Power Source Error Detection for Stable DUT Voltage Correction
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Solution Overview
Problem
Conventional Kelvin sense correction methods for power sources can lead to instability in control loops and require interrupting testing to update compensation, which is inconvenient and potentially damaging.
Innovation Solution
The method employs separate sensing and source pathways to determine and correct voltage drops without direct use of sensed voltage, creating a stable control loop that operates independently and allows for periodic updates, preventing damage from erroneous sense lead issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional Kelvin sense correction is used to accurately sense voltage at the device under test, then voltage measurement precision is improved, but control loop stability deteriorates
Solution Approach 1:
The patent segments the control loop into two separate loops: a fast local control loop that maintains stability by operating independently at the power source, and a separate sensing pathway that measures voltage at the device under test without directly closing the control loop. This segmentation allows high-precision voltage sensing while preventing the instability that would result from feeding sensed voltage directly back into the control loop.
2Measurement precision
If electrical short is used to update compensation factor, then voltage sensing accuracy is improved, but productivity deteriorates due to testing interruptions
Solution Approach 1:
The patent performs preliminary characterization of the device under test during manufacturing or initial setup, storing compensation factors in a lookup table. During actual testing, the system simply retrieves the pre-determined compensation factor based on the device identifier, eliminating the need to interrupt testing for real-time compensation updates while maintaining high voltage sensing accuracy.
3Measurement precision
If electrical short is used to check compensation, then voltage correction accuracy is improved, but reliability deteriorates due to potential damage from misconnected sense leads
Solution Approach 1:
The patent implements preliminary error checking that detects misconnected sense leads before compensation is applied. The system monitors for erroneous voltage readings and prevents the application of compensation factors when sense lead errors are detected, thereby protecting the device under test from potential damage while maintaining accurate voltage correction when connections are proper.
4Manufacturing precision
If sensed voltage is used directly for control loop adjustment, then manufacturing precision is improved, but stability deteriorates causing potential damage to device under test
Solution Approach 1:
The patent introduces an intermediary lookup table that stores pre-determined compensation factors. Instead of directly using sensed voltage to adjust the control loop, the system uses the sensed voltage to index into the lookup table and retrieve the appropriate compensation factor. This intermediary mechanism allows precise voltage sourcing while preventing the instability that would result from direct feedback control.
Data Source
AI summary
A voltage source device, including a first voltage source configured to output a first voltage, source pathways to connect the first voltage source to a device under test, sensing pathways electrically coupled to the device under test; and circuitry configured to sample a second voltage at the device under test, determine a voltage difference between the first voltage and the second voltage, and adjust the first voltage based on the difference between the first voltage and the second voltage.