Continuous time operation amplifier and operating method
AssigneesSamsung Electronics Co., Ltd., Korea Advanced Institute of Science and Technology
InventorsSeong Joong Kim, Seung Tak Ryu, Kent Edrian Lozada
Life of this patent
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Abstract
A continuous time op-amp includes a differential op-amp configured to produce, and output through output lines, output signals amplified based on a difference between input signals inputted to the differential op-amp, and a common mode feedback (CMFB) circuit configured to feed a common mode voltage back to the op-amp through a feedback line in continuous time through a capacitive coupled path, wherein the CMFB circuit includes: feedback capacitors connected between the output lines and the feedback line; switched capacitors charged based on a common mode reference voltage; and switching elements configured to control a connection between the feedback capacitors and the switched capacitors.
Claims17
A continuous time op-amp comprising:
- a differential op-amp configured to produce, and output through output lines, output signals amplified based on a difference between input signals inputted to the differential op-amp;
- and
- a common mode feedback (CMFB) circuit configured to feed a common mode voltage back to the op-amp through a feedback line in continuous time through a capacitive coupled path,
- wherein the CMFB circuit comprises:
- feedback capacitors connected between the output lines and the feedback line;
- switched capacitors charged based on a common mode reference voltage;
- and
- switching elements configured to control a connection between the feedback capacitors and the switched capacitors, and
- wherein the switching elements comprise:
- first switching elements configured to operate according to a first phase of the clock signal;
- and
- second switching elements configured to operate mutually exclusively with the first switching elements according to a second phase of the clock signal that is opposite in phase with respect to the first phase.
A method of operating a continuous time op-amp, the method comprising:
- producing output signals amplified based on a difference between input signals inputted to the continuous time op-amp, wherein the output signals are outputted through output lines of the continuous time op-amp;
- feeding a common mode voltage in continuous time back to the continuous time op-amp through a capacitive coupled path that includes feedback capacitors connected between the output lines and a feedback line of a differential op-amp, wherein a voltage corresponding to bias voltage minus the common mode voltage is provided to the feedback capacitors;
- first and second switching elements configured to control a connection between the feedback capacitors and switched capacitors;
- and wherein
- the feeding back of the common mode voltage comprises:
- charging the switched capacitors with a common mode reference voltage by turning on the first switching elements with a first phase of a clock signal;
- and
- charging the feedback capacitors with the common mode reference voltage charged in the switched capacitors by turning on the second switching elements with a second phase of the clock signal, wherein the second phase is opposite to the first phase.
Dependencies are inferred from the claim text.