Solid-state power switch prognostics

A method comprising:

• operating a power switch system including:
• a power switch,
• a current sensor coupled in series with the power switch, and
• a test current injection circuit including:
• a first direct current (DC) bus rail including an output terminal and a first power supply terminal,
• a second DC bus rail including an input terminal and a second power supply terminal,
• a diode coupled to the first DC bus rail, and
• a leg coupled to the first DC bus rail between the diode and the first power supply terminal and coupled to the second DC bus rail between the input terminal and the second power supply terminal, the leg including a capacitor and a semiconductor device coupled in series;
• transmitting, with the test current injection circuit, a test current to the current sensor;
• and
• receiving an output voltage based on the test current.

An apparatus for testing a power switch system, the apparatus comprising:

• a test current injection device including:
• a first direct current (DC) bus rail including an output terminal and a first power supply terminal;
• a second DC bus rail including an input terminal and a second power supply terminal;
• a diode coupled to the first DC bus rail;
• and
• a leg coupled to the first DC bus rail between the diode and the first power supply terminal and coupled to the second DC bus rail between the input terminal and the second power supply terminal, the leg including a capacitor and a semiconductor device coupled in series;
• wherein the test current injection device is structured to transmit a test current by way of the output terminal.