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Regulated On Chip Reference Generator for Logic Families

IP.com Disclosure Number: IPCOM000084242D
Original Publication Date: 1975-Oct-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Malaviya, SD: AUTHOR

Abstract

In Fig. 1 the uplevel of a ground-down logic family is available at the emitter of device Q1, while the downlevel is controlled by the -Vl supply. The ideal reference voltage is midway between these two levels and is available at the junction of the two equal resistors R4/R5. Ground shift, changes in the -V1 supply and VBE of the devices due to temperature etc., are automatically compensated for in this method of deriving the reference voltage. It is buffered from the output load by the current switch Q2/Q3 and emitter-follower Q4. Feedback from the output of Q4 to the base of Q3 ensures excellent regulation of the output supply.

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Regulated On Chip Reference Generator for Logic Families

In Fig. 1 the uplevel of a ground-down logic family is available at the emitter of device Q1, while the downlevel is controlled by the -Vl supply. The ideal reference voltage is midway between these two levels and is available at the junction of the two equal resistors R4/R5. Ground shift, changes in the -V1 supply and VBE of the devices due to temperature etc., are automatically compensated for in this method of deriving the reference voltage. It is buffered from the output load by the current switch Q2/Q3 and emitter-follower Q4. Feedback from the output of Q4 to the base of Q3 ensures excellent regulation of the output supply.

Circuit stability can be improved by adding shunt capacitances C1 and C2 across the base-to-collector of Q3 and Q4 (e.g., by using Schottky barrier diodes across them). The current-switch emitter follower circuit enclosed within the broken lines may be used to buffer any other voltage applied to the base of Q2.

An alter ative embodiment is depicted in Fig. 2. In this figure, the reference voltage is derived by a potentiometer consisting of R1 and R4.

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