Bandgap Voltage Reference Higher-Order Temperature Correction
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Solution Overview
Problem
Conventional bandgap voltage reference circuits fail to effectively correct for higher-order bandgap voltage variations at both higher and lower operating temperatures, often requiring multiple temperature trimming and lacking comprehensive nonlinear correction.
Innovation Solution
The implementation of low and high temperature correction circuits within the bandgap voltage reference circuit, which generate temperature-specific correction currents to adjust the output voltage, providing second-order correction across various temperature ranges, and utilizing a variable resistor for trimming at a single nominal temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional bandgap voltage reference circuits are used, then the circuit is simple and requires no correction circuits, but the bandgap voltage varies substantially at higher and lower temperatures outside the nominal temperature range
Solution Approach 1:
The temperature range is segmented into multiple zones (low temperature range, nominal temperature range, high temperature range), and different correction circuits are activated in each zone. The low temperature correction circuit is enabled when temperature is below a first threshold, the nominal range operates without correction, and the high temperature correction circuit is enabled when temperature exceeds a second threshold. This segmentation allows targeted correction for higher-order variations in specific temperature zones without unnecessarily complicating the circuit operation in the nominal range.
Solution Approach 2:
The correction circuits are dynamically enabled and disabled based on temperature conditions. Temperature sensing mechanisms detect the current temperature zone and activate the appropriate correction circuit accordingly. This dynamic approach allows the system to adapt its complexity to the operating conditions, providing necessary correction only when temperature deviations occur, thereby maintaining simplicity during normal operation while ensuring reliability under extreme conditions.
2Reliability
If existing bandgap voltage reference circuits attempt to correct for higher-order bandgap voltage variation at higher and/or lower operating temperatures, then the bandgap voltage stability improves, but trimming at multiple temperatures is required
Solution Approach 1:
The correction approach is segmented into temperature-specific correction circuits rather than a single comprehensive correction mechanism. The low temperature correction circuit handles higher-order variations in the low temperature range, while the high temperature correction circuit handles variations in the high temperature range. This segmentation allows each correction circuit to be optimized for its specific temperature zone, achieving effective correction across the full temperature range while simplifying the trimming process to a single nominal temperature calibration point.
Data Source
AI summary
Methods and apparatus for higher-order correction of bandgap voltage references are disclosed. An example bandgap voltage reference circuit disclosed herein comprises a bandgap voltage generation circuit comprising a first resistor, the bandgap voltage generation circuit configured to generate a proportional-to-absolute-temperature current to drive the first resistor to produce a first voltage, the first voltage contributing to an output bandgap voltage, and a first correction circuit electrically coupled to the first resistor and configured to provide a first correction current, the first correction circuit comprising a first nonlinear device configured to generate the first correction current only within a first temperature range, the first correction current decreasing with increasing temperature, the first correction current to drive the first resistor to increase the first voltage only within the first temperature range.