Back to results
US 7,564,306 B2Granted
Amplifier with common-mode feedback circuit
AssigneeRealtek Semiconductor Corp.
InventorsChao-Cheng Lee, Chieh-Min Feng
Life of this patent
Estimating the term…
Abstract
A common-mode feedback circuit is provided. An amplifier with a common-mode feedback circuit is compensated by adding a compensating unit so that the amplifier totally has two poles and one zero in its frequency response. Accordingly, the gain of the amplifier is not sacrificed, and both the stability and the phase margin of the circuit are improved.
Claims15
An amplifier, comprising:
- an operational amplifier having a first output terminal and a second output terminal for amplifying an input signal and generating an output signal;
- a common-mode detector coupled between the first output terminal and the second output terminal for detecting a common-mode output voltage of the output signal;
- and
- a common-mode feedback amplifier, coupled to the common-mode detector, for generating a control signal to the operational amplifier in accordance with the common-mode output voltage and a reference voltage, comprising:
- a first transistor for receiving the common-mode output voltage;
- a second transistor for receiving the reference voltage;
- a first compensating capacitor for compensating the amplifier;
- and
- a first compensating resistor for compensating the amplifier.
6 more elements
Dependencies are inferred from the claim text.