An On-Chip Temperature Sensor With a Self-Discharging Diode in 32-nm SOI CMOS

Abstract

We report a 39 μm × 27 μm on-chip temperature sensor which uses the temperature-dependent reverse-bias leakage current of a lateral silicon on insulator (SOI) CMOS p-n diode to monitor the thermal profile of a 32-nm microprocessor core. In this sensor, the diode junction capacitance is first charged to a fixed voltage. Subsequently, the diode capacitance is allowed to self-discharge through its temperature-dependent reverse-bias current. Next, by using a time-to-digital-converter circuit, the discharge voltage is converted to a temperature-dependent time pulse, and finally, its width is measured by using a digital counter. This compact temperature sensor demonstrates a 3σ measurement inaccuracy of ±1.95 • C across the 5 • C-100 • C temperature range while consuming only 100 μW from a single 1.65-V supply.

Study of CMOS-SOI Integrated Temperature Sensing Circuits for On-Chip Temperature Monitoring

“…The circuit measured power consumption at room temperature is 0.25 mW for the resistor based design and 45 µW for the diode based design. Errors similar to the errors calculated for the resistor based design, in order of 2 K, have been presented in [12] after two-point calibration for temperature sensing from 278 K up to 373 K using fully depleted single lateral SOI diode consuming 100 µW.…”

“…Most of the CMOS based temperature sensors are not compatible with CMOS-SOI technology due to the thin device layer. The two most commonly used elements for temperature sensing available in CMOS-SOI technology are: lateral diodes [7,8,9,10,11,12] and standard MOSFET transistors [13]. The SOI-based diode is an attractive choice for a temperature sensor because it is compact in size, gives linear response up to ultra-high temperature [11] and is simpler to integrate with on-chip, sensor drive and readout circuitry.…”

“…The SOI-based diode is an attractive choice for a temperature sensor because it is compact in size, gives linear response up to ultra-high temperature [11] and is simpler to integrate with on-chip, sensor drive and readout circuitry. While SOI diode temperature sensors have been utilize for temperature monitoring in different application [7,8,9,10,11,12] the effect of device mismatches and consequently calibration needs are rarely discussed. One of these [8], describes a work that uses a SOI lateral PIN diode for temperature sensing from 100 K to 400 K and suggests to improve the diodes accuracy by reducing the temperature range of the diode.…”

“…One of these [8], describes a work that uses a SOI lateral PIN diode for temperature sensing from 100 K to 400 K and suggests to improve the diodes accuracy by reducing the temperature range of the diode. In other study [12], a smart CMOS-SOI temperature sensor has been described that uses a self-discharging SOI diode for temperature sensing and an error of ±1.95C (3ϭ) has been achieved after two-point calibration.…”

Compact Thermal-Diffusivity-Based Temperature Sensors in 40-nm CMOS for SoC Thermal Monitoring

“…It demonstrates that the performance of TD sensors indeed continues to improve with scaling. Without temperature calibration, the sensor achieves ±1.4°C (3σ) inaccuracy from -40°C to 125 °C, which is 5x better than previous (non-TD) sensors intended for thermal monitoring [4,[14][15][16].…”