Battery booster
How higher on resistance can improve efficiency in high frequency switch mode power supplies. By Roger Kenyon.
A common way to reduce the size of a switched mode power supply (smps) is to increase its switching frequency. Higher frequency allows the use of smaller inductances and capacitances, which allows physically smaller components.
Unfortunately, increasing an smps’ switching frequency can lower its conversion efficiency, despite a low on resistance in the mosfet. Dynamic mosfet properties, such as gate charge and switching time, become significant and it’s surprising to note that at higher switching frequencies, a mosfet with a higher Rds(on) can improve smps efficiency.
