Bandgap Voltage Reference With Second-Order MOS Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Standard bandgap voltage reference circuits face inaccuracies and noise due to temperature variations, particularly exacerbated by the second-order bow effect, which affects the accuracy of reference voltages generated in integrated circuits.
Innovation Solution
A bandgap circuit design that incorporates a first-order compensated bandgap unit and a second-order compensation circuit, utilizing metal oxide semiconductor (MOS) transistors and bipolar transistors, with a controllable current source and operational amplifiers, to generate a compensation voltage that reduces the second-order convex behavior, thereby improving temperature stability and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a standard bandgap voltage reference circuit is used, then reference voltage is generated, but temperature variations cause inaccuracies and second-order bow effect reduces accuracy
Solution Approach 1:
The patent changes the temperature dependency parameters of the bandgap circuit by adding compensation circuits that introduce opposite temperature coefficients. The first compensation circuit generates a voltage with negative temperature coefficient to counteract the positive temperature coefficient of the bandgap voltage, while the second compensation circuit addresses second-order temperature effects, thereby improving temperature stability and reference voltage accuracy across varying temperatures.
Solution Approach 2:
The patent introduces compensation voltages as intermediary elements that mediate between the temperature variations and the reference voltage output. These compensation voltages, generated through specific circuit configurations with bipolar and MOS transistors, act as intermediaries that cancel out the harmful temperature effects before they affect the final reference voltage, thus improving measurement precision without directly controlling temperature.
2Stability of the object's composition
If second-order bow compensation is added, then temperature stability improves, but circuit complexity increases
Solution Approach 1:
The patent segments the temperature compensation function into two distinct compensation circuits: a first compensation circuit for first-order temperature effects and a second compensation circuit for second-order temperature effects. This segmentation allows each circuit to be optimized independently and simplifies the overall design by dividing the complex compensation task into manageable modules, thereby improving temperature stability while controlling circuit complexity through functional decomposition.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed solution significantly enhances the temperature stability of bandgap voltage references, reducing errors and noise by up to a factor of three to ten, with minimal calibration requirements and applicability to various bandgap circuit architectures with minor modifications.
Implementation Method 1
the first MOS transistor is biased with an inverse proportional to absolute temperature (PTAT) voltage
Implementation Method 2
The proposed solution significantly enhances the temperature stability of bandgap voltage references
Data Source
Figure 1
Figure 2a
Figure 2b
AI summary
A bandgap circuit, comprising a first order compensated bandgap unit generating a first output voltage, and a second order compensation circuit adding a second output voltage to said first output voltage and comprising a first metal oxide semiconductor (MOS) transistor coupled in parallel with a first resistor, wherein the first MOS transistor is biased with an inverse proportional to absolute temperature (PTAT) voltage