Transcript ACTIVITIES OF THE GROUP OF HIGH PERFORMANCE …

High Efficiency RF Power
Amplification for 3G Mobile
Communications
Lázaro Marco,
Thesis Advisor: Eduard Alarcón (UPC)
Dragan Maksimović (University Of Colorado)
Electronic Engineering Department
Universitat Politècnica de Catalunya
Outline
•
•
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•
•
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Motivation
EER Technique
Implementation
Improvements
Circuit/System co-characterization
Conclusions
1st Barcelona Forum on Ph.D. Research in Electronic Engineering
Motivation
“Actual” modulations:
•Constant envelope
modulation techniques
Non linear amplifiers
New schemes
of highly
efficient and
highly linear
amplification
Audio, data and video
streaming
Increased data rates
High number of users/cell
Actual standards pushed
to the limit
 Improved modulations:
• Non-constant envelope
modulation techniques
•High bandwidth
modulations
High linearity in
amplifiers
Miniaturization reduces
battery size
Extended capabilites
increase the overall power
consumption
Linear Amplifiers
exhibit Low Efficiency
Long battery life required
1st Barcelona Forum on Ph.D. Research in Electronic Engineering 3
Envelope Elimination and Restoration
Envelope Elimination and Restoration (EER)
/ Kahn technique (proceedings IRE 1952)
s1(t)
0
s(t)
Generation
of
POLAR
components
s1 (t )  i (t )  q (t )
2
Envelope
-20
Power Spectrum (dB)
t
2
BB PA
-40
-60
-80
2
2
-100 i (t )  q (t ) cos2f t   (t )   s (t )
s1 (t ) s 2 (t ) 
o
s 2 (t )  cos2f o t   (t )
s2(t)
-120
-1
vout
-0.5
RF PA
0
0.5
Frequency (MHz)
1
t
t
-20
-60
-80
-0.5
0
0.5
Frequency (MHz)
Phase
-20
-40
-100
-1
0
Signal
Mask
Power Spectrum (dB)
Power Spectrum (dB)
0
1
-40
-60
-80
-100
-120
-1
-0.5
0
0.5
Frequency (MHz)
1
1st Barcelona Forum on Ph.D. Research in Electronic Engineering 4
Envelope Elimination and Restoration
Implementation Issues
RFIN
COMPONENT SEPARATOR
Numerous limits due
to its high bandwidth
env
EA
Ф or
RF
Delay mismatch
between paths
envOUT 1
RFPA
RFOUT
AM/PM and supply
distortion modulation
1st Barcelona Forum on Ph.D. Research in Electronic Engineering 5
EER: Successful Implementation
D/A converters
I(t)
I 2  Q2
DAC
BUF
Q(t)
Envelope
Tracker
Envelope-tracking Power Supplies
DAC
board
t
DAC
+
I (t )
A(t )
RF Quadrature
Modulator
FPGA board
Digital baseband FPGA
GSM-type nonlinear PA
DAC
+
Q(t )
A(t )
PA
+
90º
0º
IQ Modulator
Output spectrum for EER
10
RF Oscillator
Delay adj.
Offset + delay adj.
EDGE Mask
0
-10
-20
Power [dB]
• Successful EDGE envelope tracking
with the new prototype including
4.3MHz switcher
• High-efficiency class-E PA
• 50% system efficiency
• Complete prototype system meets
EDGE spectral mask
-30
-40
-50
-60
-70
-80
879
879.5
880
Frequency [MHz]
880.5
881
1st Barcelona Forum on Ph.D. Research in Electronic Engineering 6
Improvements (I): Multiple Level PWM
Twice equivalent
switching frequency
• Higher Bandwidth
(fixed Ripple)
• Lower Ripple (fixed LC)
1st Barcelona Forum on Ph.D. Research in Electronic Engineering 7
Improvements (II): Linear Assisted
Switching Converter
L1
Q1
I,Q
Vg
C1
Q2
Switching +_
Amplifier
g1
Envelope
command
VLP(t)
g2
LP( f )
PWM
fB
I,Q
to
Polar
L2
f
Linear
Amplifier
Delay
+
D/A _
VHP(t)
C2
Vo(t)
Phase command
RFin
Phase
Modulator
RFPA
RFout
1st Barcelona Forum on Ph.D. Research in Electronic Engineering 8
Improvements (III): Time-optimal
nonlinear control
10mV
vs
Q1
+ V
g
–
iL
Q2
L
+
0
ic
load
-10mV
vout
_
c2
Controller
V
-20mV
C
c
vout-Vref
Output voltage error
-30mV

-40mV
0
Vref
+
Example: Vg = 6.5 V, L = 1 mH, C = 288 mF,
fs = 780 KHz, Vref = 1.3 V, Iload = 0-10 A
4A
2us
4us
10us
12us
i2
ton1
toff
ton2
-4A
-8A
V. Yousefzadeh, A. Babazadeh, B. Ramachandran, L. Pao,, D.
Maksimovic, E. Alarcón, “Proximate Time-Optimal Digital
Control for DC-DC Converters” IEEE PESC 2007
8us
ic
0
-12A
6us
Capacitor current
-i1
0
2us
4us
6us
8us
10us
12us
10us
12us
c
1
Switch
control
0
0
2us
4us
6us
8us
1st Barcelona Forum on Ph.D. Research in Electronic Engineering 9
Circuit/System co-characterization
Lsw fo=1/2LC
Csw
Vbat
fs
to
Polar
e(t)
j(t)
PWM
LDC
io
10
10
10
10
10
10
10
vout(t)
Lr
M1 Cb
BER
vin(t)
Cartesian
Rload
0
-1
-2
-3
fo=10MHz;fs=10MHz
fo=10MHz;fs=30MHz
fo=30MHz;fs=30MHz
fo=10MHz;fs=100MHz
fo=30MHz;fs=100MHz
fo=100MHz;fs=100MHz
-4
-5
-6
-5
0
5
10
15
SNR (dB)
20
25
30
1st Barcelona Forum on Ph.D. Research in Electronic Engineering 10
Conclusions
• EER Technique is ready to be used in some midgeneration wireless standards
• Future-generation standards require sophisticated
converter topologies and control methods
• Circuit/System co-characterization to validate new
envelope trackers for wideband power
management
• Eventual target is complete circuit-level co-design
aiming appropriate system performance in the
communications layer
1st Barcelona Forum on Ph.D. Research in Electronic Engineering
High Efficiency RF Power
Amplification for 3G Mobile
Communications
Lázaro Marco ([email protected])
Thanks for your attendance.
Questions?
1st Barcelona Forum on Ph.D. Research in Electronic Engineering