Transconductance improvement method for low-voltage bulk-driven input stage

Author-Highlights
• We propose a transconductance improvement method for bulk-driven input stage.
• The proposed method enhances transconductance without additional power.
• The proposed input stage is suitable for low-voltage and low-power application.
• We propose a modified composite-transistor to enhance dc gain of OTA.

A proposed transconductance enhanced method for low-voltage bulk-driven input stage is presented in this paper. The basic idea is to use current–shunt auxiliary amplifier to improve the voltage gain from the inputs to the gates of bulk-driven pairs. The enhanced voltage gain of the auxiliary amplifier leads to the improvement of the effective transconductance of the input stage. Results show that the transconductance of the OTA using the proposed bulk-driven input stage improves almost 200% without additional power and area dissipation compared to the conventional bulk-driven counterpart.