GaN in a Silicon world: competition or coexistence? Tim McDonald GaN Technology Development Worldwide Applications and Marketing Infineon Technologies Eric Persson, Andrea Bricconi, Felix Grawert APEC 2016, Long Beach, CA
Abstract Significant development resources have been expended and Gallium Nitride (GaN) based power conversion devices are now being introduced to the market on the heels of much hype. It remains to be seen how widely GaN power transistors will be adopted.
Outline 1 Historical Perspective for new power switch technology 2 GaN vs. Silicon Technology 3 First uses of GaN 4 Crystal gazing: where will silicon thrive and where will GaN be adopted over time? 5 Concluding comments 14.04.2016 Copyright © Infineon Technologies AG 2016. All rights reserved.
Today‘s switch technology use by power and frequency Future scenario power electronics Application HVDC HC-supplier 100M Large drives Ships 10M Locomotives Large solar plants 1M Trams, buses Electric cars 100k On-roof PV Small drives 10k Air conditioner Robotics 1k Washing machine › SMPS › Chargers/Adapters 100 10 10 Power by application (W) ULTRA HIGH POWER HIGH POWER Thyristor › › › › › › › › › › › › › 1G Starting with Bipolar Junction Transistors (BJT), new technologies pushed out the (frequency
1b Historical perspective: “conversion” from power bipolar transistor to power MOSFET Power Transistor Market Size ($M) Technology 1984 (HTE, 1991) 2015(IHS) Bipolar Junction Transistor MOSFET Superjunction MOSFET IGBT Total (Less SJ MOSFET) $957 $115 $0 $0 $1,072 $881 $6,034 $895 $4,946 $11,861 › › › After 30 years of “conversion” the bipolar market is basically unchanged in size (not accounting for inflation) New power transistor technologies nibbled at the edge of predecessor technologies but b
2a Technology comparison: GaN vs Silicon* E-mode GaN Equivalent Super junction FET Vdss 600 V 600 V RDSon typ 25°C 52 mΩ 52 mΩ Parameter Comments Eoss 7 uJ 8 uJ Near parity for hard switching performance Tk,RDS(on) (150°C/25°C) 1.8 2.37 RDS(on) Tempco 6 nC 68 nC 1 nC 6,000 nC GaN >100X lower than SJ (including Qoss) 110 pF 1,050 pF GaN ~10x lower 1.0 0.
Superjunction vs GaN: why no large difference is seen in hard switching losses 2b Blue = superjunction Red = e-mode HEMT Both ~70 mΩ max RDS(on) › › Superjunction capacitances are much higher when compared to GaN Superjunction Coss and Crss behave very nonlinearly with voltage 14.04.2016 › › Output charge difference is very large (up to 10x at 100 V) between superjunction and GaN But gap in Eoss is much smaller (eg: 20% at 400 V) Copyright © Infineon Technologies AG 2016. All rights reserved.
Nonlinear Qoss charge affects deadtime 2c 500 450 -SJ FET has 3.3X longer charge-up time 400 350 Volts 300 250 200 150 Qoss Measurement Circuit 100 50 0 0 14.04.2016 10 20 30 40 50 60 70 80 Time (µs) 90 100 Copyright © Infineon Technologies AG 2016. All rights reserved.
2d Non linearity of Coss results in longer minimum dead time for SJ FET in ZVS CoolMOS™ P6 Cascode GaN 110 nSec Vgs_ls 50V Vds_ls Tdelay Id_ls Vgs=10 V, Id=2 A, Rg=10 ohm 14.04.2016 20 nSec SJ FET High capacitance at low voltage results in 5-6x longer delay time (110 nsec vs 20 nsec)and therefore longer required deadtime which increases RMS current and therefore conduction losses. The higher the frequency the more the losses Copyright © Infineon Technologies AG 2016. All rights reserved.
2e Superjunction devices continue to improve Reference: G. DeBoy, PCIM 2015 Yet the more the improvement in hard switching figure of merit the longer the delay times (limits performance in ZVS applications at higher frequency) 14.04.2016 Copyright © Infineon Technologies AG 2016. All rights reserved.
2f Significant efficiency gains in superjunction – C7 600 V with ≥0,5% improvement across load PFC efficiency difference for 90 Vac (PFC CCM, 1150 W @ 65 kHz) Efficiency Low Line 97 Superjunction FET performance continues to improve in hard switching PFC applications eta [%] 96 95 0,5% 0,6% IPW60R045CP IPP60R040C7 IPZ60R040C7 fps@IFX 94 0 200 400 600 800 1000 1200 ≥ 0,5% efficiency increase across entire load range with CoolMOSTM C7 4-pin vs. CP 1400 Pout [W] 14.04.
Benefits of C7 CoolMOSTM enables operation at higher (hard) switching frequencies 2g Total simulated MOSFET losses [W] IPW60R045CP vs IPZ60R060C7, highline 2.5 kW Gate charge Turn off Turn on Conduction CP 18,3 0,4 12,4 0,2 8,7 0,2 2.3 6.0 7,1 0,1 3.0 4,7 0.1 0.8 6,6 0,1 1.5 4.1 2.1 6.3 1,0 1.9 2.8 2.1 2.9 2.3 3.0 CP C7 CP C7 CP C7 130 kHz C7 3.2 2.1 65 kHz 14.04.2016 9.
