A low temperature drift coefficient crystal-less frequency reference clock compensated by temperature sensor for microsystem

2018 ◽  
Vol 32 (12) ◽  
pp. 1850146 ◽  
Author(s):  
Zhiqiang Gao ◽  
Ruixuan Wu ◽  
Yuteng Wang ◽  
Yuan Gao ◽  
Xiaowei Liu ◽  
...  
Keyword(s):  
Temperature Sensor ◽  
Current Source ◽  
Ring Oscillator ◽  
Frequency Variation ◽  
Control Voltage ◽  
Crystal Oscillator ◽  
Temperature Drift ◽  
Frequency Reference ◽  
Quartz Oscillator ◽  
Reference Clock

Quartz oscillator has been widely used as reference clock source in the microsystems due to its good performance. But a good crystal oscillator costs too much and its bulky size is not desired. This paper aims at designing an alternative integrated oscillator to replace the external quartz oscillator. The proposed circuit used maneatis delay cell to construct a ring oscillator for its superior linear I–V characteristic. As for a frequency reference clock, its frequency stability over temperature is required at first. After detailed mathematical deducing and careful analysis, a formula is proposed to describe the relationship between desired control voltage and temperature by assuming the frequency as constant. This paper utilized bipolar transistor as the temperature sensor, combining it with CTAT current source and resistor to create a first-order temperature compensation control voltage. The chip with typical frequency of 10 MHz was fabricated in a 0.35 [Formula: see text]m CMOS technology and occupied 0.45 mm2. The measured results show that the frequency variation is ±0.2% for supply changes from 4.8 V to 5 V, and frequency variation is 48 ppm when the temperature change is from −40[Formula: see text]C to 85[Formula: see text]C, while the average current of the tested chip consumes 50 [Formula: see text]A from 5 V.

A Temperature-Stable Low-Power Wide-Range CMOS Voltage Controlled Oscillator Design for Biomedical Applications

2019 ◽  
Vol 29 (08) ◽  
pp. 2050128
Author(s):  
Zied Sakka ◽  
Nadia Gargouri ◽  
Mounir Samet
Keyword(s):  
Low Power ◽  
Biomedical Applications ◽  
Cmos Technology ◽  
Average Frequency ◽  
Absolute Temperature ◽  
Ring Oscillator ◽  
Frequency Variation ◽  
Control Voltage ◽  
Voltage Controlled Oscillator ◽  
Wide Range

This paper presents a low power temperature compensated CMOS ring oscillator for biomedical applications across a wide temperature range. The proposed circuit deploys an IPTAT (inversely proportional to absolute temperature) bias current by generating an adaptive control voltage in each stage of the oscillator to compensate the overall oscillator’s temperature coefficient (TC). Simulations using TSMC 0.18[Formula: see text][Formula: see text]m CMOS technology show that this configuration can achieve a frequency variation less than 0.25%, leading to an average frequency drift of 20.83[Formula: see text]ppm/∘C. Monte Carlo simulations have also been performed and demonstrate a 3[Formula: see text] deviation of about 2.15%. The power dissipated by the proposed circuit is only 8.48[Formula: see text]mW at 25∘C.

A High-Speed Temperature Sensor with Low Supply Sensitivity for SoC Thermal Monitoring

2018 ◽  
Vol 27 (07) ◽  
pp. 1850116
Author(s):  
Yuanxin Bao ◽  
Wenyuan Li
Keyword(s):  
Temperature Sensor ◽  
Conversion Rate ◽  
High Speed ◽  
Supply Voltage ◽  
Ring Oscillator ◽  
Temperature Sensitive ◽  
Cmos Process ◽  
Digital Code ◽  
Thermal Monitoring ◽  
Worst Case

A high-speed low-supply-sensitivity temperature sensor is presented for thermal monitoring of system on a chip (SoC). The proposed sensor transforms the temperature to complementary to absolute temperature (CTAT) frequency and then into digital code. A CTAT voltage reference supplies a temperature-sensitive ring oscillator, which enhances temperature sensitivity and conversion rate. To reduce the supply sensitivity, an operational amplifier with a unity gain for power supply is proposed. A frequency-to-digital converter with piecewise linear fitting is used to convert the frequency into the digital code corresponding to temperature and correct nonlinearity. These additional characteristics are distinct from the conventional oscillator-based temperature sensors. The sensor is fabricated in a 180[Formula: see text]nm CMOS process and occupies a small area of 0.048[Formula: see text]mm2 excluding bondpads. After a one-point calibration, the sensor achieves an inaccuracy of [Formula: see text][Formula: see text]1.5[Formula: see text]C from [Formula: see text]45[Formula: see text]C to 85[Formula: see text]C under a supply voltage of 1.4–2.4[Formula: see text]V showing a worst-case supply sensitivity of 0.5[Formula: see text]C/V. The sensor maintains a high conversion rate of 45[Formula: see text]KS/s with a fine resolution of 0.25[Formula: see text]C/LSB, which is suitable for SoC thermal monitoring. Under a supply voltage of 1.8[Formula: see text]V, the maximum energy consumption per conversion is only 7.8[Formula: see text]nJ at [Formula: see text]45[Formula: see text]C.

