US Patent 7233191 JFET driver circuit and JFET driving method

To turn on a JFET, a two-stage turn-on current control is employed in a JFET driver circuit and a JFET driving method, by which a shortly pulsed high sourcing current is provided to turn on the JFET rapidly and efficiently, and a continuous low sourcing current is provided after the JFET turns on for reducing the power dissipation. After the JFET turns off, a negative charge pump is also employed to promise the JFET at a turn-off state. A special power sequence is further employed to ensure the JFET could be turned off during the power supply coupled to the JFET starts up.