Global | October 23, 2024

Designing High-Voltage SiC-Based Disconnect Switches

Design considerations for power semiconductors in a high-voltage, high-current battery disconnect switch.

 

Image for illustration purposes.

Among the key factors are semiconductor technology, device type, thermal packaging, device ruggedness, and managing the inductive energy during circuit interruption. The article discusses the importance of characterizing a system’s parasitic inductance and over-current protection limits.

Optimizing High-Density Power with SiC Devices and Advanced Circuit Design

Power electronics are under pressure to perform in applications such as AI data centers and EV battery chargers. These systems need to handle high voltages and run efficiently to minimize losses and prevent excess heat generation. Silicon carbide (SiC) and other new materials for power devices can help solve some of these problems, while more advanced circuit designs can tackle others.

Resolving Voltage Spikes, Ringing, and EMI in SiC Power Designs

As SiC power devices support higher switching speeds and lower switching losses during turn-off transients, a new challenge arises – the increased risk of voltage spikes and ringing. One method to address this issue is to use high gate resistance (Rg) to slow down device switching speed. However, this is unwelcome in designs that aim to use higher frequencies to reduce converter size and cost.

Using low-Rg with a drain-to-source snubber Cs to rapidly absorb the voltage spike results in a 50% savings in turn-off switching loss versus the use of high gate resistance. When replacing the SiC MOSFET module with Qorvo’s JFET-based devices, the snubber delivers another 74% reduction in turn-off switching losses.

Source: EE Power