Time-Domain CMOS Temperature Sensors With Dual Delay-Locked Loops for Microprocessor Thermal Monitoring

摘要

We report on CMOS temperature sensors that work by measuring temperature-dependent delays in CMOS inverters. Two new features distinguish this work from the prior delay-based temperature sensors. First, our sensor operates with simple, low-cost one-point calibration. Second, it uses delay-locked loops (DLLs) to convert inverter delays to digital temperature outputs: the use of DLLs enables low energy (0.24 $mu$ J/sample) and high bandwidth (5 kilo-samples/s), facilitating fast thermal monitoring. After calibration, measurement errors for 15 chips fabricated in digital CMOS 0.13 $mu$ m fall within $-4.0sim 4.0, ^{circ}{hbox {C}}$ in a temperature range of $0sim 100, ^{circ}{hbox {C}}$ , where the temperature chamber used has a control uncertainty of $pm 1.1, ^{circ}{hbox {C}}$ . Microprocessor thermal profiling can be a potential application.