Current-mode switched-capacitor circuit synthesis by C-invariant dual transformation

The dual transformation which keeps a capacitor invariant is proposed for the synthesis of current-mode switched-capacitor (SC) circuits from their voltage-mode counterparts. A switch is also invariant to this transformation if regarded as a voltage-controlled capacitance which assumes an infinite capacitance when on and zero capacitor when off. A resistor can be replaced, in discrete-time sense, by a capacitor and switches. Therefore, the original network in a voltage-domain can be an active-or passive-RC or SC circuit. Two examples are given to show the synthesis procedure. The transfer function of a synthesized current-mode SC filter is compared experimentally with that of the original to demonstrate its validity.<>