Ultra-high precision bandgap voltage reference using a novel current trimming technique

A low dropout (LDO) voltage regulator with high power supply rejection ratio (PSRR) and low temperature coefficient (TC) is presented in this paper. Large 1µF off-chip load capacitor is used to achieve the high PSRR. However, this decreases the gain and pushes the LDO’s output pole to lower frequency causing the circuit to become unstable. The proposed LDO uses rail-to-rail folded cascode amplifier to compensate the gain and stability problems. 2nd order curvature characteristic is used in bandgap voltage reference circuit that is applied at the input of the amplifier to minimize the TC. The characteristic is achieved by implementing MOSFET transistors operate in weak and strong inversions. The LDO is designed using 0.18µm CMOS technology and achieves a constant 1.8V output voltage for input voltages from 3.2V to 5V and load current up to a 128mA at temperature between -40°C to 125°C. The proposed LDO is targeted for RF application which has stringent requirement on noise rejection over a broad range of frequency.

In this paper, a Bandgap reference (BGR) with high power supply rejection ratio (PSRR) and low temperature coefficient (TC) is presented. On the basis of first-order temperature-compensated BGR, a complementary curvature-compensation technique (CCCT) is realized by using the saturation region current characteristics of PMOS transistors with proportional to absolute temperature (PTAT) bias voltage. Besides, in addition to the effect of cascode structure and the isolation of the current amplifier, the PSRR of proposed BGR is further improved by adopting self-bias power supply with feedback. The presented BGR is implemented in a standard 0.35 μm BCD process. The post-simulation results show that the TC of the BGR is 4.740 ppm/∘C with a 2.50V average output voltage, and the PSRR is up to -78.5dB.

The design of CMOS bandgap voltage references focusing on high accuracy and low temperature coefficient methodologies is discussed in this paper. Several solutions of total bandgap voltage reference error minimization are considered. As a summary it is proposed bandgap voltage reference with output voltage accuracy 1.2V ± 0.08% in temperature range -40...125°C.

Design analysis of CMOS bandgap voltage references focusing on high accuracy and low temperature coefficient methodologies and structures are discussed in this paper. Some wide temperature range bandgap voltage reference circuits are included and analysed. Several solutions for total bandgap voltage reference error minimization are proposed. A proposed bandgap voltage reference with output voltage accuracy 1.2V plusmn 0.35% over the temperature range of -40 to 125degC

Studies on use of lead iron tungstate-lead titanate relaxor binary system as a pressure sensing material

A novel high-order curvature-compensated CMOS bandgap voltage reference (BGR) is proposed in CSMC 0.5μm CMOS process. By adding a piecewise-curvature current in the low temperature region and a piecewise-curvature current in the high temperature region to a conventional BGR, the proposed high-order curvature-compensated BGR achieves a reference voltage with lower temperature coefficient (TC). Simulation results show that the TC of the proposed high-order curvature-compensated BGR is only 0.62ppm/°C while the TC of the conventional BGR is about 2.82ppm/°C. The proposed high-order curvature-compensated BGR achieves the power supply rejection ratio (PSRR) of −53.98dB, −53.97dB, −52.84dB, −39.097dB and −21.75dB at 10Hz, 1kHz, 10kHz, 100kHz and 1MHz respectively.

Ultra-low-power (ULP) sensor technologies for the future internet of things have presented challenges in ULP implementation of reference circuits while keeping traditional requirements of stable performance. For voltage reference circuits, as an essential block in SoCs to generate various internal supply voltages, the bandgap voltage-reference (BGVR) scheme has been widely used since it provides a well-defined value with strong immunity to process/voltage/temperature variations. Nanowatt-consuming BGVR circuits have been recently proposed using a capacitor network [4] and a leakage-based proportional-to-absolute-temperature (PTAT) circuit [5]. On the other hand, the current reference circuit that is required to set internal bias current still presents difficulties in achieving both stable performance and ULP consumption. The general approach to building a current reference is to use a BGVR with additional resistors for V-to-I conversion. Though it can provide a well-defined stable current reference, it also requires excessively large resistance for ULP consumption. Another approach is a CMOS-based current reference circuit that tries to make the exponential term in the subthreshold current equation constant or temperature-independent, hence reducing process and temperature dependencies. While CMOS reference circuits have achieved ULP implementations, the current is still determined by a number of process and design parameters, resulting in large sensitivity to process variations. This paper presents a sub-10nW bandgap-reference (BGR) circuit that implements both voltage and current references in one circuit. The BGR circuit is implemented with a 0.18µm CMOS process and generates voltage and a current references of 1.238V and 6.64nA while consuming 9.3nW. The voltage and current references show standard deviations of 0.43% and 1.19% with temperature coefficients of 26ppm/°C and 283ppm/°C, respectively.

