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Combined Reference Voltage Switch

IP.com Disclosure Number: IPCOM000098783D
Original Publication Date: 1959-Dec-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Margopoulos, WP: AUTHOR [+2]

Abstract

A switching circuit is provided in which an accurate voltage level e(o) across a load L is derived under control of a voltage e, from a non precision power supply +V.

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Combined Reference Voltage Switch

A switching circuit is provided in which an accurate voltage level e(o) across a load L is derived under control of a voltage e, from a non precision power supply +V.

The value of the control voltage e(s) may, as an example, be determined by the state of a single bistable trigger position T(32) in a digital register, T(32)-T(n), such as that used in an analog digital converter. Each of the other triggers T(16)- T(n) would control an associated voltage switch similar to that shown.

The voltage es may be related to the condition of the trigger T(32) so that, when the trigger T(32) is in its 0 state, the voltage e(s) is negative and, when the trigger T(32) is in its 1 state, the voltage e(s) is positive.

If e(s) is driven negative, the transistor S becomes saturated, and the level of the output e(s) is zero, which corresponds to the state of the trigger T(32). If e(s) is driven positive, the transistor S is cut off, the output e(o) approaches the level of +V which, since +V is a non precision reference, may be inaccurate.

Accuracy of the output e(o) is assured, however, by the response of the Zener diode ZD, which is placed across the reference +V and breaks down at an accurately predetermined point to divert excessive +V. Because of the action of ZD, e(o) is established at an accurate volt age level when T(32) is in its 1 state.

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