JP3753928B2

JP3753928B2 - Printed circuit board and power supply using the same

Info

Publication number: JP3753928B2
Application number: JP2000177666A
Authority: JP
Inventors: 正文桑原
Original assignee: Origin Electric Co Ltd
Current assignee: Origin Electric Co Ltd
Priority date: 2000-06-14
Filing date: 2000-06-14
Publication date: 2006-03-08
Anticipated expiration: 2020-06-14
Also published as: JP2001358427A

Description

【０００１】
【産業上の利用分野】
この発明は、パワー回路となる厚肉の内部銅箔層によるトランス巻線を基板内部に備えた回路基板及びそれに電子部品を搭載してなる電源に関する。
【０００２】
【従来の技術】
回路基板に細幅の金属膜を渦巻き状に形成してなるプリントコイルを巻線として利用したトランスは広く知られている。例えば、特開昭６１−１５６８０２号公報には多層回路基板を用い、トランスの１次巻線を回路基板の表面に形成し、２次巻線を内部に形成することが開示されている。また、特開昭６１−１５６８０２号公報には大きな面積をもつ回路基板を使用し、他の電子部品を搭載しても良いと述べている。
【０００３】
【発明が解決しようとする課題】
しかしながら、特開昭６１−１５６８０２号公報は実質的にプリントコイル型トランスの基本的な構造について述べているに過ぎず、この構造のものは電流の比較的小さな電源などに用いることは可能であるが、２次巻線又は１次巻線を数アンペア以上の電流が流れる場合には対応できない。また、特開昭６１−１５６８０２号公報に開示されたものでは、回路基板に表側遮蔽内部銅箔層と裏側遮蔽内部銅箔層とその間に設けられた放熱用内部銅箔層の３層からなる内部銅箔層を備え、スルーホールを利用して電子部品の熱を放熱用内部銅箔層に放熱するものなので、基板内部に配線用の内部銅箔層を有しておらず、制御用配線や検出用配線は勿論のこと、電力用配線も基板表面に形成された表面銅箔層で行わなければならないという欠点がある。また、実開昭５９−１０１４４１号公報のものでは互いに独立した電源用、アース用、配線用の３層の内部銅箔層を有しているので、多層回路基板の厚みが厚くなったり、コストが高くなるという欠点があった。
【０００４】
したがって、この発明は従来に比べて小型で電力容量の大きなプリントコイル型のトランスをもった高密度実装の可能な回路基板、及びオンボード型の電源を提供することを主目的としている。
【０００５】
【課題を解決するための手段】
【０００６】
この発明の請求項１は前記課題を解決するため、回路基板に設けられたコア穴を中心にしてそのいずれか一方又は双方の基板表面に形成されてトランスの１次巻線となる渦巻き状の１次巻線部を備える表面銅箔層と、該表面銅箔層の厚みよりも厚い肉厚をもち、基板内部における第１の平面に形成された第１の内部銅箔層と、第１の平面とは異なる第２の平面に形成された第２の内部銅箔層と、前記基板表面から前記第１、第２の内部銅箔層に延びる複数のスルーホールとを備えた回路基板であって、前記第１の内部銅箔層は複数の個別の内部銅箔領域からなり、前記第２の内部銅箔層は連続的に形成された広面積部と前記コア穴を中心にほぼ１タ−ン以上の前記トランスの２次巻線を形成する２次巻線部とからなり、前記２次巻線部はその終端部又は両端部が前記スルーホールにより前記第１の内部銅箔層の個別の内部銅箔領域に接続されることを特徴とする回路基板を提供する。
【０００７】
この発明の請求項２は前記課題を解決するため、回路基板に設けられたコア穴を中心にしてそのいずれか一方又は双方の基板表面に形成されてトランスの１次巻線となる渦巻き状の１次巻線部を備える表面銅箔層と、該表面銅箔層の厚みよりも厚い肉厚をもち、基板内部における第１の平面に形成された第１の内部銅箔層と、第１の平面とは異なる第２の平面に形成された第２の内部銅箔層と、前記基板表面から前記第１、第２の内部銅箔層に延びる複数のスルーホールとを備えた回路基板であって、前記第１の内部銅箔層は前記コア穴を中心に一方向にほぼ１タ−ン以上で形成される２次巻線部と複数の個別の内部銅箔領域とからなり、前記第２の内部銅箔層は連続的に形成された広面積部からなり、前記２次巻線部はその終端部が前記スルーホールにより前記第２の内部銅箔層に接続されることを特徴とする回路基板を提供する。
【０００８】
この発明の請求項３は前記課題を解決するため、回路基板に設けられたコア穴を中心にしてそのいずれか一方又は双方の基板表面に形成されてトランスの１次巻線となる渦巻き状の１次巻線部を備える表面銅箔層と、該表面銅箔層の厚みよりも厚い肉厚をもち、基板内部における第１の平面に形成された第１の内部銅箔層と、第１の平面とは異なる第２の平面に形成された第２の内部銅箔層と、前記基板表面から前記第１、第２の内部銅箔層に延びる複数のスルーホールとを備えた回路基板であって、前記第１の内部銅箔層は前記中央穴を中心に一方向にほぼ１タ−ン以上で形成される第１の２次巻線部と複数の個別の内部銅箔領域とからなり、前記第２の内部銅箔層は連続的に形成された広面積部とこの広面積部から伸びて前記コア穴を中心に逆方向にほぼ１タ−ン以上で形成される第２の２次巻線部とからなり、前記第１と第２の２次巻線部はそれぞれの終端部と相手の始端部を通る前記スルーホールにより互いに直列接続されて、ほぼ２ターン以上の巻数のトランス２次巻線を形成することを特徴とする回路基板を提供する。
【０００９】
この発明の請求項４は前記課題を解決するため、回路基板に設けられたコア穴を中心にしてそのいずれか一方又は双方の基板表面に形成されてトランスの１次巻線を形成する渦巻き状の表面銅箔層と、該渦巻き状の表面銅箔層の厚みよりも厚い肉厚をもち、基板内部における第１の平面に形成された第１の内部銅箔層と、第１の平面とは異なる第２の平面に形成された第２の内部銅箔層と、前記基板表面から前記第１、第２の内部銅箔層に延びて接続される複数のスルーホールとを備えた回路基板であって、前記第１の内部銅箔層は前記コア穴を中心に一方向にほぼ１タ−ン以上で形成される第１の２次巻線部と、複数の個別の内部銅箔領域とからなり、前記第２の内部銅箔層は連続的に形成された広面積部とこの広面積部から伸びて前記コア穴を中心に前記第１の巻線部と同方向にほぼ１タ−ン以上で形成される第２の２次巻線部とからなり、前記第１と第２の巻線部はそれぞれの終端部と相手の始端部を通る前記スルーホールにより互いに並列接続されて、ほぼ１ターン以上の巻数のトランス２次巻線を形成したことを特徴とする回路基板を提供する。
【００１０】
この発明の請求項５は前記課題を解決するため、回路基板に設けられたコア穴を中心にしてそのいずれか一方又は双方の基板表面に形成されてトランスの１次巻線を形成する渦巻き状の表面銅箔層と、該渦巻き状の表面銅箔層の厚みよりも厚い肉厚をもち、基板内部における第１の平面に形成された第１の内部銅箔層と、第１の平面とは異なる第２の平面に形成された第２の内部銅箔層と、前記基板表面から前記第１、第２の内部銅箔層に延びて接続される複数のスルーホールとを備えた回路基板であって、前記第１の内部銅箔層は複数の個別の内部銅箔領域と、該内部銅箔領域の一つである第１の内部銅箔領域から延びる、前記コア穴を中心に一方向にほぼ１タ−ン以上で形成される第１の２次巻線部とからなり、前記内部銅箔領域は一方の巻線端子を構成し、また前記個別の内部銅箔領域の他の一つである第２の内部銅箔領域が他方の巻線端子の役割を行い、前記第２の内部銅箔層は連続的に形成された広面積部とこの広面積部とは分離して形成され、かつ前記コア穴を中心にほぼ１タ−ン以上で形成される第２の２次巻線部とからなり、前記第１の巻線部の終端部と前記第２の巻線部の一方の端部は前記スルーホールにより接続され、前記第２の巻線部の他方の端部は前記スルーホールにより前記第２の個別の内部銅箔領域に接続されてほぼ２ターン以上の巻数のトランス２次巻線を形成したことを特徴とする回路基板を提供する。
【００１１】
この発明の請求項６は前記課題を解決するため、請求項１、請求項３ないし請求項５のいずれかにおいて、前記第２の内部銅箔層に形成された２次巻線部は前記広面積部に囲まれていることを特徴とする回路基板を提供するものである。
【００１２】
この発明の請求項７は前記課題を解決するため、請求項１ないし請求項６のいずれかにおいて、前記渦巻き状の表面銅箔層が双方の前記基板表面に形成される場合には、それぞれの前記渦巻き状の表面銅箔層の終端部から他方の前記渦巻き状の表面銅箔層に延びる前記スルーホールにより互いに直列接続されることを特徴とする回路基板を提供する。
【００１３】
この発明の請求項８は前記課題を解決するため、請求項１ないし請求項６のいずれかにおいて、前記渦巻き状の表面銅箔層が双方の前記基板表面に形成される場合には、それぞれの前記渦巻き状の表面銅箔層の終端部から他方の前記渦巻き状の表面銅箔層に延びる前記スルーホールにより互いに並列接続されることを特徴とする回路基板を提供する。
【００１４】
この発明の請求項９は前記課題を解決するため、請求項１ないし請求項８のいずれかにおいて、前記回路基板は、前記渦巻き状の表面銅箔層と前記内部銅箔層の前記第１の巻線部と第２の巻線部の両外側で、かつ前記コア穴を通る直線上にコア用の別の穴を備えたことを回路基板を提供する。
【００１５】
