On-Chip Trim Circuit for Voltage Reference Auto-Trimming
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Solution Overview
Problem
Conventional trimming methods for on-chip reference voltage sources in integrated circuits are time-consuming due to the need for external voltage measurement, which requires long settling times and extensive use of tester resources.
Innovation Solution
An on-chip trim circuit compares the generated reference voltage against a target voltage, allowing for faster trimming by performing voltage comparisons internally and storing the trim code when the desired level is reached, reducing reliance on external tester resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional external voltage measurement is used for trimming, then measurement accuracy is ensured, but trimming time increases significantly due to long settling times
Solution Approach 1:
The patent extracts the voltage measurement function from the external tester and implements it internally within the integrated circuit using a dedicated on-chip comparator. This allows the trimming process to occur internally without waiting for external measurement settling, thereby reducing trimming time while maintaining measurement accuracy through the specialized comparator design.
Solution Approach 2:
The patent performs preliminary voltage comparison actions on-chip before final trimming completion. The comparator continuously monitors the reference voltage during the trimming process and provides immediate feedback, eliminating the need to wait for external measurement settling and enabling faster trim code determination.
2Reliability
If external tester resources are used for voltage measurement, then comprehensive testing is possible, but tester resource consumption increases
Solution Approach 1:
The patent implements self-service by incorporating an on-chip comparator that performs voltage measurements and trimming operations internally within the integrated circuit. This eliminates the need for external tester resources to perform routine voltage measurements during trimming, freeing up tester resources for other tasks and improving overall productivity while maintaining testing reliability.
Solution Approach 2:
The on-chip comparator serves multiple functions: it performs voltage comparison during trimming, validates reference voltage accuracy, and can be used for other on-chip measurements. This multi-functionality reduces reliance on external tester resources while maintaining comprehensive testing capability.
3Productivity
If on-chip voltage comparison is implemented, then trimming speed increases, but circuit complexity increases
Solution Approach 1:
The patent merges the voltage comparison function with the existing reference voltage generation circuitry by integrating a comparator directly on-chip. This consolidation allows the same circuit block to perform both reference voltage generation and comparison functions, increasing trimming speed while minimizing the increase in overall circuit complexity through shared infrastructure.
Solution Approach 2:
The on-chip comparator acts as an intermediary between the reference voltage source and the trim code storage, enabling fast internal voltage comparison and automatic trim code determination. This intermediary component facilitates high-speed trimming while maintaining modularity, so the added complexity is localized to a single functional block rather than propagating throughout the entire circuit.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly speeds up the trimming process and reduces the need for tester resources, enabling the integration circuit to generate a stable reference voltage efficiently during normal operation.
Implementation Method 1
a comparator configured to compare the reference voltage to a target voltage
Data Source
AI summary
A method to trim a reference voltage source formed on an integrated circuit includes configuring the integrated circuit in a test mode; providing a power supply voltage and a trim code sequence to the integrated circuit where the power supply voltage is provided by a precision reference voltage source; generating a target voltage on the integrated circuit using the power supply voltage; generate a reference voltage using the reference voltage source formed on the integrated circuit; applying one or more trim codes in the trim code sequence to the reference voltage source to adjust the reference voltage; comparing the reference voltage generated based on the trim codes to the target voltage; asserting a latch signal in response to a determination that the reference voltage generated based on a first trim code is equal to the target voltage; and storing the first trim code in response to the latch signal being asserted.