# GaN FET technology and the future of VRM design



## T.Sharp

Gallium Nitride (GaN) switching transistors offer many advantages over standard MOSFETs. Lower resistance, lower capacitance and very high switching frequencies (MHz-GHz) allow for significant efficiency and power density improvements. Higher switching frequency also means smaller inductors and capacitors can be used to achieve equivalent or better regulation.

GaN tech is in its early stages and there are only a few manufacturers, but it has already shown great promise in class D audio amplifiers and switch mode power supplies. Some high power ATX PSUs already use GaN FETs. It seems like it's only a matter of time until we see the technology used in low voltage buck converter applications for CPU and GPU VRM.

Some resources if you want to learn more -






StackPath

Evaluation of Gallium Nitride HEMTs for VRM Designs

What is GaN?

https://www.powerelectronicsnews.co...apter-of-class-d-audio-amplifier-performance/









GaN FET size compared to MOSFETs


Thoughts, opinions?


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## 8051

Do they work better for high power applications than BJT's?


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## T.Sharp

8051 said:


> Do they work better for high power applications than BJT's?


I think It would still be application dependent.

This is interesting though - From Pushing the Boundaries of High Voltage GaN Power Conversion | Electrical Engineering News and Products

"There is demand for individual discrete devices that can deliver 5 kW+ power levels in many different markets and applications such as datacenter rack-mounted power supplies, renewable string inverters, and electric vehicle on-board charges to name a few. Transphorm is meeting that demand by effectively scaling its high voltage D-mode GaN HEMT and integrating it with a low-voltage e-mode Si MOSFET in a TO-247 package to form a high-power cascode switch. The integration combines the high performance of Transphorm’s GaN with the ease of driving Si MOSFETs—giving the best of both worlds in an industry-standard thru-hole package capable of handling high power applications.

The resulting device is a 650 V rated power FET with a high threshold of 4 V, an on-resistance of less than 15 mΩ, and single-chip-like package simplicity. Using a simple gate drive (as all of Transphorm’s FETs do), the GaN device exhibits faster switching transitions and 2x lower switching losses than a competing SiC MOSFET. When implemented in a 240 V:400 V half-bridge synchronous boost converter, *12 kW output power with greater than 99 percent peak efficiency is achieved.*'


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## T.Sharp

@8051 This is a pretty good overview of the different switching technologies. I had to play it at 1.25x speed. 😄


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## kiriakos

T.Sharp said:


> Gallium Nitride (GaN) ................ Higher switching frequency to achieve equivalent or better regulation.
> 
> Thoughts, opinions?


Gallium Nitride (GaN) this is old news to me, regular MOSFET switching frequency this is not a problem at 98% of applications.
I do repair switching PSU and battery chargers for EV. 
Switching frequency it becomes an issue for DC to DC converters when switching this is at 1MHz or higher.


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## T.Sharp

kiriakos said:


> Gallium Nitride (GaN) this is old news to me, regular MOSFET switching frequency this is not a problem at 98% of applications.
> I do repair switching PSU and battery chargers for EV.
> Switching frequency it becomes an issue for DC to DC converters when switching this is at 1MHz or higher.


Texas Instruments is talking about 50% less conversion losses, 60% smaller inductors and double the power density.

Seems pretty revolutionary as far as transistors go. It's already becoming quite affordable but it will only get less expensive. I think it will be adopted in most places where MOSFETs are used, if not for any other reason than cost savings.


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## kiriakos

T.Sharp said:


> I think it will be adopted in most places where MOSFETs are used, if not for any other reason than cost savings.


I will make my closer by writing this simple line of text, today fresh R&D for every one application this operating with MOSFET so this to switch using new component instead, this is extremely expensive.
TI and other developers, it is their job releasing every day new components and they beg to find new customers. 
While all these developers are not saying it clearly and upfront, their solutions are designed for the sector of telecommunications.
The armory of power-electronics it is full of weapons to use about the delivery of solutions.


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