Bandgap Voltage Reference Calibration for Low-Ripple Accuracy
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Solution Overview
Problem
Existing bandgap voltage reference circuits suffer from accuracy loss due to age-related effects and dynamic element matching, leading to voltage ripple and intermodulation interferences.
Innovation Solution
A device comprising a PTAT switching circuit, a CTAT switching circuit, and a current-bias circuit with a calibration circuit to maintain a target ratio of currents through diode elements, minimizing errors and voltage ripple.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dynamic element matching is used to compensate for current source deviations, then accuracy is improved, but voltage ripple and intermodulation interferences occur
Solution Approach 1:
The patent applies periodic action by using alternating current paths in a systematic sequence. Multiple current paths are activated in periodic cycles, with each path being used for a defined duration. This periodic activation pattern allows the system to average out deviations while maintaining a stable overall current ratio, thereby reducing voltage ripple compared to random or arbitrary switching patterns.
Solution Approach 2:
The patent implements preliminary action through a calibration circuit that pre-adjusts current source parameters before normal operation. The calibration circuit sets initial current ratios to target values and compensates for manufacturing variations and age-related effects in advance. This preliminary calibration ensures that subsequent dynamic element matching operates from an accurate baseline, improving reference voltage accuracy while minimizing the magnitude of adjustments needed during operation.
2Stability of the object's composition
If current ratios are fixed to achieve precise reference voltage, then voltage stability is improved, but age-related effects cause accuracy loss over time
Solution Approach 1:
The patent applies dynamics by transitioning from fixed current ratios to dynamically adjustable current paths. The system uses switching circuits to alternately activate different current paths, allowing the current distribution to adapt over time. This dynamic approach enables the system to compensate for age-related drift in individual current sources while maintaining the overall current ratio, thereby preserving long-term accuracy without sacrificing short-term stability.
Solution Approach 2:
The patent implements feedback through a calibration circuit that monitors and adjusts current source parameters. The calibration circuit continuously or periodically checks the actual current ratios against target values and applies corrective adjustments. This feedback mechanism compensates for age-related effects and other drift phenomena, ensuring that the reference voltage maintains both short-term stability and long-term accuracy.
3Measurement precision
If multiple current sources are alternately utilized to compensate deviations, then current ratio accuracy is improved, but current path switching complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the current source system into multiple independent current paths, each with its own switching control. Instead of using a single complex current source, the system segments the current generation into several simpler parallel paths that can be independently activated. This segmentation simplifies the switching logic for each individual path while achieving improved current ratio accuracy through the combined effect of multiple paths.
Data Source
AI summary
A device for providing a bandgap voltage reference. The device comprises a first switching circuit for providing a first temperature voltage which behaves proportionally to a present temperature, wherein the first switching circuit has two parallel current paths, first and second diode elements being respectively arranged in first and second current paths of the parallel current paths, a second switching circuit for providing a second temperature voltage which behaves in a complementary manner relative to the present temperature, a control circuit which is designed to control a voltage difference between the parallel current paths of the first switching circuit, and a current-bias circuit which is designed to control a ratio of a flow of current through the first diode element to a flow of current through the second diode element, the current-bias circuit comprising a calibration circuit which sets the ratio to a target value.