fager pasymposium09 final

7/31/2019 Fager PASymposium09 Final

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CENTRE

Ev a lua t ion o f H igh Ef f i ciency PAs fo r u se in- -

r s an ager, osse n as a ema ,Ulf Gustavsson, ,*Rik Jos, and Herbert Zirath

Chalmers University of Technology, Sweden,

Ericsson, Sweden,* NXP Semiconductors, Netherlands

[email protected]


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Out ine

PA efficiency for modulated signals

Efficiency enhancement techniques

General polar architectures

Static polar characterization of LDMOS class D-1 PA

Load modulation transmitters Load impedance tuning

Static load modulation characterization of LDMOS class D-1 PA

Optimum operation for maximized efficiency

Summary and conclusions Summar of efficienc redictions with modulated si nal statistics Comparison between supply- and load modulation results

Conclusions

22009-01-19 Power Amplifier Symposium 2009


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Out ine





Dynamic load modulation transmitter Load impedance tuning




Conclusions



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PA e iciency or mo u ate signa s

Overall efficiency is maximized by minimizing the dissipatedpower, P

diss

=

Average PAE is determined by the probability: p(Pou t)Pdiss To im rove efficienc PAE must be increased at intermediate P where

diss out in


the signal spends most of its time


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PA e iciency or mo u ate signa s

Different efficiency enhancement techniques have beenproposed Dynam ic supp ly m odu la t ion ( EER / enve lope t rack ing / hyb r id EER)

Dynam ic load m odu la t ion

Outphasing (Chireix / LINC)

Doherty


u se-w mo u a on - , an pass ...


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Out ine





Load modulation transmitter Load impedance tuning




Conclusions



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Dynamic supp y mo u ation princip e

decreased for lower power levels

Different techniques can be defined depending on how the RFin ut ower and V are ointl controlled...



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modulation

PA supply voltage is alwayssufficiently high

Out ut ower is controlled binput signal, i.e. PA in linear mode

Pre-distortion of the RF inputonly, like in ordinary PA

Envelope elimination and restoration (EER) Output power is controlled

only by the PA supply voltage

PA operated in saturation

PA operation

Time alignment betweensupply voltage and RF signal


cr ca


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Genera po ar transmitter arc itecture

all power levels EER: Lower efficiency at low output power

Hybrid EER is considered PAE can be maximized for all power levels by simultaneous control of both RF

in ut ower and su l volta e



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Measurement examp e: LDMOS c ass D-

PA ou t . in dd

( ),, out in dd inP P V PPAE P V =

-1

,dc in dd P V

Devices: 2Freescale MRF282

Performance summary =

Pou t = 20W

PAEMAX

= 70%

Gain = 15 dB

Bandwidth (PAE>50%): 90 MHz



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Static po ar c aracterization resu tsNumbered contours represent output power levels in dBm

Efficiency and output power have mutual dependence on inputpower and supply voltage The V and combination that maximizes efficienc can be determined


for every given Pout


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class D-1 PASimulated results with W-CDMA input signal statistics

O timal drive

D r i v e c ond i t i on

PA ( % )

PAPR

10 . 3 dB

PAPR

6. 6 dB

Traditional PATraditional (Vdd fixed) 24% 36%

EER (Pin fixed) 37% 48%

Optimum Pin/Vdd drive 53% 60%

EER

( )out out out PA

P p P dP

=

Pinand Vddare independent parameters in the figurein out out dc out out p p +

Simultaneous Pin and Vdd control can give a substantialefficiency improvement for the presented LDMOS class D-1 PA



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Out ine









Conclusions


Gi H t C t


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Dynamic oa mo u ation princip e

increased at low power Average dc current is decreased, while maintaining full voltage swing

Desired load impedance variations can be generated actively


. .

or using a reconfigurable load network...

Gi H t C t


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Dynamic oa mo u ation arc itecture

PA load network

Varactors typically used as tuneable elements

Breakdown voltage > 100V ow ser es res s ance, arge un ng range

Simple and efficient electronics can be used for the control No need for high power dc converters etc.


o en a y w e an mo u a on

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Static oa mo u ation measurements-

load impedance

ou t . in L

( ) ( ),, out in L inPA in L P P PPAE P =

Similar type of characterization as the supply modulation case

,dc in L


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Measure optimum oa impe ance ocus

Load impedance points tested

e L an in com na on a max m zes e c ency can edetermined for every given Pout At max output power, efficiency is maximized for 50


g er mpe ance s es re a re uce ou pu power

GigaHertz Centre


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LDMOS class D-1 PAin L

Simulated results with W-CDMA input signal statistics

Variable Pin and LVariable Pin and L = 0

Optimized Pin and L

D r i v e c ond i t i on

PA %

PAPR10 . 3 dB

PAPR6. 6 dB

Traditional (ZL = 50 ) 24% 36%

Optimal drive

Optimum Pin

/L

drive 43% 57%L =

mu aneous in an L con ro can a so g ve a s gn canefficiency improvement even with an existing PA Design of tunable matching networks for high power applications is still a


GigaHertz Centre


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Out ine








Summary and conclusions Summar of efficienc redictions with modulated si nal statistics

Comparison between supply- and load modulation results

Conclusions


GigaHertz Centre


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characterization for LDMOS class D-1 PA

Summary of efficiency predictions with WCDMA signal statistics

PAPR = 10.3 dB PAPR = 6.6 dB

y[%]

PA peak efficiency

y[%]

PA peak efficiency

erageeffic

ien

erageeffic

ien

A

Traditional Supply mod. Load mod.

A

Traditional Supply mod. Load mod.

Both supply voltage and load impedance modulation showhigh potential for efficiency enhancement with existing PAs


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Conc usions

- modulation transmitter architectures Static characterization used

Both architectures show promising results with the PA tested Similar performance enhancement is observed with other transistor

technolo ies and am lifier classes

Modulator losses are not included Efficiency and bandwidth limitations in envelope modulators for supply

modulation

Varactor and network losses/limitations in load modulation architectures

Careful co-control of two input signals needed for maximum

efficiency performance New challenges in linearization and behavoural modelling


GigaHertz Centre


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g

an y ou o r y ou r a en on

Acknowledgements ga er z cen re

Swedish Governmental Agency of Innovation Systems (VINNOVA)

ComHeat Microwave

Infineon Technologies

NXP Semiconductors

Saab


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