a high efficiency class-e amplifier utilizing gan hemt technology - presentation

8/3/2019 A High Efficiency Class-E Amplifier Utilizing GaN HEMT Technology - Presentation

1/12

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


2/12

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


3/12


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!


4/12


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


5/12


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


6/12


Basic Class E Equations/LimitationsBasic Class E Equations/Limitations

Fundamental frequency limit for ideal class-eoperation related to output capacitance

0

0.2

0.4

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


7/12


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


8/12


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)


9/12


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


10/12


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


11/12


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, %


12/12


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

a high efficiency class-e amplifier utilizing gan hemt technology - presentation

Documents