A switching power supply apparatus includes a PFM control circuit that outputs a clock signal Set such that a switching frequency of a switching element varies in accordance with a load state. The clock signal Set determines a turn-on timing of the switching element. A reference value of a current flowing through the switching element determines a turn-off timing of the switching element. A modulation signal is applied to the turn-off timing of the switching element to modulate one of a peak value of a drain current flowing through the switching element and an on-time of the switching element. Input control is performed separately on the clock signal Set and the modulation signal. Accordingly, even when the clock signal Set and the modulation signal contribute to each other to offset each other, modulation effects are not cancelled.

An order may be received for an apparatus such as a power converter or other power device, where the apparatus may be housed in a packing box. A configuration device may be programmed with information responsive to details of the order and an ID associated with the apparatus. A label or other identifying object may be created or configured (e.g., printed) and attached to the apparatus or may otherwise accompany the apparatus prior to dispatch of the packing box. The label may provide details of operating parameters of the apparatus responsive to the details of the order. Upon receipt and unpacking of the packing box, the configuration device may be connected to the apparatus, thereby to causing the apparatus to become configured.

A switching power supply apparatus includes a PFM control circuit that outputs a clock signal Set such that a switching frequency of a switching element varies in accordance with a load state. The clock signal Set determines a turn-on timing of the switching element. A reference value of a current flowing through the switching element determines a turn-off timing of the switching element. A modulation signal is applied to the turn-off timing of the switching element to modulate one of a peak value of a drain current flowing through the switching element and an on-time of the switching element. Input control is performed separately on the clock signal Set and the modulation signal. Accordingly, even when the clock signal Set and the modulation signal contribute to each other to offset each other, modulation effects are not cancelled.

A switched-mode power supply with near valley switching includes a quasi-resonant converter. The converter includes a switch element that is turned on not only at the valley, but also in a window range of t.sub.NVW close to the valley, where the voltage across the switch element is at its minimum. This advantageously reduces switching loss and maintains a balance between efficiency and frequency variation.

A switched-mode power supply with near valley switching includes a quasi-resonant converter. The converter includes a switch element that is turned on not only at the valley, but also in a window range of t.sub.NVW close to the valley, where the voltage across the switch element is at its minimum. This advantageously reduces switching loss and maintains a balance between efficiency and frequency variation.

A welding-type power supply includes a controller, a preregulator, a preregulator bus, and an output converter. The controller has a preregulator control output and an output converter control output. The preregulator receives a range of inputs voltages as a power input, and receives the preregulator control output as a control input, and provides a preregulator power output signal. The preregulator includes a plurality of stacked boost circuits. The preregulator bus receives the preregulator output signal. The output converter receives the preregulator bus as a power signal and receives the output converter control output as a control input. The output converter provides a welding type power output, and includes at least one stacked inverter circuit.

According to one aspect, embodiments herein provide a DC-AC inverter comprising a DC-DC converter portion, an inverter portion, a clamp circuit, a controller configured to operate, in a first mode, the DC-DC converter portion to convert input DC power into DC power having a desired voltage level at a first polarity and the inverter portion to provide output power having the desired voltage level at the first polarity to the output, operate, in a second mode, the DC-DC converter portion to convert the input DC power into DC power having a desired voltage level at a second polarity and the inverter portion to provide output power having the desired voltage level at the second polarity to the output; and operate, in a third mode, the clamp circuit to drive voltage at the output to zero and to store energy discharged by a load capacitance in an energy storage device.

An order may be received for an apparatus such as a power converter or other power device, where the apparatus may be housed in a packing box. A configuration device may be programmed with information responsive to details of the order and an ID associated with the apparatus. A label or other identifying object may be created or configured (e.g., printed) and attached to the apparatus or may otherwise accompany the apparatus prior to dispatch of the packing box. The label may provide details of operating parameters of the apparatus responsive to the details of the order. Upon receipt and unpacking of the packing box, the configuration device may be connected to the apparatus, thereby to causing the apparatus to become configured.

The present application discloses a DC-to-DC converter circuit and a circuit board layout structure for the same. The DC-to-DC converter circuit is electrically connected between a first power supply side and a second power supply side, and comprises a first branch with a primary side coupled to the first power supply side and a secondary side coupled to the second power supply side; a second branch with a primary side coupled to the first power supply side and a secondary side coupled to the second power supply side; and a first inductor. The secondary sides of the first branch and the second branch are connected in series via the first inductor.

A secondary controller drives a light emitting element of a photocoupler such that a detection voltage V.sub.OUTS corresponding to an output voltage V.sub.OUT generated in an output capacitor C approximates to a reference voltage V.sub.REF. A primary controller controls a switching transistor M according to a feedback signal V.sub.FB. A protection circuit is activated and drives the light emitting element of the photocoupler when detecting an abnormal state. An auxiliary power supply circuit includes a power supply capacitor C provided separately from the output capacitor C and supplies a power supply voltage V.sub.CC to the protection circuit and an anode of the light emitting element of the photocoupler.