A Temperature-Robust Envelope Detector Receiving OOK-Modulated Signals for Low-Power Applications.

Area of Science:

• Electrical Engineering
• Integrated Circuit Design
• Wireless Communications

Background:

• Wireless Sensor Networks (WSN) and the Internet of Things (IoT) rely on energy-efficient Wake-Up Receivers (WuR).
• Passive Envelope Detectors (EDs) are crucial components in WuRs for On-Off Keying (OOK) signal demodulation.
• ED performance, particularly input resistance, can vary significantly with temperature, impacting receiver sensitivity.

Purpose of the Study:

• To develop a passive ED with enhanced temperature stability for OOK signal reception.
• To maintain a constant input resistance over temperature, ensuring a stable load for the preceding matching network.
• To preserve the overall receiving chain sensitivity across a wide temperature range (-40 °C to 120 °C).

Main Methods:

• Designed a passive Envelope Detector (ED) using 90 nm CMOS technology.
• Integrated a Proportional-to-Absolute Temperature (PTAT) current block for temperature compensation.
• Compared two implementations: one minimizing mismatch and another minimizing area.
• Simulated performance for 1 kbps OOK signals at a 433 MHz carrier frequency with a 0.6 V supply.

Main Results:

• Achieved a 5 dB reduction in sensitivity temperature variation over the -40 °C to 120 °C range.
• The minimal area implementation demonstrated superior estimated overall chain sensitivity across all tested temperatures.
• Despite higher sensitivity spread, the minimal area version proved more effective for maintaining consistent performance.

Conclusions:

• The proposed temperature-compensated passive ED effectively stabilizes receiver sensitivity in WuRs.
• PTAT current integration is a viable method for mitigating temperature-induced performance drifts in passive EDs.
• The minimal area design offers a practical trade-off for achieving good sensitivity stability in IoT applications.