US 11,888,451 B2
Amplifier with sample and average common mode feedback resistor
Rohit Rothe, Ann Arbor, MI (US); Sechang Oh, Ann Arbor, MI (US); Kyojin Choo, Ann Arbor, MI (US); Seok Hyeon Jeong, Ann Arbor, MI (US); Dennis Sylvester, Ann Arbor, MI (US); and David T. Blaauw, Ann Arbor, MI (US)
Assigned to THE REGENTS OF THE UNIVERSITY OF MICHIGAN, Ann Arbor, MI (US)
Filed by THE REGENTS OF THE UNIVERSITY OF MICHIGAN, Ann Arbor, MI (US)
Filed on Apr. 29, 2021, as Appl. No. 17/243,721.
Claims priority of provisional application 63/017,911, filed on Apr. 30, 2020.
Prior Publication US 2021/0344306 A1, Nov. 4, 2021
Int. Cl. H03F 1/02 (2006.01); H03F 1/34 (2006.01); H03F 3/45 (2006.01)
CPC H03F 1/34 (2013.01) [H03F 3/45475 (2013.01); H03F 2200/171 (2013.01); H03F 2200/331 (2013.01)] 17 Claims
OG exemplary drawing
 
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; and
a 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.