| 摘要 |
A differential amplification circuit includes a differential amplifier and common mode control circuitry configured to control output common mode of the differential amplifier. However, this control circuitry does not use feedback. The circuitry controls the output common mode in either, or in a combination of two ways, neither of which employs feedback from the output common mode. One control technique uses a dummy circuit and comparator to cancel out the effect of variations in process, temperature and supply voltage on output common mode. Another control technique measures input common mode voltage, compares the measured common mode to a reference, and based on the difference, applies a current to the output that compensates for the variation in output common mode that a given input common mode would otherwise cause.
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