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Q.6 In what ways are both companies’ technologies complementary?
A.6 The cascode (depletion mode) concept has the advantage of being suitable for standard gate drivers.
Furthermore, the cascode solution offers a very low Vf body diode for reverse operation; turn-off speed is very fast
and unconstrained by any feedback capacitance. The cascode can also be used in low to medium switching
frequencies in resonant applications such as ZVS PFC up to a few MHz. The enhancement mode concept in contrast
offers fast turn-on and turn-off speed and offers a better path towards integration either on a chip or package level.
Enhancement mode works better for hard switching applications such as Totem pole. Low-voltage applications will
require enhancement mode concepts in order to achieve the highest performance with regards to next-generation
Silicon transistors. Finally, enhancement mode is more suitable for multi-chip integration. First products will focus on
high-power applications.
In addition to technology, we also complement each other on the product level: the first cascode production
generation focuses on medium-power applications, while the first enhancement mode products will focus on high-
power applications.
Q.7 Which approach does Infineon pursue for GaN: cascode or enhancement mode?
A.7 Infineon GaN devices will be normally OFF. Depending on the system, cascode configuration or enhancement
mode render advantages that we are looking into and considering with regard to the target application.
Q.8 Infineon has now cascode and enhancement mode GaN: what´s the best that fits a given application?
A.8 Both device concepts have specific advantages depending on the target application. Cascode and enhancement-
mode GaN are two different methods to achieve the same goal: a GaN HEMT-based power switch with performance
benefits of GaN and a normally-off characteristic, making it easier to deploy in power electronic systems.
The cascode configuration is fully compatible with existing drivers for low-voltage MOSFETs and offers a low Vf
integrated body diode for reverse operation. The enhancement mode concept is a single-chip solution and hence
facilitates further integration either on the chip or package level. For most early GaN applications so far identified
either cascode or enhancement mode GaN devices will suffice. Therefore, early applications will be chosen around
the maturity of the solution including availability of appropriate R
DS(on)
switch, drivers and controllers. As
enhancement mode-based solutions reach maturity, ease-of-use and solution costs will very likely make them the
more prominent solution.
Q.9. What are the benefits for customers?
A.9 Customers receive a greater level of power density and higher efficiency: the ultimate goal is to bring
applications, such as a Power Supplies, into a new era of miniaturization and light weight.
GaN – in comparison to the next best silicon alternative – will enable higher power density through the ability to
switch at high frequencies, as well as highest efficiency, especially in the partial load range, through novel
topologies, such as the Totem pole PFC stage. Moreover, GaN switch performance features low charge and excellent
dynamic performance in reverse conduction compared to Silicon FET options. This enables more efficient operation
at existing frequencies, and much higher frequency operation which can improve power density by shrinking the size
of passive components in power electronics.