Voltage comparison circuit with ripple component elimination

Claim 1

An amplification circuit comprising: a signal input terminal and signal output terminal; amplifying means having input and output terminals and including a CMOS inverter having MOS transistors of different channel types, said output terminal being coupled to said signal output terminal; at least one switching MOS transistor whose current path is connected between said signal input terminal and said output terminal of said amplifying means and whose gate is connected to receive a clock signal to set an operation point of said amplifying means; and a first low-pass filter connected between said switching MOS transistor and said input terminal of said amplifying means; a second low-pass filter connected between said switching transistor and said output terminal of said amplifying means; and wherein each of said first and second low-pass filters includes a CR filter comprising a semiconductor substrate, an impuirty layer functioning as resistance means and capacitance means, said impurity layer having a conductivity type opposite to that of said semiconductor substrate and being formed in a surface area of said semiconductor substrate.