National Semiconductor Corporation

Jose F Albarran

Adib R Hamade

In a three JFET switch, a first transistor when turned on is utilized to pass an input voltage to an output. The first transistor is turned on by a second and third transistor having their gates commoned with the first transistor to form a turn on circuit. In its idle state, when the switch is off, a drain circuit conducts through the third transistor, dissipating power. In order to reduce the size of the second and third transistors and hence the power dissipated while maintaining a fast switching speed a bipolar transistor and a fourth JFET are utilized to amplify the drain current of the third transistor for discharging the common gate capacitance of the switch. This allows the second and third transistors to be made small since their current need not be large for high speed switching. Furthermore, the bipolar transistor only turns on during the transition from the open to closed state of the switch and therefore its conduction does not contribute to the quiescent power consumption of the circuit.

Growing community of inventors

Mexico City, Mexico

Jose F Albarran