MOSFET comparator with chopper amplifier - has bias voltage adjusting MOSFET, compensating MOSFET and inputs for oppositely phased switching signals per amplifier stage

摘要

The comparator uses a chopper amplifier and is made exclusively using MOS techniques. It has several amplifying stages coupled by capacitors. Each amplifying stage used to amplify the alternately selected input signals appearing on the preceding coupling capacitor (C11) and has a MOSFET (T01) to adjust bias voltage and a first input (9) for a switching input signal to the gate of the bias adjusting transistor. Each stage also has amplifying MOSFETs (T21, T31), a compensation MOSFET (T11) and a second input (10) to apply a second switching input signal with the opposite phase to the bias MOSFET (T01). The amplifying MOSFETs are N-channel depletion and enhancement types.