Low on-resistance SOI power MOSFET using dynamic threshold (DT) concept for high efficient DC-DC converter

A newly low on-resistance (R-on) power MOSFET using dynamic threshold (DT) concept was studied. The R-on at low gate-driving-voltage was effectively improved using DT concept. We carried out numerical simulations based on the experimental measurements. It was clarified that the R., of the thin-film DT-SOI power MOSFET was 30% lower than that of conventional thin-film SOI power MOSFET at the gate voltage of 1.2 V. Although the R-on of the DT-SOI device was lower, the total gate charge of it was slightly lager than that of the conventional device because of an additional device structure. The lower R-on reduces the power loss of a synchronous rectifier while the lager gate charge increases it. We compared the power loss of the thin-film DT-DOI device as an synchronous rectifier of a DC-DC converter with that of the conventional thin-film SOI device. It was clarified that the power loss of the new thin-film DT-SOI power MOSFET was 36% lower than that of conventional thin-film SOI device at the gate voltage of 1.2 V.