Short circuit protection for semiconductor switches

A semiconductor control system for a semiconductor switch comprising:

• a fast detection circuit structured to:
• receive a first voltage during a second blanking period following a first blanking period, the first blanking period beginning when an increasing gate voltage is applied to the semiconductor switch, the first blanking period ending when the semiconductor switch is turned on, and
• determine whether a short circuit fault is occurring by comparing the first voltage to a fast detection threshold corresponding to a first value of a drain-source voltage of the semiconductor switch;
• and
• a slow detection circuit structured to perform the following if the fast detection circuit does not determine a short circuit fault is occurring:
• receive a second voltage after the second blanking period ends;
• determine whether a short circuit fault is occurring by comparing the second voltage to a slow detection threshold corresponding to a second value of the drain-source voltage,
• wherein the semiconductor control system is structured to open the semiconductor switch in response to either the fast detection circuit or the slow detection circuit determining a short circuit fault is occurring, and
• wherein the first value of the drain-source voltage is greater than the second value of the drain-source voltage;
• receiving a third voltage during the first blanking period;
• and
• determining whether a short circuit fault is occurring by comparing the third voltage to a third detection threshold corresponding to a third value of the drain-source voltage,
• wherein the third value of the drain-source voltage is greater than the first value of the drain-source voltage.

A power converter system comprising:

• a semiconductor switch;
• a fast detection circuit structured to:
• during a second blanking period, receive a first voltage, the second blanking period following a first blanking period, the first blanking period beginning when an increasing gate voltage is first applied to the semiconductor switch, the first blanking period ending when the semiconductor switch is turned on, and
• determine whether a phase leg short circuit fault is occurring by comparing the first voltage to a fast detection threshold corresponding to a first value of a drain-source voltage of the semiconductor switch;
• and
• a slow detection circuit structured to perform the following if the fast detection circuit does not determine a phase leg short circuit fault is occurring:
• receive a second voltage after the second blanking period ends;
• determine whether a load short circuit fault is occurring by comparing the second voltage to a slow detection threshold corresponding to a second value of the drain-source voltage,
• wherein the power converter system is structured to open the semiconductor switch in response to determining a phase leg short circuit fault is occurring or a load short circuit is occurring, and
• wherein the first value of the drain-source voltage is greater than the second value of the drain-source voltage;
• receiving a third voltage during the first blanking period;
• and
• determining whether a short circuit fault is occurring by comparing the third voltage to a third detection threshold corresponding to a third value of the drain-source voltage,
• wherein the third value of the drain-source voltage is greater than the first value of the drain-source voltage.