scholarly journals A 0.026 mm2 Time Domain CMOS Temperature Sensor with Simple Current Source

Micromachines ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 899 ◽  
Author(s):  
Sangwoo Park ◽  
Sangjin Byun

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.

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 2053 ◽  
Author(s):  
Zhiwei Xu ◽  
Sangjin Byun

This paper presents a new type of time domain CMOS temperature sensor with a 9b successive approximation register (SAR) control logic and a fine delay line. We adopted an N-type poly resistor as the sensing element for temperature linearity. The chip was implemented in a standard 0.18 m 1P6M bulk CMOS process with general VTH transistors and the active die area was 0.432 mm2. The temperature resolution was 0.49 °C and the temperature error was from −1.6 to +0.6 °C over the range of 0 to 100 °C after two-point calibration. The supply voltage sensitivity was 0.085 °C/mV. The conversion rate was 25kHz and the energy efficiency was 7.2 nJ/sample.


2018 ◽  
Vol 27 (07) ◽  
pp. 1850116
Author(s):  
Yuanxin Bao ◽  
Wenyuan Li

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.


2018 ◽  
Vol 27 (13) ◽  
pp. 1830008
Author(s):  
Jin Wu ◽  
Pengfei Dai ◽  
Jie Peng ◽  
Lixia Zheng ◽  
Weifeng Sun

The fundamental theories and primary structures for the multi-branch self-biasing circuits are reviewed in this paper. First, the [Formula: see text]/[Formula: see text] and [Formula: see text]/[Formula: see text] structures illustrating the static current definition mechanism are presented, including the conditions of starting up and entering into a stable equilibrium point. Then, the AC method based on the loop gain evaluation is utilized to analyze different types of circuits. On this basis, the laws which can couple the branches of self-biasing circuits to construct a suitable close feedback loop are summarized. By adopting Taiwan Semiconductor Manufacturing Company (TSMC)’s 0.18[Formula: see text][Formula: see text]m complementary metal–oxide–semiconductor (CMOS) process with 1.8[Formula: see text][Formula: see text] supply voltage, nearly all the circuits mentioned in the paper are simulated in the same branch current condition, which is close to the corresponding calculated results. Therefore, the methods summarized in this paper can be utilized for distinguishing, constructing, and optimizing critical parameters for various structures of the self-biasing circuits.


Micromachines ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 124 ◽  
Author(s):  
Jing Li ◽  
Yuyu Lin ◽  
Siyuan Ye ◽  
Kejun Wu ◽  
Ning Ning ◽  
...  

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.


2018 ◽  
Vol 28 (02) ◽  
pp. 1950027 ◽  
Author(s):  
Dhara P Patel ◽  
Shruti Oza-Rahurkar

A novel tuning principle for simple gyrator-based CMOS active inductor (AI) circuit is presented. The method makes use of Widlar current source to enhance the quality factor. The simulation of the proposed AI provides a maximum quality factor of 1819 at 2.88[Formula: see text]GHz. The AI shows the inductive bandwidth of 1.66[Formula: see text]GHz to 3.16[Formula: see text]GHz and power consumption of 6.87[Formula: see text]mW. The other characterization factors such as linearity, supply voltage sensitivity and noise analysis are discussed. The performance of the tunable AI using Widlar current source are compared with the same using a simple current mirror. An AI using a conventional current mirror (CCM) and Widlar current source have been implemented in the 0.18[Formula: see text][Formula: see text]m CMOS technology.


2014 ◽  
Vol 556-562 ◽  
pp. 1842-1846
Author(s):  
Fang Ming Deng ◽  
Yi Gang He

This paper presents a capacitive humidity sensor in CMOS technology. The humidity sensor element is implemented in standard CMOS technology without any further post-processing, which results in low fabrication cost. The sensor interface is based on a delta-sigma converter and can be easily reconfigured to compensate for process variation of the sensing element. The proposed humidity sensor is fabricated in 0.16μm standard CMOS process and the chip occupies 0.25mm2. The measurement result shows that this humidity sensor acquires a resolution of 0.1%RH in the range of 20%RH to 90%RH. The interface achieves a 12.5-bits capacitance-to-digital conversion and consumes only 9.6μW power at 1.2V supply voltage.


