Itt Industries, Inc.

Wolfgang Hoehn

Wolfgang Sauer

An integrated circuit is described which includes a digital/analog converter which together with a reference voltage generator and a current-to-voltage converter is driven by a single supply voltage. To obtain a variable output voltage from a second supply voltage, the reference voltage is dependent on this second voltage. The output voltage can be used as the tuning voltage of tuner diodes.

Integrated circuit for generating a terminal voltage adjustable by a

In a parallel analog-to-digital converter wherein the comparator inputs are switched between +1/2 the voltage corresponding to the least significant bit and -1/2 said voltage. There is provided a bipolar differential amplifier-like circuit with a resistor connecting the collectors of the two transistors and a constant current source disposed in the emitter circuit. The comparator inputs are provided with the analog signal through said resistor, while the base of one of said transistors is provided with a clock signal having one-half the frequency of the converter clock signal.

Parallel analog-to-digital converter

The manufacturing, fluctuations in electrical parameters of I.sup.2 L double-collector current source transistors each of which is connected in series with a bias transistor having a base zone common with the base zone of the other bias transistors, are compensated by means of a bias voltage generator whose output voltage is fed to said common base. The bias voltage generator consists of a current mirror comprising a further I.sup.2 L double-collector current source transistor and a further bias transistor having the same configuration and conductivity type as the I.sup.2 L double-collector current source transistors and the bias transistors.

Bias voltage generator for a monolithic integrated circuit

An I.sup.2 L circuit for superimposing audio-frequency electrical signals in an electronic organ is provided. With each current unit of audio-frequency to be superimposed a double-collector I.sup.2 L transistor is associated, and each key is coordinated to an injector, the current of which is switched by said key. In addition to the collecting bars into which said current units are fed, there is provided a separate collecting bar into which the non-audio-frequency collector currents of double collector transistors are fed, each of which being coordinated to each injector. A bounce effect is avoided by subtracting the signal of the separate collecting bar from the signals on the other collecting bars.

Integrated I.sup.2 L circuit for superimposing audio-frequency

A monolithic integrated circuit for an RC oscillator includes a differential amplifier acting as a switching stage for comparing a threshold voltage corresponding to the maximum oscillator voltage with the capacitor voltage of the RC circuit. An output of the differential amplifier is connected to the S input of an R-S flip-flop which is set when the capacitor voltage reaches the threshold voltage. A switching transistor has its collector and emitter connected across the capacitor and a base connected to the output of the R-S flip-flop for discharging the capacitor when the flip-flop is set. A second transistor has its base-emitter junction connected across the base-collector junction of the switching transistors so that when the switching transistor has discharged the capacitor to a point that only its collector-to-emitter saturation voltage dropped across it, the second transistor is turned on to provide a signal to the reset input of the flip-flop, thereby inhibiting the discharge of the capacitor and allowing the capacitor to recharge through a current source.

Monolithic integrated circuit for an RC oscillator

The push-pull stage contains a special double emitter transistor which prevents current spikes during switch-over transition. One of two emitters is connected to the base of the double emitter transistor. The junction area of this emitter is many times greater than that of the other emitter.

Bipolar monolithic integrated push-pull power stage for digital signals

This relates to a temperature-compensated zener diode arrangement in the form of a semiconductor integrated circuit which consists of several transistor structures disposed in a common semiconductor body and interconnected by deposited metallizations. The base-emitter pn junctions of the transistor structures are so connected in series with respect to the direction of the total current flowing during operation that some of them are operated in the reverse direction up to the breakdown region as zener diodes and the remainder in the forward direction as forward bias diodes. The emitter of the first transistor structure acting as a zener diode or the base of a transistor structure acting as a forward bias diode, as well as the collector of the latter transistor structure, are connected to the first external terminal. The emitter of the latter transistor structure, acting as a forward bias diode, is connected to the second external terminal. The transistor structures acting as zener diodes are disposed in a first isolating island of the semiconductor body and the transistor structures acting as forward biased diodes are disposed in additional isolating islands.

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Kirchzarten, Germany

Wolfgang Hoehn