• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.10
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• pp.425-430
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• 2003

A CMOS Voltage-Controlled Oscillator(VCO) for application at temperature stable system is designed. The VCO consists of bandgap voltage reference circuit, comparator, and voltage-to-current converter and the VCO has a temperature stable characteristics. The difference between simulated and calculated values is less than about 5% in output characteristics when the input voltage range is from 1V to 3.25V. The CMOS VCO has error less than about $\pm$0.85% in the temperature range from $-25^{\circ}C$ to $75^{\circ}C$.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.612-614
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• 2000

We propose a new curvature-compensated CMOS bandgap reference circuit that is achieved by varying a current ratio. The proposed circuit is shown to have small temperature coefficient that the output voltage variation is 0.4mV.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.229-229
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• 2004

• Transactions on Electrical and Electronic Materials
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• v.5 no.2
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• pp.71-75
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• 2004

This paper proposes a new bandgap reference (BGR) circuit which takes advantage of a cascode current mirror biasing to reduce the V$\_$ref/ variation, and sizing technique, which utilizes two related ratio numbers k and N, to reduce the PNP BJT area. The proposed BGR is designed and fabricated on a test chip with a goal to provide a reference voltage to the 10 bit A/D(4-4-4 pipeline architecture) converter of the CMOS Active Pixel Sensor (APS) imager to be used in X-ray imaging. The basic temperature variation effect on V$\_$ref/ of the BGR has a maximum delta of 6 mV over the temperature range of 25$^{\circ}C$ to 70$^{\circ}C$. To verify that the proposed BGR has radiation hardness for the X-ray imaging application, total ionization dose (TID) effect under Co-60 exposure conditions has been evaluated. The measured V$\_$ref/ variation under the radiation condition has a maximum delta of 33 mV over the range of 0 krad to 100 krad. For the given voltage, temperature, and radiation, the BGR has been satisfied well within the requirement of the target 10 bit A/D converter.

• Journal of information and communication convergence engineering
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• v.7 no.2
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• pp.215-218
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• 2009

In this paper, temperature stable current and voltage references using simple CMOS bias circuit are proposed. To obtain temperature stable characteristics of bias circuit a bandgap reference concept is used in a conventional circuit. The parasitic bipolar transistors or MOS transistors having different threshold voltage are required in a bandgap reference. Thereby the chip area increase or the extra CMOS process is required compared to a standard CMOS process. The proposed reference circuit can be integrated on a single chip by a standard CMOS process without the extra CMOS process. From the simulation results, the reference current variation is less than ${\pm}$0.44% over a temperature range from - $20^{\circ}C$ to $80^{\circ}C$. And the voltage variation is from - 0.02% to 0.1%.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.12
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• pp.59-65
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• 2004

A stable reference voltage generator is necessary to the infrared image signal readout circuit(ROIC) to improve noise characteristics of signal originated from infrared devices, that is, to gain good images. In this paper, bandgap circuit operating at cryogenic temperature of 77K for Infrared image ROIC(readout integrated circuit) was first made. It demonstrates practical use possibility through taking measurements and estimations. Bandgap circuit is a representative voltage reference circuit. Most of bandgap reference circuits which are presented so far operate at room temperature, and their characteristic are not suitable for infrared image ROIC operating at liquid nitrogen temperature, 77K. To design bandgap circuit operating at cryogenic temperature, suitable circuit is selected and the parameter characteristics of used devices as temperature change are seen by a theoretical study and fitted at liquid temperature with considering such characteristics. This circuit has been fabricated in the Hynix 0.6um standard CMOS process, and the output voltage measured shows that the stability is 1.042±0.0015V over the temperature range of 60K to 110K and is better than bandgap circuits operated at room temperature.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.375-378
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• 2013

A reference voltage generator which is insensitive to PVT (process-voltage-temperature) variation necessary for NVM memory IPs such as EEPROM and MTP memories is designed in this paper. The designed BGR (bandgap reference voltage) circuit based on MagnaChip's $0.18{\mu}m$ EEPROM process uses a low-voltage bandgap reference voltage generator of cascode current-mirror type with a wide swing and shows a reference voltage characteristic insensitive to PVT variation. The minimum operating voltage is 1.43V and the VREF sensitivity against VDD variation is 0.064mV/V. Also, the VREF sensitivity against temperature variation is $20.5ppm/^{\circ}C$. The VREF voltage has a mean of 1.181V and its three sigma ($3{\sigma}$) value is 71.7mV.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.4
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• pp.42-50
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• 2003

This paper presents an embedded RC oscillator which has temperature compensation circuits. The conventional RC oscillator has frequency deviation about 15%, which is caused by variation of resistors and the reference voltage of schmitt trigger from the temperature condition. In this paper, the proposed circuit use a CMOS bandgap reference having balanced current temperature coefficients as a triggering voltage of schmitt trigger. The constant current sources consist of current mirror circuit with the positive and negative temperature coefficient. The proposed circuit shows less 3% frequency deviation for variation of temperature, supply voltage and process parameters.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.6
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• pp.52-57
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• 2009

This paper presents a low-noise low-dropout linear regulator that is suitable for on-chip integration with RF transceiver ICs. In the bandgap reference, a stacked diode structure is adopted for saving silicon area as well as maintaining low output noise characteristic. Theoretical analysis for supporting the approach is also described. The linear regulator is fabricated in $0.18{\mu}m$ CMOS process. It operates with an input voltage range of 2.2 V - 5 V and provide the output voltage of 1.8 V and the output current up to 90 mA. The measured line and load regulation is 0.04%/V and 0.46%, respectively. The output noise voltage is measured to be 479 nV/$^\surd{Hz}$ and 186 nV/$^\surd{Hz}$ from 100 Hz and 1 kHz offset, respectively.

• Journal of IKEEE
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• v.20 no.2
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• pp.192-195
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• 2016

In this paper, we present a nanopower CMOS bandgap voltage reference working in sub-threshold region without resisters and bipolar junction transistors (BJT). Complimentary to absolute temperature (CTAT) voltage generator was realized by using two n-MOSFET pair with body bias circuit to make a sufficient amount of CTAT voltage. Proportional to absolute temperature (PTAT) voltage was generated from differential amplifier by using different aspect ratio of input MOSFET pair. The proposed circuits eliminate the use of resisters and BJTs for the operation in a sub-1V low supply voltage and for small die area. The circuits are implemented in 0.18um standard CMOS process. The simulation results show that the proposed sub-BGR generates a reference voltage of 290mV, obtaining temperature coefficient of 92 ppm/$^{\circ}C$ in -20 to $120^{\circ}C$ temperature range. The circuits consume 15.7nW at 0.63V supply.