The four-pin TO-247-4L package uses a Kelvin connection for the gate-drive source terminal in order to reduce the inductance of the internal source wiring and thereby allow a MOSFET chip to achieve a high switching speed.
Power MOSFETs in the TO-247-4L package help further improve the efficiency of the high-efficiency medium to large switching power supplies (with a level required by 80 PLUS*1TITANIUM and 80 PLUS PLATINUM).
Accompanying the increasing switching speed and current capability of the DTMOS chip, the inductance of source wiring in a package has begun to have an adverse effect on its switching performance. In the TO-247-4L package, the gate-drive source terminal separates the power-line current from the gate drive current, reducing the impact of inductance from the gate-source voltage.
The waveform of gate-source voltage close to the MOSFET chip obtained from the simulation shows that the turn-on time of the MOSFET chip housed in the TO-247-4L package is shorter than that of the chip in the TO-247 package due to a difference in LSource. Actual measurements show that the TK62Z60X in the TO-247-4L package exhibits a turn-on loss 19% lower than that of the TK62N60X housed in the TO-247 package.
Both the simulation and actual measurements show that the use of the TO-247-4L package contributes to a reduction in the turn-on loss and an increase in switching speed.
Toshiba has added four devices in the TO-247-4L package (TK25Z60X, TK31Z60X, TK39Z60X and TK62Z60X) to the portfolio of its 600-V DTMOSIV-H*2power MOSFET series. Fabricated using a super-junction structure, the DTMOSIV-H series exhibits lower on-resistance and higher switching speed than the previous series.
*1 A certification program promoted by 80 PLUS for efficient energy use of electric appliances. It certifies products that have more than 80% DC-to-AC conversion efficiency.
*2 Fourth-generation high-speed-switching series (DTMOIV-H) with a super-junction structure