Post on 04-Apr-2022
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Corporate presentation 2013-06-06
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GaN has emerged as the technology of choice for power conversion in green transport applications Geoff Haynes Vice President Business Development
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Why are GaN transistors important ?
Power Supply with Silicon Same PSU with GaN switches
Customers get improved power designs
• More efficient (cuts losses 50-90%)
• Smaller (1/4 the size per Watt)
• Lighter (1/4 the weight per Watt)
• Lower system BOM cost
Major transportation applications • Traction Drive Inverter • On-board Battery Charger • DC-DC Conversion • 300V and 48V electronic systems
Better performance vs silicon
GaN Systems transistor on TO-220 silicon transistor
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• True Enhancement-Mode - Normally Off • Industry’s highest current ratings • 45x better FOM than 650V MOSFETs or IGBTs • 15x better FOM than 100V MOSFETs • +10V Gate tolerance – uses MOSFET drivers • Drive Assist™ on high-current devices • GaNPX™ packaging for ultra-low inductance
Switches to fit all applications
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GaN - an inherently low cost, high volume technology
Si substrate
GaN Al GaN
S D G
2DEG
P
E-HEMT
• Simple structure • Normally off operation • Majority carriers in channel for speed & low specific on-resistance • No diffusions to create reverse conduction • No forward voltage saturation
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GaN e-Mode Reverse Conduction Advantage
• Reverse conduction is an intrinsic operation of a GaN e-Mode – no Fast Recovery Diodes are required
• There are no diffusions so there is zero Qrr
• When the GaN e-Mode active switch mode is used, as shown, very low losses are achieved because the ‘diode like’ offsets are eliminated
GaN e-Mode forward & reverse conduction
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600/650V Device Comparison
1. GaN e-Mode FOM is:
• 3 - 4 times better than Cascode • 25 - 30 times better than MOSFET • 40 - 50 times better than FRD/IGBT
2. GaN e-Mode Hard Switching FOM is:
• 2 - 3 times better than Cascode • 20 - 30 times better than MOSFET • 30 - 40 times better than FRD/IGBT
3. GaN e-Mode has no diode charge storage losses!
Parameter
GaN e-Mode
GaN Cascode Si MOSFET Si/FRD IGBT
FOM: QG·Ron (nC·mΩ) 375 1,400 10,000 17,000
FOMHS:(QGD+QGS2)·Ron (nC·mΩ) 185 550 4,400 7,300
QRR DIODE (400A) (nC) 0 2,000 190,000 6,000
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• Full bridge total power loss using GaN @100kHz: • 9x better than CoolMOS • 7x better than IGBT • 2x better than SiC
• Full bridge total power loss using GaN
@1MHz • 3x better than SiC • Not possible with IGBT or CoolMOS
Inverter system: 2 kVA, 400VDC input, 240V/8.3A 60Hz output, p.f. = 0.9
Heatsink temperature THS,max = 60C
TO-220/TO-247 Package: Thermal insulation material Rth_TIM ~=1°C/W
GaN EHEMT: 4-layer FR4 PCB bottom side cooling using thermal vias: Rth_PCB ~= 5°C/W
More efficient, smaller & lighter
Power losses are simulated using Pspice model or calculated using datasheet parameters
GaN
SiC
Silicon
• GaN shows lower power loss over all switching frequencies
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GS66508T Simple drive requirements using standard parts
Gate driver design (Si8261BAC + Bootstrap)
SI8261BAC
MIC5205YM5
BOOTSTRAP
RON=10-20Ω
7V+ 12V
CBOOT
0.22uF
DBOOT
ROFF=2Ω
PWM IN
DGS (clamping diode)
.
