As smartphone multi-camera modules keep evolving, features like periscope telephoto, OIS, and high-frame-rate HDR are being rolled out continuously—with most of the spotlight on lenses, sensors, and imaging algorithms. Yet as the number of cameras grows, imaging modules demand more independent power rails. Within the tight confines of FPCs, weak analog pixel signals are highly vulnerable to interference from digital circuits and transient currents from VCM motors, and managing the power-up/power-down sequencing of multiple rails becomes increasingly complex. Bugs that are hard to reproduce reliably—such as horizontal banding in images, low-light noise, focus jitter, and random black screens—often trace back to the power supply circuit after root-cause analysis.