この発明の請求項１０は前記課題を解決するため、請求項９において、前記コア穴及び前記コア用の別の穴にコアのそれぞれの磁脚が挿入され固定されていることを特徴とする回路基板を提供する。
【００１６】
この発明の請求項１１は前記課題を解決するため、請求項１ないし請求項１０のいずれかの回路基板において、前記スルーホールに跨がって前記回路基板上に形成された前記電極パッドに所定の電子部品を接続し、前記第２の内部銅箔層の前記広面積部は安定電位に接続されることを特徴とする電源を提供する。
【００１７】
この発明の請求項１２は前記課題を解決するため、請求項１ないし請求項１０のいずれかの回路基板を用い、前記スルーホールを通して前記第１の内部銅箔層における前記第１の巻線部と前記個別の内部銅箔領域との間に前記電極パッドを介して電子部品が接続されることを特徴とする電源を提供する。
【００１８】
この発明の請求項１３は前記課題を解決するため、請求項１ないし請求項１１のいずれかの回路基板を用い、前記スルーホールを通して前記第１の内部銅箔層の前記個別の内部銅箔部と前記第２の内部銅箔領域との間に前記電極パッドを介して電子部品が接続されることを特徴とする電源を提供する。
【００１９】
この発明の請求項１４は前記課題を解決するため、請求項５の回路基板に整流用ＦＥＴを表面実装してなる同期整流式の電源において、前記整流用ＦＥＴのドレイン電極とソース電極をそれぞれ前記スルーホールを通して前記第１の内部銅箔層における前記第１の個別の内部銅箔領域と前記第２の個別の内部銅箔領域に接続したことを特徴とする電源を提供する。
【００２０】
この発明の請求項１５は前記課題を解決するため、請求項５の回路基板にフリホイーリング用ＦＥＴ又はダイオードを表面実装してなる同期整流式の電源において、前記フリホイーリング用ＦＥＴ又はダイオードを、前記第１の内部銅箔層の第１の個別の内部銅箔領域と前記第２の内部銅箔層の広面積部との間に前記スルーホールを通して接続したことを特徴とする電源を提供する。
【００２２】
【発明の実施の形態及び実施例】
先ず、図１及び図２により本発明の回路基板におけるトランス部の基本的な構造について説明する。この回路基板１は、３枚の個々の基板１Ａと１Ｂと１Ｃを貼り合わせてなる。これら基板１Ａ〜１Ｃは貼り合わされたとき互いに合致する位置にトランスのコア２Ａと２Ｂのそれぞれの磁脚を受け入れるコア穴３Ａ〜３Ｃをそれぞれ有する。基板１Ａは回路基板１の一方の表面になる面に、コアの中央磁脚用のコア穴３Ａを中心に螺旋状に形成された表面銅箔層からなる第１の１次巻線部４Ａを有する。
【００２３】
基板１Ｂはその一方の面に同様にコアの中央磁脚用のコア穴３Ａを中心にほぼ１ターンで形成された第１の２次巻線部５Ａが形成される。第１の２次巻線部５Ａは第１の内部銅箔層５の一部分である。この第１の内部銅箔層５は前記表面銅箔層に比べて厚みが厚く、したがって２次巻線部５Ａの膜厚は１次巻線部４Ａよりも厚く、幅も広くなっているので、大きな電流を流せる。また、第１の２次巻線部５Ａの他に、互いに分離された複数の個別の内部銅箔領域５Ｂ、５Ｃなどを備える。
【００２４】
基板１Ｃには、図示の都合上基板１Ｃと分離して示してあるが実際には回路基板１の他方の面になる面にコアの中央磁脚用のコア穴３Ａを中心にして螺旋状に形成された表面銅箔層からなる第２の１次巻線部７Ａが形成されている。この第２の１次巻線部７Ａは第１の１次巻線部４Ａの巻回方向と逆向きである。また、基板１Ｃの他方の面には基板１Ｂと同様にコアの中央磁脚用のコア穴３Ａを中心に逆向きにほぼ１ターンに形成された第２の内部銅箔層からなる第２の２次巻線部６Ａ及び後述する広面積部６Ｂが形成されており、第２の１次巻線部６Ａは第１の２次巻線部５Ａとは逆方向になっている。ここで、第１と第２の内部銅箔層は図２からもわかるように基板内部の第１と第２のレベル形成されている。
【００２５】
第１の１次巻線部４Ａの終端部は小丸で示された基板１Ａ〜１Ｃのスルーホールａ１を通して第２の１次巻線部７Ａの終端部に結合され、これらは互いに巻き方向が異なるので第１の１次巻線部４Ａと第２の１次巻線部７Ａとは直列接続され、これら１次巻線部は双方の巻線数の和に等しい１次巻線を形成する。また、第１の２次巻線部５Ａの終端部と第２の２次巻線部６Ａの終端部は基板１Ｂと基板１Ｃのスルーホールｂ１を通して直列接続され、これら２次巻線部はほぼ２ターンの２次巻線を形成する。そしてコア穴３Ａ〜３Ｃにコア２Ａ，２Ｂの磁脚を挿入してトランスを構成する。
【００２６】
図２においてトランスの第１の２次巻線部５Ａの根元である始端部は個別の内部銅箔領域５Ｂに接続されており、第２の２次巻線部６Ａの根元である始端部は広面積部６Ｂに接続されている。個別の内部銅箔領域５Ｂ、５Ｃはスルーホール８Ａ、８Ｂにより基板表面に形成された電極パッド９Ａ、９Ｂに接続される。スルーホール８Ａ、８Ｂは同一構造であり、制御信号電流よりも大きな主電流を流すので比較的大きな径の貫通孔の壁面に膜厚の厚い導電膜ａが形成されている。そして貫通孔内には回路基板の材質と比較的特性の似た合成樹脂材料ｂが表面まで充填され、スルーホール８Ａ、８Ｂの上面に跨がって平坦な電極パッド９Ａ、９Ｂを形成し易いようになっている。なお、１０は後述する表面実装型の整流用ダイオードであり、そのアノード電極は電極パッド９Ａに、またカソード電極は電極パッド９Ｂにそれぞれハンダ付けされている。特に、以後詳しくは説明しないが、少なくとも２次側のスルーホールはスルーホール８Ａ、８Ｂとほぼ同一の構造をもち、スルーホールの上面に跨がって平坦な電極パッドが形成されている。
【００２７】
この基本的な例では説明し易いように基板１Ｂに第１の２次巻線部５Ａを形成したが、基板１Ａの裏側面に形成しても良い。このように表面銅箔層、内部銅箔層の形成された基板１Ａ〜１Ｃはコア穴３Ａ〜３Ｃが合致するようにして重ね合わされ貼り合わされる。表面銅箔層の第１、第２の１次巻線部４Ａと７Ａに電気絶縁を施し、コア２Ａと２Ｂの磁脚がコア穴３Ａ〜３Ｃに挿入され固定されてトランス部が完成する。１次巻線、２次巻線の必要な巻数によっては第１、第２の１次巻線部４Ａと７Ａはいずれか一方で良く、また内部銅箔層の第１、第２の２次巻線部５Ａと６Ａも一方であっても良い。
【００２８】
内部銅箔層の第１、第２の２次巻線部５Ａと６Ａを並列接続したい場合には、図３に示すようにそれぞれ１ターンの第１の２次巻線部５Ａの始端部と第２の２次巻線部６Ａの終端部を通るスルーホールｂ１、及び第１の２次巻線部５Ａの終端部と第２の２次巻線部６Ａの始端部を通るスルーホールｂ２により並列接続される。したがって、この構成ではトランス２次巻線は２次巻線部５Ａと６Ａを並列接続した１ターンの巻数からなり、２次側の主電流が大きな低出力電圧のオンボード型の電源に用いるのに適する。なお、電流容量に適した数のスルーホールで必要な箇所の接続を行う。
【００２９】
次に図１の基板１Ｃに相当する基板の好ましい実施例について図４により説明する。基板１の一方の面には、２次巻線部６Ａとこれを囲むように形成された広面積部６Ｂからなる第２の内部銅箔層６が形成されている。２次巻線部６Ａはほぼ１ターンのものであり、中央のコア穴３Ａをほぼ囲むように、かつコア穴３Ｂ、３Ｃとコア穴３Ａの間を通って広面積部６Ｂから延びている。広面積部６Ｂは２次巻線部６Ａの始端部以外では接触しないように、コア穴３Ｂと３Ｃの外側から２次巻線部６Ａを取り囲むように形成されている。図４では２次巻線部６Ａの左側にスルーホールの１例としてトランスの１次側の二つのスルーホールｃ１とｃ２を示し、また２次巻線部６Ａの右側にトランスの２次側の二つのスルーホールｄ１とｄ２だけを示している。１次側の電圧は２次側の電圧よりも高いので、スルーホールｃ１とｃ２と広面積部６Ｂとの間隔はスルーホールｄ１とｄ２と広面積部６Ｂとの間隔よりも大きくなっている。小さな丸印で示されるＩｎは入力側の各端子を示し、Ｏｔは正又は負の出力端子であり、Ｓｔは広面積部６Ｂを接地電位のような安定電位に接続するための端子である。なお、鎖線で示す３ａ〜３ｃはフィルタ用のチョークコイルをトランス同様に組み込む場合のコア穴である。
【００３０】
この実施例の特徴は、従来の場合にはシールド層としてだけ用いていたベタの広面積部に代えて、その一部分にトランスの２次巻線部６Ａを形成しているところにあり、これにより広面積部６Ｂと一体的に形成されたトランスの２次巻線部を得ることができ、さらに広面積部６Ｂを安定電位に接続すればシールド作用は従来通り得られると同時に、電位の安定側の主回路導体として用いることができるところにある。なお、前記実施例と同様に、ａ１は内部銅箔層の形成されていない部分に設けられたスルーホールであって、前記１次巻線部同士、あるいは１次巻線部を他方の表面の入力端子に接続するためのものであり、また、２次巻線部６Ａの終端部に形成されたスルーホールｂ１は、第１の内部銅箔層の一部に形成された他の２次巻線部、あるいは２次巻線部６Ａを別の内部基板の２次側端子に接続するためのものである。
【００３１】
次に図５によりトランスＴｒの２ターンの２次巻線がセンタタップ構成になっている実施例を説明する。１次巻線側は前述のようなものなので説明を省く。同図（Ａ）に示す一方の巻線端Ｘは、同図（Ｂ）に示す第１の内部基板１Ｂに形成された個別の内部銅箔領域５Ｂからなり、他方の巻線端Ｙは、基板１Ｂに内部銅箔領域５Ｂとは分離された個別の内部銅箔領域５Ｄで形成される。中間タップＹは第２の内部基板１Ｃに形成された広面積部６Ｂがその役割を果たす。内部銅箔領域５Ｂから延びる第１の２次巻線部５Ａの終端部は、スルーホールｂ１により広面積部６Ｂから延びる第２の２次巻線部６Ａの始端部に接続される。そして、第２の２次巻線部６Ａの終端部はスルーホールｂ２により基板１Ｂ面の内部銅箔領域５Ｄに接続される。このようなセンタタップ構成になっている２次巻線にダイオードを接続して両波整流回路を構成する場合には、図２に示すように内部銅箔領域５Ｂと５Ｃ間に第１のダイオードを接続し、図示していないスルーホールと第２のダイオードを介して内部銅箔領域５Ｃと５Ｄ間を接続すれば良い。
