Bandgap Reference Circuit Using Correction Currents for Wide Temperature Range
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Solution Overview
Problem
Reference voltage generators, particularly bandgap reference circuits, face significant variations in output voltage across extended temperature ranges, limiting their operational effectiveness from 0°C to 70°C and beyond.
Innovation Solution
The introduction of correction currents, generated by current synthesizers, is applied to bandgap reference circuits to extend the operating temperature range by compensating for temperature-induced voltage fluctuations, using CTAT and PTAT characteristics to maintain a stable reference voltage across a broader temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If bandgap reference circuits are used to generate reference voltage, then voltage stability is improved, but operating temperature range is limited
Solution Approach 1:
The patent applies parameter changes by introducing correction currents with specific temperature coefficients (CTAT and PTAT) to compensate for the temperature-dependent variations in the bandgap reference voltage. By adjusting the magnitude and temperature characteristics of these correction currents, the overall reference voltage stability is maintained across an extended temperature range while preserving the inherent voltage stability of the bandgap circuit.
2Temperature
If correction currents are added to extend temperature range, then operating temperature range is improved, but circuit complexity increases
Solution Approach 1:
The patent uses correction currents as intermediary elements to bridge the gap between the bandgap reference circuit and the extended temperature range requirement. These correction currents act as mediators that compensate for temperature-induced voltage variations without requiring fundamental changes to the core bandgap reference architecture, thereby extending the operating temperature range while limiting complexity growth.
Solution Approach 2:
The patent segments the temperature compensation function into separate correction current paths with different temperature coefficients (CTAT and PTAT components). This segmentation allows independent optimization of each correction path and enables modular implementation, extending the temperature range while managing 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
This approach effectively reduces voltage variations, allowing reference voltage generators to maintain a stable output from -40°C to 125°C, with variations of less than 1 mV across the extended range, enhancing the operational reliability and flexibility of electronic circuits.
Implementation Method 1
A bandgap reference circuit based on the bandgap voltage characteristics of PN junctions in PN junction devices, like diodes and transistors
Implementation Method 2
using CTAT and PTAT characteristics to maintain a stable reference voltage across a broader temperature range
Data Source
AI summary
A reference voltage circuit includes a first circuit including a first PN junction device and a first resistor connected in series between a power supply node and a first node, and a second resistor connected between the first node and an intermediate node, and a third resistor connected between the intermediate node and a reference voltage output node, and a second circuit including a second PN junction device connected between the power supply node and a second node and a fourth resistor connected between the second node and the intermediate node. A feedback current causes voltage across the first resistor to offset changes in voltage across the first PN junction device. A correction current is applied to boost and or sink current in the voltage reference generator to extend the operating temperature range.