Circuite integrate de joasă putere pentru senzor / Integrated circuits with low power for sensors

The proposed PhD paper is dedicated to the digital temperature sensors with integrated interfaces for memory modules used in DIMM DDR4 (Dual In Line Memory Module with Double Data Rate 4th Generation). The integrated sensor monitors the temperature on chip and it generates an alert signal in case of detecting an excessive temperature. The presented research investigates the accuracy of the sensor and the communication between the system and a microcontroller. Several low power blocks are proposed for the integrated sensor: the autozero circuit, digital output buffers with open drain and push pull topologies and trimming circuits with EEPROM cells. The temperature sensor with I2C High Speed interface adjusted with EEPROM cells (EEPROM DTS I2C HS) is SI implemented in a 0.18µm CMOS EEPROM. The functionality of the integrated sensor was validated by wafer measurements and encapsulated circuits. The temperature sensor with the proposed open drain digital output buffer communicates with the microcontroller using an I2C High Speed interface at 3.4MHz. Measurement results of 25 encapsulated EEPROM DTS I2C HS exhibit an accuracy of +1.56°C/-1.00°C for the detected temperature range between -20,...,125°C and voltage power supplies of 1.7...3.6V. The current consumption of the system is 235µA, while the integrated sensor occupies 2.07mm2. A good agreement between the proposed sensor and several products on the TS’s market for DDR4 DIMM memory modules was obtained