DUT Power Supply Auto-Tuning for Stable Loop Compensation
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Solution Overview
Problem
The complexity of tuning DUT Power Supply (DPS) instruments for High Density Modular Testers is high due to varying load and decoupling conditions, differing voltage and current ranges, and multiple load board variants, requiring manual tuning that is time-consuming and prone to human error, leading to costly re-tuning and stability issues.
Innovation Solution
An auto-tuning method using an optimization objective function and ADCs to measure and adjust loop compensation parameters, such as rise time, overshoot, settling time, and DC error, to optimize DUT power supply performance across different environments and configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual tuning methodology is used for DUT power supply, then human operators can adjust parameters, but the process becomes extremely time-consuming and prone to human error due to 6 degrees of freedom in type-3 compensators and nearly 100 combinations of test environments
Solution Approach 1:
The system performs self-tuning by automatically measuring performance metrics and adjusting compensator parameters without human intervention. The DPS instrument autonomously iterates through parameter combinations, measures outcomes, and converges on optimal settings, eliminating the need for manual tuning operations.
Solution Approach 2:
The system implements closed-loop feedback by continuously measuring performance metrics (such as transient response and steady-state accuracy) and using these measurements to guide parameter adjustments. The feedback mechanism enables the system to learn from each measurement and progressively improve tuning accuracy.
2Reliability
If manual tuning is performed across nearly 100 combinations of test environments and load board variants, then each configuration can be adjusted, but the iterative process takes multiple quarters to over a year to complete
Solution Approach 1:
The system achieves universal tuning capability that works across all test environments, load board variants, and DUT configurations through a single automated methodology. The same measurement and adjustment process adapts to different environments without requiring separate manual tuning procedures for each case.
Solution Approach 2:
The system performs preliminary characterization measurements in each environment to establish baseline performance metrics before optimization begins. This preliminary action enables the automated tuning to start from informed initial conditions rather than requiring exhaustive iterative searching.
3Ease of operation
If human operators perform the tuning task, then adjustments can be made to compensator parameters, but human error has led to sightings at High Volume Manufacturing requiring costly task forces and post-deployment retuning
Solution Approach 1:
The system replaces manual mechanical adjustment operations with automated electronic control. The automated system uses digital parameter setting and electronic adjustment mechanisms, eliminating the need for physical manual manipulation of compensator components and reducing human error.
Solution Approach 2:
The system performs self-verification by automatically checking whether tuned parameters meet performance specifications and repeating the tuning process if requirements are not satisfied. This self-service capability ensures consistent quality without relying on human operators to detect and correct errors.
Data Source
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AI summary
Methods and apparatus for auto tuning for tester DUT Power Supply (DPS). The DPS includes one or more voltage rail blocks that employ DUT voltage feedback and output a voltage rail that is supplied to a DUT on a load board. The voltage rail block includes an amplifier coupled to compensator circuitry, which in turn is coupled to an output control and driver block that outputs a voltage rail. I/O interfaces are provided to receive a voltage signal corresponding to the voltage rail at the DUT input, where the analog voltage signal is used as a DUT voltage feedback and a digitized voltage signal is used by a DPS controller that provides loop compensation parameters to adjust capacitor and resistors and gain in the compensator circuitry to tune the voltage rail to meet signal characteristics defined by an objective function such as voltage rise time, voltage overshoot, voltage undershoots, and settling time.