【００３２】
次に、２次巻線がほぼ２ターンで２次捲線の両端が第１の内部銅箔層５の二つの個別の内部銅箔領域５Ｂ、６Ｂに接続される実施例について、図６により説明する。第１の２次巻線部５Ａは内部銅箔領域５Ｂから延びて前述のようなパターンで基板１Ｂ上に形成され、内部銅箔領域５Ｂは第１の巻線端子Ｔｒ１の働きも行う。基板１Ｂ上には内部銅箔領域５Ｂとは分離された個別の内部銅箔領域５Ｃが同一平面に形成され、これは第２の巻線端子Ｔｒ２の働きを行う。基板１Ｃには広面積部６Ｂとは分離されて第２の２次巻線部６Ａが形成される。そして、第１の２次巻線部５Ａの終端部と第２の２次巻線部６Ａの一端部はスルーホールｂ１により接続され、第２の２次巻線部６Ａの他端部はスルーホールｂ２により第１の内部銅箔層５の内部銅箔領域５Ｃに接続される。したがって、第１の２次巻線部５Ａと第２の２次巻線部６Ａは直列接続され、ほぼ２ターンのトランス２次巻線を構成する。なお、他の構成については前述と同様であるので説明を省略する。
【００３３】
次に、第１の実施例のようなトランス構造を備える回路基板を用いたオンボード型の電源の１実施例について、図７及び図８により説明する。先ず、オンボード型の電源の一般的な回路構成を図７により説明する。ここで、オンボード型の電源とは、表面実装用電子部品又はリード線を有する電子部品などを回路基板に搭載して主回路配線の一方が安定な電位にある電源機能部を有する電源をいう。また、主回路素子とは下記の主回路配線間に接続される電子部品をいう。トランスＴｒの１次巻線Ｎ１側には、商用交流電源ＡＣ、その交流電圧を整流する整流回路ＲＥ、直流電圧を所定の周波数、例えば２００ｋＨｚの高周波交流電圧に変換する高周波インバータ回路ＩＮが接続されている。トランスＴｒはその１次巻線Ｎ１に印加される電圧を降圧して２次巻線Ｎ２に所定の低い電圧を発生させる降圧トランスであり、２次巻線Ｎ２の巻数は１次巻線Ｎ１よりも少なく、例えば１ターンから数ターンである。したがって、１次巻線Ｎ１よりも２次巻線Ｎ２を流れる電流は大きい。
【００３４】
トランスＴｒの２次巻線Ｎ２の一方の端子には、主回路配線Ｕ１、整流用ダイオードＤ１、主回路配線Ｕ２、出力フィルタ用のインダクタＬ、主回路配線Ｕ３、及び一方の出力端子ＯＵＴ１が直列接続されている。また、トランスＴの２次巻線Ｎ２の他方の端子と他方の出力端子ＯＵＴ２との間には、接地電位のような安定な低電位に接続された主回路配線Ｕ４が接続されている。また、主回路配線Ｕ２と主回路配線Ｕ４との間にはフリーホイーリングダイオードＤ２が接続され、主回路配線Ｕ３と主回路配線Ｕ４との間には互いに並列の出力フィルタ用のキャパシタＣ１が接続されている。
【００３５】
この構成のオンボード型の電源は、図８に示すような回路基板１の一方の面又は双方の面に電子部品が搭載される。この電力用の回路基板１は、主回路配線Ｕ１〜Ｕ３及び他方の主回路配線Ｕ４が回路基板１の内部に形成されると共に、主回路配線Ｕ１〜Ｕ３を形成する第１の内部銅箔層５（一点鎖線で示す）は回路基板１内の第１のレベルにあり、主回路配線Ｕ４を形成する第２の内部銅箔層６（鎖線で示す）は第１のレベルとは異なる第２のレベルにある。第１の内部銅箔層５は前述したように第１の巻線部５Ａの他に複数の個別の内部銅箔領域５Ｂ、５Ｃなどからなる。第２の内部銅箔層６は図４に示したパターンとほぼ同じようなパターンで形成され、安定な低電位に接続される。なお、トランスＴｒの構造は図１ないし図４の実施例で説明したような構造をもつので、この実施例では詳述するのを省く。
【００３６】
このような回路基板１を使用した本発明のオンボード型の電源の第１の特徴は、所定の電力用の主回路素子の各電極がスルーホール及び電極パッドを介してほぼ最短距離で第１又は第２の内部銅箔層５、６に接続され、第２の内部銅箔層６の広面積部６Ｂは一方の主回路配線となると共に、接地電位のような安定な低電位に接続されてシールド層の作用も行うところにある。第２の特徴は、所定の主回路素子はスル−ホール及び電極パッドを介して、第１の内部銅箔層５の個別の内部銅箔領域間、第１の内部銅箔層５の個別の内部銅箔領域と第２の内部銅箔層６との間に接続されるところにある。
【００３７】
次に、オンボード型の電源の２次側の配置及び構造について説明する。図９、図１０、図１１はそれぞれ図８におけるＸ−Ｘ’、Ｙ１−Ｙ１’、Ｙ２−Ｙ２’での切断面を示している。第１、第２の内部銅箔層５、６は主回路電流を担持することができる厚みと幅を有し、その厚みは回路基板１の表面に形成されている通常の回路パターン層４、７よりもかなり厚く、数十μｍ以上、好ましくは５０μｍ以上である。なお、後述するスルーホールＴ１〜Ｔ１０は図２のスルーホール８Ａ、８Ｂと同様な構造のものである。
【００３８】
トランスＴｒの２次巻線の一方の端子Ｔｒ１は前述のように第２の内部銅箔層６の広面積部６Ｂ（主回路配線Ｕ４に相当する）に一体的に接続されており、その他方の端子Ｔｒ２は第１の内部銅箔層５の個別の内部銅箔領域５Ｂ（主回路配線Ｕ１に相当する）に一体的に接続されており、２次巻線の接続工程は不要である。ダイオードＤ１のアノードはスルーホールＴ１を通して内部銅箔領域５Ｂ（Ｕ１）に接続され、そのカソードはスルーホールＴ２を通して第１の内部銅箔層５の個別の内部銅箔領域５Ｃ（主回路配線Ｕ２に相当する）に接続される。ここでスルーホールＴ１とＴ２との間の間隔はダイオードＤ１のアノード電極とカソード電極間の間隔にほぼ等しい。
【００３９】
次に、ダイオードＤ２のカソードはスルーホールＴ３を通して内部銅箔領域５Ｃ（Ｕ２）に接続され、そのアノードはスルーホールＴ４を通して第２の内部銅箔層６の広面積部６Ｂ（Ｕ４）に接続される。スルーホールＴ３とＴ４との間の間隔はダイオードＤ１のアノード電極とカソード電極間の間隔にほぼ等しい。インダクタＬの一方の電極Ｌ１はスルーホールＴ５を通して内部銅箔領域５Ｃ（Ｕ２）に接続され、その他方の電極Ｌ２はスルーホールＴ６を通して第１の内部銅箔層５の個別の内部銅箔領域５Ｄ（Ｕ３）に接続される。スルーホールＴ５とＴ６との間の間隔はインダクタＬの双方の電極間の間隔にほぼ等しい。キャパシタＣ１の一方の電極はスルーホールＴ７を通して第２の内部銅箔層６の広面積部６Ｂ（Ｕ４）に接続され、その他方の電極はスルーホールＴ８を通して内部銅箔領域５Ｄ（Ｕ３）に接続される。これらスルーホール間の間隔もコンデンサＣ１の両電極間の間隔にほぼ等しい。出力端子ＯＵＴ１は内部銅箔領域５Ｄ（Ｕ３）に接続され、出力端子ＯＵＴ２は第２の内部銅箔層６の広面積部６Ｂ（Ｕ４）に接続される。
【００４０】
ここで、スルーホールＴ１、Ｔ２、Ｔ３、Ｔ５、Ｔ６、Ｔ８は第１の内部銅箔層５の対応する内部銅箔領域まで延びて電気的に結合され、またスルーホールＴ４、Ｔ７は途中で第２の内部銅箔層６の広面積部６Ｂに電気的に結合されて回路基板１の裏面まで延びている。このように各電力用の主回路素子の電極は、電極間間隔とほぼ等しい間隔で設けられたスルーホール、つまり各電極の位置に形成されたスルーホールにより最短距離で内部銅箔領域に接続されるので、高密度実装化を可能にするだけでなく、電気抵抗の低減による電力損失及び配線によるストレイキャパシタンス、浮遊インダクタンスを低減できる。
【００４１】
次に、同期整流方式のオンボード型電源の実施例について説明ずる。図１２は同期整流回路の基本的な回路例であり、同図（Ａ）に示す同期整流部Ｒｅは、トランスＴｒの２次巻線の端子Ｔｒ１、Ｔｒ２、整流用ＦＥＴ１、フリーホイーリング機能を行うＦＥＴ２、それらＦＥＴのゲートに接続された駆動回路Ｚ１、Ｚ２からなる。同期整流部Ｒｅの出力側にインダクタＬとコンデンサＣとからなる出力フィルタが接続される。その構成配置は同図（Ｂ）のようになる。同期整流回路に用いるトランスの２次巻線部の構成は図６に示したようなものであり、１次巻線側も前述と同様なものであるので説明を省略する。
【００４２】
トランスＴｒの２次巻線の一方の端子Ｔｒ１は内部銅箔層５の個別の内部銅箔領域５Ｂ（主回路配線Ｕ５に相当する）に一体的に接続されており、その他方の端子Ｔｒ２は内部銅箔層５の個別の内部銅箔領域５Ｃ（主回路配線Ｕ６に相当する）に一体的に接続されており、２次巻線の接続工程は不要である。図において、前述と同様にこの回路基板１は、主回路配線Ｕ５〜Ｕ７及び他方の主回路配線Ｕ８が回路基板１の内部に形成され、回路基板１内において主回路配線Ｕ５〜Ｕ７を形成する第１の内部銅箔層５は回路基板１内の第１のレベルにあり、主回路配線Ｕ８を形成する第２の内部銅箔層６の広面積部６Ｂは第１のレベルとは異なる第２のレベルにある。第１の内部銅箔層５は複数の個別の内部銅箔領域５Ｂ〜５Ｄからなる。第２の内部銅箔層６は第２の２次巻線部６Ａと回路基板１の広い範囲に一面に、つまりベタで形成され、安定な低電位に接続されてシールド導体の作用も行う広面積部６Ｂとで構成される。
【００４３】
整流用ＦＥＴ１のドレイン電極はスルーホールＴ１を通して第１の内部銅箔層５の内部銅箔領域５Ｃ（Ｕ６）に接続され、そのソース電極はスルーホールＴ２を通して第２の内部銅箔層６の広面積部６Ｂ（主回路配線Ｕ８に相当する）に接続される。一方、ＦＥＴ２のドレイン電極はスルーホールＴ３を通して第１の内部銅箔層２の内部銅箔領域５Ｂ（Ｕ５）に接続され、そのソース電極はスルーホールＴ４を通して第２の内部銅箔層３の広面積部６Ｂ（Ｕ８）に接続される。
【００４４】
