On-chip analog filter is a key part for integrated circuits preprocessing physiological signals, which influences the quality of signals acquired. Since the frequency of the physiological signals is of ultra-low range, the on-chip large capacitance in the analog filter is the key problem to be solved immediately. The paper summaries the recent progress of the capacitance multiplier development, such as current mode capacitance multiplier, voltage mode capacitance multiplier, capacitance multiplier based on current-to-voltage converter and unbalanced capacitance multiplier, and then analyzes the key technology. Finally the paper looks into the future of the capacitance multiplying circuits.

analog filter  /  physiological signals  /  integrated circuit  /  capacitance multiplier