Abstract: An IGBT has striped cell with source stripes 2a, 2b continuous or segmented along the length of the base stripe 3. The opposite stripes are periodically connected together by the N+ contact regions 20 to provide channel resistance along the width of the source stripes 2a, 2b. For continuous stripes the resistance between two sequential contact areas 20a, 20b is greatest in the middle and current concentrates near the source contact regions 20. The wider the spacing between the contacts 20, the larger the resistive drop to the midpoint between two N+ contacts 20.

Abstract: An IGBT has a thick buffer region with increased doping to improve self-clamped inductive switching and device manufacture. A planar or trench gate IGBT has a buffer layer more than 25 microns thick. The buffer layer is doped high enough so that its carriers are more numerous than minority carriers, particularly at the transition between the N buffer & N drift region.

Abstract: An IGBT has a thick buffer region with increased doping to improve self-clamped inductive switching and device manufacture. A planar or trench gate IGBT has a buffer layer more than 25 microns thick. The buffer layer is doped high enough so that its carriers are more numerous than minority carriers, particularly at the transition between the N buffer & N drift region.

Abstract: An IGBT has striped cell with source stripes 2a, 2b continuous or segmented along the length of the base stripe 3. The opposite stripes are periodically connected together by the N+ contact regions 20 to provide channel resistance along the width of the source stripes 2a, 2b. For continuous stripes the resistance between two sequential contact areas 20a, 20b is greatest in the middle and current concentrates near the source contact regions 20. The wider the spacing between the contacts 20, the larger the resistive drop to the midpoint between two N+ contacts 20.

Abstract: Gate-turn-off silicon controlled rectifiers (GTO's) are selectively rendered conductive to control the direction of rotation of a bi-directional motor. To this end a digital logic network is responsive to either one or both of a pair of remotely located switches being operated to either a first or a second condition, for controlling a transistorized gate signal generating network to apply an operating voltage to the gate electrode of the appropriate one(s) of the GTO's. The gate signal generating network includes circuitry for grounding the gates of the GTO's, turning them off if on and thereby inhibiting operation of the motor, whenever either of two operating conditions obtains.