An abnormality detection method according to one aspect of the present disclosure is a method of detecting an abnormality in an AC signal to be input from an AC power supply. The method includes, where an ideal AC signal is represented as V.sub.0 sin ωt (V.sub.0: amplitude, co: angular frequency, t: time), calculating an arithmetic value including a value represented by sin.sup.2ωt+cos.sup.2ωt and determining that the AC signal is abnormal when the arithmetic value is out of a threshold range.

A voltage level detector includes a voltage divider that generates a first division voltage and a second division voltage. A first comparator compares any one of the first and second division voltages with a reference. A second comparator compares the other of the first and second division voltages with the reference. A first switch converts a connection path between the first and second division voltages and the first and second comparators based on a clock signal. A determination circuit determines, based on a first comparison signal and a second comparison signal, whether the voltage level detector is normal. A second switch converts a connection path between the first and second comparison signals and input terminals of the determination circuit based on the clock signal.

The voltage conversion apparatus includes a voltage holding unit that holds a maximum voltage of an output voltage and a determination unit that determines whether or not the maximum voltage held by the voltage holding unit is within a predetermined voltage range; when starting control of opening/closing operation by an opening/closing device, a control unit makes the opening/closing device perform the opening/closing operation, based on a predetermined starting switching frequency and a predetermined starting duty; the determination unit detects a failure in a smoothing capacitor by determining that the held maximum voltage is out of the voltage range.

A detector circuit included in a computer system filters the voltage level of a power supply node to generate filtered signals. The detector circuit either compares the filtered signals or samples the filtered signal and compares the samples to reference levels to detect changes in the voltage level of the power supply node that exceed thresholds for magnitude and duration. A control circuit included in the computer system generates, using the glitch signal, control signals that can be used to change operating parameters of functional circuits included in the computer system.

A power delivery system includes a power sourcing equipment, a powered device and a transmission cable. When the power sourcing equipment is electrically connected to the powered device via the transmission cable, an over-current detecting circuit in the power sourcing equipment is configured to detect over-current occurrence of the powered device. Meanwhile, the power sourcing equipment is configured to determine the functionality of the over-current detecting circuit based on its specific pin and provide single fault protection when the over-current detecting circuit fails.

According to one embodiment, a deterioration checking apparatus includes an inductor that is connected in series to a main current path of a MOS transistor to be checked, and forms a closed loop together with the MOS transistor when the MOS transistor is in an ON-state, a control circuit that controls ON/OFF of the MOS transistor, a current sensor that detects a current released from the inductor, and a calculation circuit that calculates an ON-resistance of the MOS transistor from an attenuation characteristic of a current released from the inductor when the MOS transistor is in an ON-state, and calculates a threshold voltage of the MOS transistor from an attenuation characteristic of a current released from the inductor when the MOS transistor is in an OFF-state. Therefore, it is possible to easily check a deterioration state of the MOS transistor.

A power semiconductor module including at least first and second power semiconductor elements, includes a first terminal, a first gate terminal, a second terminal, a second gate terminal, a third terminal and a common terminal. The first terminal connected to a first electrode of the first power semiconductor element. The first gate terminal connected to a gate of the first power semiconductor element. The second terminal connected to a first electrode of the second power semiconductor element. The second gate terminal connected to a gate of the second power semiconductor element. The third terminal connected to a second electrode of the first power semiconductor element and a second electrode of the second power semiconductor element. The common terminal that is connected to the first gate terminal through a first resistor and is connected to the second gate terminal through a second resistor.

A power semiconductor module including at least first and second power semiconductor elements, includes a first terminal, a first gate terminal, a second terminal, a second gate terminal, a third terminal and a common terminal. The first terminal connected to a first electrode of the first power semiconductor element. The first gate terminal connected to a gate of the first power semiconductor element. The second terminal connected to a first electrode of the second power semiconductor element. The second gate terminal connected to a gate of the second power semiconductor element. The third terminal connected to a second electrode of the first power semiconductor element and a second electrode of the second power semiconductor element. The common terminal that is connected to the first gate terminal through a first resistor and is connected to the second gate terminal through a second resistor.

Circuit arrangement via which a voltage type and value of an input voltage of a. power supply or a switching-mode power supply is ascertained is configured such that the input voltage of the power supply decreases at the input side and includes a differential amplifier for converting the input voltage into a signal rectified by a first rectifier such that a forward voltage of the first rectifier is compensated, includes an inverter which generates an inverted signal rectified by a second rectifier such that a forward voltage of the second rectifier is compensated, includes a mixer via which a first output signal is generated from the useful signals, from which first output signal a second output signal is derived via a filter such that the voltage type is determinable from the first output signal, and a voltage value of the input voltage can be determined from the second output signal.

Systems and methods for direct heater diagnostics for a hot melt liquid dispensing system are disclosed. At least one of a current measurement or a voltage measurement is received from a respective current and/or voltage sensor positioned at an electrical circuit that supplies electric power to a heater associated with the dispensing system. The heater can be for an applicator or heated hose attached to the dispensing system, a melter of the dispensing system, or a pump of the dispensing system. A state of the electrical circuit is determined based on the at least one of the current or voltage measurement.