Magnetically coupled load modulation

Patent metadata

Field	Value
Publication number	US-2016181992-A1
Application number	US-201414573927-A
Country	US
Kind code	A1
Filing date	Dec 17, 2014
Priority date	Dec 17, 2014
Publication date	Jun 23, 2016
Grant date	—

Abstract

A method, packaged semiconductor device, and system for controlling a secondary amplifier output current based on an input signal received from an amplifier input, converting electrical energy to magnetic energy at a secondary amplifier output inductor, coupling the magnetic energy from the secondary amplifier output inductor to a primary amplifier output inductor, converting the coupled magnetic energy to induced electrical energy at the primary amplifier output inductor, combining the induced electrical energy with output electrical energy from a primary amplifier gain element, and applying a combined electrical energy including the output electrical energy and the induced electrical energy to a primary amplifier load are provided.

First claim

What is claimed is:

1 . A method comprising:
controlling a secondary amplifier output current of a secondary radio frequency (RF) amplifier gain element based on an input signal received from an amplifier input; providing the secondary amplifier output current to a secondary amplifier output inductor to convert electrical energy to magnetic energy; coupling the magnetic energy from the secondary amplifier output inductor to a primary amplifier output inductor, wherein the coupled magnetic energy is converted to induced electrical energy at the primary amplifier output inductor; combining the induced electrical energy with output electrical energy from a primary RF amplifier gain element; and applying a combined electrical energy including the output electrical energy and the induced electrical energy to a primary amplifier load.

2 . The method of claim 1 wherein the combining the induced electrical energy with the output electrical energy from the primary RF amplifier gain element further comprises:
modulating a primary amplifier load impedance of the primary amplifier load as a function of the induced electrical energy.

3 . The method of claim 2 wherein the modulating comprises:
modulating the primary amplifier load impedance according to an equation Z m =jωL+R m +jX m +jωM(I p /I m ), where Z m equals the primary amplifier load impedance, j equals the square root of negative one, w equals two times pi times a frequency of operation, L equals a self inductance of the primary amplifier output inductor, R m equals a primary amplifier load resistance of the primary amplifier load, X m equals a primary amplifier output capacitive reactance, M equals a mutual inductance, I p equals a secondary amplifier output current, and I m equals a primary amplifier output current.

4 . The method of claim 1 wherein the converting the electrical energy to the magnetic energy at the secondary amplifier output inductor further comprises:
providing impedance inversion of a secondary amplifier load impedance of the secondary RF amplifier gain element.

5 . The method of claim 1 wherein the combining the induced electrical energy with the output electrical energy from the primary RF amplifier gain element comprises:
combining a main amplifier output signal with a peaking amplifier output signal, wherein a Doherty amplifier comprises the primary RF amplifier gain element outputting the output electrical energy and the secondary RF amplifier gain element outputting the output electrical energy.

6 . The method of claim 1 further comprising:
configuring the primary amplifier output inductor and the secondary amplifier output inductor to have a maximum separation of 40 mils.

7 . The method of claim 1 further comprising:
configuring the primary amplifier output inductor and the secondary amplifier output inductor as arcuate planar coils.

8 . A packaged semiconductor device comprising:
a primary radio frequency (RF) amplifier gain element; a primary amplifier output inductor electrically coupled to the primary RF amplifier gain element; a primary amplifier load electrically coupled to the primary amplifier output inductor; a secondary RF amplifier gain element; a secondary amplifier output inductor electrically coupled to the secondary RF amplifier gain element and magnetically coupled to the primary amplifier output inductor; and a secondary amplifier load electrically coupled to the secondary amplifier output inductor, wherein the secondary amplifier output inductor magnetically couples a majority of a secondary amplifier output power of the secondary RF amplifier gain element to the primary amplifier output inductor to be applied to the primary amplifier load.