Research and Analysis of a Portable Precision Temperature Sensor

2014 ◽  
Vol 945-949 ◽  
pp. 1924-1931
Author(s):  
Hai Qing Yao ◽  
Heng Cao ◽  
Fei Jiang ◽  
Bo Sun
Keyword(s):  
Temperature Sensor ◽  
Low Cost ◽  
Current Source ◽  
Control Unit ◽  
Constant Current ◽  
Interference Signal ◽  
Constant Current Source ◽  
Differential Signal ◽  
Precision Temperature ◽  
Micro Control Unit

Based on the excellent performance of Pt100, a portable low-cost precision temperature sensor has been designed, whose core chips are REF03, AD8603, AD7788 and precision resistors. Constant current source (CCS) for 4-wire Pt100 is constituted by REF03, AD8603 and precision resistors. AD7788 measures the differential signal on Pt100 and suppresses the common mode interference signal. Analysis software running on the micro control unit (MCU) filters the digital code from AD7788, and then calculates the current temperature value according to the resistance-temperature mathematical model of Pt100. Analysis and experimental results show that the temperature measurement accuracy of the sensor can reach ±1°C within the range of 0°C-650°C.

scholarly journals A CMOS-Thyristor Based Temperature Sensor with +0.37 °C/−0.32 °C Inaccuracy

Micromachines ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 124 ◽  
Author(s):  
Jing Li ◽  
Yuyu Lin ◽  
Siyuan Ye ◽  
Kejun Wu ◽  
Ning Ning ◽  
...  
Keyword(s):  
Power Consumption ◽  
Temperature Sensor ◽  
Current Source ◽  
Average Power ◽  
Bias Current ◽  
Cmos Process ◽  
Linear Temperature ◽  
Temperature Characteristics ◽  
Period Ratio ◽  
Average Power Consumption

This paper describes a voltage controlled oscillator (VCO) based temperature sensor. The VCOs are composed of complementary metal–oxide–semiconductor (CMOS) thyristor with the advantage of low power consumption. The period of the VCO is temperature dependent and is function of the transistors’ threshold voltage and bias current. To obtain linear temperature characteristics, this paper constructed the period ratio between two different-type VCOs. The period ratio is independent of the temperature characteristics from current source, which makes the bias current generator simplified. The temperature sensor was designed in 130 nm CMOS process and it occupies an active area of 0.06 mm2. Based on the post-layout simulation results, after a first-order fit, the sensor achieves an inaccuracy of +0.37/−0.32 °C from 0 °C to 80 °C, while the average power consumption of the sensor at room temperature is 156 nW.

The High-Power of DC Power with Auto Tracking Power Frequency

2011 ◽  
Vol 383-390 ◽  
pp. 321-324
Author(s):  
Gui Yin Yu
Keyword(s):  
Power Supply ◽  
Large Scale ◽  
Current Source ◽  
Control Voltage ◽  
Dc Power ◽  
Wide Range ◽  
Power Frequency ◽  
Voltage Frequency ◽  
The Common ◽  
Frequency Changes

This paper analyzes the reason that the common thyristor trigger is unable to fulfill power supply in wide range changes of frequency. The high precise frequency/voltage converter is used to monitor and track frequency changes of the simultaneous power supply. The simultaneous signal and charge current source are provided by the converter for saw tooth wave trigger. The frequency of saw tooth wave changes as the same time the frequency of power supply changes in wide range. However, the amplitude of the saw tooth wave can be kept constant. This can achieve the controlled angle of the thyristor trigger does not change with the large-scale voltage frequency changes of the simultaneous power supply when the same Phase-shifted control voltage was used.

Study on Electrical Automation with Design of Programmable Control Voltage/Current Source

2013 ◽  
Vol 703 ◽  
pp. 273-277
Author(s):  
Yu Wen Zhai ◽  
Wei Liu ◽  
Xiao Yang
Keyword(s):  
Current Source ◽  
Control Voltage ◽  
Signal Source ◽  
Digital Display ◽  
Dc Voltage ◽  
Standard Signal ◽  
Signal Amplifier ◽  
Dc Current

The design of programmable control voltage/current source based on MCU C8051F410 is introduced. The system mainly consists of D/A converter with PWM, voltage/current conversion circuit and digital display circuit. It can provide with DC voltage within the ranges of 0 to 200mV, 0 to 2V, -10V to +10V; and provide with DC current within the range of 4 to 20 mA. The programmable control voltage/current source can be used as the standard signal source for thermodynamic instrumentation, especially for the adjusting and testing for ADC or precise litter signal amplifier in the field of electrical automation.

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