CMOS DIFFERENTIAL AMPLIFIER CIRCUIT AND DELTASIGMA CIRCUIT USING IT

摘要

PURPOSE: To obtain the CMOS differential amplifier circuit in which fluctuation in an operating point is effectively suppressed. CONSTITUTION: Amplitude limit circuits 21, 22 are provided in a feedback circuit of a CMOS operational amplifier 20. The amplitude limit circuit 21 is made up of two PMOS TRs QP11, QP14 of diode connection which are connected between input and output in opposite polarity to each other and two NMOS TRs QN12, QN13 of diode connection which are connected between input and output in opposite polarity to each other similarly. The other amplitude limit circuit 22 is made up of two PMOS TRs QP21, QP24 of diode connection and two NMOS TRs QN22, QN23 of diode connection similarly.