ADC Switch Testing Using Digital Signals for Full Coverage
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Solution Overview
Problem
Conventional testing methods for analog-to-digital converters (ADCs) are time-consuming, requiring several hours to complete, leading to partial testing during manufacturing, which does not guarantee failure-free operation, as only a limited set of conversion codes are tested.
Innovation Solution
The development of an ADC configuration that enables rapid testing of all circuit elements using a digital test signal to activate switches, bypassing analog-to-digital conversion, and applying a test voltage to a resistive network to determine switch functionality, allowing for complete testing in seconds or less without the need for numerous accurate analog voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complete testing of all circuit elements in ADC is performed using conventional analog testing techniques, then testing coverage is improved, but testing time increases prohibitively
Solution Approach 1:
The patent replaces the conventional analog testing system with a digital testing system. A digital test input receives digital test signals that activate control logic (such as successive approximation register control logic) to control the switches, eliminating the need for discrete analog voltage levels and significantly reducing testing time while maintaining complete testing coverage
Solution Approach 2:
The patent changes the testing parameter from analog voltage levels to digital test signals. By applying digital test signals to control logic that drives the switches, the system transforms the testing approach from time-consuming analog measurements to rapid digital signal processing, reducing testing time from hours to seconds or milliseconds
2Loss of time
If partial testing of ADC is performed to reduce testing time, then testing time is reduced, but testing reliability deteriorates
Solution Approach 1:
The patent creates a universal digital test input that can test all circuit elements in the ADC through a single integrated approach. The digital test signal activates control logic that systematically controls all switches in the resistive network, providing complete testing coverage for all conversion codes rather than relying on a limited set of pre-selected codes
3Measurement precision
If numerous accurate analog voltage levels are used for testing, then measurement precision is improved, but device complexity and testing time increase
Solution Approach 1:
The patent substitutes the complex analog voltage generation and measurement system with a digital test signal system. The digital test input and control logic eliminate the need for generating and measuring numerous accurate analog voltage levels, simplifying the testing system while maintaining complete testing capability
Solution Approach 2:
The patent uses digital test signals as a simplified copy or representation of the analog testing approach. Instead of physically generating and measuring actual analog voltage levels, the system uses digital signals to control the ADC's internal switches and resistive network, achieving the same testing objective with greater simplicity and speed
Data Source
AI summary
Complete testing of an analog-to-digital converter (ADC) can be carried out using digital signals and at high speeds. Circuit elements are added to an ADC so that a first phase of testing may be carried out using a limited number of analog test voltages. The ADC may then be reconfigured using added circuit elements to disable conventional analog-to-digital conversion. A digital signal may then be applied to the ADC to rapidly test all switching elements used in analog-to-digital conversion. According to some implementations, testing times for ADCs may be reduced from hours to milliseconds.