1200V SiC JFET in Cascode Light Configuration: Comparison versus Si and SiC Based Switches

Abstract

A 1200 V SiC JFET has been demonstrated to achieve ultra-low switching losses ten times lower than for industrial grade 1200V Si IGBT. The low switching losses are also shown to compete with the fastest 600V class MOSFET in the market, yielding 1.1% higher PFC stage efficiency for 340 kHz switching frequency, when same device on-resistances were measured. The proposed normally-on JFET also differentiates over the IGBT by its purely Ohmic output characteristics without any voltage threshold, and by a monolithically integrated body diode with practically zero reverse recovery. In this paper we outline as well how the other pre-requisites for a 1200 V SiC switch in applications such as photovoltaic systems and UPS can be fulfilled by the proposed JFET solution: long-term reliability, product cost optimization by low specific on-resistance combined with reasonable process window expectations. Finally, a normally-off like safe operation behavior is ensured by a dedicated driving scheme utilizing a low-voltage Si MOSFET as protection device at system start-up and for system failure conditions.

A universal automatic and self‐powered gate driver power supply for normally‐ON SiC JFETs

“…By solving this equation, the analytical expression for i st can be derived. Thus, the energy released from C in and dissipated in J m can also be calculated using Equation (2). In this equation, I st is the peak value of the shoot-through current and t su is the time needed for J m to start its switching process in a converter.…”

“…Silicon Carbide SiC power switching devices exhibit lower power losses, enable utilisation of high switching frequencies and can operate at higher temperatures (> 200 • C) compared to state-of-the-art silicon (Si) counterparts [1][2][3][4][5][6][7][8][9][10][11][12][13]. Today, SiC power metal-oxide-semiconductor field-effect transistors (MOSFETs) [14][15][16] and the SiC junction-field-effect transistors (JFETs) [17][18][19][20][21] are available with voltage ratings in the range of 650-1700 V. SiC JFETs can be designed as either normally-OFF or normally-ON switches.…”

Reliable Operation of 1200-V SiC Vertical Junction-Field-Effect-Transistor Subjected to 16,000-Pulse Hard Switching Stressing

“…There is a high demand for large area SiC JFETs, which are currently being developed, for use in power conditioning applications [4][5][6]. A unit-cell cross-sectional view of the p + ion-implanted vertical-channel JFET used in these tests is shown in Fig.…”

Evaluation of SiC Stack Cascode for 200°C Operations

“…An alternative approach, which can overcome the weaknesses of the above devices, utilizes the cascode concept, as illustrated in Fig. 1a, combining a high voltage SiC normally-on JFET and a low-voltage normally-off silicon MOSFET [6,7]. The advantages of the cascode configuration include normally-off operation mode, built-in body diode, very low miller capacitance, and simple gate drive circuits.…”