Making Reliable and High-Density GaN Solutions a Reality

Transcription

1 Making Reliable and High-Density GaN Solutions a Reality December 5, 2017 Franz Xaver Arbinger Masoud Beheshti 1

2 Today s Topics Why is GaN Exciting GaN Fundamentals Cost and Reliability Totem Pole PFC Isolated LLC Wide-Vin DCDC Motor Drive Driving GaN GaN Device Examples Choosing a GaN Supplier 2

3 Why GaN? 3

4 Why GaN: 3x Power Density from AC-to-POL 1kW GaN Solution COOLER: 99% efficient Totem Pole PFC FASTER: 1 MHz Isolated DC/DC LLC SMALLER: Single stage Stackable 48V-to-POL 230V 400V 48V 1V GaN: 156 W/in 3 (9.5 W/cm 3 ) GaN: 140 W/in 3 (8.5 W/cm 3 ) GaN: 140 W/in 3 (8.5 W/cm 3 ) Versus Versus Versus Silicon: 55 W/in 3 (3.4 W/cm 3 ) Silicon: 95 W/in 3 (5.8 Silicon: 40 W/in 3 (2.4 LMG3410, UCD3138, UCC27714 W/cm 3 ) LMG5200, W/cm 3 ) UCD x 84 mm 94 x 84 mm 102 x 102 mm 4

5 Cost and Reliability 5

6 GaN Cost: Demystifying the Myth GAN is not a drop-in replacement for silicon MOSFET. FET to FET cost comparison is misleading. GaN achieves new levels of power density not possible by silicon, and by enabling: New topologies eliminates costly power components 10x switching frequencies reduce the cost and size of magnetics and cooling New architectures cuts component count by half In these applications GaN enables solution cost parity with silicon at a minimum 2X increase in power density. Example: PFC designs, GaN delivers total cost on par with silicon at double the power density Silicon Dual Boost W/in 3-4% Total +10% -30% 0% GaN Totem Pole >75 W/in 3 6

7 GaN Reliability: Not a Science Fiction After years of work by industry leaders, GaN is delivering the reliability and the ruggedness that the power supply engineers expect. For instance Texas Instruments has long implemented a comprehensive methodology to ensure reliable operation and lifetime of GaN devices under the harshest operating conditions Our >7 million device reliability includes: JEDEC JESD47I test conditions for temperature, bias, and operating life test Accelerated hard-switching testing Power supply system-level operation New JEDEC committee, JC70, is working on releasing a standard on GaN reliability and qualification procedures 7

8 Example: Isolated DCDC LLC 8

9 GaN: A Superior Solution for LLC Reduced Output Capacitance Low COSS reduces dead-time, increasing the time when current delivered to the output Low COSS allows larger magnetizing inductance and lower circulating current losses as well as transformer fringe-field losses Reduced Gate Driver Losses GaN superior switching characteristics significantly reduce gate driver loss for LLC application System Optimization GaN enables higher switching frequency to reduce magnetic components significantly GaN enables LLC converter with higher efficiency and higher power density

10 TI-GaN: 1MHz Isolated LLC DCDC Converter Design Target Input voltage (V) 380 ~ 400 Output voltage (V) 48V Nom unregulated Power (W) 1000 Integrated Transformer size (mm) 33 x 53 x 43 Power density 140 W/in3 (8.5 W/cm3) High power density Efficiency >97% High Efficiency Switching frequency 1 MHz High Frequency LMG3410 Half bridge Power Density: 140 W/in 3 (8.5 W/cm 3 ) Versus Silicon: 95 W/in 3 (5.8 W/cm 3 ) 94 x 84 mm Integrated Transformer Click Here for more information. 10

11 Efficiency: Comparison with Silicon GaN Si Superjunction Efficiency 98,5% 98,0% 97,5% 97,0% 96,5% 96,0% 95,5% 95,0% 94,5% 94,0% Output Current [A] Reduced capacitance & circulating currents dramatically improve lightload efficiency Resistance Limited (slight improvement) 11

12 GaN Solutions: 6X Smaller and Lighter Solutions Example based on 1kW 480V:48V Isolated DCDC Design Si Solution: >650 Grams 100 khz transformer design 1 MHz Integrated transformer design GaN Solution: <100 Grams

13 GaN Device Example 13

14 LMG3410: 600V/70mΩ 12A GaN Power Stage Slew rate control by one external resistor: 30 V/ns to 100 V/ns Integrated direct gate driver with zero common source inductance D Digital PWM input Only +12V unregulated supply needed Built-in 5V LDO to power external digital Isolator Low power mode for standby conditions RDRV IN VDD 5V LPM FAULT Slew Rate LDO, BB Direct- Drive S VNEG UVLO, OC,TEMP Current S 600V GaN Enable Switch 70mΩ-600V GaN FET for 12A continuous operation High speed over current protection with <100ns response time Fault feedback to system controller Click Here for more information. Integrated temperature protection and UVLO 14

15 Choosing a GaN Supplier 15

16 Choosing a GaN Supplier: What Questions to Ask End-to-End GaN Reliability Supply Chain Solution Total Solution Cost Reliable switching at 100v/ns and frequencies to 1MHz and beyond Robustness under short circuit and thermal conditions Solution size Power managements expertise GaN ecosystem of advanced controllers Fully developed reference Designs Qualification beyond JEDEC MOSFET standards Hard-switching and application relevant stress data High volume supply chain to ensure continuity of supply Includes fab, assembly, and test strategy Proven System cost parity with silicon at 2X the power density. Committed to long term cost reduction investments

17 Conclusion GaN is enabling a new generation of power conversion designs not possible before. GaN enables 3X power density improvement from AC to Point-of-Load 1MHz isolated LLC design delivers 6x reduction in size and weight of the solution GaN enables the integration of 100kHz drive and motor by reducing the solutions size and eliminating heatsink Integration of driver and GaN in a low inductance package provides an optimal solution for fast and reliable switching When selecting a GaN, we need to consider switching performance, supplier s power management expertise, reliability methodology and supply chain Learn more at 17