The electrical wiring layer (left) and discharge layer (right) of the new product (image courtesy of Oki Electric Cable)
The electrical wiring layer (left) and discharge layer (right) of the new product (image courtesy of Oki Electric Cable)
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Oki Electric Cable Co Ltd developed a flexible printed circuit (FPC) board designed for applications that use large currents such as switching power supplies and inverters.

The FPC board, "Power FPC," can be applied to various devices including consumer devices, FA (factory automation) equipment, automobiles, airplanes and power generation facilities.

According to Oki Electric Cable, FPC boards are used in various electronic devices as printed circuit boards (PCBs) that do not take much space because they are thin, lightweight and flexible. However, the maximum thickness of the conductive layer of a conventional FPC is only 35μm, making it difficult to use a large current.

The only way to deal with a larger current is to increase the width of the conductive layer, but it increases the size of the FPC board. Also, heat generation caused by a large current and the increase in the number of components has been a serious problem.

The Power FPC was developed to deal with large currents. Oki Electric Cable enabled to increase the thickness of a conductive layer from 35μm to 100μm or more by using its own thick conductive material based on a multi-layer printed circuit board technology. As a result, the amount of current that can be used was nearly doubled without changing the width of conductive layer.

Also, because the Power FPC has two thick conductive layers, it has a high heat dissipation performance. Specifically, one of the two layers is used to conduct electricity while the other is used for heat dissipation. In other words, it is electrically a one-layer board. Compared with rigid PCBs, which are common in the market, the heat dissipation performance of the new FPC board is about 30% or more higher, Oki Electric Cable said.

The thickness of the Power FPC can be selected from 105μm, 140μm, 175μm and 210μm. Its wiring pitch is 1,500μm (minimum). Its base material and coating material are polyimide. Its reinforcing plates include polyimide, PET (polyethylene terephthalate) and glass epoxy boards.

Oki Electric Cable will release the Power FPC in April 2014. The company aims at sales of ¥100 million (approx US$986,680) or more in fiscal 2014.