Performance characteristics and design of voltage references

Integrated circuits comprise the core of essentially all electronic systems. In the design of many integrated circuits, one task of the design engineer is to provide accurate voltages to sub blocks in the circuit structure. The circuits that provide these voltages are often referred to as voltage references. A widely used class of voltage references that typically have low supply, process, and temperature sensitivities are bandgap references whose output voltage is dominated by the bandgap voltage of silicon. Though several structurally different bandgap reference circuits are widely used in industry, there is little in the literature that focuses on how the performance of these circuits can be optimized or how the performance of different bandgap circuits compare. The task of optimization and comparison is complicated by the realization that each of the bandgap circuits themselves have several degrees of freedom in the design. In this work, a metric for fairly comparing the basic performance of different bandgap references based upon the normalized second-order temperature derivative is introduced. This metric is used to compare the performance of several of the most popular bandgap reference circuits that are used in the production. The comparisons show that even though the structure of these reference circuits are fundamentally different and even though each circuit has several degrees of design freedom, the normalized temperature coefficients of all circuits in the comparison group at a fixed operating temperature are the same. The comparisons also show that the designer cannot optimize the basic performance of any of these circuits through judicious utilization of the degrees of design freedom. In this work, a new very low power voltage reference obtained by replacing the diode-connected bipolar transistors in a basic bandgap circuit with diode-connected MOS transistors operating in deep weak inversion is also discussed. An analytical formulation of the weak-inversion MOS voltage reference shows that the MOSFET-based structure has even lower temperature sensitivity than the basic bandgap circuits. The issue of practicality of the MOS-based reference is, however, of concern since the extremely low currents appear to create the need for very large resistors which are not realistically available in most standard CMOS processes

Precise voltage references

Cieľom práce je realizácia pracoviska pre meranie dlhodobej stability a teplotného koeficientu precíznych napäťových referencií. Analyzuje riešenia jednotlivých precíznych napäťových referencií a ich dôležitých parametrov z hľadiska stability referenčného napätia. Zaoberá sa vplyvom termoelektrických napätí a metódami ich minimalizácie V závere navrhuje riešenie meracieho pracoviska a vyhodnocuje získané výsledky merania dlhodobej stability a teplotného koeficientu na vybraných precíznych napäťových referenciách.The aim of this thesis is the realization of the workplace to measure long-term stability and temperature coefficient of precision voltage references. It analyses individual solutions precision voltage references and their important parameters for the stability of the reference voltage. It deals with the influence of thermoelectric voltages and methods how to minizme their effect on measurement error . In conclusion it proposes a solution of this measuring workplace, and evaluate the results measuring of long-term stability and temperature coefficient on selected precision voltage references.

Distributed Generation as Voltage Support for Single Wire Earth Return Systems

Key issues for distributed generation (DG) inclusion in a distribution system include operation, control, protection, harmonics, and transients. This paper analyzes two of the main issues: operation and control for DG installation. Inclusion of DG in distribution networks has the potential to adversely affect the control of voltage. Both DG and tap changers aim to improve voltage profile of the network, and hence they can interact causing unstable operation or increased losses. Simulations show that a fast responding DG with appropriate voltage references is capable of reduction of such problems in the network. A DG control model is developed based on voltage sensitivity of lines and evaluated on a single wire earth return (SWER) system. An investigation of voltage interaction between DG controllers is conducted and interaction-index is developed to predict the degree of interaction. From the simulation it is found that the best power factor for DG injection to achieve voltage correction becomes higher for high resistance lines. A drastic reduction in power losses can be achieved in SWER systems if DG is installed. Multiple DG can aid voltage profile of feeder and should provide higher reliability. Setting the voltage references of separate DGs can provide a graduated response to voltage correction

Аналіз впливу роботи пристроїв контактної зварки на параметри напруги мережі

Three fully integrated bandgap voltage references (BGVRs) have been demonstrated in a 4H-SiC bipolar technology. The circuits have been characterized over a wide temperature range from 25 degrees C to 500 degrees C. The three BGVRs are functional and exhibit 46 ppm/degrees C, 131 ppm/degrees C, and 120 ppm/degrees C output voltage variations from 25 degrees C up to 500 degrees C. This letter shows that SiC bipolar BGVRs are capable of providing stable voltage references over a wide temperature range.QC 20160311HOTSi

Analysis of total ionizing dose effects on 0.13 µm technology-temperature-compensated voltage references

ABSTRACT: The purpose of this work is to briefly discuss the effects of the total ionizing dose (TID) on MOS devices in order to estimate the results of future irradiation tests on temperature-compensated voltage references that are implemented on a mixed-signal chip fabricated using IBM 0.13 µm technology. The analysis will mainly focus on the effects of the parametric variations on different voltage references. Monte-Carlo analyses were performed in order to determine the effects of threshold voltage shifts in each transistor on the output voltage

A system-on-chip digital pH meter for use in a wireless diagnostic capsule

This paper describes the design and implementation of a system-on-chip digital pH meter, for use in a wireless capsule application. The system is organized around an 8-bit microcontroller, designed to be functionally identical to the Motorola 6805. The analog subsystem contains a floating-electrode ISFET, which is fully compatible with a commercial CMOS process. On-chip programmable voltage references and multiplexors permit flexibility with the minimum of external connections. The chip is designed in a modular fashion to facilitate verification and component re-use. The single-chip pH meter can be directly connected to a personal computer, and gives a response of 37 bits/pH, within an operating range of 7 pH units

Components for the LISA local interferometry

This article describes some preliminary results on essential components for the LISA interferometry, namely photodiode preamplifiers and voltage references

An analog cell to detect single event transients in voltage references

A reliable voltage reference is mandatory in mixed-signal systems. However, this family of components can undergo very long single event transients when operating in radiation environments such as space and nuclear facilities due to the impact of heavy ions. The purpose of the present paper is to demonstrate how a simple cell can be used to detect these transients. The cell was implemented with typical {COTS} components and its behavior was verified by {SPICE} simulations and in a laser facility. Different applications of the cell are explored as well