Abstract: An integrated silicon circuit includes a plurality of high current power transistors. Each of the power transistors is formed in an epitaxial pocket of N-type conductivity being defined by a surrounding P-type isolation wall. A large N-type plug region occupies a central position in the pocket over which lies a large aluminum collector terminal pad. The P-type base region is an elongated strip region essentially surrounding the N-type plug. An elongated emitter lies within the base strip region and is contacted along its entire length by a metal layer that extends broadly in radial directions from the pocket to contact the isolation wall and leading to a ground terminal pad of the entire integrated circuit. The ratio of the current carrying capability of this power transistor to the silicon area occupied by the transistor is high.

Abstract: A low-voltage bias circuit for a photo-diode includes first and second bipolar transistors with a common base connection and grounded emitters, the photo-diode being connected between the emitter of the first transistor and ground in the reverse polarity direction. A current-mirror circuit uses as the reference current the collector current from the first transistor, which is essentially the photo-current, and produces a feed-back current through the base-emitter junction of the second transistor to hold the voltage across the photo-diode at a near zero value for a wide range in values of photo-current. Thus there is minimum delay in the response of the photo-current to step-functions of the incident light.

Abstract: A full wave rectifying junction-diode bridge rectifier is formed in an integrated silicon circuit. One of the two bridge output terminals is ohmically connected to the bulk doped silicon body so that this portion of the body may serve as the ground reference plane for the entire integrated circuit, including other signal processing circuits, and these other circuits may obtain their d.c. power from the other bridge output terminal. Thus, when the bulk doped body is of P-type conductivity, two of the four bridge diodes (grounded diodes) have their anodes connected to this ground reference terminal. Each of the grounded diodes is formed in an epitaxial pocket having two concentric P-type guard rings and a N-type guard ring positioned concentrically therebetween, all of which are tied to the ground point.

Abstract: A semiconductor integrated circuit includes an integrated resistor body of one conductivity type being contained in a lightly doped pocket of the opposite conductivity type. A metal contact is made to a surface portion of the lightly doped pocked forming a Schottky diode. The metal contact is connected to the hot (Vcd) power supply terminal and thus the diode is normally forward biased. When the power supply is inadvertently reversed, the Schottky diode is reverse biased and prevents destructive currents from flowing in a forward biased p-n isolation junction between the substrate and the pocket.