Trimming Code Voltage Generator for Nonvolatile Memory Testing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Nonvolatile semiconductor memories face challenges in testing due to supply voltage dependency of drive voltages, making it difficult to control drive voltages without changing the supply voltage, especially in burn-in tests where voltage control is limited.
Innovation Solution
Incorporating a voltage generator circuit that uses trimming codes to adjust drive voltages, with test trimming codes used only during testing to recreate supply voltage dependency without actual voltage changes, allowing for controlled drive voltage application in nonvolatile semiconductor memory testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the supply voltage is changed to adjust drive voltage, then the drive voltage control is improved, but the testing cost and complexity increase
Solution Approach 1:
The patent introduces trimming codes as an intermediary mechanism between the fixed supply voltage and the required drive voltage. The voltage generator circuit uses these trimming codes to adjust the drive voltage output without changing the supply voltage, thereby resolving the contradiction between easy voltage control and system complexity.
Solution Approach 2:
The patent changes the parameter being controlled from supply voltage to drive voltage through the voltage generator circuit. By using trimming codes to adjust the drive voltage while keeping the supply voltage fixed, the system achieves voltage control capability without the complexity of variable supply voltage testing equipment.
2Device complexity
If the supply voltage is kept fixed, then the testing cost is reduced, but the drive voltage cannot be adjusted
Solution Approach 1:
The voltage generator circuit acts as an intermediary that decouples the relationship between fixed supply voltage and adjustable drive voltage. It accepts the fixed supply voltage input and produces adjustable drive voltage output based on trimming codes, maintaining simplicity while enabling adaptability.
Solution Approach 2:
The patent creates a virtual supply voltage dependency by using trimming codes to simulate different supply voltage conditions. Instead of actually changing the supply voltage, the system copies the effect of voltage variation through the voltage generator circuit's response to different trimming codes.
3Device complexity
If stress levels are not properly controlled, then testing is simpler, but defective chips are misidentified
Solution Approach 1:
The patent implements feedback control through the voltage generator circuit that monitors and adjusts the drive voltage based on trimming codes. This ensures that the appropriate stress levels are applied during testing, improving the reliability of chip quality assessment while maintaining a relatively simple testing process.
Data Source
AI summary
A nonvolatile semiconductor memory, includes a nonvolatile memory array, a voltage generator circuit that generates a drive voltage which changes depending on a supply voltage and a code, a control circuit that applies the generated drive voltage to the nonvolatile memory array, and a code output circuit that outputs any one of a plurality of codes to the voltage generator circuit, wherein the plurality of codes includes a first code and a second code, wherein the second code is different from the first code, wherein, in a first state, the code output circuit outputs the first code to the voltage generator circuit, and the voltage generator circuit generates the drive voltage according to the first code, and wherein, in a second state, the code output circuit outputs the second code to the voltage generator circuit, and the voltage generator circuit generates the drive voltage according to the second code.