Patent Application
20070051535
The invention relates to circuit boards, and particularly to circuit board that are integrated together.
Printed circuit boards (PCBs) used in electronic products provide connections among electronic components. With the ongoing development of electronics technology, many electronic components are often required to be disposed on a single PCB. Therefore the circuits disposed on the PCB may be very complex. Nowadays, PCBs are mainly categorized as single-sided boards, double-sided boards, and multi-layer boards. Single-sided boards are the most common kind of PCB in mass-produced consumer electronic products. A single-sided board has all the conductors (copper traces) on one side of the board. Therefore the circuit layout disposed on the single-sided board is restricted, because the traces must not cross each other. Thus, single-sided boards are only suitable for simple circuits. With double-sided boards, the traces can travel from one side of the board to the other through vias. Therefore, double-sided boards are suitable for relatively complex circuits. A multi-layer circuit board is equivalent to an integrated combination of a plurality of single-sided boards and/or double-sided boards. In multi-layer boards, the traces can run on different layers, and use plated through holes or vias to jump from one layer to another. Thus multi-layer boards are used for complex circuits, and are applied as motherboards in computers for example.
Even though multi-layer boards enable construction of circuits of greater complexity and density, they are not always used. This is because of the greater cost of manufacture, and the near impossibility of inspecting, modifying, and repairing the inner layers. In addition, in general, the cost of a single-sided board or of a double-sided board without vias is lower than the cost of a double-sided board with vias and lower than the cost of a multi-layer board. Thus on the one hand, single-sided boards and double-sided boards without vias are preferred in order to reduce costs. On the other hand, double-sided boards with vias or multi-layer boards are needed for more complex circuits. Many PCB designers and manufacturers are liable to be faced with an unsatisfactory choice between simple circuits at a lower cost or more powerful, versatile complex circuits at a greater cost.
Therefore, what is needed is to provide a PCB that can be manufactured at a reduced cost but still have reliable complex circuits.
An exemplary embodiment of the present invention provides an electronic device. The electronic device includes an electronic component, a first printed circuit board (PCB) and a second printed circuit board. The electronic component includes a first pin and a second pin. The first PCB and a second PCB, respectively including first conductor trace lines and second conductor trace lines for electrically connecting the first pin and the second pin. The first PCB is disposed above the second PCB, and is parallel with the second PCB. The first PCB is electrically connected to the second PCB via at least one of the first conductor trace lines and the second conductor trace lines. A surface area of the first PCB is smaller than that of the second PCB.
Other advantages and novel features will become more apparent from the following detailed description of preferred embodiments when taken in conjunction with the accompanying drawings, in which:
The first PCB 100 comprises first conductor trace lines 102 disposed on a top surface and a bottom surface thereof, for providing electrical connections among a plurality of electronic components. The first conductor trace lines 102 are typically etched copper foils. In the exemplary embodiment, a plurality of vias (not shown) are embedded in the first PCB 100. Metal layers (not shown) are formed on inner walls of the vias, for electrically connecting the first conductor trace lines 102 disposed on the top surface of the first PCB 100 to the first conductor trace lines 102 disposed on the bottom surface of the first PCB 100.
The second PCB 200 comprises second conductor trace lines 108 disposed on a top surface thereof. In the exemplary embodiment, the second PCB 200 is electrically connected to the first PCB 100 via the first conductor trace lines 102 disposed on the bottom surface of the first PCB 100 and the second conductor trace lines 108 disposed on the top surface of the second PCB 200. The PCB assembly further comprises a plurality of solder portions 106a to electrically connect the first conductor trace lines 102 of the first PCB 100 and the second conductor trace lines 108 of the second PCB 200. In the exemplary embodiment, the first PCB 100 further comprises a plurality of metal layers 104 for connecting the first conductor trace lines 102 disposed on the top surface of the first PCB 100 to the first conductor trace lines 102 disposed on the bottom surface of the first PCB 100, and for providing joint points for the corresponding solder portions 106a. Each metal layer 104 is typically a thin metal film directly plated on the first PCB 100. Thus, both the metal layers 104 and the metal layers formed on the inner walls of the vias electrically connect the first conductor trace lines 102 disposed on the top surface of the first PCB 100 and the first conductor trace lines 102 disposed on the bottom surface of the first PCB 100.
In any of the above-described embodiments, preferably, complex or high voltage circuits are disposed on the first PCB 100, and other circuits are disposed on the second PCB 200. The first PCB 100 is typically a more expensive double-sided board with a smaller surface area. The second PCB 200 is typically a less expensive single-sided board that serves as the primary circuit board with a larger surface area. Thus overall, the PCB assembly can provide circuits with great complexity and high reliability at a relatively low cost.
In addition, in various alternative embodiments of any of the above-described first through sixth embodiments, the first PCB 100 can be a multi-layer board and is relatively thin. Hence, capacitors with either high capacitance or low capacitance can be formed and embedded in the PCB assembly.
In various further alternative embodiments of any of the above-described first through sixth embodiments and alternatives thereof, the second PCB 200 can be a double-sided board. Furthermore, means of connecting any of the first conductor trace lines 102 of the first PCB 100 and any of the second conductor trace lines 108 of the second PCB 200 can be any suitable one or combination of the means described above in relation to the first through sixth embodiments and alternatives thereof.
In the exemplary embodiment, the electronic component 40, such as a transformer, or an inductor, includes a body 400, a first pin 401, and a second pin 402. The first pin 401 includes a first output end A1 and a first connecting end B1, and the second pin 402 includes a second output end A2 and a second connecting end B2. The first output end A1 and the second output end A2 are electrically connected to the body 400 of the electronic component 40 respectively. The first connecting end B1 is disposed on the top surface of the first PCB 100, and electrically connected to the first conductor trace lines 102. The second connecting end B2 is disposed on the top surface of the second PCB 200, and electrically connected to the second conductor trace lines 108. In the exemplary embodiment, the first output end A1 and the second output end A2 are disposed at the same height. Contrarily, the first connecting end B1 and the second connecting end B2 are disposed at different heights.
While embodiments and methods of the present invention have been described above, it should be understood that they have been presented by way of example only and not by way of limitation. Thus the breadth and scope of the present invention should not be limited by the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 200510037027.9 | Sep 2005 | CN | national |
This application is a continuation-in-part of U.S. application Ser. No. 11/308,052, filed on Mar. 4, 2006.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11308052 | Mar 2006 | US |
| Child | 11308935 | May 2006 | US |
