| 摘要 |
A common-mode feedback circuit is provided for fully-differential operational amplifier stages of a multistage amplifier. A first stage of the circuit establishes a substantially constant current output level for a feedback generating stage of the circuit. An exemplary embodiment using MOSFET devices illustrates using a diode-connected MOSFET and mirror MOSFET first stage and a generating the current for a common-source connected MOSFET second stage connected to the respective outputs for said fully-differential operational amplifier. An output stage of the circuit provides feedback voltage at a first level when inputs to said fully-differential operational amplifier are in equilibrium and at a second level for balancing said fully-differential operational amplifier when inputs to said fully-differential operational amplifier are not in equilibrium.
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