All-digital cost-efficient CMOS pulse-expanded temperature sensor with digital set-point programming

Area of Science:

• Integrated Circuits
• Sensor Technology
• Digital Electronics

Background:

• Conventional time-domain temperature sensors (TS) often require complex dual-core architectures for digital set-point programming.
• Existing designs may rely on analog circuits for temperature compensation, increasing complexity and cost.

Purpose of the Study:

• To present a cost-efficient, all-digital time-domain temperature sensor (TS) architecture with digital set-point programming.
• To reduce hardware complexity and area compared to existing TS designs.
• To achieve high accuracy and resolution in temperature sensing.

Main Methods:

• Developed a pulse-expanded temperature sensor (PETS) utilizing a single cyclic delay line as a shared core.
• Integrated a D-type flip-flop for simultaneous temperature sensing and offset-error cancellation.
• Implemented a programmable counter for generating programmable set-point time, eliminating analog compensation circuits.

Main Results:

• The PETS prototype, fabricated in a 0.35-μm CMOS process, occupies a minimal core area of 0.021 mm².
• Achieved a maximum inaccuracy within ±1°C over the 0-100°C range.
• Demonstrated a sensor resolution of 0.23°C/LSB with the most compact architecture among comparable studies.

Conclusions:

• The proposed PETS offers a highly compact and cost-efficient all-digital temperature sensing solution.
• The simplified architecture and digital nature ensure straightforward portability and scalability for advanced CMOS processes.
• This design effectively reduces circuit complexity and area while maintaining high performance.