PROTECTION CIRCUIT THAT DETECTS FAULT IMPEDANCE DURING POWER UP OF A DEVICE

A protection circuit or electronic circuit breaker protects and supplies power to a device load. The protection circuit includes a current mirror, a reference load that models the device load, and a comparator circuit that outputs a signal indicating that a fault has been detected in the device load during turn on. The current minor provides an amount of current in proportion to the current supplied to the device load. The same proportion is used to calculate the capacitance and resistance of the reference load. Accordingly, if the device load has no fault, the reference voltage remains proportional to the output voltage to the device load. However, if the device load has a fault, the reference voltage will increase faster than the output voltage such that the comparator will generate a fault signal that turns off a transistor pass element that was supplying current to the device load.