Methods and Apparatus to Test Electronic Devices

An apparatus to test a field-effect transistor (FET), comprising:

• a FET controller to receive a current detect signal from a comparator, the FET controller to turn off the FET when the current detect signal indicates an overcurrent condition;
• a first controlled switch coupled to the comparator and the FET controller, the first controlled switch to prevent the current detect signal from reaching the FET controller;
• a current source coupled to the FET to send a calibration current corresponding to a target threshold current through the FET;
• a resistor coupled to a sense FET mirroring the FET, the resistor to detect a first voltage associated with the FET while the calibration current flows through the FET;
• and
• a voltage adjuster to set a reference voltage substantially equal to the first voltage, the comparator to receive the reference voltage to be used to generate the current detect signal.

A method of testing a field-effect transistor (FET), comprising:

• setting a first controlled switch to prevent a current detect signal from reaching a FET controller, the FET controller to turn off the FET when the current detect signal indicates an overcurrent condition;
• setting a second controlled switch to route a first voltage associated with the FET to a voltage adjuster;
• sending a calibration current corresponding to a target threshold current through the FET;
• measuring the first voltage while the calibration current flows through the FET;
• measuring a second voltage associated with the FET while the calibration current flows through the FET;
• removing the calibration current from the FET after the first and second voltages are measured;
• calculating an on-resistance of the FET using the second voltage;
• and
• setting a reference voltage substantially equal to the first voltage, the reference voltage to be used to generate the current detect signal.