鎖線２重丸で示される整流用ＦＥＴ１のゲート電極は、通常の表面実装の場合と同様に回路基板１表面の表面銅箔層７ａに接続され、駆動回路Ｚ１の一方の電極も表面銅箔層７ａに接続される。駆動回路Ｚ１の他方の電極はスルーホールＴ５を通して第１の内部銅箔層５の内部銅箔領域５Ｂ（Ｕ５）に接続される。鎖線２重丸で示されるＦＥＴ２のゲート電極は、通常の表面実装の場合と同様に回路基板１表面の表面銅箔層７ｂに接続され、駆動回路Ｚ２の一方の電極も表面銅箔層７ｂに接続される。駆動回路Ｚ２の他方の電極はスルーホールＴ６を通して第１の内部銅箔層５の個別の内部銅箔領域５Ｃ（Ｕ６）に接続される。また、インダクタＬの双方の電極はスルーホールＴ７、Ｔ８を通して第１の内部銅箔層５の内部銅箔領域５Ｂ（Ｕ５）、５Ｄ（主回路配線Ｕ７に相当する）それぞれに接続される。コンデンサＣの双方の電極はスルーホールＴ９、Ｔ１０を通して第１の内部銅箔層５の内部銅箔領域５Ｄ（Ｕ７）、第２の内部銅箔層６の広面積部６Ｂ（Ｕ８）にそれぞれ接続される。なお、以上の実施例では各２次巻線部の巻数を１ターンにしたが、２ターン又は３ターンなど複数巻数にしても勿論よい。
【００４５】
なお、以上述べた実施例では内部銅箔層を２層のものとして説明したが、２次巻線の巻数が更に多い場合で、電流容量及びコアの大きさの関係から２層の内部銅箔層では必要な巻線を形成できないときには、前述と同様な２次巻線部を有する必要なだけ内部銅箔層を更に増やせば良い。また、本発明によるトランス構造は前記実施例に限らす通常の種々の回路構成の整流回路やインバータ回路などに適用できることは言うまでもない。また、この発明の大きな効果として、表面実装される電子部品、少なくとも電流容量の大きな電子部品の電極をスルーホールを通して最短で内部銅箔層に接続できるので、実装密度を大幅に向上でき、電源の小型化と電力損失の低減を達成できること、さらに多くの又はほとんどの電子部品の電極をスルーホールを通して最短で内部銅箔層に接続できる可能性があげられる。
【００４６】
【発明の効果】
以上述べたように、本発明回路基板は、電圧の変動する側の複数の主回路配線を回路基板内の第１のレベルにある第１の内部銅箔層の複数の内部銅箔領域で形成し、他方の安定電位にある主回路配線を回路基板内の第２のレベルにあるシールド導体の作用も行う第２の内部銅箔層で形成し、第１と第２の内部銅箔層の双方又はいずれか一方に２次巻線部を形成し、スルーホールで接続しているので、トランス部の２次巻線のハンダ付けによる接続工程が不要で、電力容量の大きい小型のトランス部を有する回路基板を得ることができる。また、トランス部の２次巻線の接続部が無いため高密度実装が可能で、回路配線によるストレイキャパシタンスや浮遊インダクタンスの悪影響を小さくできるなど、実用上の効果は大きい。この回路基板を用いれば各スルーホールを通して電力用電子部品の主電極から最短で前記第１の内部銅箔層又は第２の内部銅箔層に接続できると共にハンダ付け部を最少にできるで、オンボード型の電源をより一層小型化できると同時に、回路の電気抵抗を小さくすることができる。
【図面の簡単な説明】
【図１】本発明に係る回路基板のトランス部の基本構造を示す図である。
【図２】本発明の回路基板の一実施例を説明するための配置図である。
【図３】本発明の回路基板のトランス部の２次巻線部の一実施例を説明するための図である。
【図４】本発明に用いられる内部基板の好ましい１例を示す図である。
【図５】本発明の回路基板のトランス部の２次巻線部の一実施例を説明するための図である。
【図６】本発明の回路基板のトランス部の２次巻線部の別の一実施例を説明するための図である。
【図７】電源回路の回路構成の１例を示す図である。
【図８】本発明の電源装置の実装構造の１実施例を示す図である。
【図９】図７の一部断面を示す図である。
【図１０】図７の他の一部断面を示す図である。
【図１１】図７の他の一部断面を示す図である。
【図１２】本発明の電源装置の一実施例を説明するための図である。
【符号の説明】
１・・回路基板２・・第１の内部銅箔層
２Ａ，２Ｂ・・トランスのコア３Ａ−３Ｂ・・コア用の穴
４Ａ・・第１の１次巻線部５Ａ・・第１の２次巻線部
６Ａ・・第２の２次巻線部７Ａ・・第２の１次巻線部
８Ａ，８Ｂ・・スルーホール９Ａ，９Ｂ・・電極パッド
ａ１，ｂ１，ｂ２，ｃ１，ｃ２，ｄ１，ｄ２，Ｔ１−Ｔ１０・・スルーホール
Ｃ・・コンデンサＬ・・インダクタ
Ｔｒ・・トランス[0001]
[Industrial application fields]
The present invention relates to a circuit board provided with a transformer winding of a thick internal copper foil layer serving as a power circuit inside the board, and a power source on which electronic components are mounted.
[0002]
[Prior art]
A transformer using a printed coil formed by forming a narrow metal film in a spiral shape on a circuit board as a winding is widely known. For example, Japanese Patent Laid-Open No. 61-156802 discloses that a multilayer circuit board is used, a primary winding of a transformer is formed on the surface of the circuit board, and a secondary winding is formed inside. Japanese Patent Application Laid-Open No. 61-156802 discloses that a circuit board having a large area may be used and other electronic components may be mounted.
[0003]
[Problems to be solved by the invention]
However, Japanese Patent Application Laid-Open No. 61-156802 only substantially describes the basic structure of a printed coil transformer, and this structure can be used for a power source with a relatively small current. However, it cannot cope with the case where a current of several amperes or more flows through the secondary winding or the primary winding. Moreover, in what was disclosed by Unexamined-Japanese-Patent No. 61-156802, it consists of three layers, a front side shielding internal copper foil layer, a back side shielding internal copper foil layer, and a heat dissipation internal copper foil layer provided between them on the circuit board. Since it has an internal copper foil layer and uses the through-holes to dissipate the heat of the electronic components to the internal copper foil layer for heat dissipation, it does not have an internal copper foil layer for wiring inside the board, and control wiring In addition to the wiring for detection and the wiring for power, there is a disadvantage that the wiring for power must be formed by the surface copper foil layer formed on the surface of the substrate. Further, the one disclosed in Japanese Utility Model Laid-Open No. 59-101441 has three internal copper foil layers for power supply, grounding and wiring, which are independent from each other. There was a disadvantage that it became high.
[0004]
