US 12,283,928 B2
Operational amplifier for use in coulomb counter circuit
Sven Soell, Edinburgh (GB); Paul Wilson, Linlithgow (GB); James T. Deas, Edinburgh (GB); and Axel Thomsen, Austin, TX (US)
Assigned to Cirrus Logic Inc., Austin, TX (US)
Filed by Cirrus Logic International Semiconductor Ltd., Edinburgh (GB)
Filed on Jan. 27, 2022, as Appl. No. 17/586,111.
Claims priority of provisional application 63/193,282, filed on May 26, 2021.
Prior Publication US 2022/0385252 A1, Dec. 1, 2022
Int. Cl. H03F 3/45 (2006.01); H03M 1/66 (2006.01)
CPC H03F 3/45475 (2013.01) [H03M 1/66 (2013.01); H03F 2200/165 (2013.01); H03F 2200/459 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A circuit comprising a two-stage feedforward compensated operational transconductance integrated amplifier, the two-stage feedforward compensated operational transconductance integrated amplifier comprising:
an input terminal;
an output terminal;
a signal path between the input terminal and the output terminal, the signal path comprising a first signal path gain stage and a second signal path gain stage; and
ripple rejection circuitry coupled between the input terminal and an intermediate node of the signal path located between the first signal path gain stage and the second signal path gain stage, the ripple rejection circuitry comprising:
a first ripple rejection circuitry gain stage coupled at its input to the input terminal and coupled at its output to an input terminal of a chopper circuit;
a notch filter coupled at its input to an output terminal of the chopper circuit; and
a second ripple rejection circuitry gain stage coupled at its input to an output terminal of the notch filter and coupled at its output to the intermediate node;
a filter having its output coupled to the input terminal of the two-stage feedforward compensated operational transconductance integrated amplifier, the filter configured to receive an input signal and generate a filtered input signal to the input terminal of the two-stage feedforward compensated operational transconductance integrated amplifier;
a digital-to-analog converter having its output coupled to the input terminal of the two-stage feedforward compensated operational transconductance integrated amplifier, the digital-to-analog converter configured to receive a digital signal and generate an equivalent analog signal to the input terminal of the two-stage feedforward compensated operational transconductance integrated amplifier; and
a signal assist path gain stage coupled at its input to the filter and coupled at its output to the output terminal and configured to inject a current from the filter into an integrating capacitor of the two-stage feedforward compensated operational transconductance integrated amplifier.