SemiSouth Laboratories Inc of Starkville, MS, USA (which designs and manufactures silicon carbide device for high-power, high-efficiency, harsh-environment power management and conversion applications) claims that, after first releasing commercial 1200V trench JFETs in 2008 (currently being used in volume production by manufacturers of UPS, hi-rel products, audio systems and solar inverters), it is now delivering the industry's first 650V SiC JFET power transistors.
The firm says that the fast switching speeds, large current-handling capability, combined with the superior thermal properties of SiC, makes the devices suitable candidates for power electronic applications. The devices employ vertical trench JFET (junction field-effect transistor) structures, which allow what is claimed to be industry-leading on-resistance per unit area (as much as five to ten times lower than competing technologies).
''Customers in markets such as EV drive train, UPS, welding, solar, induction heating have long been asking for SiC switches which are very reliable, cost-effective, and capable of high efficiency at high power densities,'' says president/chief technology officer Dr Jeffrey B. Casady.
''Markets where we are already in volume production using our 1200V switch, such as solar and UPS, also require lower-voltage switching at 650V for efficiency and higher-power-density solutions where grid voltage or bus voltages are lower,'' says senior VP of sales & marketing Dieter Liesabeths. ''Also, the automotive industry is split on the EV drive train, with some customers requiring 1200V and higher, and others requiring only 650V,'' he adds. ''So, we can now serve these markets even better with power transistor solutions from 650V through 1700V.''
Like many SemiSouth devices, the 650V/55m Ω SJDA065R055 SiC JFETs feature a positive temperature coefficient for ease of paralleling and extremely fast switching with no 'tail' current at 1500C. Rds(on) typical for these new voltage-controlled devices is 0.044 Ω, which also exhibit a low gate charge and low intrinsic capacitance.
Typical applications for the TO-220-packaged JFETs include solar inverters, SMPS (switched-mode power supplies), PFC (power factor correction) circuits, induction heating, UPS (uninterruptible power supplies) and motor drives.