Accordingly, it is a main object of the present invention to provide a circuit board capable of high-density mounting having a printed coil type transformer that is smaller and has a larger power capacity than the prior art, and an on-board type power supply.
[0005]
[Means for Solving the Problems]
[0006]
In order to solve the above-mentioned problem, the first aspect of the present invention has a spiral shape that is formed on the surface of one or both of the substrates around the core hole provided in the circuit board and serves as the primary winding of the transformer. A surface copper foil layer having a primary winding portion, a first internal copper foil layer formed on a first plane inside the substrate, having a thickness greater than the thickness of the surface copper foil layer; A circuit board comprising: a second internal copper foil layer formed on a second plane different from the first plane; and a plurality of through holes extending from the substrate surface to the first and second internal copper foil layers. The first internal copper foil layer is composed of a plurality of individual internal copper foil regions, and the second internal copper foil layer is approximately 1 centered on the continuously formed wide area portion and the core hole. A secondary winding portion that forms a secondary winding of the transformer above the turn, and the secondary winding portion is Providing a circuit board and an end or both ends are connected to a separate internal copper area of the first inner copper foil layer by the through-hole.
[0007]
According to a second aspect of the present invention, in order to solve the above-mentioned problem, a spiral shape is formed on the surface of one or both of the substrates around a core hole provided in the circuit board and becomes the primary winding of the transformer. A surface copper foil layer having a primary winding portion, a first internal copper foil layer formed on a first plane inside the substrate, having a thickness greater than the thickness of the surface copper foil layer; A circuit board comprising: a second internal copper foil layer formed on a second plane different from the first plane; and a plurality of through holes extending from the substrate surface to the first and second internal copper foil layers. The first internal copper foil layer is composed of a secondary winding portion formed by approximately one turn or more in one direction around the core hole and a plurality of individual internal copper foil regions, The second inner copper foil layer is formed of a continuously formed wide area portion, and the secondary winding portion has a terminal portion at the end. Providing a circuit board and being connected to said second internal copper foil layer by Horu.
[0008]
According to a third aspect of the present invention, in order to solve the above-mentioned problem, a spiral shape is formed on the surface of one or both of the substrates around the core hole provided in the circuit board and becomes the primary winding of the transformer. A surface copper foil layer having a primary winding portion, a first internal copper foil layer formed on a first plane inside the substrate, having a thickness greater than the thickness of the surface copper foil layer; A circuit board comprising: a second internal copper foil layer formed on a second plane different from the first plane; and a plurality of through holes extending from the substrate surface to the first and second internal copper foil layers. The first internal copper foil layer is composed of a first secondary winding portion formed in about one turn or more in one direction around the central hole and a plurality of individual internal copper foil regions. The second inner copper foil layer is formed from a continuously formed wide area portion and extends from the wide area portion to the core hole. And a second secondary winding portion formed in approximately 1 turn or more in the opposite direction, and the first and second secondary winding portions pass through the respective end portions and the mating start portion. Provided is a circuit board characterized in that a transformer secondary winding having a number of turns of approximately 2 turns or more is formed by being connected in series with each other through the through hole.
