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An High Speed Linear Inverting Differential Amplifier

IP.com Disclosure Number: IPCOM000017291D
Original Publication Date: 2000-Jul-01
Included in the Prior Art Database: 2003-Jul-25
Document File: 3 page(s) / 90K

Publishing Venue

Siemens

Related People

Michael Moyal: AUTHOR [+2]

Abstract

For operational amplifiers, it is desirable to have certain properties such as maximal gain, maximal speed, and optimal current efficiency. Current solutions use either complicated common mode (CM) feedback loops - such as the nested miller amplifier - thereby reducing speed and increasing complexity, or do not feature input drives, making them inefficient for high current loads.

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Bauelemente

An High Speed Linear Inverting Differential Amplifier

Idee: Michael Moyal, Israel; Martin Gröpl, Sonthofen

For operational amplifiers, it is desirable to have certain properties such as maximal gain,maximal speed, and optimal current efficiency.

Current solutions use either complicated common mode (CM) feedback loops - such as thenested miller amplifier - thereby reducing speed and increasing complexity, or do not featureinput drives, making them inefficient for high current loads.

By introducing a reflection in the lower drive (fig 1, block B) and a level shifter inside theinput amplifier (fig 1, block A), an independent path is created to drive the upper p-channel(fig 1, m29). This results in an improvement of the push-pull-action in the output stagewhile there is no common mode added to the path.

The area addressed by the invention is shown in fig 2, block 1. The inventive step is to addm4 and m2 to the amplifier input stage, thus giving m16 and m18 the proper DC biasvoltage without an extra current bias stage. Moreover m15, m16, m17, m18, and m19 areadded to drive the gate of m19.

In differential mode, two amps are used with shared biasing lines (fig. 3). Because of thedifferentiality, path delays are cancelled as symmetry errors, so that no common mode isneeded.

Siemens Technik Report

Jahrgang 3� Nr. 8� Juli 2000

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Fig. 1

Fig. 2

Siemens Technik Report

Jahrgang 3� Nr. 8� Juli 2000

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Fig. 3

Siemens Technik Report

Jahrgang 3�...