Isolation Mosfet-driver Ic Gets Improved Power Efficiency At Lighter Loads

摘要

Many modern power MOSFETs reach low values of on-resistance at 5V even when the gate-to-source voltage is 5 V. For heavy-duty power MOSFETS and, especially, IGBTs (insulated-gate bipolar transistors), however, engineers prefer gate-to-source voltages of 12 to 15V because the on-resistance of those power switches further decreases at higher gate-to-source voltages. The 17A-rated IRFR024 power MOSFET from International Rectifier, for example, has an on-resistance of 0.075Ω (Reference 1). When the gate-to-source voltage is 12V, the device's on-resistance drops to 41% of its value compared to a case of a gate-to-source voltage of 5 V. At a switching current of 10A, the device dissipates 6W less when the gate-to-source voltage is 12V.