2h Technology comparison summary › Superjunction Coss and Crss behave very nonlinearly with voltage and frequency › Comparable RDS(on) GaN devices have much lower capacitance than their SJ FET counterparts when measured at low voltage; this difference greatly diminishes at higher voltages; there is not a large difference in Eoss at 400 V › Co(tr) of GaN device is ~10x lower than SJ FET and this difference is sustainable; this benefit can be leveraged in ZVS applications where it can result in lower power
3a First uses for GaN › Initial Applications for GaN Devices: › Leverage Qrr: Class D Audio Amplification for lowest distortion › Leverage Qrr and switching: high efficiency AC:DC power conversion for operational cost sensitive applications such as datacenters › Leverage Co(tr): high density power conversion applications from servers to consumer electronics › The list above is just the start! The study of other applications (to leverage GaN FOM’s vs Silicon) is an ongoing effort 14.04.
3b First use of GaN: 100 V cascode device for class D audio amplifier Leverages extremely low Qrr Key values GaN benefit vs Silicon Audio Quality Lower - THD improves from faster/cleaner switching characteristics Efficiency Higher - from lower resistance More channels, smaller size Smaller – Full SMD w/o heatsink, high frequency for smaller LPF Fast switching GaN Si FET 14.04.2016 MP: 2013 Copyright © Infineon Technologies AG 2016. All rights reserved.
3c First Uses of GaN: GaN value proposition for data centers Effect of higher efficiency on electricity costs › Total Cost of Ownership (TCO) matters: hardware/software + operational costs really matters › Electricity costs is ranked in TOP 5 costs › Efficiency of electricity usage can lead to significant system cost savings 14.04.2016 Stage Efficiency increase Savings per server per year PFC 0.5% 4.5$ DCDC (LLC) 0.5% 4.5$ Total 1.0% 9.0$ Based on energy cost: 0.06USD/kWh, 1.
3d High Power SMPS in datacenters: Evolution of high efficiency topologies for PFC Classic HB TotemPole TODAY´S BEST Dual Boost Higher efficiency (>98%) › TOMORROW´S BEST TODAY/ TOMORROW TCM PFC 14.04.2016 › Highest efficiency (>98%) › Simpler › Reduced part cont FB TotemPole › Higher efficiency (99%) › 2-phases (high part count) › Complex control › 100 kHz+ operation › Higher efficiency (>99%) TCM PFC w/ GaN › Highest efficiency (99.
3e GaN enables >99% PFC efficiency >99% efficiency from 18-70% load 45kHz Leverages: extremely low Qrr 65kHz › Measurements: Infineon 2015 › Complete Power Stage. 2.5 kW, Vin=230 V, Tamb=25° C › Full SMD solution 14.04.2016 Copyright © Infineon Technologies AG 2016. All rights reserved.
1. 600 V CoolGaN™ for density: 3 kW LLC PD~140 W/in3 SJ based 130 kHz design GaN based 350 kHz design H=42 mm W=91 mm H=32 mm 140W/in3 L=220 mm L=152 mm 50W/in3 W=140 mm KEY MESSAGES › LLC w/ CoolMOS™ (380 V-54.3 V): >98% peak efficiency at 50 W/in3 density (res freq: 130 kHz) › LLC w/ CoolGaN™ (380 V-52 V): same efficiency at 140 W/in3 density (res freq: 350 kHz) › GaN enables ~3x increase in power density.
CoolGaN™ enables dramatic increase in power conversion density using ZVS in LLC 3g Practical Frequency limit of Superjunction FET’s in LLC 450 Density (W/in3) 350 Today’s Today’s GaN Superjunction HEMT FET based FET based designs designs 250 Tomorrow? 9-10x improvement over SJ FET (Work of CPES, Virginia Tech University) 150 3x Improvement over SJ FET (Infineon Work) 50 150 14.04.2016 350 Frequency (kHz) Copyright © Infineon Technologies AG 2016. All rights reserved.
In which power and frequency domain might GaN be used? Future Scenario Power Electronics Application › › › › › › › › › › › › › 1G HVDC HC-supplier 100M Large drives Ships 10M Locomotives Large solar plants 1M Trams, buses Electric cars 100k On-roof PV Small drives 10k Air conditioner Robotics 1k Washing machine › SMPS › Chargers/Adapters 100 10 10 Power by application (W) ULTRA HIGH POWER HIGH POWER Thyristor 4 IGBT SiC MID POWER GaN LOW POWER BJT 100 MOSFET 1k 10k 100k Reduced size 1M Degr
5 Concluding comments › The historical record shows new switch technologies are adopted and grow new market segments where they push the performance window › KEY GaN device FOM‘s are demonstrated with 10-100x improvement over silicon (Coss TR, Qrr) › It is clear this can be leveraged for higher density power conversion solutions using ZVS and LLC topology › Early applications identified but more will follow as cost of GaN device lowers and investment continues in new topology and application infrastruc
