Wiring Circuit

This is the Scarce Level Power Fet Driver Method Circuit Diagram. This schema operates from a 16- to 50-V supply. Adding the buffer schema (within the dashed lines) offers 100-ns switching times. Otherwise, the schema 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 schema 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 dissipation in the resistors and Ql. Alternatively, a buffer schema can be added to produce switching times of 100 ns without generating significant power dissipation.