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8/3/2019 A High Efficiency Class-E Amplifier Utilizing GaN HEMT Technology - Presentation
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Creating Technologies That Create Solutions
High Efficiency ClassHigh Efficiency Class--EEAmplifier UtilizingAmplifier Utilizing GaNGaN HEMTHEMT
TechnologyTechnology
William L. Pribble, Jim M Milligan, andRaymond S. Pengelly
Cree Inc
4600 Silicon Drive,Durham, NC 27703
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Creating Technologies That Create Solutions 2
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
0.4 0.5 0.6 0.7 0.8 0.9 1
Effciency
DissipatedPower/OutputPower
Does Efficiency Matter?Does Efficiency Matter?Class A
Class B
SwitchmodeClass D,EClass C,F?
Increasing efficiency from 50% to 80% reduces dissipated power by
80% for a fixed output power Switchmode amplifier configurations can operate above 80% efficiency
Problem: Extend switchmode operating frequency beyond VHF
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Creating Technologies That Create Solutions 3
Why Switch Mode Amplifiers?Why Switch Mode Amplifiers?Why Switch Mode Amplifiers? With a suitable high frequency transistorWith a suitable high frequency transistor
technology they offer very high efficienciestechnology they offer very high efficiencies
compared with Class A/B amplifierscompared with Class A/B amplifiers
GaNGaN HEMT technology is idealHEMT technology is ideal
HighHigh ffTT Low input capacitanceLow input capacitance
Manageable output capacitanceManageable output capacitance
Low RLow RDSONDSON
GaNGaN HEMT is the first technology to offer theHEMT is the first technology to offer the
ability of realizing switch mode amplifiers toability of realizing switch mode amplifiers to
well over 3.5 GHz!well over 3.5 GHz!
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Creating Technologies That Create Solutions 4
Class E Amplifier BasicsClass E Amplifier Basics
FET used as switch isassumed to have high off-
resistance Switch on-resistance
assumed to be constantand must be minimized to
achieve high PAE Output capacitance
assumed to beindependent of switchvoltage
Q factor of output circuitassumed large enough tosuppress harmonics flywheel effect insures
sinusoidal output
G
D
S
T1
2
3
INDID=L1L=L2 nH
INDID=L2L=L1 nH
DCVSID=V1V=1 V
ACVSID=V2Mag=1 VAng=0 Deg
CAPID=C1C=C2 pF
RESID=R1
R=RL Ohm
Zloado
C1e
j :=
Optimum Class-E fundamentalload for ideal operation Mader1995
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Creating Technologies That Create Solutions 5
Class E Power CalculationsClass E Power Calculations
To achieve peak Class-E output power as shown,peak voltage is calculated to be 3.56Vcc, peak drain
current 2.86Idc (Solid State Radio Engineering Krauss, Bostian, Raab
) Typical class-B voltage waveforms peak at ~2X the
supply voltage
Ideal class-E operation produces lower power for
higher peak voltage but with 100% efficiency
The optimum class-E device must exhibit both low Ronand high breakdown voltage to function as a switch
vccpout rl
0.577:=
Relates peak output power for ideal class-E wavefroms to supply voltage Thisvalue is ~78% of peak Class-B output
power
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Creating Technologies That Create Solutions 6
Basic Class E Equations/LimitationsBasic Class E Equations/Limitations
Fundamental frequency limit for ideal class-eoperation related to output capacitance
0
0.2
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0.6
0.8
1
1.21.4
1.6
1.8
2
0 10 20 30 40 50
Operating Drain Voltage (V)
Class-EPeakCurren
t(A/mm)
0.050.1
0.15
0.2
GaAs PHEMT
High-Voltage GaAs
Cree GaN qualifiedprocess available 1st
quarter 2006
Cree GaN Process Goal
Plot shows required peak current vs supplyvoltage for operation at 4GHz for given output
capacitance
fmaxImax
56.5 10
12 cs vcc
:=
cs=C1
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Creating Technologies That Create Solutions 7
