TECHNIQUE TO IMPROVE THE GAIN AND SIGNAL TO NOISE RATIO IN CMOS SWITCHED CAPACITOR AMPLIFIERS

摘要

The present invention comprises switched capacitor amplifiers including positive feedback on semiconductor devices, wafers, and systems incorporating same and methods for amplifying signals using positive feedback, while maintaining a stable gain and producing an improved signal-to-noise ratio. One embodiment includes a switched capacitor amplifier comprising a CMOS amplifier, a feed-in switched capacitor, and a feedback switched capacitor. The feed-in switched capacitor couples an input signal to the non-inverting input of the CMOS amplifier. Similarly, the feedback switched capacitor couples the amplifier output to the non-inverting input to create a positive feedback loop. A capacitance of the feedback switched capacitor relative to a capacitance of the feed-in switched capacitor comprises a feedback proportion. This feedback proportion may be configured to maintain a stable gain of the switched capacitor amplifier and increase a signal-to-noise ratio of the switched capacitor amplifier, even with the switched capacitor amplifier in a positive feedback arrangement