OPPOSITE PHASE PRIMARY HIGH PASS FILTER CIRCUIT

摘要

PURPOSE:To decrease the capaciatance ratio of capacitors used for the titled circuit when the ratio of a clock frequency to the cut-off frequency of a filter is large by connecting an even number of stages of inverted amplifier circuits including the 2nd switched capacitor in cascade and connecting the connection in cascade with the 1st switched capacitor in the feedback path. CONSTITUTION:An input terminal 1 is connected to an inverting input of an operational amplifier OP1 via a capacitor C0, and an output terminal of the operational amplifier OP1 and the inverting input terminal of the operational amplifier OP1 are connected via a capacitor C1. A common terminal of a switch S1 and a common terminal of a switch S2 are connected via a capacitor C2. The output of the operational amplifier OP1 is given to the input of an inverted amplifier A2, the output of an inverted amplifier A2 is connected to the input of the inverted amplifier A1 and the output of the inverted amplifier A1 is connected to a switched terminal of the switch S1. A switched terminal of the switch S2 and the inverted input terminal of the operational amplifier OP1 are connected and the output of the operational amplifier OP1 and an output terminal 2 are connected.