FAQ: Nexperia's high-power GaN FETs enable a new generation of efficient power supply designs

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FAQ: Nexperia's high-power GaN FETs enable a new generation of efficient power supply designs [Copy link]

Live broadcast details: Nexperia's high-power GaN FETs enable a new generation of efficient power supply designs

Live lecturer:

Chen Qiuming | Nexperia GaN FET Chief Application Engineer

FAQ

1. In actual application cases, how high can the switching frequency of GAN devices be? Can it reach a frequency of 4M?
A: The theoretical operating frequency of GaN can reach a switching frequency of more than 10M, such as RF-GAN, but in the actual design of switching power supplies, the operating frequency is generally not higher than 1MH, because it is limited by the current technical limitations of magnetic core devices, and the efficiency will also be significantly reduced.
2. Does GAN increase the switching frequency to achieve low power consumption?
A: GaN can provide lower on-resistance, faster switching speed and extremely low reverse recovery charge, which can achieve lower switching loss and conduction loss, and achieve high-efficiency design.
3. What level of voltage resistance is generally considered for GaN?
A: GaN voltage resistance can currently reach 900V, and will reach 1200V in the future, but Nexperia 650V GaN has a transient overvoltage capability of 800V.
4. How many hours can Nexperia's GaN FET be used reliably?
A: Nexperia GaN can pass the strict certification of JEDEC and AEC-Q101. According to the power supply and temperature acceleration test model, it is estimated that at 480V/-40℃, it can have a life of 300~500 years at a failure rate of 1%.
5. Does Nexperia's GaN FET have an overcurrent protection function?
A: Nexperia GaN is a discrete power semiconductor device and does not integrate overcurrent protection.
6. Conversion efficiency, how much is it generally?
A: Nexperia GaN has faster switching speed and smaller energy loss. Taking 230V to 400V DC/DC Boost as an example, it can achieve a peak efficiency of 99.1%.
7. Does Nexperia now have GAN chips for consumer-grade 65w and 120w?
A: Nexperia GaN focuses on the high-efficiency, high-power density industrial and automotive markets.
8. What are the advantages and characteristics of Nexperia's GaN?
A: Nexperia's cascode gallium nitride has an industry-standard driver that is compatible with traditional silicon MOSFETs, and gate drive is very simple; reliable gate oxide quality (Vgs.max=± 20 V); high gate threshold voltage (+4 V), good gate noise immunity, and no need for negative voltage drive; excellent body diode (low Vf), ultra-low reverse recovery loss; transient overvoltage capability (800 V for 650 V devices).
9. What is GaN's diode-like behavior in reverse current conduction?
A: Nexperia uses a cascode structure design, which is composed of a depletion-type D-mode GaN and a 30V traditional Si-FET in series. It has excellent reverse conduction capability and very low Vf, achieving lower losses during dead time. Taking GaN039-650WSA as an example, at 12.5A, the reverse conduction is only 1.35V
10. What are the application areas?
A: Nexperia focuses on the application market of high power density, high efficiency and high reliability, mainly including energy systems such as automobiles, data centers, telecommunication base stations-5G, power systems, inverters and charging piles.
11. Is there a system evaluation board for GaN technology? Can I apply for it?
A: Nexperia has made a series of gallium nitride evaluation boards based on its own gallium nitride products. You can contact Nexperia sales or apply for Nexperia's evaluation board through an agent.
12. Compared with traditional MOS, which one has greater switching loss, GaN FET?
A: Gallium nitride has faster switching speed and extremely low reverse recovery charge, and has lower switching loss.
13. In which topologies can gallium nitride be used?
A: Gallium nitride can be used in AC-DC PFC, or DC/DC and DC-AC topologies of PSFB and LLC.
14. Is solar inverter useful?
A: Gallium nitride is very suitable for photovoltaic inverter. Taking household inverters as an example, there are DC/DC Boost and DC-AC. Gallium nitride can be used to improve system efficiency, reduce the size of output filters, and reduce system costs.
15. When comparing GaN FET with Si FET in boost converters, what outstanding performance does GaN FET have?
A: Faster switching speed and extremely low reverse recovery charge, lower switching loss, can achieve 99.1% peak efficiency.
16. Does the power GaN solution have reverse recovery loss?
A: Depletion-type gallium nitride has no parasitic body diode, so there is no reverse recovery loss of minority carriers. However, according to the JEDEC test circuit, after the MOSFET is turned off, the output charge still needs to be charged, which is also the energy for the reverse recovery test. Nexperia's cascaded GaN has a reverse Qrr that is more than 15 times lower than that of traditional silicon MOSFETs .
17. If there is no body diode, there will be a lot of application space. Should rise time control be added to the drive circuit? Otherwise, the voltage stress can only be solved by the absorption circuit.
A: Even traditional silicon MOSFETs have parasitic body diodes inside, and some absorption circuits need to be added during design to suppress oscillation. However, the lower Qoss and Qrr of gallium nitride can reduce voltage spikes and ringing time. In the design of the drive circuit, it is necessary to adjust the resistance value of Rgate and the rise and fall slopes according to the actual test waveform to ensure efficient and stable operation of the system.
