Common-mode feedback differential amplifier
AssigneeFairchild Semiconductor Corporation
InventorLei Huang
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Abstract
The present invention discloses a common-mode feedback differential amplifier circuit, a common-mode feedback differential amplification method, and an integrated circuit. In an example, a common-mode feedback (CMFB) loop conducts voltage division on a first common-mode signal to generate a second common-mode signal and a third common-mode signal, a differential amplifier sets a voltage of the signal with the higher voltage between the second common-mode signal and the third common-mode signal equal to a voltage of a first input terminal or a second input terminal, and the CMFB loop controls the differential amplifier to output an output signal with the minimum voltage equal to the voltage of the first common-mode signal.
Claims21
A common-mode feedback differential amplifier circuit, comprising:
- a common-mode feedback (CMFB) loop;
- and
- a differential amplifier,
- wherein the CMFB loop is configured to perform voltage division on a first common-mode signal to generate a second common-mode signal and a third common-mode signal, output the second common-mode signal and the third common-mode signal to the differential amplifier, and control, according to a negative feedback principle, the differential amplifier to output an output signal with a minimum voltage equal to a voltage of the first common-mode signal, and
- wherein the differential amplifier is configured to receive the second common-mode signal and the third common-mode signal, set a higher one of voltages of the second common-mode signal and the third common-mode signal equal to a voltage of a first input terminal or a second input terminal, and output, under control of the CMFB loop, the output signal with the minimum voltage equal to the voltage of the first common-mode signal.
A common-mode feedback differential amplification method, comprising:
- dividing, by a differential amplifier circuit, a voltage on a first common-mode signal to generate second and third common-mode signals;
- receiving the second and third common-mode signals at an input stage using a differential amplifier in the differential amplifier circuit,
- setting a higher one of the second and third common-mode signals equal to a voltage of the first input terminal or the second input terminal;
- and
- controlling the differential amplifier, using the differential amplifier circuit according to a negative feedback principle, to output an output signal with a minimum voltage equal to the voltage of the first common-mode signal.
An integrated circuit, comprising:
- a common-mode feedback differential amplifier circuit, the differential amplifier circuit comprising:
- a common-mode feedback (CMFB) loop;
- and
- a differential amplifier,
- wherein the CMFB loop is configured to perform voltage division on a first common-mode signal to generate a second common-mode signal and a third common-mode signal, output the second common-mode signal and the third common-mode signal to the differential amplifier, and control, according to a negative feedback principle, the differential amplifier to output an output signal with a minimum voltage equal to a voltage of the first common-mode signal, and
- wherein the differential amplifier is configured to receive the second common-mode signal and the third common-mode signal, set a higher one of voltages of the second common-mode signal and the third common-mode signal equal to a voltage of a first input terminal or a second input terminal, and output, under control of the CMFB loop, the output signal with the minimum voltage equal to the voltage of the first common-mode signal.
Dependencies are inferred from the claim text.