Secured shutdown and delayed re-start of DC power supply in broadband network

摘要

Power supply to network is fed by switch mode power supply circuit controlled by PWM controller (204). When system input voltage falls below a reference voltage, latching comparator which is a UJT (231) transmits an overcurrent signal to shutdown the power supply system. The restarting of power supply system automatically after a delay, is determined by the charging time of the capacitor (222).