Systems, methods, techniques and apparatuses of prognostic testing are disclosed. One exemplary embodiment is a power switch system comprising a power switch; a current sensor; a test current injection circuit comprising: 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; and a controller configured to operate the test current injection circuit to transmit a test current to the current sensor and receive a voltage based on the test current.

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 testing circuit includes a first circuit and a second circuit. The first circuit and second circuit have a first capacitor and a second capacitor. The first circuit is connected to a first transistor. The second circuit is connected to a second transistor. A first inductor has a first terminal connected to an input of the testing circuit and a second terminal connected to a source of the second transistor. A first diode has an anode connected to ground and a cathode connected to the second terminal of the first inductor. The second capacitor has a first terminal connected to a drain of the second transistor and a second terminal connected to ground. The first capacitor has a first terminal connected to the input of the testing circuit and a second terminal connected to ground.

The disclosed technology relates to a method and apparatus for graphically displaying a switching cycle of a switching device. A switching voltage and a switching current are acquired for a device under test via a voltage probe and a current probe, respectively, for a plurality of switching cycles of the device under test. The switching current versus the switching voltage is plotted on a current versus voltage plot as a curve for each of the switching cycles. Each of the curves on the current versus voltage plot overlap each other and are displayed to a user.

A testing circuit includes a first circuit and a second circuit. The first circuit and second circuit have a first capacitor and a second capacitor. The first circuit is connected to a first transistor. The second circuit is connected to a second transistor. A first inductor has a first terminal connected to an input of the testing circuit and a second terminal connected to a source of the second transistor. A first diode has an anode connected to ground and a cathode connected to the second terminal of the first inductor. The second capacitor has a first terminal connected to a drain of the second transistor and a second terminal connected to ground. The first capacitor has a first terminal connected to the input of the testing circuit and a second terminal connected to ground.

A testing circuit includes a first circuit and a second circuit. The first circuit has a first capacitor and a second capacitor. The first circuit is configured to transfer at least a portion of a first voltage across the first capacitor to the second capacitor. The second circuit has the first capacitor and the second capacitor. The second circuit is configured to transfer at least a portion of a second voltage across the second capacitor to the first capacitor.

A detection circuit for open, close and suspension states of a high and low level effective switch in a vehicle. The circuit includes an optocoupler circuit module, a low-level active path module, a high-level active path module, a filtering and debouncing module, a transient suppression module, and a wiring terminal. The optocoupler circuit module is connected to the low-level active path module, the high-level active path module and the low-level active path module are connected in parallel to the filtering and debouncing module, and the filtering and debouncing module is connected to the transient suppression module, and then connected to the external high-level active switch or low-level active switch through the wiring terminal. Whether it is a high-level active switch or a low-level active switch, the detection circuit can distinguish whether the switch is in the closed or suspended state, and the strong and weak voltages are isolated.

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.

A method for identifying a malfunctioning current sensor in an electrical apparatus, in which an electrical power supply of the electrical apparatus is at least partly supplied by a switched-mode electrical power supply circuit connected to at least one current sensor which samples an electrical current in a phase conductor of an electrical installation, the power supply circuit delivering a regulated electrical voltage, the method including: determining a switching duty cycle of a power switch of the switched-mode electrical power supply; analysing the determined switching duty cycle; and identifying a failure condition if the behaviour of the switching duty cycle is representative of a malfunctioning of at least one of the current sensors.

Provided is a testing apparatus for testing a semiconductor device including a first main terminal to which a first power source voltage is applied and a second main terminal to which a second power source voltage is applied, comprising: a condition setting unit for setting a changing speed of a terminal voltage of the first main terminal at turn-off of the device; an operation controlling unit for turning off the device under a condition set by the condition setting unit; and a determining unit for screening the device based on an operation result of the device, wherein: a time waveform of the terminal voltage at turn-off of the device includes a maximum changing point where a changing speed becomes maximum; and the condition setting unit sets the changing speed at a first set voltage higher than a voltage at the maximum changing point, to a predetermined value.