An audio driver circuit includes a modulator circuit configured to receive an audio input signal and produce a first modulated digital pulse signal. The first modulated digital pulse signal has a magnitude that switches between a supply power voltage and a supply ground voltage. The audio driver circuit also includes a switched driver circuit coupled to the modulator circuit to receive the first modulated digital pulse signal and configured to provide a second modulated digital pulse signal for driving an MOS (metal oxide semiconductor) output transistor. The second modulated digital pulse signal has a same timing pattern as the first modulated digital pulse signal and has a magnitude that tracks linearly with the magnitude of the audio input signal.

A load controller includes a control device, a switching device, an arc suppression circuit, and a control section. The control device is provided on an electric power supply path between first and second terminals coupled to an alternating-current electric power source, and controls electric power supply to a load provided on the electric power supply path. The switching device is provided on the electric power supply path and is to be in an open state or a closed state. The arc suppression circuit is to suppress discharge at the switching device. The arc suppression circuit is to be set to an enabled state or a limited state. The control section controls operation of the control device, the switching device, and the arc suppression circuit. The control section varies the arc suppression circuit from the limited state to the enabled state after bringing the switching device into the closed state.

The invention provides a power converter apparatus for converting an alternating current (AC) power input to a direct current (DC) power output. The apparatus comprises a plurality of n single-phase power converting circuits arranged in parallel, where n is equal to or greater than 2, wherein one of said n single-phase power converting circuits comprises a single-stage AC/DC converter module having an operating AC/DC converter; and each of a remaining n−1 of said single-phase power converting circuits comprises a two-stage converter module having an AC/DC converter as an input stage and a DC/DC transformer as an output stage.

Apparatus, systems, and/or methods are disclosed relating to a welding-type power supply with a pre-regulator circuit configured to provide a pre-regulated direct current (DC) bus at two or more voltage levels, responsive to various operating conditions. In some examples, the pre-regulator circuit may be configured to provide a pre-regulated DC bus voltage at one voltage level for certain input line voltages, weld processes, and/or target weld output levels, and at another voltage level for other input line voltages, weld processes, and/or target weld output levels. In some examples, the pre-regulator circuit may be configured to provide a pre-regulated DC bus voltage for certain input line voltages, weld processes, and/or target weld output levels and an unregulated DC bus voltage at other input line voltages, weld processes, and/or target weld output levels. In some examples, the pre-regulator circuit may be configured to provide a pre-regulated DC bus at a service voltage in response to detecting a service mode of operation, and/or at an idle voltage in response to detecting an idle mode of operation.

Apparatus, systems, and/or methods are disclosed relating to a welding-type power supply with a pre-regulator circuit configured to provide a pre-regulated direct current (DC) bus at two or more voltage levels, responsive to various operating conditions. In some examples, the pre-regulator circuit may be configured to provide a pre-regulated DC bus voltage at one voltage level for certain input line voltages, weld processes, and/or target weld output levels, and at another voltage level for other input line voltages, weld processes, and/or target weld output levels. In some examples, the pre-regulator circuit may be configured to provide a pre-regulated DC bus voltage for certain input line voltages, weld processes, and/or target weld output levels and an unregulated DC bus voltage at other input line voltages, weld processes, and/or target weld output levels. In some examples, the pre-regulator circuit may be configured to provide a pre-regulated DC bus at a service voltage in response to detecting a service mode of operation, and/or at an idle voltage in response to detecting an idle mode of operation.

An inverter type engine generator includes an alternator; and a converter composed of the a three-phase rectifying bridge circuit including an upper and lower three sets of elements, and converting three-phase alternating current output from the alternator into direct current. The upper and lower three sets of elements of the three-phase rectifying bridge circuit of the converter are configured such that upper elements are configured at least from duty-controllable diode elements, and lower elements are configured at least from duty-controllable switching elements having diodes.

A prevention switching device is provided. The apparatus includes a switching circuit and a controller. The switching circuit includes a switching relay capable of switching a connection destination of a first power conversion circuit other than a second power conversion circuit among the plurality of power conversion circuits between a phase corresponding to the first power conversion circuit and a certain phase of the external power supply. The second power conversion circuit corresponds to the certain phase of the external power supply. The controller controls an operation of the switching relay at a zero-crossing time of an AC voltage estimated based on the AC voltage.

A power converter for a bioelectrochemical system includes first converters each including a direct current terminal for supplying electric current via electrodes of the bioelectrochemical system, and a second converter for supplying energy to the first converters from an external electric power grid. Each first converter includes an electric element for receiving energy from the second converter and a circuitry for converting voltage of the electric element into electrolysis voltage suitable for the bioelectrochemical system. The electric element can be a secondary winding of a transformer or a direct voltage energy storage. Each first converter is galvanically isolated from the other first converters at least when the first mentioned first converter supplies energy to the bioelectrochemical system. Thus, each first converter drives its own electrode pair without disturbing the other first converters.

A motor drive device includes a reactor, a converter circuit, a capacitor, an inverter circuit, and overcurrent determination units. The converter circuit converts a first AC voltage output from an AC power supply into a DC voltage. The capacitor smooths a second voltage on the DC side of the converter circuit. The inverter circuit converts DC power stored in the capacitor into AC power. One of the overcurrent determination units determines overcurrent based on a detected value of the first AC current, flowing between the AC power supply and the converter circuit. Another overcurrent determination unit determines overcurrent based on a detected value of the second DC current, flowing between the converter circuit and the capacitor. The converter and inverter circuits stop operating when the determination result of one of the overcurrent determination units indicates an overcurrent.

An AC-DC converter circuit can include a plurality of passive components configured to convert AC to DC and to non-linearly regulate output DC voltage to about a selected maximum throughout an AC input voltage range and/or generator frequency. The plurality of passive components can be configured to also limit power loss as a function of load on a DC side.