Amplifiers – With semiconductor amplifying device – Including differential amplifier
Patent
1991-12-12
1993-04-13
Mullins, James B.
Amplifiers
With semiconductor amplifying device
Including differential amplifier
330257, 330311, 330260, H03F 345
Patent
active
052026450
ABSTRACT:
Operational amplifiers are often used in unity gain configurations where the output is fed back to the input. In the noninverting buffer configuration the output is directly connected to the inverting input and the circuit becomes a voltage follower. In many cases, the input stage includes cascode coupled transistors which isolate the current mirror load from the differentially operated input transistors. Such cascode transistors act to increase gain to reduce noise and to increase the power supply rejection ratio. When cascode coupled transistors are employed the frequency compensation capacitor can be isolated from loading effects on the input stage, thus, further enhancing the value of a cascoded input stage. However, when such an operational amplifier is operated as a unity gain device its transient response can suffer. Negative output transitions can result in circuit ringing following the negative output transient steps. The invention consists of adding constant current transistors in parallel with the first stage current mirror load elements. It has been shown that such constant current transistors remove the ringing problem without degrading any of the desired circuit parameters.
REFERENCES:
patent: 4405900 (1983-09-01), Van De Plassche
patent: 4829266 (1989-05-01), Pernici et al.
Phan Christina P. Q.
Wieser James B.
Mullins James B.
National Semiconductor Corporation
Rappaport Irving S.
Rose James W.
Woodward Gail W.
LandOfFree
Stabilized transient response of a cascode CMOS amplifier does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Stabilized transient response of a cascode CMOS amplifier, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Stabilized transient response of a cascode CMOS amplifier will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1157909