A method of detecting a diode fault in an AC signal rectifier circuit, the AC signal rectifier circuit including a plurality of diodes, and being arranged to supply a rectified output voltage to a load, wherein the method includes the steps of deriving an operating value indicative of the ratio of the voltage magnitudes of a first harmonic frequency and another harmonic frequency of the rectified output voltage across the load; and determining whether a fault has occurred in one or more diodes on the basis of the derived operating value. The first harmonic frequency is preferably the fundamental harmonic frequency, and/or the another harmonic frequency is preferably the 6.sup.th harmonic frequency.

Non-contact measurement of one or more electrical response characteristics of a p-n junction includes illuminating a surface of the p-n junction with light of a first intensity having a modulation or pulsed characteristic sufficient to establish a steady-state condition in a junction photovoltage (JPV) of the p-n junction, measuring a first JPV from the p-n junction within the illumination area, illuminating the surface of the p-n junction with light of an additional intensity, measuring an additional photovoltage from the portion of the p-n junction within the illumination area, determining a photocurrent density of the p-n junction at the first intensity. The non-contact measurement further includes determining the forward voltage, the saturation current density, the ideality factor or one or more I-V curves with the measured first photovoltage, the measured additional photovoltage and/or the determined photocurrent density of the p-n junction.

Embodiments of the invention are directed to using a DC multimeter configured for checking device amperage. A DC voltmeter is electrically-connected in series with the DC multimeter. A linear circuit is electrically connected in series between the DC multimeter and the DC voltmeter. A device under test is electrically-connected between positive and negative terminals of the DC voltmeter.

The present invention provides a method for manufacturing silicon carbide semiconductor apparatus including a testing step of testing a PN diode for the presence or absence of stacking faults in a relatively short time and an energization test apparatus. The present invention sets the temperature of a bipolar semiconductor element at 150 C. or higher and 230 C. or lower, causes a forward current having a current density of 120 [A/cm.sup.2] or more and 400 [A/cm.sup.2] or less to continuously flow through the bipolar semiconductor element, calculates, in a case where a forward resistance of the bipolar semiconductor element through which the forward current flows reaches a saturation state, the degree of change in the forward resistance, and determines whether the calculated degree of change is smaller than a threshold value.

A short-circuit detecting circuit is applied for a DESAT detecting circuit provided with a diode of which the cathode is connected to a high potential side terminal of an insulated gate type semiconductor element and a capacitor of which the first end is connected to an anode side of the diode and a second end is connected to a low potential side of the semiconductor switching element, detecting a short-circuit of the semiconductor element. The short-circuit detecting circuit includes a gate voltage terminal though which a gate voltage of the semiconductor is acquired; a DESAT voltage terminal through which a desaturation voltage corresponding to a capacitor voltage of the capacitor is acquired; and a determination circuit that detects, based on (i) the gate voltage exceeding a predetermined gate voltage threshold and (ii) the DESAT voltage exceeding a predetermined DESAT voltage threshold, a short-circuit of the semiconductor switching element.

A semiconductor device includes a substrate, first electronic circuitry formed on the substrate, a first diode buried in the substrate under the first electronic circuitry, and a first fault detection circuit coupled to the first diode to detect energetic particle strikes on the first electronic circuitry.

Embodiments are directed to a transient protection circuit configured for use in a SSPC having a plurality of power channels. The transient protection circuit includes a shared transient voltage suppressor, and a shared protection line communicatively coupled to the shared transient voltage suppressor. The shared protection line is configured to be communicatively coupled to and shared by the plurality of power channels. When the shared protection line is communicatively coupled to and shared by the plurality of power channels, energy above a threshold on any one of the plurality of power channels is dissipated through the shared protection line and the shared transient voltage suppressor.

A method for monitoring an ideal diode comprises controlling a source-gate voltage of a MOSFET of the ideal diode such that the ideal diode can be changed between an off and an on state with a first target value for a source-drain voltage. To detect error states, the source-drain voltage and the source-gate voltage are measured. A check is carried out to determine whether the source-drain voltage reaches the first target value within predefined error limits in the on state. A test mode is carried out, in which a second target value, smaller than the first target value, is set for the source-drain voltage. A check is carried out to determine whether the source-gate voltage reaches an upper threshold value when the test mode is being carried out. An error signal is output when the first target value and/or the upper threshold value is/are not reached.

A life estimation circuit includes a temperature detector configured to detect temperature of a power element unit, an inflection point detection unit configured to detect an inflection point of temperature variation in the power element unit based on an output signal from the temperature detector, an operation unit configured to determine an absolute value of a difference between the temperature of the power element unit at an inflection point detected this time and the temperature of the power element unit at an inflection point detected last time, a count circuit configured to count the number of times that the absolute value of the difference in temperature has reached a threshold temperature, and a signal generation unit configured to output, when a count value from the count circuit reaches a threshold number of times, an alarm signal indicating that the power element is about to reach the end of its life.

According to some embodiments, a computer-implemented method is applied to calibrate a wireless test module (WTM) of a wireless harness automated measurement system (WHAMS) using a computer server and a calibration fixture. The WTM includes a plurality of field effect transistors (FETs). The calibration fixture includes a plurality of resistors. The method measures, using the calibration fixture, a first/second resistance value of the plurality of FETs from a first/second internal measurement test for the WTM. The method determines a resistance calibration value by subtracting the first resistance value from the second resistance value. The method measures a plurality of calibration factors to determine a measured resistor value for a target resistor value for a respective resistor of the calibration fixture.