Summary of Class-E Device RequirementsSummary of Class-E Device Requirements
High switching speed (related to input capacitance)required for switchmode operation Ft as much as10X operating frequency to minimize transition-timeloss
Low on-resistance/high peak current to approximate
ideal switch and increase peak operating frequency High breakdown voltage to accommodate class-E
peak voltage for > 50 watt output power
Gallium Nitride HEMT is the only presently availabletechnology which provides these attributes
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Creating Technologies That Create Solutions 8
Class-E Switch Mode Amplifier Simulation using
Cree GaN HEMT Large-Signal Model
ClassClass--E Switch Mode Amplifier Simulation usingE Switch Mode Amplifier Simulation using
CreeCree GaNGaN HEMT LargeHEMT Large--Signal ModelSignal Model
0.2 0.4 0.6 0.80.0 1.0
20
40
60
0
80
0.5
1.0
1.5
0.0
2.0
time, nsec
Voltage(V)
Current(A)
Freq = 2.0 GHzFreq = 2.0 GHz
Q1 = Cree 15 wattQ1 = Cree 15 watt GaNGaN HEMTHEMT
RRONON = 1.7= 1.7
VVDD=V=35V=V=35V
RRLL=26, C1=0.64pF, L1 = 50uH=26, C1=0.64pF, L1 = 50uH
L2=13nH,C2=0.612pFL2=13nH,C2=0.612pF
PPOUTOUT=10 Watts, =82%=10 Watts, =82%
12 14 16 18 20 22 24 2610 28
10
20
30
40
0
50
20
40
60
80
0
10
OutputPower(dBm)
PAE(%
)
Input Power (dBm) @ 2GHz
Voltage (across Q1)Current (I)
C1 absorbedin device
RL(I)
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Creating Technologies That Create Solutions 9
World Record 2.0 GHz
High Efficiency GaN Amplifier
World Record 2.0 GHzWorld Record 2.0 GHz
High EfficiencyHigh Efficiency GaNGaN AmplifierAmplifier
Class E Hybrid amplifierClass E Hybrid amplifier
VdVd = 30 volts= 30 volts
50 input/output50 input/output
10 W P10 W POUTOUT,, 88% Drain Efficiency!88% Drain Efficiency!
1.91.92.1 GHz!2.1 GHz!
Fabricated High Efficiency GaN Hybrid
34
35
36
37
38
39
40
41
42
43
1.7 1.8 1.9 2 2.1 2.2 2.3
Frequency (GHz)
OutputPower(dBm
)
0
10
20
30
40
50
60
70
80
90
power
pae
Measured Performance @ 30 V
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Approach Validated at Higher
Frequencies and Moderate Bandwidths
30
32
34
36
38
40
42
44
46
48
50
3.25 3.3 3.35 3.4 3.45 3.5 3.55
Frequency (GHz)
OutputPower(dBm)
60
62
64
66
68
70
72
74
76
78
80
power
pae
30
32
34
36
38
40
42
44
46
48
50
2.5 2.6 2.7 2.8 2.9 3 3.1
Frequency (GHz)
OutputPower(dBm)
0
10
20
30
40
50
60
70
80
90
power
pae
~10 Watts RF Out
12 dB Power Gain
76-82% PAE
2.7 2.9 GHz
~10 Watts RF Out
11 dB Power Gain
72-78% PAE
3.3 3.5 GHz
Measured DataMeasured Data
Crees GaN Technology Enables High-Power
High Frequency Class-E Operation
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Creating Technologies That Create Solutions 11
63 Watts Peak RF Output Power63 Watts Peak RF Output Power
18 dB Power Gain18 dB Power Gain
75% PAE75% PAE
2 GHz Operation2 GHz Operation
Approach Validated at Higher Power LevelsApproach Validated at Higher Power Levels
amp 1
50
55
60
65
70
75
80
1.85 1.9 1.95 2 2.05 2.1
frequency (ghz)
pae
amp 1
amp 1
46
46.5
47
47.548
48.5
49
49.5
50
1.85 1.9 1.95 2 2.05 2.1
frequency (ghz)
outputpow
er(dBm
)
amp 1
Output Power, dBm
Power Added Efficiency, %
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SummarySummarySummary GaNGaN HEMTHEMT--Class E amplifier / ETClass E amplifier / ET
demonstrated linear PAE of 54%demonstrated linear PAE of 54% Much Superior toMuch Superior to GaAsGaAs MESFET and LDMOSFETMESFET and LDMOSFET
Demonstrates leapfrog in efficiency when comparedDemonstrates leapfrog in efficiency when comparedto conventional Class A/B biased amplifiers deployedto conventional Class A/B biased amplifiers deployed
todaytoday High PowerHigh Power GaNGaN HEMTHEMT--Class E modules built &Class E modules built &
measuredmeasured
Overall efficiency in ET system at 56% with 20 Wattsaverage power under CDMA 2000
Approach suitable for telecom. bands including 3.5GHzApproach suitable for telecom. bands including 3.5GHzWiMaxWiMax