9 . The packaged semiconductor device of claim 8 wherein the secondary amplifier output inductor modulates a primary amplifier output inductor impedance of the primary amplifier output inductor via magnetic coupling as a function of a secondary amplifier output of the secondary RF amplifier gain element.

10 . The packaged semiconductor device of claim 8 wherein a primary amplifier gain element output impedance presented to a primary amplifier output of the primary RF amplifier gain element conforms to an equation Z m =jωL+R m +jX m +jωM(I p /I m ), where Z m equals the primary amplifier load impedance, j equals the square root of negative one, w equals two times pi times a frequency of operation, L equals a self inductance of the primary amplifier output inductor, R m equals a primary amplifier load resistance of the primary amplifier load, X m equals a primary amplifier output capacitive reactance, M equals a mutual inductance, I p equals a secondary amplifier output current, and I m equals a primary amplifier output current.

11 . The packaged semiconductor device of claim 8 wherein the secondary amplifier output inductor, in conjunction with the primary amplifier output inductor, functions as an impedance inverter.

12 . The packaged semiconductor device of claim 8 wherein a Doherty amplifier comprises the primary RF amplifier gain element and the secondary RF amplifier gain element.

13 . The packaged semiconductor device of claim 8 wherein the primary amplifier output inductor and the secondary amplifier output inductor have a maximum separation of 40 mils.

14 . The packaged semiconductor device of claim 8 wherein the primary amplifier output inductor and the secondary amplifier output inductor are arcuate planar coils.

15 . A system comprising:
a signal input; a phase adjustment circuit coupled to the signal input for receiving a radio frequency (RF) input signal; a primary RF amplifier gain element coupled to the phase adjustment circuit for receiving a first instance having a first phase of an RF signal; a secondary RF amplifier gain element coupled to the phase adjustment circuit for receiving a second instance having a second phase of the RF signal; a primary amplifier output inductor electrically coupled to a primary amplifier output of the primary RF amplifier gain element; a primary amplifier load electrically coupled to the primary amplifier output inductor; a secondary amplifier output inductor electrically coupled to a secondary amplifier output of the secondary RF amplifier gain element and magnetically coupled to the primary amplifier output inductor; and a secondary amplifier load electrically coupled to the secondary amplifier output inductor, wherein the secondary amplifier output inductor magnetically couples a majority of a secondary amplifier output power of the secondary RF amplifier gain element to the primary amplifier output inductor to be applied to the primary amplifier load.

16 . The system of claim 15 wherein the secondary amplifier output inductor modulates a primary amplifier output inductor impedance of the primary amplifier output inductor via magnetic coupling as a function of a secondary amplifier output of the secondary RF amplifier gain element.

17 . The system of claim 15 wherein a primary amplifier output impedance presented to the primary amplifier output conforms to an equation Z m =jωL+R m +jX m +jωM(I p /I m ), where Z m equals the primary amplifier load impedance, j equals the square root of negative one, w equals two times pi times a frequency of operation, L equals a self inductance of the primary amplifier output inductor, R m equals a primary amplifier load resistance of the primary amplifier load, X m equals a primary amplifier output capacitive reactance, M equals a mutual inductance, I p equals a secondary amp

Assignees

• Holmes Damon G
• Embar Ramanujam Srinidhi
• Staudinger Joseph
• Watts Michael E
• Freescale Semiconductor Inc

Inventors

• Holmes Damon G
• Embar Ramanujam Srinidhi
• Staudinger Joseph
• Watts Michael E

Classifications

• H03F2200/541

  Transformer coupled at the output of an amplifier · CPC title

• H03F2200/537

  A transformer being used as coupling element between two amplifying stages · CPC title

• H03F3/195

  in integrated circuits · CPC title

• H03F1/0288

  using a main and one or several auxiliary peaking amplifiers whereby the load is connected to the main amplifier using an impedance inverter, e.g. Doherty amplifiers · CPC title

• H03F1/083 Primary

  in transistor amplifiers (H03F1/10 - H03F1/22 take precedence) · CPC title