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 multi-input voltage converter includes an output circuit, a first conversion circuit, and a second conversion circuit. The first conversion circuit includes a first voltage receiving module, a first transformer, a first switch. The second conversion circuit includes a second voltage receiving module, a second switch. When the second voltage receiving module receives the second input voltage, the second switch is turned on to operate, and the output circuit outputs the output voltage.

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.

An apparatus comprises an isolated power converter coupled to an input dc power source, wherein the isolated power converter comprises a first switch network coupled to a first transformer winding and a second switch network coupled to a second transformer winding and a non-isolated power converter coupled to the second switch network of the isolated power converter, wherein a current flowing through the non-isolated power converter is a fraction of a current flowing through the isolated power converter.

An object of the present invention is to provide a charging apparatus having high efficiency of charging a battery by inputting an alternating current voltage. A charging apparatus that charges a direct current battery includes a step-down converter unit to which a direct current voltage from a power supply is input and that converts the direct current voltage, and when a voltage of the direct current battery is between a predetermined first voltage smaller than a charge completion voltage of the direct current battery and the charge completion voltage, a variable voltage that increases from the first voltage to the charge completion voltage in accordance with charging of the direct current battery is input to the step-down converter unit.

An apparatus includes an isolated power converter having an input connected to an input dc power source, a first output and a second output, and a non-isolated power converter having an input connected to the second output of the isolated power converter, wherein the first output of the isolated power converter and an output of the non-isolated power converter are connected in series.

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.

Described is a supply circuit for a corona ignition device, with an input for connection to a direct voltage source, a first converter, a second converter, and an output for connecting a load. The two converters each generate an output voltage, which is provided on its secondary side and exceeds the input voltage. The two converters each contain a transformer that galvanically separates the primary side of the converter from its secondary side. At least one transistor switch is arranged between the input and primary side of the two converters for pulse width-modulation of the input voltage. The primary side of the second converter is connected in parallel with the primary side of the first converter, the secondary side of the second converter is connected in series with the secondary side of the first converter, the secondary sides of the two converters are each bridged in this series connection by at least one diode, so that an output voltage can be provided at the output of the supply circuit even given a failure of one of the two converters.

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.