Apparatus, system, and method to prevent smoke in a power supply powered by a current limited source

A positive temperature coefficient device is configured in parallel with a bypass switch and implemented at an input to a switching regulation stage of a switching power supply. A monitoring module determines that a voltage across the regulation switch in the switching power supply is below a predefined threshold voltage for greater than a predefined threshold time period. A control module controls operation of the bypass switch. The control module opens the bypass switch in response to the monitoring module determining that the voltage across the regulation switch is below the predefined threshold voltage for greater than the predefined threshold time period such that substantially all of the current entering the switching regulation stage passes through the PTC device. By causing substantially all of the current to pass through the PTC device, the device will enter a high impedance state thereby preventing smoke and smell from occurring.