18. What kind of gate driver is better to use?
A: It is recommended to use an isolated driver with a CMTI greater than 50V/ns, such as Silicon Lab Si8230
19. What is the switch quality factor?
A: The switch quality factor is a very important indicator for evaluating power semiconductor devices, such as the product of Qg and RDson
20. Where can I download GaN technical data?
A: You can visit Nexperi.com to learn more about Nexperia GaN
21. What is the maximum withstand voltage of Nexperia's GaN?
A: The voltage level that has been mass-produced is 650V, but it has a transient overvoltage capability of 800V. In the future, higher voltage levels of GaN will be launched, such as 900V and 1200V.
22. Does Nexperia have factories in mainland China?
A: Nexperia has its own factories, with the front-end in Hamburg, Germany and Manchester, UK, and the back-end in Seremban, Malaysia, Cabuyao, Philippines, and Dongguan, Guangdong. For GAN, the front-end is in Hamburg, Germany, and the back-end is in Cabuyao, Philippines.
23. What are the automotive-grade models of Nexperia's gallium nitride field effect transistors (GaN FETs)?
A: Currently, GAN039-650NBBA and GAN039-650NTBA are suitable for automotive grade. If you have any needs, please follow Nexperia's official account Nexperia_China and leave a message saying that you need GAN's support. We will arrange for relevant personnel to contact you!
24. Will there be a GaN FET with built-in driver?
A: Currently, it will mainly be discrete devices
. 25. Which generation of semiconductors does it belong to ?
A: It is a wide bandgap semiconductor material, known as the third generation semiconductor material in China.
26. At what power level does the Anshi product have a better cost-effectiveness advantage?
A: Power supply designs above 1000W will have better advantages. Our products are designed for high power density power supply designs.
27. What is the future development trend of GaN? Higher voltage and current?
A: Yes, it will develop in the direction of system integration, higher power density, and higher voltage and current.
28. Does GaN FET have a better suppression effect on the Miller effect?
A: Yes, due to the extremely low Qgd of GaN FET, faster switching speeds can be achieved, improving system efficiency.
29. Is Nexperia GaN FET in mass production?
A: Yes, there are mass-produced products. For details, please refer to our relevant product website https://www.nexperia.cn/products/gan-fets.html
30. What is the delivery cycle like? Can it be supplied stably?
A: The 650V 50 mohm GaN063-650WSA has been mass-produced and can be supplied stably at present.
31. Will the price of Nexperia Semiconductor's high-power GaN FET be much higher than traditional solutions?
A: Taking a 3-4KW switching power supply as an example, the use of traditional Si FET requires the use of an active full-bridge cross-parallel solution, while the use of GaN only requires the use of a Tutt column bridgeless PFC solution, which greatly reduces the number of devices and reduces the system cost by up to 30%.
32. Is there a high-current IC?
A: Taking Nexperia's latest copper clip package CCPAK1212 GaN039-650NBB as an example, 25C can support a rated current of 60A and a peak pulse current of up to 240A.
33. How is the gate drive anti-interference performance?
A: The threshold voltage is as high as 4V, no negative voltage drive is required, and the gate has better anti-noise capability.
34. Can all switching applications benefit from GaN field-effect transistors?
A: In power electronics design, if you are pursuing high-efficiency, high-power density, and high-reliability product design, the switching power supply can achieve better switching performance and lower system cost by using GaN.
35. What should be paid more attention to in the PCB design of power IC?
A: When using GaN, special attention should be paid to the power and drive traces of the PCB to reduce parasitic inductance, achieve higher efficiency and ensure stable and reliable operation of the system.
36. In the soft-switching topology power supply, can GaN FET improve power density and efficiency like hard-switching topology applications? Thank you
A: In the soft-switching circuit design using silicon MOSFET, due to the limitations of the output charge and reverse recovery characteristics of silicon devices, the current mainstream switching frequency is still around 100KHz. In the same circuit, Nexperia GaN's fast switching speed and reverse recovery time support higher switching frequencies, up to more than 500kHz. Due to the limitation of diode reverse recovery, the hard-switching application topology (totem pole PFC) that cannot use super Si FET can now be used with GaN FET, giving full play to the advantages of small number of devices and high efficiency through a simple control scheme.
37. How much worse is the efficiency of GaN than that of IGBT?
A: Among devices with the same specifications, taking a 200V to 400V boost as an example, the loss of gallium nitride is only half of that of IGBT. In addition, IGBT does not have reverse conduction capability, so a SIC diode must be connected in parallel when used. Taking 100KHz as an example, there will be a 1% difference. The higher the frequency, the more obvious the difference will be.
38. Do you buy from an agent or directly from the original manufacturer?
A: For early technical evaluation, you can contact the original manufacturer's sales or go through an agent. At the same time, you can buy Nexperia's gallium nitride samples on Mouser.
39. Can this be used to replace relays?
A: This is a potential application market that pursues low conduction loss. Gallium nitride can achieve lower on-resistance, replace solid-state relays, eliminate mechanical noise, and provide life and