白丝美女被狂躁免费视频网站,500av导航大全精品,yw.193.cnc爆乳尤物未满,97se亚洲综合色区,аⅴ天堂中文在线网官网

Amplifier with sample and average common mode feedback resistor

專利號
US11888451B2
公開日期
2024-01-30
申請人
THE REGENTS OF THE UNIVERSITY OF MICHIGAN（US MI Ann Arbor）
發(fā)明人
Rohit Rothe; Sechang Oh; Kyojin Choo; Seok Hyeon Jeong; Dennis Sylvester; David T. Blaauw
IPC分類
H03F1/02; H03F1/34; H03F3/45
技術(shù)領(lǐng)域
amplifier,resistor,feedback,ffb,capacitor,circuit,corner,in,inverting,frequency
地域： MI MI Ann Arbor

摘要

An amplifier is presented with a sample and average common mode feedback resistor. The amplifier circuit includes a feedback capacitor and a feedback resistor in parallel with the feedback capacitor, where the feedback capacitor and the feedback resistor form part of the negative feedback path for the amplifier. Of note, the feedback resistor is comprised of a low pass filter in series with a switched capacitor resistor, such that the low pass filter is electrically coupled to the output of the amplifier circuit and the switched capacitor resistor is electrically coupled to the inverting input of the amplifier circuit. The amplifier circuit further includes a control circuit interfaced with switches of the switched capacitor resistor. The high pass corner of the switched capacitor resistor is preferably lower than corner of the low pass filter.

說明書

1 2 3 4 5 6 7 8 9 10 11 12 13 14
CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 63/017,911, filed on Apr. 30, 2020. The entire disclosure of this application is incorporated herein by reference.

GOVERNMENT CLAUSE

This invention was made with government support under FA8750-18-C-0134 awarded by the U.S. Department of Defense, Defense Advanced Research Projects Agency. The government has certain rights in the invention.

FIELD

The present disclosure relates to an amplifier with sample and average common mode feedback resistor.

BACKGROUND

Sensors play an integral role in numerous domains, from medical applications to acoustic sensing. Many of these applications have small bandwidths, with frequencies as low as 100 s of mHz. FIG. 1 depicts an example of a continuous-time feedback amplifier. A capacitively coupled amplifier is a common choice in these cases due to its low-power consumption. To establish an input common-mode voltage, the output is typically fed back using a resistor, thereby also aiding input offset cancellation. This presents the key challenge of maintaining a sufficiently low high-pass corner, which is further exacerbated by a small feedback capacitor for high input impedance requirements in low power applications, resulting in the need for tens of teraohms of feedback resistance.

There is a need of a feedback resistor for amplifiers that effectively controls the high-pass corner across temperature with the added benefit of corner frequency programmability.

