Browse Prior Art Database

Voltage Conversion Circuit

IP.com Disclosure Number: IPCOM000084046D
Original Publication Date: 1975-Sep-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Brearly, A: AUTHOR [+3]

Abstract

This circuit, which minimizes temperature effects, is a signal or voltage translation circuit which is suitable for use in address buffers for shifting and amplifying signals. The circuit is of the type disclosed in U. S. Patent 3,778,640.

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Voltage Conversion Circuit

This circuit, which minimizes temperature effects, is a signal or voltage translation circuit which is suitable for use in address buffers for shifting and amplifying signals. The circuit is of the type disclosed in U. S. Patent 3,778,640.

In operation, input signals are applied to transistor T1 which is coupled to a current switch emitter-follower having transistors T2, T4, T5 and T6 and resistors R5, R6 and R7, as indicated in the drawing. The voltage at the emitter of T2, which is connected to a voltage supply of -4.25 volts through R1, T3 and R2, is used to generate a reference voltage at the base of transistor T7, which has its emitter connected to the -4.25 voltage supply through resistor R3. This reference voltage determines the collector current in T7.

The voltage at the collector of T7 is determined by the voltage at the emitter of T6 minus the voltage drop across resistor R4. An output driver, e.g., a conventional push-pull circuit, not shown, may be connected to the output of this conversion circuit. The voltage swing at the collector of T7 can be used to switch the output driver on and off.

With a high input signal, e.g., 0 volts, as indicated on the drawing, T1 and T4 turn on and T5 is off. The emitter of T6 goes to -0.75 volt and the emitter of T2 goes to -1.6 volts, which establishes the current in T7 at 0.66 milliampere, and the voltage at the collector of T7 goes to -2.65 volts. This output voltage would be sufficient t...