直流电源纹波去除电路(DC voltage Ripple Remover)
Figure 1 shows a simple circuit for removing an AC ripple from a DC voltage. The main component of the circuit is an operational amplifier configured as a simple amplifier in common-mode operation. This means that both the inverting and non-inverting inputs of the op-amp get the same input voltage, i.e., a DC voltage Vin with an AC ripple Vripple. The only difference is that the inverting input has an input capacitor that blocks the DC voltage.
Figure 1. Schematic Diagram for a Simple DC Voltage Ripple Remover
Since the op-amp amplifies just the difference between the voltages at its two inputs, it cancels out the AC ripple (which appears at both inputs). On the other hand, the op-amp amplifies the DC voltage Vin since this is only present at the non-inverting input. However, the op-amp is configured to have a DC voltage gain equal to 1, so the output of this circuit is just equal to Vin.
Since the AC ripple can only be cancelled cleanly if both op-amp inputs have equal gains, the 10K potentiometer is used to compensate for any inherent differences between the inputs' gains.