[0009]
According to a fourth aspect of the present invention, in order to solve the above-described problem, a spiral shape is formed on the surface of one or both of the core holes provided in the circuit board to form the primary winding of the transformer. A surface copper foil layer, a first inner copper foil layer having a thickness greater than the thickness of the spiral surface copper foil layer, formed on the first plane inside the substrate, and the first plane A circuit board comprising: a second internal copper foil layer formed on a different second plane; and a plurality of through-holes extending from the substrate surface to the first and second internal copper foil layers and connected thereto The first internal copper foil layer includes a first secondary winding portion formed in approximately one turn or more in one direction around the core hole, and a plurality of individual internal copper foil regions. The second internal copper foil layer is formed from a continuous wide area portion and extends from the wide area portion. The first and second winding portions are formed of a second secondary winding portion formed at substantially one turn or more in the same direction as the first winding portion around the hole. Provided is a circuit board characterized in that a transformer secondary winding having a number of turns of approximately 1 turn or more is formed by being connected in parallel with each other by the through-hole passing through a terminal end and a partner start end.
[0010]
According to a fifth aspect of the present invention, in order to solve the above-mentioned problem, a spiral shape is formed on the surface of one or both of the core holes provided in the circuit board to form the primary winding of the transformer. A surface copper foil layer, a first inner copper foil layer having a thickness greater than the thickness of the spiral surface copper foil layer, formed on the first plane inside the substrate, and the first plane A circuit board comprising: a second internal copper foil layer formed on a different second plane; and a plurality of through-holes extending from the substrate surface to the first and second internal copper foil layers and connected thereto The first inner copper foil layer has a plurality of individual inner copper foil regions and a central portion extending from the first inner copper foil region which is one of the inner copper foil regions. A first secondary winding portion formed in about 1 turn or more in the direction, the inner copper foil region being one side The second internal copper foil region constituting the winding terminal and the other internal copper foil region, which is another one of the individual internal copper foil regions, serves as the other winding terminal, and the second internal copper foil layer is continuous. The wide area part formed separately and the second secondary winding part formed separately from the wide area part and formed with approximately one turn or more around the core hole, The terminal portion of the first winding portion and one end portion of the second winding portion are connected by the through hole, and the other end portion of the second winding portion is connected by the through hole. There is provided a circuit board characterized in that a transformer secondary winding having a number of turns of about 2 turns or more is formed by being connected to two individual internal copper foil regions.
[0011]
According to a sixth aspect of the present invention, in order to solve the above-mentioned problem, in any one of the first, third, and fifth aspects, the secondary winding portion formed in the second internal copper foil layer is the wide coil portion. A circuit board characterized by being surrounded by an area portion is provided.
[0012]
According to a seventh aspect of the present invention, in order to solve the above-mentioned problem, in any of the first to sixth aspects, when the spiral surface copper foil layer is formed on both the substrate surfaces, There is provided a circuit board characterized in that the circuit boards are connected in series with each other by the through hole extending from the terminal portion of the spiral surface copper foil layer to the other spiral surface copper foil layer.
[0013]
According to an eighth aspect of the present invention, in order to solve the above-mentioned problem, in any one of the first to sixth aspects, when the spiral surface copper foil layer is formed on both the substrate surfaces, There is provided a circuit board characterized in that the circuit boards are connected in parallel to each other by the through hole extending from the terminal portion of the spiral surface copper foil layer to the other spiral surface copper foil layer.
[0014]
According to a ninth aspect of the present invention, in order to solve the above-mentioned problem, in any one of the first to eighth aspects, the circuit board includes the first surface of the spiral surface copper foil layer and the inner copper foil layer. A circuit board is provided in which another hole for the core is provided on both sides of the winding part and the second winding part and on a straight line passing through the core hole.
[0015]
According to a tenth aspect of the present invention, in order to solve the above problem, the circuit according to the ninth aspect, wherein the magnetic legs of the core are inserted and fixed in the core hole and another hole for the core. Providing a substrate.
[0016]
According to an eleventh aspect of the present invention, in order to solve the above-mentioned problem, in the circuit board according to any one of the first to tenth aspects, the electrode pad formed on the circuit board over the through hole is predetermined. The electronic component is connected, and the wide area portion of the second internal copper foil layer is connected to a stable potential.
[0017]
According to a twelfth aspect of the present invention, in order to solve the above problem, the circuit board according to any one of the first to tenth aspects is used, and the first winding portion in the first internal copper foil layer is formed through the through hole. An electronic component is connected to the individual internal copper foil region through the electrode pad.
[0018]
According to a thirteenth aspect of the present invention, in order to solve the above problem, the individual internal copper foil portion of the first inner copper foil layer is formed through the through hole using the circuit board according to any one of the first to eleventh aspects. An electronic component is connected to the second internal copper foil region through the electrode pad.
[0019]
Claim 14 of the present invention solves the above-mentioned problem, 6. The synchronous rectification type power supply comprising a circuit board according to claim 5 and a rectifying FET mounted on the surface thereof, wherein the drain electrode and the source electrode of the rectifying FET are respectively connected to the first internal copper foil layer through the through hole. Connected to one individual internal copper foil region and the second individual internal copper foil region A power supply is provided.
[0020]
Claim 15 of the present invention solves the above problem, 6. The synchronous rectification type power supply comprising a circuit board according to claim 5 and surface-mounting a freewheeling FET or diode, wherein the freewheeling FET or diode is connected to the first individual copper foil layer. The through-hole is connected between the inner copper foil region of the second inner copper foil region and the wide area portion of the second inner copper foil layer. A power supply is provided.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
First, the basic structure of the transformer part in the circuit board of the present invention will be described with reference to FIGS. The circuit board 1 is formed by bonding three individual boards 1A, 1B, and 1C. These substrates 1A to 1C have core holes 3A to 3C for receiving the magnetic legs of the transformer cores 2A and 2B, respectively, at positions that match each other when bonded. The substrate 1A has a first primary winding portion 4A made of a surface copper foil layer spirally formed around the core hole 3A for the central magnetic leg of the core on the surface to be one surface of the circuit board 1. Have.
[0023]
Similarly, the substrate 1B is provided with a first secondary winding portion 5A formed on the one surface of the core 1B in substantially one turn around the core hole 3A for the central magnetic leg of the core. The first secondary winding portion 5 </ b> A is a part of the first internal copper foil layer 5. Since the first internal copper foil layer 5 is thicker than the surface copper foil layer, the thickness of the secondary winding portion 5A is larger than that of the primary winding portion 4A and wider. A large current can flow. Further, in addition to the first secondary winding portion 5A, a plurality of individual internal copper foil regions 5B, 5C and the like separated from each other are provided.
[0024]
The substrate 1C is shown as being separated from the substrate 1C for convenience of illustration, but in reality, the other surface of the circuit substrate 1 is spirally formed around the core hole 3A for the central magnetic leg of the core. A second primary winding portion 7A made of the formed surface copper foil layer is formed. The second primary winding portion 7A is opposite to the winding direction of the first primary winding portion 4A. The second surface of the substrate 1C is formed of a second inner copper foil layer formed in the opposite direction about the core hole 3A for the central magnetic leg of the core in the opposite direction in the same manner as the substrate 1B. A secondary winding portion 6A and a wide area portion 6B described later are formed, and the second primary winding portion 6A is in the opposite direction to the first secondary winding portion 5A. Here, the first and second inner copper foil layers are formed at the first and second levels inside the substrate as can be seen from FIG.
[0025]
The end portion of the first primary winding portion 4A is coupled to the end portion of the second primary winding portion 7A through the through holes a1 of the substrates 1A to 1C indicated by small circles, and these have different winding directions. Therefore, the first primary winding portion 4A and the second primary winding portion 7A are connected in series, and these primary winding portions form a primary winding equal to the sum of the numbers of both windings. The terminal end of the first secondary winding 5A and the terminal end of the second secondary winding 6A are connected in series through the through-hole b1 of the substrate 1B and the substrate 1C. A 2-turn secondary winding is formed. And a magnetic leg of core 2A, 2B is inserted in core holes 3A-3C, and a transformer is constituted.
[0026]
In FIG. 2, the starting end portion that is the root of the first secondary winding portion 5A of the transformer is connected to the individual internal copper foil region 5B, and the starting end portion that is the root of the second secondary winding portion 6A is It is connected to the wide area portion 6B. The individual internal copper foil regions 5B and 5C are connected to electrode pads 9A and 9B formed on the substrate surface by through holes 8A and 8B. The through holes 8A and 8B have the same structure, and a main current larger than the control signal current flows. Therefore, a thick conductive film a is formed on the wall surface of the through hole having a relatively large diameter. The through hole is filled with a synthetic resin material b having characteristics relatively similar to the material of the circuit board, and flat electrode pads 9A and 9B are easily formed across the upper surfaces of the through holes 8A and 8B. It is like that. Reference numeral 10 denotes a surface mount type rectifying diode described later, the anode electrode of which is soldered to the electrode pad 9A and the cathode electrode of which is soldered to the electrode pad 9B. In particular, although not described in detail later, at least the secondary through hole has substantially the same structure as the through holes 8A and 8B, and a flat electrode pad is formed across the upper surface of the through hole.
