Low-Level Power Fet Driver Method
Posted on Mar 7, 2013 5118
This circuit operates from a 16- to 50-V supply. Adding the buffer circuit (within the dashed lines) offe
rs 100-ns switching times. Otherwise, the circuit switches in 1 /xs. Ql and R1 form a switched current source of about 12 mA. The current flows through R2, which supplies 12 V to the FET. The circuit works well over a wide range of supply voltages. Furthermore, it switches smoothly in the presence of large ripple and noise on the supply. The switching time (about 1 /as) can be reduced considerably by lowering the values of Ri and R2 at the expense of higher power dissipations in the resistors and Ql. Alternatively, a buffer circuit can be added to produce switching times of 100 ns without generating significant power dissipation.