Tdk Corporation

Yasuhiro Murai

Masahiko Hirokawa

Wataru Nakahori

Hisanori Cho

Kenichi Aonuma

Tomomi Yamada

Tomohiko Uchiyama

In the printed circuit boardin the power supply device, cover layers Cand Care formed on a surface other than the connection areasA' andB&#x2032; within a coil pattern EC, which corresponds to a surface-shaped exposure area exposed to the outside so that the size of the surface-shaped exposure area to which the conductive pattern E is exposed is adjusted, so that an effect, which restrains a conductor from being damaged, especially at a time of carrying the printed circuit boardwhile maintaining a heat radiating property of the conductor, is achieved.

Printed circuit board and power supply device

The present invention provides a switching power supply unit capable of suppressing a surge voltage generated in a rectifier element more effectively. A first resonance circuit is constructed by capacitors in a surge voltage suppressing circuit and an inductor, and resonance time of the first resonance circuit is set to be longer than recovery time of a diode in a rectifier circuit. According to at least one of a DC input voltage and an output current, either a first bridge circuit or a second bridge circuit is selectively allowed to perform switching operation. At the time of forward-direction operation, the first resonance circuit is formed by the capacitors in the surge voltage circuit and the inductor on the high voltage side. At the time of reverse-direction operation, a second resonance circuit is formed by the capacitors and an inductor on the low voltage side.

Switching power supply unit

A switching power supply unit capable of adjusting the inductance value of a resonance circuit and outputting a rated output voltage regardless of any fluctuation in an input voltage and a load. The switching power supply unit comprises first to fourth switching elements connected with each other in a bridge connection. A diode having a reverse polarity and a capacitor are disposed between main electrodes of each of the switching elements. A first winding of a transformer is connected between first and second connection points An inductor is inserted into a path ranging from the first connection point through the first winding to the second connection point and forms a resonance circuit in conjunction with the capacitors The inductance value L2 of the inductor is arranged to provide the output voltage Vout of an output circuit greater than or equal to the rated output voltage Vout (nom), in a minimum input voltage Vin (mm), a maximum output current Iout (max), and a switching phase-difference f of zero.

A switching power supply comprises a transformer a switching circuit an output rectifier circuit, an output smoothing circuit, and a snubber circuit. A snubber capacitor has one terminal connected to the one terminal of a snubber diode The other end of the snubber capacitor is led to an output winding of the transformer, while the other terminal of the snubber diode is led to the other of the electrode of an output rectifier diode A snubber inductor has one end connected to the connecting point of the snubber capacitor and the snubber diode, and the other end is. connected to the input side of the output smoothing circuit. The polarity of the diode is arranged to establish a charging loop circulating through the snubber diode, the snubber capacitor and the output winding of the transformer, so as to provide a reduced loss, in a cycle in which the voltage appearing at the output winding of the transformer is the reverse direction to the output rectifier diode.

Switching power supply

A switching power source device in which recovery current can be decreased. The power source device includes a magnetic element connected one of terminals of a power source section, a switch having one end connected with the magnetic element and the other end connected with the other terminal of the power source section, a smoothing capacitor connected between the magnetic element and the other terminal of the power source section, and a diode connected between the magnetic element and the smoothing capacitor with forward direction directed to pass current from the power source section through the magnetic element to the smoothing capacitor. A second magnetic element is provided in a path of recovery current which flows during a closing operation of the switch from the diode to the switch, whereby the second capacitor is charged by current from the first magnetic element during an open state of the switch and a resonance circuit is formed between the first magnetic element and the diode through the second magnetic element, the switch and the second capacitor to pass discharge current from the second capacitor.

Growing community of inventors

Tokyo, Japan

Yasuhiro Murai