Amplifiers – With semiconductor amplifying device – Including current mirror amplifier
Reexamination Certificate
2000-03-17
2002-05-21
Mottola, Steven J. (Department: 2817)
Amplifiers
With semiconductor amplifying device
Including current mirror amplifier
C330S257000
Reexamination Certificate
active
06392489
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
(Not Applicable)
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
This invention did not result in any way from finding or sponsorship of any governmental entity, including the Federal Government of the United States of America.
BACKGROUND OF THE INVENTION
This invention relates to integrated circuit current mirror, and more specifically to such current mirrors requiring large but accurate multiplication ratios or low power supply voltage.
Current mirrors are used to establish the desired bias currents in transistors in integrated circuits. Typically an accurate bias current is developed in a single multiple transistor circuit. The design of these circuits to provide temperature compensated sources is not a subject of this patent, and can be found, for example, in textbooks such as Gray and Meyer (“Analysis and Design of Analog Integrated Circuits”—Paul Gray and Robert G. Meyer. Third Edition published by John Wiley and Sons 1997.) A reference current from such circuits is used, along with current mirrors, to establish the proper bias currents for many circuits. Current mirrors are used in both bipolar and MOS integrated circuits for biasing. The present invention improves the accuracy and reduces the operating voltage required for current mirrors.
BRIEF SUMMARY OF THE INVENTION
This invention incorporates an elementary operational amplifier (opamp) as an integral part of various current mirrors. Use of an opamp provides accurate reproduction of the “rail” (the node to which all the bases or gates in the mirror circuit are connected) voltage of the current mirror, and obviates the usual “helper” transistor, thus reducing the voltage required for the current mirror to function properly. While the opamp requires more transistors than the simple “helper” transistor, there are many applications where the lower operating voltage or better precision justify the additional silicon area required.
REFERENCES:
patent: 6072359 (2000-06-01), Branbilla et al.
Gehring Mark Richard
Ragan Lawrence Henry
Mottola Steven J.
RadioCom Corporation
Suiter & Associates PC
LandOfFree
Precise integrated current mirrors does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Precise integrated current mirrors, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Precise integrated current mirrors will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2912381