If you want to do battery FPC, we know the principles of the laminate design

If you want to do battery FPC, we know the principles of the laminate design

The circuit board manufacturer, circuit board designer and PCBA manufacturer explain to you that they want to make FPC for batteries, and these principles of lamination design should not be unknown

When designing the battery FPC, it is necessary to pay attention to the basic situation, that is, how many wiring layers, grounding planes and power supply planes are required to achieve the required functions of the circuit. The establishment of the number of wiring layers, grounding planes and power supply planes of the circuit board is related to the requirements of the basic functions of the circuit, signal integrity, EMI, EMC, manufacturing costs, etc.

Compared with most designs, the performance requirements, cost, manufacturing technology, system complexity and other key factors of FPC have many conflicting requirements. Generally speaking, the laminated design of FPC is a compromise decision after considering the key factors in all aspects. In general, high-speed digital circuits and RF circuits are designed with multilayer boards.

In multilayer battery FPC, there are usually signals, power planes and ground planes. The power plane and the grounding plane are generally undivided solid planes. They will provide a good current return path with low impedance for the current of adjacent signal lines.

The signal layer is mostly located between such power or ground reference plane layers, forming symmetric striplines or asymmetric striplines. The top and bottom layers of multi-layer FPC are generally used to prevent components and a small amount of wiring. The wiring of such signals shall not be too long to reduce the direct radiation caused by wiring.

Safe use of decoupling capacitors is a crucial measure to deal with power integrity. The decoupling capacitor can only be stored at the top and bottom layers of the battery FPC.

The wiring, pad and via of decoupling capacitor will seriously affect the effect of decoupling capacitor. Therefore, the wiring connecting the decoupling capacitor must be fully considered in the design, which should be as short and wide as possible, and the wire connected to the via should also be as short as possible.

The multi power reference plane will be divided into several solid areas with different voltages. If the signal layer is next to the multiple power supply layer, the signal current on the signal layer nearby may suffer from an unsatisfactory return path, resulting in gaps in the return path.

Compared with high-speed digital signals, these unreasonable return path designs may cause serious problems. Therefore, high-speed digital signal wiring is required to be far away from multiple power reference planes.

Many ground reference planes can create a good current return path with low impedance, which can greatly reduce common mode EMI.

The ground plane and the power plane must be closely coupled, and the signal layer must also be closely coupled with the adjacent reference plane. The thickness of the medium between layers is reduced to facilitate this purpose.

The two levels crossed by a signal path are one [wiring combination]. The most suitable wiring combination design is to avoid the return current as much as possible, flowing from one reference plane to another; Instead, it is left from one point (face) of a reference plane to another point (face).

In order to realize complex cabling, the inter layer conversion of routing is unavoidable. When switching between signal layers, it is necessary to ensure that the return current can flow smoothly from one reference plane to another. The circuit board manufacturer, circuit board designer and PCBA manufacturer explain to you that they want to make FPC for batteries, and the principles of the lamination design should not be unknown.