International Business Machines Corporation

James R Struk

Yuen H Chan

Michel S Michail

Jack A Dorler

Paul David Hendricks

Dennis C Banker

Walter S Klara

Carlos G Rivadeneira

Frank M Masci

Rolf H Nijhuis

Tore A Carlson

Richard I Spadavecchia

Relatively constant current sources and current mirrors are formed with vertical bipolar transistors operated in the inverse mode. In one embodiment of the invention, an integrated circuit current mirror includes a dual collector vertical NPN bipolar transistor having first and second regions of one conductivity type defining first and second collector regions, respectively, formed within a common third region of opposite conductivity type defining the base of the transistor. The third region is formed within a fourth region defining the emitter of the transistor. The structure of the dual collector vertical transistor is very compact since the two collectors share the same base region which is embedded in a common emitter (inverse collector) pocket. The 'inverse' mode vertical transistor can function as a relatively constant current source with a voltage drop (VCEi) across its collector-to-emitter which is substantially less than that of a bipolar transistor operated in a normal mode. Transistors embodying the invention may be used to provide relatively constant current sources to numerous utilization means, such as logic or analog circuits. Due to the low VCEi of the 'inverse' mode transistor, the resultant circuits can be operated at a lower operating voltage than prior art circuits. This results in a decrease of power dissipation.

Integrated circuit employing inverse transistors

A logic circuit has a plurality of serially connected logic units wherein each unit is a gate comprising a resistor serially connected to a combination of a plurality of transistors connected together in parallel. The transistors of the logic circuit are arranged to enable reduction of the requisite voltage to be provided by an external power source. By reduction of the voltage, the values of resistance can be reduced without exceeding a power dissipation budget. Alternate logic units, in a series of logic units, are constructed of PNP and NPN transistors. Furthermore, the voltage drop across a transistor of a preceding logic unit, as measured between the emitter and collector terminals of a transistor, is applied, essentially, across the base-emitter junction of a transistor in a succeeding logic unit so as to provide a supply of base current to the transistor of the succeeding logic unit without danger of saturating the transistor and without cutting off current flow to the transistor. Furthermore, the magnitude of resistance of the resistor of the preceding logic unit is sufficient to limit base current to the transistor of the succeeding logic unit so as to avoid saturation of the transistor in the succeeding logic unit. An output signal of the logic unit may be applied to an inverter circuit, and speed-up capacitors may be applied in emitter circuits of the inverter and the preceding logic unit for a sharpening of both leading and trailing edges of a logic signal.

Composite logic gate circuit with means to reduce voltage required by

An asymmetrical delay generator for use in a clock chopping circuit is disclosed. The circuit has a complementary transistor switch memory cell in it. That cell is operated in a mode where one half of the cell operates in saturation mode. That half of the cell controls the pulse width of the chopper. The other half of the cell is not operated in saturation and controls the resetting of the chopper and hence the maximum clock rate at which the circuit will operate.

Asymmetrical clock chopper delay circuit

Disclosed is an improved bit selection circuit for a RAM, in particular one employing CTS (complementary transistor switch) cells. The bit select circuitry includes interconnected first and second level matrix decoders, each memory column has a pair of bit lines, each pair of bit lines has connected thereto a bit select circuit, each of the bit select circuits being connected to an output of the second level decoder, a bit up-level clamp circuit connected to each of the bit select circuits of each pair of bit lines, each of the bit select circuits including a first circuit for increasing the speed of selection of the selected pair of lines, the bit up-level clamp circuit cooperating with the bit select circuit of the selected pair of bit lines for positively limiting the upper potential level of the selected pair of bit lines, and each of the bit select circuits including a second circuit for increasing the speed of deselection of the selected pair of bit lines.

Random access memory employing complementary transistor switch (CTS)

The disclosure is directed to an improved random access memory (RAM). More particularly, to improved word line selection circuitry for use in an array employing CTS (Complementary Transistor Switch) type memory cells.

Voltage mode operation scheme for bipolar arrays

An improved random access word addressable monolithic memory having a storage cell for each binary bit of each binary word of storage capacity. The storage cells being arranged in groups. Each cell of any given group being adapted to store a binary bit corresponding to a given bit position of each word stored in said memory. Each cell of each group being connected via first and second bit lines to a sense amplifier. Each sense amplifier coupled to a reference voltage source. The magnitude of the reference voltage supplied by the reference voltage source bearing a substantially invariant mathematical relationship to first and second potentials manifested by said storage cells during a read mode. The storage cells may each be generally of the type disclosed and claimed in U.S. Pat. No. 3,423,737 entitled 'Non Destructive Read Transistor Memory Cell' granted Jan. 21, 1969 to L. R. Harper and of common assignee with the instant application.

Growing community of inventors

Poughkeepsie, NY, United States of America

James R Struk