Effect of Temperature on Circuit Performance of Temperature Sensor in Time Domain and Corresponding Improvements
In view of the influence of temperature on the performance of time-domain temperature sensor circuit, corresponding improvements have been made. First, according to the qualitative relationship between the temperature coefficient and the transistor size, the temperature coefficient is increased by reducing the transistor aspect ratio of the sensing portion. Secondly, a current mirror for temperature compensation is added to the TDC (Time-to-Digital Converter) oscillating ring and the parameters of the inverter are adjusted to make the temperature drift of the TDC oscillating ring close to 0 in the selected temperature range. This method reduces the total power consumption and power density of the circuit, thereby reducing the performance loss caused by self-heating of the circuit and self-heating.
introduction
Conventional temperature sensor designs typically convert the temperature to an analog signal and then obtain a digital signal via an ADC (Analog-to-Digital Converter). However, with the development of new applications such as chip thermal management and Internet of Things, high requirements have been placed on the power consumption, area and digital circuit compatibility of temperature sensors. Therefore, more and more designers are beginning to explore the synthesizable and high integration of temperature sensors in the direction of digitalization. The time domain temperature sensor has the advantages of small area, low power consumption, and easy implementation of digital devices, and has received extensive attention in recent years.
There are many research results of time domain temperature sensors, such as the time domain temperature sensor based on a single delay chain and the time domain temperature sensor based on double delay chain in the literature. They all have a simpler temperature measurement principle, but require more inverters to form a long delay chain to meet the measurement range and accuracy requirements. Another type of time domain temperature sensor based on ring oscillators, such as the all-digital temperature sensor based on a single ring oscillator, is proposed in the literature. This type of sensor has higher accuracy when measuring temperatures below 80 °C. Two sensing methods for ring oscillators with different temperature sensitivities are proposed in the literature. The temperature measurement error is reduced by adjusting the size of the two ring oscillator transistors and taking their frequency ratios to eliminate the effects of supply voltage and process parameters on the circuit.
In application scenarios such as processor thermal management, the accuracy of the high temperature section above 50 °C is more important, and the general temperature sensor considers this less. Based on the circuit structure of the reference, this paper improves the temperature coefficient of the original sensing part and the temperature drift of TDC. In order to make the circuit meet the specific application requirement of high precision in the temperature range of key monitoring.
introduction
Conventional temperature sensor designs typically convert the temperature to an analog signal and then obtain a digital signal via an ADC (Analog-to-Digital Converter). However, with the development of new applications such as chip thermal management and Internet of Things, high requirements have been placed on the power consumption, area and digital circuit compatibility of temperature sensors. Therefore, more and more designers are beginning to explore the synthesizable and high integration of temperature sensors in the direction of digitalization. The time domain temperature sensor has the advantages of small area, low power consumption, and easy implementation of digital devices, and has received extensive attention in recent years.
There are many research results of time domain temperature sensors, such as the time domain temperature sensor based on a single delay chain and the time domain temperature sensor based on double delay chain in the literature. They all have a simpler temperature measurement principle, but require more inverters to form a long delay chain to meet the measurement range and accuracy requirements. Another type of time domain temperature sensor based on ring oscillators, such as the all-digital temperature sensor based on a single ring oscillator, is proposed in the literature. This type of sensor has higher accuracy when measuring temperatures below 80 °C. Two sensing methods for ring oscillators with different temperature sensitivities are proposed in the literature. The temperature measurement error is reduced by adjusting the size of the two ring oscillator transistors and taking their frequency ratios to eliminate the effects of supply voltage and process parameters on the circuit.
In application scenarios such as processor thermal management, the accuracy of the high temperature section above 50 °C is more important, and the general temperature sensor considers this less. Based on the circuit structure of the reference, this paper improves the temperature coefficient of the original sensing part and the temperature drift of TDC. In order to make the circuit meet the specific application requirement of high precision in the temperature range of key monitoring.
