In accordance with an embodiment, a method includes using a monitoring circuit disposed on a monolithic integrated circuit to monitor an output signal of a first switching transistor for a first output edge transition at a monitoring terminal of the monolithic integrated circuit; using a time measuring circuit disposed on the monolithic integrated circuit to measure a first time delay between a first input edge transition of a first drive signal and the first output edge transition, where the first drive signal is configured to cause a change of state of the first switching transistor; using an analysis circuit disposed on the monolithic integrated circuit to compare the measured first time delay with a first predetermined threshold to form a first comparison result; and indicating a first error condition based on the first comparison result.

An operating condition monitor (100) for monitoring an operating condition of a transistor-based power converter (102), comprising: a sensing apparatus (106) configured to measure a turn-off transient energy of the power converter (102), a processor (108) in communication with the sensing apparatus (106) to receive the measurement of the turn-off transient energy, the processor being configured to: compare the measurement of the turn-off transient energy to a threshold; and issue an event signal based on the comparison to the threshold meeting a comparison criterion. A method (200, 200) of monitoring an operating state of a transistor-based power converter is also disclosed.

The present disclosure relates to a connection circuit including a first circuit and a second circuit. The first circuit includes a first impedance unit. The first impedance unit is electrically connected to a first detecting terminal of an electronic device for receiving a first voltage. The second circuit includes a second impedance unit. The second impedance unit is electrically connected to a second detecting terminal of the electronic device. The second impedance unit includes a transistor switch. A control terminal of the transistor switch is electrically connected to the first circuit such that the transistor switch is turned on according to the first voltage, and the second circuit receives a second voltage transmitted from the second detecting terminal.

A method of monitoring the health of a semiconductor power electronic switch such as an insulated gate bipolar transistor (IGBT) is provided. The method having the steps of: measuring one or more parameters selected from the group consisting of: a rate of change of voltage $\left(\frac{\mathrm{dV}}{\mathrm{dt}}\right)$
across the switch; a rate of change of current $\left(\frac{\mathrm{di}}{\mathrm{dt}}\right)$
through the switch, a charge present on a gate of the switch (Q.sub.G), a peak overshoot voltage (V.sub.PO) across the switch, and a peak overshoot or reverse recovery current (I.sub.RR) through the switch; and estimating the health of the switch based on the measured parameter(s).

The invention provides a method for checking a semiconductor switch for a fault, wherein the semiconductor switch is driven with a PWM signal with a variable duty cycle. To the benefit of determining faults on the semiconductor switch reliably and cost-effectively, it is provided that if the semiconductor switch is operated with a duty cycle of 100% or 0%, the current measurement of the overall system is evaluated, while if the semiconductor switch is operated with a duty cycle of between 0% and 100%, the generated voltage pulses across the semiconductor switch are evaluated.

A switch short-circuited diagnosis method includes steps of: determining an initial voltage interval of multiple voltage intervals according to voltage relationships between voltages of a first phase wire, a second phase wire, and a third phase wire; performing a switch short-circuited diagnosis of a first bidirectional switch module in the three consecutive voltage intervals from the initial voltage interval, and including steps of: turning on a first switch branch, a second switch branch, or a third switch branch of the first bidirectional switch module according to the voltage relationships between the voltages of the first, second and third phase wires, determining whether an overcurrent occurs to diagnose whether the first switch branch, the second switch branch, or the third switch branch of the first bidirectional switch module is in a short-circuited state, and performing the switch short-circuited diagnosis for the next voltage interval.

Disclosed are an apparatus and a method for predicting a fault state of an inverter. The apparatus for predicting a fault state of an inverter includes: an inverter converting DC power into AC power; a switching element provided in the inverter; and a controller extracting a fault sign factor based on an output signal output from the inverter and predicting a fault of the switching element based on the fault sign factor.

A method for determining a switching current of at least one switching element of a converter of a system for inductive power transfer, including determining a phase current of at least one AC phase line of the converter; determining at least one switching time point of the at least one switching element and the phase current value at said switching time point; and determining switching current of the at least one switching element depending on the at least one phase current value.

A testing apparatus, including: a variable resistor coupled to a control electrode of a switching device; a storage circuit storing information indicating a relation between a resistance value of the variable resistor and a voltage change rate at which a voltage between power-source-side and ground-side electrodes of the switching device changes when the switching device is turned off; and a control circuit controlling the variable resistor. The control circuit sets the variable resistor to have a first resistance value and obtains a first value of the voltage change rate, sets the variable resistor to have a second resistance value based on the first value of the voltage change rate and the information, obtains a second value of the voltage change rate when the variable resistor is of the second resistance value, and determines whether the second value of the voltage change rate meets a specification of the switching device.

Provided is a test method of a semiconductor device under test, the test method comprising: controlling the semiconductor device under test to an on state by inputting a control signal to the semiconductor device under test; and observing the semiconductor device under test at a time of controlling the semiconductor device under test in the on state to an off state and evaluating the semiconductor device under test, wherein the semiconductor device under test includes one semiconductor device under test or a plurality of semiconductor devices under test, and in the controlling to the on state, a length of an on-time for which the one semiconductor device under test or the plurality of semiconductor devices under test are set to the on state is adjusted based on a magnitude of a variation in a delay time of the control signal.