[0027]
In this basic example, the first secondary winding 5A is formed on the substrate 1B for easy explanation, but it may be formed on the back side surface of the substrate 1A. Thus, the board | substrates 1A-1C with which the surface copper foil layer and the internal copper foil layer were formed are piled up and bonded so that the core holes 3A-3C match. The first and second primary winding portions 4A and 7A of the surface copper foil layer are electrically insulated, and the magnetic legs of the cores 2A and 2B are inserted and fixed in the core holes 3A to 3C to complete the transformer portion. Depending on the required number of turns of the primary winding and the secondary winding, either the first or second primary winding 4A or 7A may be used, and the first or second secondary of the internal copper foil layer. The winding portions 5A and 6A may be one.
[0028]
When it is desired to connect the first and second secondary winding portions 5A and 6A of the internal copper foil layer in parallel, as shown in FIG. 3, the first end portion of the first secondary winding portion 5A having one turn and Through hole b1 passing through the terminal end of second secondary winding part 6A and through hole b2 passing through the terminal part of first secondary winding part 5A and the starting end part of second secondary winding part 6A Connected in parallel. Therefore, in this configuration, the transformer secondary winding has a number of turns of one turn in which the secondary winding portions 5A and 6A are connected in parallel, and is used for an on-board power source with a large secondary current and a low output voltage. Suitable for. In addition, the connection of a required location is performed by the number of through holes suitable for current capacity.
[0029]
Next, a preferred embodiment of a substrate corresponding to the substrate 1C of FIG. 1 will be described with reference to FIG. On one surface of the substrate 1, a second internal copper foil layer 6 is formed which includes a secondary winding portion 6A and a wide area portion 6B formed so as to surround the secondary winding portion 6A. The secondary winding portion 6A has approximately one turn, and extends from the large area portion 6B so as to substantially surround the central core hole 3A and between the core holes 3B and 3C and the core hole 3A. The wide area portion 6B is formed so as to surround the secondary winding portion 6A from the outside of the core holes 3B and 3C so as to avoid contact except at the start end portion of the secondary winding portion 6A. In FIG. 4, two through holes c1 and c2 on the primary side of the transformer are shown as an example of the through hole on the left side of the secondary winding part 6A, and the secondary side of the transformer is on the right side of the secondary winding part 6A. Only two through holes d1 and d2 are shown. Since the voltage on the primary side is higher than the voltage on the secondary side, the distance between the through holes c1 and c2 and the large area portion 6B is larger than the distance between the through holes d1 and d2 and the large area portion 6B. In indicated by a small circle represents each terminal on the input side, Ot is a positive or negative output terminal, and St is a terminal for connecting the wide area portion 6B to a stable potential such as a ground potential. Reference numerals 3a to 3c indicated by chain lines are core holes when a choke coil for a filter is incorporated in the same manner as a transformer.
[0030]
The feature of this embodiment is that instead of the solid wide area portion used only as a shield layer in the conventional case, a secondary winding portion 6A of the transformer is formed in a part thereof. A secondary winding portion of a transformer formed integrally with the large area portion 6B can be obtained. Further, if the large area portion 6B is connected to a stable potential, a shielding action can be obtained as before, and at the same time a stable potential side. It can be used as a main circuit conductor. As in the previous embodiment, a1 is a through hole provided in a portion where the internal copper foil layer is not formed, and the primary winding portions or the primary winding portions are connected to each other on the other surface. The through-hole b1 formed for connection to the input terminal and formed in the terminal portion of the secondary winding portion 6A is another secondary winding formed in a part of the first internal copper foil layer. This is for connecting the wire portion or the secondary winding portion 6A to the secondary terminal of another internal substrate.
[0031]
Next, an embodiment in which the secondary winding of the transformer Tr has a center tap configuration will be described with reference to FIG. Since the primary winding side is as described above, the description is omitted. One winding end X shown in FIG. 2A is made up of individual internal copper foil regions 5B formed on the first internal substrate 1B shown in FIG. 1B, and the other winding end Y is The substrate 1B is formed of individual internal copper foil regions 5D separated from the internal copper foil regions 5B. In the intermediate tap Y, the large area portion 6B formed on the second internal substrate 1C plays a role. A terminal portion of the first secondary winding portion 5A extending from the internal copper foil region 5B is connected to a starting end portion of the second secondary winding portion 6A extending from the large area portion 6B through the through hole b1. The terminal portion of the second secondary winding portion 6A is connected to the internal copper foil region 5D on the surface of the substrate 1B through the through hole b2. When a double-wave rectifier circuit is configured by connecting a diode to the secondary winding having such a center tap configuration, the first diode is interposed between the internal copper foil regions 5B and 5C as shown in FIG. And the internal copper foil regions 5C and 5D may be connected via a through hole (not shown) and the second diode.
[0032]
Next, an embodiment in which the secondary winding is approximately two turns and both ends of the secondary winding are connected to the two individual internal copper foil regions 5B and 6B of the first internal copper foil layer 5 will be described with reference to FIG. To do. The first secondary winding portion 5A extends from the internal copper foil region 5B and is formed on the substrate 1B in the pattern as described above, and the internal copper foil region 5B also functions as the first winding terminal Tr1. An individual internal copper foil region 5C separated from the internal copper foil region 5B is formed on the same plane on the substrate 1B, and this acts as the second winding terminal Tr2. A second secondary winding portion 6A is formed on the substrate 1C separately from the large area portion 6B. The terminal end of the first secondary winding 5A and one end of the second secondary winding 6A are connected by a through hole b1, and the other end of the second secondary winding 6A is a through hole. The hole b2 connects to the internal copper foil region 5C of the first internal copper foil layer 5. Therefore, the first secondary winding portion 5A and the second secondary winding portion 6A are connected in series to constitute a transformer secondary winding having approximately two turns. Since other configurations are the same as those described above, description thereof is omitted.
[0033]
Next, an embodiment of an on-board type power supply using a circuit board having a transformer structure as in the first embodiment will be described with reference to FIGS. First, a general circuit configuration of an on-board type power supply will be described with reference to FIG. Here, the on-board type power supply means a power supply having a power supply function unit in which one of main circuit wirings is at a stable potential by mounting electronic components for surface mounting or electronic components having lead wires on a circuit board. . The main circuit element is an electronic component connected between the following main circuit wirings. On the primary winding N1 side of the transformer Tr, a commercial AC power source AC, a rectifier circuit RE that rectifies the AC voltage, and a high-frequency inverter circuit IN that converts a DC voltage into a high-frequency AC voltage of a predetermined frequency, for example, 200 kHz, are connected. ing. The transformer Tr is a step-down transformer that steps down the voltage applied to the primary winding N1 and generates a predetermined low voltage in the secondary winding N2. The number of turns of the secondary winding N2 is smaller than that of the primary winding N1. There are few, for example, one turn to several turns. Therefore, the current flowing through the secondary winding N2 is larger than that of the primary winding N1.
[0034]
A main circuit wiring U1, a rectifying diode D1, a main circuit wiring U2, an output filter inductor L, a main circuit wiring U3, and one output terminal OUT1 are connected in series to one terminal of the secondary winding N2 of the transformer Tr. It is connected. A main circuit wiring U4 connected to a stable low potential such as a ground potential is connected between the other terminal of the secondary winding N2 of the transformer T and the other output terminal OUT2. A freewheeling diode D2 is connected between the main circuit wiring U2 and the main circuit wiring U4, and a parallel output filter capacitor C1 is connected between the main circuit wiring U3 and the main circuit wiring U4. Has been.
