Driving circuit for an indicating device using insulated-gate field effect transistors

Claim 1

A driving circuit for an indicating device using insulatedgate field effect transistors comprising: a first insulated-gate field effect transistor of one channel conductivity type whose gate is supplied with a bias potential; a second insulated-gate field effect transistor of said one channel conductivity type whose gate is supplied with an input logic driving signal; a series connection of said first and second transistors including a first connection between an output terminal and said first transistor providing an output signal to drive an indicating device, a second common connection between said first transistor and said second transistor, and a third connection between said second transistor and a second terminal; and a power source having a voltage magnitude greater than avalanche breakdown of said first and second transistors connected across said first and second transistors wherein said bias potential is of a magnitude which maintains said first transistor in saturation when said second transistor is in an off condition whereby avalanche breakdown in each of said transistors is prevented.