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GS66508T Switching and gate driver test
GS66508T DPT Switching Test VDS
IL
VGS_L
400V
30A
• Gate Driver: • Si8610 + UCC27511 • Isolated gate drive supply • RON = 10Ω / ROFF = 2Ω
• Tested up to 400V/35A hard switching
35A
D
S
D
S
VSW
QH
GS66508T
VIN+
HS Gate
Driver
LS Gate
Driver
G
GQL
GS66508T
VIN-
VOUT
VDS
IL
VGS_L
VGS_H
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GS66508T Switching and gate driver test
Double Pulse Test
Turn-on (400V/30A) Turn-off (400V/35A)
VDS
IL
VGS_L
Tfall = 7.3ns 55V/ns
Trise = 4.6ns ~90V/ns
VPK = 428V
• Gate driver UCC27511: RON = 10Ω / ROFF = 2Ω • Top-side cooled package makes the tight layout possible: Low drain voltage overshoot • Clean gate waveform
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100 V E-HEMT vs 100 V OptiMOS - Faster switching & no reverse charge
36 V to 12 V buck converter power loss comparison
Symmetric • Same device on high/low sides • GaN EHEMT:
• GS61008P V2 (100V,7.4mΩ) • Si MOSFET:
• BSC070N10NS5 (100V,7mΩ)
GaN
Silicon
• GaN shows overall better efficiency & lower power loss
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E-HEMT vs OptiMOS - Faster switching & no reverse charge
Power Loss Breakdown
TJ = 39°C TJ = 39°C
TJ = 75°C
TJ = 36°C
• GaN: GS61008P (100V, 7.4mΩ)
• OptiMOS: BSC070N10NS5 (100V, 7mΩ)
• IOUT = 10A, POUT = 120W
• Case-Ambient (PCB) Thermal resistance Rth,C-A = 20°C/W
• High Side: GaN has lower switching loss and zero reverse recovery loss
• Low Side: GaN has higher dead time conduction loss
• GaN shows lower total power loss & lower junction temperature TJ
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Island Technology® road map - High current structures
Island Technology® enables commercialization of higher current GaN switches
• High yields • High currents
• 100 V – 250 A • 650 V – 200 A
• High speeds
• Low costs
• Low inductance packaging Isolated island structure
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650 V 60 A switch in top-side cooled GaNPX™ pack
• 8.95 mm x 7.59mm x 0.5mm
• Reduced thermal resistance
• Shorter vias to improve Rds(on) & Inductance
• Dual Gate connections to optimise layout for high switching frequency
• Available now
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GaN challenges Si & SiC for electric vehicle traction systems
Blocking Voltage 600/650 V
Blocking Voltage 900V
• 650 V & 900 V devices are required by 2 level inverters
• IGBT devices are currently used
• Both SiC & GaN are regarded as potential replacements
• A 3 level inverter using 650V GaN switches, offers the best choice for 900V operation. Higher FOMSW & lower switched voltage increase efficiency
• SiC MOSFETs are more expensive & are more difficult to protect & drive
• IGBTs are too inefficient T. Kachi, et al “GaN Power device and Reliability for Automotive Applications” Reliability physics Symposium (iRPS) 2012.J.
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• Addition of 48 V power system in new vehicles is reducing wiring harness current, weight & voltage drop
• The GS61040 250 A, 100 V, 2.4 mΩ high speed E-GaN switch enables: • Higher efficiency • Air cooling • Lower component count • Smaller passive components
100V, 250 Amp switch ideal for 12 V 48 V conversion
Immunity to single event failure
• Single event cosmic radiation causes failure in Si power systems A single particle impact while switching can destroy an IGBT Significant voltage de-rating of IGBTs is needed to maintain reliability
• GaN E-HEMTs do not suffer from this effect E-HEMT majority carrier channel is intrinsically radiation-resistant 2014 IEEE paper by Leif Scheick, NASA Confirmed E-HEMT radiation immunity in power circuits
• Testing of GaN Systems devices is underway High dose with devices energized - 800 MeV protons, 0.3 x 1014 protons/cm2 Initial results – devices unaffected
• What does this mean in practice? Increased reliability No need for de-rating in critical applications
IGBT radiation de-rating curve at sea level
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DRS Technologies - 2 kW vehicle power inverter
• 94% Efficient
• 28 Volt DC
• 3 phase 120 Volt AC
• Passive cooling
• Reduced part count
• Uses GaN Systems GS66508P
Production Systems
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• 2 kWh solar charged battery solution
• Air shippable – no class 9 restrictions
• 98% peak charger efficiency
• Buck-boost switching 600W at 400 kHz
• Uses 4pc GaN Systems GS61008P
Virideon - Blue Sky Mast
TPS-2C tactical power system
Production Systems
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NEXTHOME consortium - Bi directional converter
• 3 k Watt
• 800 Volt link voltage
• 2 MHz switching fq.
• 98% efficiency
• Passive cooling
Production Systems
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Where are GaN transistors important ?
Power Supply with Silicon Same PSU with GaN switches
Customers get improved power designs
• More efficient (cuts losses 50-90%)
• Smaller (1/4 the size per Watt)
• Lighter (1/4 the weight per Watt)
• Lower system BOM & operating cost
In all power conversion applications from 100 Watts to 100,000 Watts with operating voltages to 900V
Better performance vs silicon
GaN Systems transistor on TO-220 silicon transistor