System and Method for a High-Side Power Switch

A method comprising:

• storing a startup drain-source voltage of a power switch during a startup sequence;
• measuring a drain-source voltage of the power switch directly at a source terminal and a drain terminal of the power switch;
• producing a first threshold value as a continuous function of the measured drain-source voltage;
• producing a second threshold value as a discrete function of the measured drain-source voltage;
• measuring an output value of the power switch;
• and
• disabling the power switch when the output value of the power switch exceeds one of the first threshold value or the second threshold value.

A device comprising:

• a switch monitoring circuit configured to be coupled to a power switch, the switch monitoring circuit configured to produce a signal proportional to a measured value of the power switch, the switch monitoring circuit configured to provide a first cutoff threshold for the power switch;
• a filter coupled to the switch monitoring circuit and configured to filter the signal and produce a filtered signal;
• a latch coupled to the filter and configured to be coupled to a reset line, the latch configured to store the filtered signal in response to an assertion of the reset line;
• and
• a current source coupled to the latch and the switch monitoring circuit, the current source configured to provide a second cutoff threshold for the power switch when the signal exceeds the filtered signal stored in the latch.