2017 ◽  
Vol 26 (09) ◽  
pp. 1750127 ◽  
Author(s):  
Gongyuan Zhao ◽  
Mao Ye ◽  
Yiqiang Zhao ◽  
Kai Hu ◽  
Ruishan Xin

This paper presents a bandgap voltage reference (BGR), utilizing high order curvature-compensated technique with the temperature dependent resistor. Based on an improved error amplifier, [Formula: see text]80[Formula: see text]dB power supply rejection (PSR) @1[Formula: see text]kHz is achieved without additional complicated circuits. The circuit is fabricated in a standard [Formula: see text]m CMOS process, consuming 50[Formula: see text][Formula: see text]A at 25[Formula: see text]C with a supply voltage of 3.3[Formula: see text]V. Simulation results show that the proposed BGR can achieve a temperature coefficient as low as 1.18[Formula: see text]ppm/[Formula: see text]C over the temperature range from [Formula: see text]C to 120[Formula: see text]C. Monte Carlo simulation and Experimental Results validate the design.


Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6700
Author(s):  
Sangjin Byun

Time domain complementary metal-oxide-semiconductor (CMOS) temperature sensors estimate the temperature of a sensory device by measuring the frequency, period and/or delay time instead of the voltage and/or current signals that have been traditionally measured for a long time. In this paper, the time domain CMOS temperature sensors are categorized into twelve types by using the temperature estimation function which is newly defined as the ratio of two measured time domain signals. The categorized time domain CMOS temperature sensors, which have been published in literature, show different characteristics respectively in terms of temperature conversion rate, die area, process variation compensation, temperature error, power supply voltage sensitivity and so on. Based on their characteristics, we can choose the most appropriate one from twelve types to satisfy a given specification.


Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1063 ◽  
Author(s):  
Salvatore Pullano ◽  
Nishat Tasneem ◽  
Ifana Mahbub ◽  
Samira Shamsir ◽  
Marta Greco ◽  
...  

Extended-gate field-effect transistor (EGFET) is an electronic interface originally developed as a substitute for an ion-sensitive field-effect transistor (ISFET). Although the literature shows that commercial off-the-shelf components are widely used for biosensor fabrication, studies on electronic interfaces are still scarce (e.g., noise processes, scaling). Therefore, the incorporation of a custom EGFET can lead to biosensors with optimized performance. In this paper, the design and characterization of a transistor association (TA)-based EGFET was investigated. Prototypes were manufactured using a 130 nm standard complementary metal-oxide semiconductor (CMOS) process and compared with devices presented in recent literature. A DC equivalence with the counterpart involving a single equivalent transistor was observed. Experimental results showed a power consumption of 24.99 mW at 1.2 V supply voltage with a minimum die area of 0.685 × 1.2 mm2. The higher aspect ratio devices required a proportionally increased die area and power consumption. Conversely, the input-referred noise showed an opposite trend with a minimum of 176.4 nVrms over the 0.1 to 10 Hz frequency band for a higher aspect ratio. EGFET as a pH sensor presented further validation of the design with an average voltage sensitivity of 50.3 mV/pH, a maximum current sensitivity of 15.71 mA1/2/pH, a linearity higher than 99.9%, and the possibility of operating at a lower noise level with a compact design and a low complexity.


2011 ◽  
Vol 20 (04) ◽  
pp. 709-725 ◽  
Author(s):  
M. T. S. AB-AZIZ ◽  
A. MARZUKI ◽  
Z. A. A. AZIZ

This paper discusses a hybrid Digital-Analog Converter (DAC) architecture which is a combination of a binary-weighted resistor approach for eight bits in the least-significant-bit and thermometer coded approach for four bits in the most-significant-bit. The proposed design combines advantages of the binary-weighted resistor approach and thermometer coded approach. The final design is composed of two 12-bit DACs to achieve a pseudo differential output signal. The converter was designed with a Silterra 0.18 μm 1.8 V/3.3 V CMOS process technology. The post-layout simulation results show that this design achieves 12-bit resolution with INL and DNL of 0.375 LSB and 0.25 LSB, respectively. The power consumption is 6.291 mW when the designed DAC is biased with supply voltage equal to 3 V. The performance is accomplished with a design area of 230 μm × 255 μm.


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