權(quán)利要求

1
What is claimed is:1. An amplifier comprising:an amplifier circuit having an inverting input, a non-inverting input, and a negative feedback path between an output of the amplifier circuit and the inverting input of the amplifier circuit;a feedback capacitor forms part of the negative feedback path;a feedback resistor in parallel with the feedback capacitor forms part of the negative feedback path, wherein the feedback resistor is comprised of a low pass filter in series with a switched capacitor resistor, such that the low pass filter is electrically coupled to the output of the amplifier circuit and the switched capacitor resistor is electrically coupled to the inverting input of the amplifier circuit, wherein high pass corner of the switched capacitor resistor is lower than corner of the low pass filter; anda control circuit configured to supply a drive signal for controlling the switched capacitor resistor, where switching frequency of the drive signal is less than lower bound of bandwidth of an input signal to the amplifier circuit.2. The amplifier of claim 1 wherein the drive signal for the switches of the switched capacitor resistor is a pulsed signal, where duration of pulses is less than a period corresponding to an upper bound of bandwidth of an input signal to the amplifier circuit.3. The amplifier of claim 1 wherein the low pass filter further comprisesa first capacitor electrically coupled between the negative feedback path and ground;a first switch disposed along the negative feedback path and interconnected between the output of the amplifier circuit and the first capacitor;a second capacitor electrically coupled between the negative feedback path and ground; anda second switch disposed along the negative feedback path and interconnected between the first capacitor and the second capacitor.4. The amplifier of claim 3 wherein control circuit is interfaced with the low pass filter and configured to supply drive signals to the first switch and the second switch, such that the drive signals have fifty percent duty cycle substantially out of phase with each other.5. The amplifier of claim 4 wherein the drive signals to the first switch and the second switch have a frequency higher than bandwidth of an input signal to the amplifier circuit.6. The amplifier of claim 1 wherein the control circuit varies switching frequency of the drive signal from period to period of the drive signal while maintaining the switching frequency constant over a time period, where the time period is larger than two or more period of the drive signal.7. The amplifier of claim 6 wherein the control circuit varies the switching frequency using a delta sigma modulator.8. The amplifier of claim 1 wherein the control circuit is configured to detect saturation of the amplifier and, in response to detecting saturation of the amplifier, substantially increases the switching frequency of the drive signal.9. An amplifier comprising:an amplifier circuit having an inverting input, a non-inverting input, and a first feedback path between an output of the amplifier circuit and one of the inverting input or the non-inverting input of the amplifier circuit;a feedback capacitor forms part of the first feedback path;a feedback resistor in parallel with the feedback capacitor forms part of the first feedback path, wherein the feedback resistor is comprised of a low pass filter in series with a switched capacitor resistor, such that the low pass filter is electrically coupled to the output of the amplifier circuit and the switched capacitor resistor is electrically coupled to the inverting input of the amplifier circuit; anda control circuit configured to supply a drive signal for controlling the switched capacitor resistor, where switching frequency of the drive signal is less than lower bound of bandwidth of an input signal to the amplifier circuit.10. The amplifier of claim 9 further comprisesa second feedback path between a second output of the amplifier circuit and the other the inverting input or the non-inverting input of the amplifier circuit;a feedback capacitor forms part of the second feedback path;a feedback resistor in parallel with the feedback capacitor forms part of the second feedback path, wherein the feedback resistor is comprised of a low pass filter in series with a switched capacitor resistor, such that the low pass filter is electrically coupled to the output of the amplifier circuit and the switched capacitor resistor is electrically coupled to the inverting input of the amplifier circuit.11. The amplifier of claim 9 wherein the drive signal for the switches of the switched capacitor resistor is a pulsed signal, where duration of pulses is less than a period corresponding to an upper bound of bandwidth of an input signal to the amplifier circuit.12. The amplifier of claim 9 wherein high pass corner of the switched capacitor resistor is lower than corner of the low pass filter.13. The amplifier of claim 9 wherein the control circuit varies switching frequency of the drive signal from period to period of the drive signal while maintaining the switching frequency constant over a time period, where the time period is larger than two or more period of the drive signal.14. The amplifier of claim 9 wherein the control circuit is configured to detect saturation of the amplifier and, in response to detecting saturation of the amplifier, substantially increases the switching frequency of the drive signal.15. An amplifier circuit comprising:a differential amplifier circuit having an inverting input, a non-inverting input, a first output with a first feedback path between the first output of the amplifier circuit and the inverting input of the amplifier circuit, and a second output with a second feedback path between the second output of the amplifier circuit and the non-inverting input of the amplifier circuit;a first feedback capacitor forms part of the first feedback path;a first feedback resistor in parallel with the first feedback capacitor forms part of the first feedback path, wherein the first feedback resistor is comprised of a low pass filter in series with a switched capacitor resistor, such that the low pass filter is electrically coupled to the first output of the amplifier circuit and the switched capacitor resistor is electrically coupled to the inverting input of the amplifier circuit;a second feedback capacitor forms part of the second feedback path;a second feedback resistor in parallel with the second feedback capacitor forms part of the second feedback path, wherein the second feedback resistor is comprised of a low pass filter in series with a switched capacitor resistor, such that the low pass filter is electrically coupled to the second output of the amplifier circuit and the switched capacitor resistor is electrically coupled to the non-inverting input of the amplifier circuit; anda control circuit configured to supply a drive signal for controlling the switched capacitor resistors, where switching frequency of the drive signal is less than lower bound of bandwidth of an input signal to the amplifier circuit.16. The amplifier of claim 15 wherein the drive signal for the switches of the switched capacitor resistors is a pulsed signal, where duration of pulses is less than a period corresponding to an upper bound of bandwidth of an input signal to the amplifier circuit.17. The amplifier of claim 15 wherein high pass corner of the switched capacitor resistors is lower than corner of the low pass filter.
微信群二維碼
意見反饋