Bandgap Voltage Reference Compensation for Temperature Drift
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Solution Overview
Problem
Analog circuits, such as voltage reference circuits, suffer from offset error and offset drift due to component mismatches, which are exacerbated by temperature variations, leading to operational issues.
Innovation Solution
The implementation of a temperature compensation circuit that uses resistive digital-to-analog converters to generate a temperature compensation voltage, which is fed back to the bandgap circuit to adjust the output voltage, reducing low frequency noise and maintaining low power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If temperature compensation circuits are implemented to correct offset drift, then offset drift is reduced, but device complexity increases
Solution Approach 1:
The patent implements temperature compensation by feeding back a compensation voltage generated from temperature-dependent voltage sources (PTAT and CTAT) through resistive digital-to-analog converters to the bandgap circuit output. This feedback mechanism dynamically adjusts the output voltage to counteract temperature-induced offset drift, resolving the contradiction between reliability improvement and complexity increase by using a systematic feedback approach rather than static compensation.
Solution Approach 2:
The patent changes the electrical parameters of the circuit by utilizing temperature-dependent voltage sources whose characteristics vary with temperature. The PTAT voltage increases with temperature while CTAT voltage decreases, and by adjusting their weighted combination through programmable resistive DACs, the circuit parameters are dynamically modified to compensate for offset drift, thereby improving reliability without requiring fundamentally new circuit topologies.
2Object-generated harmful factors
If resistive digital-to-analog converters are used to generate temperature compensation voltage, then low frequency noise is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent uses resistive digital-to-analog converters that create precise voltage copies and weighted combinations of reference voltages through resistor networks. The resistive DACs generate accurate proportional relationships between different voltage sources by copying and scaling reference voltages with high precision, which reduces low frequency noise while the programmable nature allows post-manufacturing trimming to compensate for resistor matching variations.
Solution Approach 2:
The resistive digital-to-analog converters serve multiple functions: they generate temperature compensation voltage, provide programmable weighting of PTAT and CTAT components, and enable digital control of the compensation amount. This multi-functionality reduces the need for additional dedicated noise-filtering circuits, thereby reducing low frequency noise while managing manufacturing precision requirements through integrated design.
3Reliability
If temperature compensation voltage is provided to the bandgap circuit, then offset drift is minimized, but power consumption increases
Solution Approach 1:
The patent implements temperature compensation that operates continuously but with variable intensity based on temperature conditions. The compensation voltage is generated and applied periodically as temperature changes occur, rather than at maximum level continuously. The programmable resistive DACs allow the compensation amount to be adjusted based on actual temperature drift conditions, reducing power consumption when minimal compensation is needed while maintaining offset drift minimization when temperature variations are significant.
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
This solution effectively reduces low frequency noise and minimizes offset drift across temperature variations while maintaining low power consumption, enhancing the stability and accuracy of voltage reference circuits.
Implementation Method 1
The first resistive digital-to-analog converter is configured to generate a temperature compensation voltage, and to provide the temperature compensation voltage to the bandgap circuit
Implementation Method 2
The generating includes setting a first resistive digital-to-analog converter to produce a weighted sum of a voltage proportional to absolute temperature and a voltage complementary to absolute temperature
Implementation Method 3
The generating includes setting a first resistive digital-to-analog converter to produce a weighted sum of a voltage proportional to absolute temperature and a voltage complementary to absolute temperature
Data Source
AI summary
A voltage reference circuit includes a bandgap circuit and a temperature compensation circuit. The temperature compensation circuit includes a first trim circuit, a second trim circuit, and a resistive digital-to-analog converter. The resistive digital-to-analog converter is coupled to the first trim circuit, the second trim circuit, and the bandgap circuit. The resistive digital-to-analog converter is configured to generate a temperature compensation voltage, and to provide the temperature compensation voltage to the bandgap circuit.