Abstract: A circuit for limiting inrush current in a DC power supply is disclosed. The inrush limiting circuit should be placed between an input AC power line and a power supply input capacitor bank. A thermistor is located between the capacitor bank and the input diode bridge to limit the initial inrush current. Once the input capacitor bank is fully charged, an insulated-gate bipolar transistor or IGBT switches the rectified line voltage to a boost power factor correction converter circuit, which utilizes an inductor and diode along with a field effect transistor to boost the input to a high DC voltage. This high DC voltage blocks the thermistor through use of a diode and keeps it cold to maintain high resistance in case of a new off/on cycle. The IGBT can be replaced with a silicon control rectifier, a triac, or a field effect transistor.