Power-Efficient Recycling Folded Cascode Operational Transconductance Amplifier Based on Nested Local Feedback and...

Area of Science:

• Analog Integrated Circuit Design
• Low-Power Electronics
• CMOS Technology

Background:

• Operational Transconductance Amplifiers (OTAs) are fundamental building blocks in analog circuits.
• Traditional recycling folded cascode (RFC) OTAs face limitations in transient response and efficiency, especially under weak inversion.
• Enhancing OTA performance is crucial for modern low-power applications.

Purpose of the Study:

• To introduce a novel enhanced recycling folded cascode (ERFC) operational transconductance amplifier (OTA).
• To improve the transient response and efficiency of OTAs using adaptive biasing with nested local feedback (ABNLF).
• To achieve stable large signal responses and high slew rate (SR) and gain-bandwidth (GBW) products.

Main Methods:

• Designed and simulated a novel ERFC OTA incorporating adaptive biasing with nested local feedback (ABNLF).
• Utilized coupling capacitors at the output stage for stable large signal operation.
• Compared the proposed ERFC OTA with a traditional RFC OTA using a 0.18 μm CMOS process at 1.8 V.

Main Results:

• The ERFC OTA demonstrated significantly enhanced input transconductance and slew rate (SR).
• Post-layout simulations showed a 120-fold increase in SR and a 5.95-fold increase in gain-bandwidth (GBW) compared to the traditional RFC OTA.
• Achieved a high figure of merit (FoM) of 130.04 (V/μs)·pF/μA, indicating superior efficiency.

Conclusions:

• The proposed ERFC OTA with ABNLF offers substantial improvements in transient response and efficiency.
• This design is suitable for low-power applications requiring fast and stable signal processing.
• The ERFC OTA represents a significant advancement over traditional RFC OTA designs.