PCBA Self-Test Using Dual Current Photo Sensor Error Checks

The PCBA under test performs self-diagnosis by utilizing its own functional components (light source, photo sensors, processor) to generate and measure test signals, eliminating the need for complex external testing equipment. The processor executes test code that controls the light source and reads photo sensor outputs, enabling the device to test itself

The functional components of the PCBA (light source, photo sensors, processor) serve dual purposes: they perform their primary diagnostic device functions while simultaneously serving as test generation and measurement elements for self-diagnosis, reducing the need for separate dedicated test equipment

The testing process uses periodic measurement cycles where the light source operates at different current levels (first current level and second current level) in sequence, with measurements taken at each level. This periodic variation in operating conditions enables precise error value calculation through comparison of results from different states

The processor stores test results from measurements at different current levels and performs error value calculations based on predetermined formulas. By preparing and storing measurement data from multiple current levels before final evaluation, the system ensures accurate reliability determination without requiring continuous real-time analysis