A new structure for middle/low voltage optimizes or depresses ringing effect, shoot-through and switching loss.
With this technique, the doping concentration in the drift area could be increased which makes the resistance in that area lower than the conventional trench-gate MOSFET. Simultaneously, due to the shielding effect, the breakdown voltage still can be kept in a great amount to prevent either punch-through nor reach-through. Moreover, there is a built-in snubber resulting from the new structure which can constrain the transient oscillation while turning on the device, shown in Fig. 1 and Fig. 2.
By comparison with conventional trench-gate MOSFET, the Advanced gate MOSFET has lower QRR and TRR. With respect to this reason, the switching loss can be controlled exceedingly well. Lowering the total gate charge, especially the gate-to-drain charge, makes a big progress on improving the switching loss. Also, low ratio of QGD to QGS is a vital parameter of low side MOSFET to check the shoot-through immunity. If the ratio is much smaller than 1, it can be convinced that the synchronous buck circuit will not be easily disturbed inducing turn-on the MOSFET.