Inductor Binning via DCR Excursion Tuning
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Solution Overview
Problem
The high cost and reduced availability of power regulators due to stringent specifications on inductors, which often lead to the discarding of components with DCR values outside tight tolerance ranges, resulting in increased waste and manufacturing costs.
Innovation Solution
By statistically analyzing the DCR values of inductors and using the excursion from a nominal value to tune the gain of the droop function in power regulators, allowing the use of inductors traditionally considered out of specification, thereby reducing costs and increasing part availability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stringent specification limits are applied to inductor DCR values, then voltage error specification is met, but component yield and availability decrease
Solution Approach 1:
The patent changes the parameter being monitored from fixed DCR values to DCR excursions (deviations from nominal values). By measuring and compensating for the excursion amount, the system can accommodate a wider range of inductor variations while maintaining voltage regulation accuracy, thus improving component yield without sacrificing reliability
Solution Approach 2:
The patent implements feedback by measuring the actual DCR excursion of each inductor and using this information to adjust the current sense scaling factor. This closed-loop approach allows the system to compensate for inductor variations dynamically, enabling the use of broader tolerance components while maintaining specification compliance
2Reliability
If tight DCR tolerance ranges are enforced, then system compatibility is ensured, but manufacturing costs increase
Solution Approach 1:
The patent shifts from specifying absolute DCR values to specifying maximum allowable excursions from nominal values. This parameter change allows manufacturers to produce inductors with broader tolerances at lower cost, while the system compensates for variations through measured excursion values, maintaining compatibility without stringent tolerance requirements
Solution Approach 2:
The system performs self-adjustment by automatically measuring the DCR excursion of each inductor and configuring the current sense scaling accordingly. This eliminates the need for manual calibration or selection of precision components, reducing manufacturing complexity and cost while ensuring system compatibility
3Reliability
If inductors outside specification are discarded, then quality control is maintained, but waste increases and availability decreases
Solution Approach 1:
The patent converts what was previously considered a defect (DCR variation outside tight tolerances) into useful information (measured excursion value). By utilizing the excursion measurement to adjust current sense scaling, the system transforms discarded components into acceptable parts, reducing waste while maintaining quality control through active compensation rather than passive rejection
4Measurement precision
If current sense scaling is adjusted based on DCR excursion, then accuracy is maintained with broader tolerance components, but device complexity increases
Solution Approach 1:
The patent adjusts the current sense scaling parameter based on measured DCR excursion values. This single parameter adjustment compensates for inductor variations and maintains measurement accuracy without requiring complex hardware modifications. The approach uses software or configuration-based tuning rather than additional analog components, minimizing complexity increase
Data Source
AI summary
An apparatus, comprising, a MOSFET, a controller coupled to the MOSFET, an inductor conductively coupled to the MOSFET. A reported current output of the controller is adjusted based on a predetermined excursion of an attribute of the inductor from a fixed attribute value.