Abstract
This paper presents a time domain CMOS temperature sensor with a simple current source. This sensor chip only occupies a small active die area of 0.026 mm2 because it adopts a simple current source consisting of an n-type poly resistor and a PMOS transistor and a simple current controlled oscillator consisting of three current starved inverter delay cells. Although this current source is based on a simple architecture, it has better temperature linearity than the conventional approach that generates a temperature-dependent current through a poly resistor using a feedback loop. This temperature sensor is designed in a 0.18 µm 1P6M CMOS process. In the post-layout simulations, the temperature error was measured within a range from −1.0 to +0.7◦ C over the temperature range of 0 to 100◦ C after two point calibration was carried out at 20 and 80◦ C, respectively. The temperature resolution was set as 0.32◦ C and the temperature to digital conversion rate was 50 kHz. The energy efficiency is 1.4 nJ/sample and the supply voltage sensitivity is 0.077◦ C/mV at 27◦ C while the supply voltage varies from 1.65 to 1.95 V.
Original language | English |
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Article number | 899 |
Journal | Micromachines |
Volume | 11 |
Issue number | 10 |
DOIs | |
State | Published - Oct 2020 |
Keywords
- CMOS integrated circuits
- Poly resistor
- Temperature error
- Temperature sensor
- Threshold voltage
- Time domain