The silicon carbide (SiC) MOSFET is characterized by high operating voltage, temperature, switching frequency and efficiency which enables a converter to achieve high power density. However, at high switching frequency, the crosstalk phenomenon occurs when the gate voltage spike introduced by high dv/dt and voltage ringing forces false turn-on of SiC MOSFET which causes a crow-bar current thereby increasing switching losses. In order to increase the immunity against the crosstalk phenomenon in a half-bridge configuration, this paper presents a gate driver for SiC MOSFET capable of generating the negative turn-off voltage without using a negative power supply. In addition, the effect of parasitic inductances on the switching response is analyzed and an RC snubber is designed using high-frequency based circuit reduction technique to dampen the switching ringing. The performance of the proposed gate driver and the designed RC snubber is validated using simulation and experiment at the 1 MHz switching frequency. The results show that the proposed gate driver with RC snubber eliminates crosstalk by maintaining any spurious gate spike below the gate threshold voltage.

Since the parasitic voltage ringing and switching power losses limit the operation of active devices at elevated frequencies; therefore, a higher‐order inductor‐capacitor (LC) filter is commonly used, which offers extended attenuation above the cutoff frequency and thus, improves the total harmonic distortion (THD) of the amplifier. This paper applies the concept of integral sliding‐mode control to a fourth‐order class‐D amplifier. Two fixed‐frequency double integral sliding‐mode (FFDISM) controllers are proposed, where one uses the inductor current while the other involves the capacitor current feedback. Their equivalent control equations are derived, but from the realization viewpoint, the controller using the capacitor current feedback is advantageous and, therefore, is selected for final implementation. The performance of the proposed FFDISM controller for fourth‐order GaN class‐D amplifier is confirmed using simulation and experimental results.

An improved technique is proposed in fabricating a semiconductor surge protection device which is used in high-speed wideband information transmission systems. In order to increase the surge handling capability of the device, a double p-type diffusion is used. Specifically, in the diffusion step of gallium, SiOz is used as a mask to obtain a very small base width and to avoid the reduction of carrier 3 . high holding current, ensuring the device can be turned off when a surge current rapidly decays; 4. proper protection voltage (i.e. forward breakover voltage), whose exact value is predetermined by the detailed structure of the device: very low leakage current.A bi-directional TVS is shown in Figure l(a). It is similar to un-gated pnpn switches lifetime. It is found that this is a very useful way to reduce the on-state voltage drop and therefore the energy dissipation of the device.

Two port network based modeling approach is used to obtain the analytical expressions for dc-dc buck converter. The analytical expressions obtained include the effect of parasitic elements. The parasitic resistance associated with the filter capacitor and inductor has a significant influence on the converter's frequency responses, so a very simple and systematic procedure has been introduced for the computation of series resistance associated with capacitor and inductor from measured frequency responses. Further, the obtained small signal model is validated through experiment. Once the analytical expressions are available, a prototype of the converter is implemented and frequency responses are measured for various parameters know as g-parameters both in open as well as closed loop mode. The experimental results are compared with those obtained using modeling and it is found that the measurement results match the analytical results. The frequency response measurement based validation of small signal model, presented for dc-dc buck converter, can be used for any type of dc-dc converter working in an open or closed loop configuration.