In response to fire safety risks associated with photovoltaic (PV) systems and evolving rapid shutdown requirements, this paper proposes a cost-effective and reliable rapid shutdown solution integrated directly into the PV module junction box. The system employs analog circuitry triggered by an external pulse-width modulation (PWM) signal, with optocoupler isolation and a controlled short-circuit method to rapidly reduce the module output voltage. Simulation and experimental results confirm that the output voltage is reduced to approximately 2 V within 280 ms, satisfying the U.S. National Electrical Code (NEC) 690.12 requirements. This junction-box–integrated approach eliminates the complexity of conventional module-level power electronics (MLPE) systems and offers a highly practical alternative for building-integrated photovoltaic (BIPV) applications where partial shading is minimal.