A novel bandgap reference (BGR) with low temperature and supply voltage sensitivity without any resistor, which is compatible with standard CMOS process, is presented in this article. The proposed BGR utilises a differential amplifier with an offset voltage proportional to absolute temperature to compensate the temperature drift of emitter–base voltage. Besides, a self-biased current source with feedback is used to provide the bias current of the BGR core for reducing current mirror errors dependent on supply voltage and temperature further. Verification results of the proposed BGR implemented with 0.35 µm CMOS process demonstrate that a temperature coefficient of 10.2 ppm/°C is realised with temperature ranging from −40°C to 140°C, and a power supply rejection ratio of 58 dB is achieved with a maximum supply current of 27 µA. The active area of the presented BGR is 160 × 140 µm2.

This paper presents a high-precision, low temperature coefficient (TC) CMOS bandgap reference for high-performance multi-channel ADC working under wide temperature range. A piecewise curvature compensation technique is proposed to extend its operating temperature range and keep its low temperature coefficient. A s-compensation technique is used to cancel the PTAT and non-PTAT spread of the output due to variation of β in the BJTs. Moreover, the trimming resistors are implemented to calibrate the 1st-order temperature coefficient and absolute value of the output voltage. The bandgap reference designed in 0.18μm CMOS process has a super low temperature coefficient of 2.1ppm/°C over a wide temperature of −55 ° C to 140 ° C, making it appropriate to provide reference voltage for a high-precision ADC.

A high-precision triaxial fluxgate sensor for space applications: layout and choice of materials

In order to meet the market demand for wide temperature range and high precision bandgap voltage reference, this paper designs a bandgap reference with wide temperature range and low temperature coefficient. In this paper, the basic implementation principle of the bandgap reference is analyzed.On the basis of the traditional bandgap reference circuit structure,this design adds a trimming network and a temperature compensation network. A new Gaussian bell curve compensation technique is adopted to compensate the low temperature section, and the normal temperature section and the high temperature section respectively. Compared with the existing compensation technology, the versatility and the compensation effect is better. The designed circuit is designed and manufactured based on the Huahong HHNECGE0.35um process. The results show that the output voltage is 2.5V at 2.7V supply voltage and temperature range of -40-125°C.at typical process angle ,the temperature coefficient is 0.54618 PPm/°C,and is within 1PPm/°C at other process angles.

Sputtered layers featuring high area resistance and low temperature coefficient : J. Mirovsky. TESLA Electron. 2/72, p. 52

By using 0.35-um CMOS process, this work achieves a design of analogous band-gap reference voltage circuit with low temperature coefficient. The proposed circuit operates at 3V and generates a reference current of 44 uA. The HSPICE simulation results show the temperature coefficient of this circuit is 23 ppm/°C at range of -10 °C to 100 °C, and the line regulation (the ratio of output current variation to supply voltage variation) is estimated as 1.95 uA/V from supply voltage variation of 3 V to 5 V. The experimental chip is fabricated and measured. The circuit provides adjustable capability for output voltage among temperature variation of -10 - 100 °C. The chip area is 534 × 695 um2. In this new design, the operational amplifier is not necessary. The chip design effort can be great reduced.

A high-order curvature-compensated CMOS bandgap reference (BGR) topology with a low temperature coefficient (TC) over a wide temperature range and a high power supply reject ratio (PSRR) is presented. High-order correction is realized by incorporating a nonlinear current INL, which is generated by ∆VGS across resistor into current generated by a conventional first-order current-mode BGR circuit. In order to achieve a high PSRR over a broad frequency range, a voltage pre-regulating technique is applied. The circuit was implemented in CSMC 0.5 μm 600 V BCD process. The experimental results indicate that the proposed topology achieves TC of 0.19 ppm/°C over the temperature range of 165 °C (−40 to 125 °C), PSRR of −123 dB @ DC and −56 dB @ 100 kHz. In addition, it achieves a line regulation performance of 0.017%/V in the supply range of 2.8–20 V.

To improve the self-ignition capability of oil reservoirs and build a detailed reaction kinetics mechanism of in situ combustion (ISC), ignition and reaction characteristics of light fractions of crude oil (boiling point of <100 °C, 100–125 °C, 125–150 °C, 150–175 °C, 175–200 °C, and 200–225 °C) were investigated on a rapid compression machine at compressed pressures of 20 bar and a compressed temperature range of 660–900 K, with a stoichiometric ratio of 1.0. According to our analysis with a gas chromatography–mass spectrometry instrument (GC-MS), cyclohexane, methyl-cyclohexane, p-xylene, and mesitylene were selected as surrogate fuels and were tested under the same conditions on a rapid compression machine (RCM). The experimental results show that three groups of light fractions, <100 °C, 100–125 °C, and 175–200 °C, display strong reactions at low and high temperatures and negative temperature coefficient (NTC) behavior. These phenomena imply that these reactive components can be used as possible promoters to accelerate the development of an ISC project and to improve the reaction speed of the entire process. Two groups of 125–150 °C and 200–225 °C fractions are difficult to ignite in the low-to-medium temperature range under the compressed pressure of 20 bar, but they can be ignited at relatively higher top dead center (TDC) temperature ranges under the compressed pressure of 30 bar. Moreover, the logarithm of ignition delays and the reciprocal temperature clearly show a linear relationship, meaning that the reactivity of these two groups is poor. The results obtained with these surrogate fuels match well with the experimental results of each light fraction.