Browse Prior Art Database

Differential Amplifier

IP.com Disclosure Number: IPCOM000092639D
Original Publication Date: 1966-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Donner, EF: AUTHOR [+2]

Abstract

A signal is applied to the differential input terminals 1 and 2. The latter are connected to gate electrodes 3 and 4 of field effect transistors 5 and 6. Voltage source +V is connected to drain electrodes 7 and 8 of FET's 5 and 6 by load resistors 9 and 10 respectively. Resistors 11 and 12 connect the source electrodes 13 and 14 to constant current source 15. The differential output signal appears between conductors 16 and 17. These lead to conventional amplifier 18 having output terminals 19 and 20.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 2

Differential Amplifier

A signal is applied to the differential input terminals 1 and 2. The latter are connected to gate electrodes 3 and 4 of field effect transistors 5 and 6. Voltage source +V is connected to drain electrodes 7 and 8 of FET's 5 and 6 by load resistors 9 and 10 respectively. Resistors 11 and 12 connect the source electrodes 13 and 14 to constant current source 15. The differential output signal appears between conductors 16 and 17. These lead to conventional amplifier 18 having output terminals 19 and 20.

Feedback resistor 21 connects terminal 19 to gate electrode 22 of field effect transistor 23. The source and drain electrodes 24 and 25 are connected in parallel with the corresponding electrodes 7 and 13 of FET 5. The ratio of the values of feedback resistor 21 to resistor 26 determines the portion of the output voltage applied as feedback. Since gate electrode 22 is isolated from the input circuit, resistor 21 can be omitted entirely to give a gain of unity.

FET 27, having source and drain electrodes 28 and 29 connected in parallel with the corresponding electrodes 8 and 14 respectively, serves to complete the symmetry. Resistor 30 connects gate 31 to ground to balance the effect of gate
22.

1

Page 2 of 2

2

[This page contains 2 pictures or other non-text objects]