A 1V low power second-order delta-sigma modulator for biomedical signal application

Area of Science:

• Electrical Engineering
• Biomedical Engineering
• Integrated Circuit Design

Background:

• Biomedical applications require low-power, high-performance analog-to-digital converters.
• Delta-sigma modulators are crucial for achieving high resolution in data acquisition systems.
• Existing designs often face trade-offs between power consumption and signal quality.

Purpose of the Study:

• To design and implement a low-power delta-sigma modulator for biomedical applications.
• To optimize power consumption while maintaining high signal-to-noise-and-distortion ratio (SNDR).
• To evaluate the modulator's performance using a figure-of-merit (FOM).

Main Methods:

• Utilized a 2nd order feedforward delta-sigma architecture.
• Implemented the design in a standard 90 nm CMOS technology.
• Employed a low quiescent current operational transconductance amplifier (OTA) to minimize power usage.

Main Results:

• Achieved a signal-to-noise-and-distortion ratio (SNDR) of 64.87 dB at a 10 KHz bandwidth.
• Operated the modulator at a low 1V power supply.
• Demonstrated a power consumption of 17.14 µW.
• Attained a figure-of-merit (FOM) of 0.60 pJ/conv.

Conclusions:

• The designed low-power delta-sigma modulator is suitable for power-constrained biomedical applications.
• The 2nd order feedforward architecture with a low-power OTA effectively balances performance and energy efficiency.
• The achieved FOM indicates competitive performance compared to existing designs.