3rd generation SiC MOSFETs with New package TO-247-4L(X) released

Compared to Si (silicon) IGBTs and MOSFETs, which are currently mainstream, power MOSFETs using SiC (silicon carbide) not only excel in low conduction loss and operation in high-temperature environments, but also contribute to low-loss application through high-speed switching.
TO-247-4L(X), a new package for our 3rd generation SiC MOSFETs, is a 4-terminal type, and by reducing the influence of the inductance of the source wire inside the package, it is possible to draw out high-speed switching performance. This contributes to lower loss in applications such as servers, uninterruptible power supplies (UPS), and Photovoltaics Inverter.
Below is a comparison of features and switching loss reduction effects for our new package TO-247-4L(X) (4-terminal type) and our existing product TO-247 (3-terminal type).

In the three-terminal type, As shown in Fig. 1, when the gate drive voltage V_DRV is applied, the inductance component L of the source wire and the gradient dI_D / dt component of the drain current I_D generate a counter electromotive voltage V_LS.
Therefore, the gate drive voltage V_DRV is reduced by the back electromotive voltage V_LS. The voltage V_GS applied between the gate and source of the FET chip is the gate drive voltage V_DRV reduced by the counter electromotive voltage V_LS. This slows down the switching speed of SiC MOSFETs.

On the other hand, As shown in Fig. 2, 4-terminal type reduces the effect of back electromotive voltage V_LS by connecting the signal source terminal for gate drive close to the FET chip. As a result, in the 4-terminal type, the voltage V_GS applied between the gate and source and the gate drive voltage V_DRV are approximately the same value, and the switching speed of the SiC MOSFET is improved compared to the 3-terminal type.

Fig. 3 shows the turn-on switching waveforms of the 4-terminal type and the 3-terminal type by inductive load switching. At turn-on, the drain current I_D (dotted red line) of the 4-terminal type rises steeper than the drain current I_D (dotted blue line) of the 3-terminal type.
This is because the 4-terminal type shown in Fig. 2 reduces the influence of the inductance of the source wire compared to the 3-terminal type, and it suppresses lowering the gate drive voltage during switching. Therefore, the 4-terminal type has a faster turn-on speed than the 3-terminal type.

Fig.4 also shows the turn-on loss E_on of 4-terminal type and 3-terminal type. The turn-on loss E_on of 4-terminal type is approximately 40% lower than that of the 3-terminal type.

Fig. 5 shows turn-off switching waveforms for 4-terminal and 3-terminal types due to inductive load switching. At turn-off, the drain current I_D (dotted red line) of the 4-terminal type decreases faster than the drain current I_D (dotted blue line) of the 3-terminal type. In other words, the 4-terminal type turns off is faster than the 3-terminal type.

Fig. 6 also shows the turn-off loss E_off for the 4-terminal type and 3-terminal type. The turn-off loss E_off of the 4-terminal type is approximately 34% lower than the turn-off loss E_off of the 3-terminal type.

To summarize the above, Fig. 7 shows the relationship between turn-on loss E_on and turn-off loss E_off with respect to external gate resistance R_g for 4-terminal and 3-terminal types.

• Both the 4-terminal type and the 3-terminal type tend to increase turn-on loss Eon and turn-off loss Eoff as the external gate resistance Rg increases.
• The 4-terminal type has smaller turn-on loss Eon and turn-off loss Eoff than the 3-terminal type.

See the following page for the reference design.
Reference design

See the following pages for application examples for various applications.
Server
Uninterruptible Power Supply
LED Lighting

See the page below for packages details.
packages

see the following page for related news releases.
Release of 3rd Generation SiC MOSFETs TO-247-4L(X) package product that contributes to power efficiency of industrial application
Toshiba’s New Device Structure Improves SiC MOSFET Reliability
Toshiba’s New SiC MOSFETs Delivers Low On-Resistance and Significantly Reduced Switching Loss

See the following page for frequently asked questions.
MOSFETs

You can use various simulation models.