Embedded RF Test Circuitry for Ball Bond Failure Detection
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Solution Overview
Problem
Detecting failures in ball bonds or solder joints in high-frequency RF circuits, such as those used in automotive radar systems, is challenging due to mechanical strain and thermal expansion differences, which can lead to partial or complete breakages, causing system failures and requiring reliable detection methods to ensure safety.
Innovation Solution
A circuitry and method are introduced to detect connection failures by disabling one output path of a differential power amplifier, using switches or directional couplers, and measuring power through an RF combiner to determine if a signal is present, allowing for the identification of component failures like ball breaks or solder joint issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If ball bonds or solder joints are used to connect integrated circuit to external circuitry, then connection flexibility and mechanical mounting are improved, but connection reliability deteriorates due to mechanical strain and thermal expansion differences causing breakages
Solution Approach 1:
The patent implements preliminary detection of connection failures by incorporating test circuitry that performs bond integrity checks before the radar system is deployed. The test circuitry includes a test signal generator, a directional coupler, and a test signal detector that can detect ball bond breaks or solder joint failures in advance, preventing catastrophic system failures in safety-critical applications.
2Device complexity
If direct connection between power amplifier output and power detector is used, then signal transmission simplicity is improved, but detection capability deteriorates because power detector cannot distinguish signal direction
Solution Approach 1:
The patent introduces a directional coupler as an intermediary component between the power amplifier output and the power detector. The directional coupler is a four-port device that couples a predetermined amount of RF signal from one transmission line to another, enabling the power detector to distinguish between forward-traveling signals and reflected signals by measuring power in different directions along the transmission line.
3Measurement precision
If test circuitry is added to detect connection failures, then detection capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent designs test circuitry that can be integrated into existing radar transmitter architectures without requiring completely separate test equipment. The test signal generator, directional coupler, and test signal detector are configured to work with the existing power amplifier and transmission line infrastructure, allowing the same hardware to serve both normal radar operation and bond integrity testing functions.
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 effective detection of connection failures in high-frequency RF circuits, ensuring the radar system's reliability and safety by accurately identifying and responding to component failures, even at frequencies above 40 GHz, thereby maintaining system integrity and compliance with safety standards.
Implementation Method 1
the second output path (p) 207 is coupled to the first output path (n) 206 through a directional coupler
Implementation Method 2
An RF combiner such as a balanced-unbalanced transformer (balun) 210 is provided on the PCB 204
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A circuit (200) for testing failure of a connection between a radio frequency, RF, integrated circuit (201) and external circuitry (204), the circuit comprising: an amplifier (205) having first and second input paths (215, 216) and first and second output paths (206, 207); a first power detector (208, 209) coupled to one of said first or second output paths; at least one connection (211) between said first and second output paths (206, 207) and said external circuitry (204), connecting said outputs to a RF combiner (210) said external circuitry; at least one disabling circuit (230, 232, 234, 236, 240, 242, 260, 262) coupled to at least one of said first and second output paths (206, 207) or at least one of said first and second input path (215, 216), before said path reaches said power detector (208, 209); for disabling one of said inputs or outputs; wherein when said input or output path is disabled (206, 207), and a signal is output along the enabled output path (206, 207), the power detector (208, 209) on said disabled output path can detect if there is a failure in said at least one connection (211).