Semiconductor Chip Self-Test Circuit for Impedance Loss
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Solution Overview
Problem
Conventional methods for testing semiconductor chips with wireless communication circuitry face challenges in accurately measuring RF signal levels due to signal power loss caused by impedance in chip-to-device interconnections and require expensive analyzers.
Innovation Solution
Incorporating an input circuit to supply an oscillating test signal to the chip's functional block, a test circuit to detect the signal strength, and outputting this strength from an external terminal, allowing the chip to test its own signal without impedance effects, thereby reducing the need for expensive analyzers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If RF signal level measurement is performed using conventional test equipment with external connections, then the test setup is simple, but signal power loss occurs due to impedance in chip-to-device interconnections, reducing measurement precision
Solution Approach 1:
The patent introduces an intermediary measurement mechanism: the test circuit converts the RF signal level into a baseband voltage signal that is proportional to the signal strength. This baseband signal serves as an intermediary that can be measured accurately without suffering from impedance-related power loss in external connections, thereby resolving the contradiction between simple test setup and precise measurement.
2Measurement precision
If accurate RF signal level measurement is performed using conventional equipment, then measurement precision is improved, but expensive analyzers are required, increasing test cost
Solution Approach 1:
The patent implements self-service measurement by incorporating the measurement functionality directly into the semiconductor chip through the test circuit. The chip itself generates the baseband voltage signal that indicates its own RF signal level, eliminating the need for expensive external analyzers. This allows accurate measurement while significantly reducing test cost.
3Adaptability or versatility
If RF signals are transferred between test devices and the chip, then the chip can be tested externally, but impedance effects cause signal power loss, reducing reliability of test results
Solution Approach 1:
The patent extracts the measurement function from the external test equipment and relocates it inside the chip. By taking out the signal detection and conversion functionality and embedding it within the chip's test circuit, the system eliminates the need for RF signal transfer through external connections, thereby removing the source of impedance-related reliability issues while maintaining external testing capability.
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 enables precise and cost-effective testing of semiconductor chips by eliminating signal loss due to impedance and eliminating the need for expensive measurement equipment.
Implementation Method 1
The test circuit detects the strength of the oscillating output signal and generates a strength signal indicating the detected strength
Data Source
AI summary
A semiconductor chip having a functional block that performs a communication function includes an input circuit that supplies an oscillating test signal to the functional block, and a test circuit that detects the strength of an oscillating signal which the functional block outputs in response. A strength signal indicating the detected strength is output from the test circuit through an external terminal of the semiconductor chip to a test device. The test device evaluates the strength signal to decide whether an operating characteristic of the functional block is within a specified range. The strength information indicated by the strength signal is not affected by impedance on the signal transmission line between the semiconductor chip and the test device, so the test is not affected by impedance loss.