circuit
• CPC Class Codes: H03F 2200/36 the amplifier comprising means for increasing the bandwidth
• CPC Class Codes: H03F 2200/375 Circuitry to compensate the offset being present in an amplifier
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 2200/555 A voltage generating circuit being realised for biasing different circuit elements
• CPC Class Codes: H03F 2200/78 A comparator being used in a controlling circuit of an amplifier
• CPC Class Codes: H03F 2203/45526 the FBC comprising a resistor-capacitor combination and being coupled between the LC and the IC
• CPC Class Codes: H03F 2203/45544 the IC comprising one or more capacitors, e.g. coupling capacitors
• CPC Class Codes: H03F 2203/45594 the IC comprising one or more resistors, which are not biasing resistor
• CPC Class Codes: H03F 2203/45694 the LC comprising more than one shunting resistor
• CPC Class Codes: H03F 2203/45712 the LC comprising a capacitor as shunt
• CPC Class Codes: H03F 2203/45718 the LC comprising a resistor as shunt
• CPC Class Codes: H03F 2203/7221 the gated amplifier being switched on or off by a switch at the output of the amplifier
• CPC Class Codes: H03F 3/195 : in integrated circuits
• CPC Class Codes: H03F 3/217 : Class D power amplifiers; Switching amplifiers
• CPC Class Codes: H03F 3/245 : with semiconductor devices only
• CPC Class Codes: H03F 3/3022 : CMOS common source output SEPP amplifiers H03F3/3008 takes precedence
• CPC Class Codes: H03F 3/45475 : using IC blocks as the active amplifying circuit
• CPC Class Codes: H03F 3/505 : with field-effect devices
• CPC Class Codes: H03F 3/72 : Gated amplifiers, i.e. amplifiers which are rendered operative or inoperative by means of a control signal

Abstract

A switch mode power supply converter and a feedback delay compensation circuit are disclosed. The switch mode power supply converter has a switching voltage output and provides a switching voltage at the switching voltage output, such that a target voltage for a power amplifier supply voltage at a power amplifier supply output is based on the switching voltage. Further, the switching voltage is based on an early indication of a change of the target voltage. The feedback delay compensation circuit provides the early indication of the change of the target voltage.

Claims

1. Circuitry comprising:

a switch mode power supply converter having a switching voltage output and configured to provide a switching voltage at the switching voltage output, such that a target voltage for a power amplifier supply voltage at a power amplifier supply output is based on the switching voltage, which is based on an early indication of a change of the target voltage; and

a feedback delay compensation circuit comprising a high pass filter configured to high pass filter a V_RAMP signal to generate a derivative of the V_RAMP signal, such that the feedback delay compensation circuit is configured to;

generate a feedback delay compensation signal based on the derivative of the V_RAMP signal; and

provide the feedback delay compensation signal to the switch mode power supply converter as the early indication of the change of the target voltage.

2. The circuitry of claim 1 wherein a power inductive element is coupled between the switching voltage output and the power amplifier supply output.

3. The circuitry of claim 1 further comprising a parallel amplifier circuit, such that the switch mode power supply converter and the parallel amplifier circuit are configured to operate in tandem to generate the power amplifier supply voltage for a radio frequency power amplifier.

4. The circuitry of claim 3 wherein the parallel amplifier circuit is further configured to regulate the power amplifier supply voltage based on a difference between a V_RAMP signal and the power amplifier supply voltage.

5. The circuitry of claim 4 wherein the early indication of the change of the target voltage is based on the V_RAMP signal.

6. The circuitry of claim 4 wherein the V_RAMP signal is representative of required supply modulation information for a power amplifier collector of the radio frequency power amplifier.

7. The circuitry of claim 3 wherein the parallel amplifier circuit has a parallel amplifier output, such that a coupling circuit is coupled between the parallel amplifier output and the power amplifier supply output.

8. The circuitry of claim 7 wherein the coupling circuit comprises an offset capacitive element.

9. The circuitry of claim 1 wherein the high pass filter is a differential high pass filter.

10. The circuitry of claim 1 wherein the high pass filter has a programmable high pass time constant.

11. The circuitry of claim 10 wherein the programmable high pass time constant is based on a band of operation of a communication device.

15. The circuitry of claim 1 wherein the switch mode power supply converter is further configured to:

receive a parallel amplifier circuit output current estimate from a parallel amplifier circuit;

generate a composite feedback signal based on a combination of the parallel amplifier circuit output current estimate and the feedback delay compensation signal;

compare the composite feedback signal to a plurality of threshold levels to determine a plurality of comparison outputs of the switch mode power supply converter; and

govern generation of the switching voltage based on the plurality of comparison outputs.

16. The circuitry of claim 15 wherein the plurality of threshold levels consists of a shunt threshold level and a series threshold level.

17. The circuitry of claim 15 wherein the plurality of threshold levels consists of a shunt threshold level, a series threshold level, and a first boost threshold level.

18. The circuitry of claim 15 wherein the plurality of threshold levels consists of a shunt threshold level, a series threshold level, a first boost threshold level, and a second boost threshold level.

12. Circuitry comprising:

a switch mode power supply converter having a switching voltage output and configured to provide a switching voltage at the switching voltage output, such that a target voltage for a power amplifier supply voltage at a power amplifier supply output is based on the switching voltage, which is based on an early indication of a change of the target voltage; and

a feedback delay compensation circuit, which comprises a transconductance circuit having a transconductance, and is configured to;

generate a feedback delay compensation signal based on a derivative of a V_RAMP signal and the transconductance; and

provide the feedback delay compensation signal to the switch mode power supply converter as the early indication of the change of the target voltage.

13. The circuitry of claim 12 wherein the transconductance is programmable.

14. The circuitry of claim 12 wherein the transconductance circuit is a differential transconductance circuit.

19. A method comprising:

providing a switching voltage at a switching voltage output, such that a target voltage for a power amplifier supply voltage at a power amplifier supply output is based on the switching voltage, which is based on an early indication of a change of the target voltage;

high pass filtering a V_RAMP signal to generate a derivative of the V_RAMP signal;

generating a feedback delay compensation signal based on the derivative of the V_RAMP signal; and

providing the feedback delay compensation signal as the early indication of the change of the target voltage.