[0035]
In the on-board type power supply having this configuration, electronic components are mounted on one surface or both surfaces of a circuit board 1 as shown in FIG. In the circuit board 1 for electric power, the main circuit wirings U1 to U3 and the other main circuit wiring U4 are formed inside the circuit board 1, and the first internal copper foil layer forming the main circuit wirings U1 to U3. 5 (indicated by the alternate long and short dash line) is at the first level in the circuit board 1, and the second internal copper foil layer 6 (indicated by the chain line) forming the main circuit wiring U4 is a second different from the first level. Is at the level of As described above, the first internal copper foil layer 5 includes a plurality of individual internal copper foil regions 5B and 5C in addition to the first winding portion 5A. The second internal copper foil layer 6 is formed in a pattern substantially similar to the pattern shown in FIG. 4 and is connected to a stable low potential. Since the structure of the transformer Tr has the structure described in the embodiment of FIGS. 1 to 4, the detailed description is omitted in this embodiment.
[0036]
The first feature of the on-board type power supply of the present invention using such a circuit board 1 is that each electrode of the main circuit element for a predetermined power is first in the shortest distance through the through hole and the electrode pad. Alternatively, it is connected to the second internal copper foil layers 5 and 6, and the large area portion 6B of the second internal copper foil layer 6 becomes one main circuit wiring and is connected to a stable low potential such as the ground potential. The function of the shield layer is also performed. The second feature is that a predetermined main circuit element is connected between individual internal copper foil regions of the first inner copper foil layer 5 and individual individual inner copper foil layers 5 via through holes and electrode pads. It exists in the place connected between an internal copper foil area | region and the 2nd internal copper foil layer 6. FIG.
[0037]
Next, the arrangement and structure of the secondary side of the on-board type power supply will be described. 9, FIG. 10, and FIG. 11 show cut surfaces at XX ′, Y1-Y1 ′, and Y2-Y2 ′ in FIG. 8, respectively. The first and second internal copper foil layers 5 and 6 have a thickness and a width capable of carrying a main circuit current, and the thickness is a normal circuit pattern layer 4 formed on the surface of the circuit board 1. It is considerably thicker than 7, several tens of μm or more, preferably 50 μm or more. Note that through-holes T1 to T10 described later have the same structure as the through-holes 8A and 8B in FIG.
[0038]
One terminal Tr1 of the secondary winding of the transformer Tr is integrally connected to the large area portion 6B (corresponding to the main circuit wiring U4) of the second internal copper foil layer 6 as described above. The terminal Tr2 is integrally connected to the individual internal copper foil region 5B (corresponding to the main circuit wiring U1) of the first internal copper foil layer 5, and the secondary winding connection step is not necessary. The anode of the diode D1 is connected to the internal copper foil region 5B (U1) through the through hole T1, and the cathode thereof is connected to the individual internal copper foil region 5C (to the main circuit wiring U2) of the first internal copper foil layer 5 through the through hole T2. Connected). Here, the interval between the through holes T1 and T2 is substantially equal to the interval between the anode electrode and the cathode electrode of the diode D1.
[0039]
Next, the cathode of the diode D2 is connected to the internal copper foil region 5C (U2) through the through hole T3, and the anode is connected to the large area portion 6B (U4) of the second internal copper foil layer 6 through the through hole T4. The The distance between the through holes T3 and T4 is substantially equal to the distance between the anode electrode and the cathode electrode of the diode D1. One electrode L1 of the inductor L is connected to the internal copper foil region 5C (U2) through the through hole T5, and the other electrode L2 is connected to the individual internal copper foil region 5D of the first internal copper foil layer 5 through the through hole T6. Connected to (U3). The distance between the through holes T5 and T6 is approximately equal to the distance between both electrodes of the inductor L. One electrode of the capacitor C1 is connected to the large area portion 6B (U4) of the second internal copper foil layer 6 through the through hole T7, and the other electrode is connected to the internal copper foil region 5D (U3) through the through hole T8. Is done. The distance between these through holes is also substantially equal to the distance between both electrodes of the capacitor C1. The output terminal OUT1 is connected to the internal copper foil region 5D (U3), and the output terminal OUT2 is connected to the wide area portion 6B (U4) of the second internal copper foil layer 6.
[0040]
Here, the through holes T1, T2, T3, T5, T6, T8 extend to the corresponding internal copper foil region of the first internal copper foil layer 5 and are electrically coupled, and the through holes T4, T7 are in the middle. The second internal copper foil layer 6 is electrically coupled to the wide area portion 6 </ b> B and extends to the back surface of the circuit board 1. In this way, the electrodes of the main circuit elements for each power are connected to the internal copper foil region at the shortest distance by the through holes provided at intervals substantially equal to the intervals between the electrodes, that is, through holes formed at the positions of the respective electrodes. Therefore, not only high-density mounting can be achieved, but also power loss due to reduction in electrical resistance, stray capacitance due to wiring, and stray inductance can be reduced.
[0041]
Next, an embodiment of a synchronous rectification type on-board power supply will be described. FIG. 12 shows a basic circuit example of the synchronous rectification circuit. The synchronous rectification unit Re shown in FIG. 12A includes terminals Tr1 and Tr2 of the secondary winding of the transformer Tr, a rectifying FET1, and a freewheeling function. FET 2 to be performed and drive circuits Z1 and Z2 connected to the gates of the FETs. An output filter composed of an inductor L and a capacitor C is connected to the output side of the synchronous rectification unit Re. The arrangement is as shown in FIG. The configuration of the secondary winding portion of the transformer used in the synchronous rectifier circuit is as shown in FIG. 6, and the primary winding side is the same as described above, and thus the description thereof is omitted.
[0042]
One terminal Tr1 of the secondary winding of the transformer Tr is integrally connected to an individual internal copper foil region 5B (corresponding to the main circuit wiring U5) of the internal copper foil layer 5, and the other terminal Tr2 is It is integrally connected to the individual internal copper foil region 5C (corresponding to the main circuit wiring U6) of the internal copper foil layer 5, and the secondary winding connection step is unnecessary. As shown in the figure, the circuit board 1 has main circuit wirings U5 to U7 and the other main circuit wiring U8 formed inside the circuit board 1, and the main circuit wirings U5 to U7 are formed in the circuit board 1. The first internal copper foil layer 5 is at the first level in the circuit board 1, and the wide area portion 6B of the second internal copper foil layer 6 that forms the main circuit wiring U8 is different from the first level. It is in the 2nd level. The first internal copper foil layer 5 includes a plurality of individual internal copper foil regions 5B to 5D. The second internal copper foil layer 6 is formed over the wide area of the second secondary winding portion 6A and the circuit board 1, that is, solid, and is connected to a stable low potential so as to function as a shield conductor. It is comprised with the area part 6B.
[0043]
The drain electrode of the rectifying FET 1 is connected to the internal copper foil region 5C (U6) of the first internal copper foil layer 5 through the through hole T1, and the source electrode thereof is widened through the through hole T2 of the second internal copper foil layer 6. Connected to area portion 6B (corresponding to main circuit wiring U8). On the other hand, the drain electrode of the FET 2 is connected to the internal copper foil region 5B (U5) of the first internal copper foil layer 2 through the through hole T3, and its source electrode is widened through the through hole T4. Connected to the area 6B (U8).
[0044]
The gate electrode of the rectifying FET 1 indicated by a chain double circle is connected to the surface copper foil layer 7a on the surface of the circuit board 1 as in the case of normal surface mounting, and one electrode of the drive circuit Z1 is also connected to the surface copper foil layer. 7a. The other electrode of the drive circuit Z1 is connected to the internal copper foil region 5B (U5) of the first internal copper foil layer 5 through the through hole T5. The gate electrode of the FET 2 indicated by a chain line double circle is connected to the surface copper foil layer 7b on the surface of the circuit board 1 as in the case of normal surface mounting, and one electrode of the drive circuit Z2 is also connected to the surface copper foil layer 7b. Connected. The other electrode of the drive circuit Z2 is connected to the individual internal copper foil region 5C (U6) of the first internal copper foil layer 5 through the through hole T6. Further, both electrodes of the inductor L are connected to the internal copper foil regions 5B (U5) and 5D (corresponding to the main circuit wiring U7) of the first internal copper foil layer 5 through the through holes T7 and T8. Both electrodes of the capacitor C are connected to the inner copper foil region 5D (U7) of the first inner copper foil layer 5 and the large area portion 6B (U8) of the second inner copper foil layer 6 through through holes T9 and T10, respectively. Is done. In the above embodiment, the number of turns of each secondary winding portion is one turn, but it is needless to say that a plurality of turns such as two turns or three turns may be used.
[0045]
In the embodiment described above, the internal copper foil layer has been described as having two layers. However, in the case where the number of turns of the secondary winding is larger, the two layers of the internal copper foil are obtained from the relationship between the current capacity and the size of the core. When the necessary windings cannot be formed by the layers, the internal copper foil layer may be further increased as much as necessary having the secondary winding portion similar to the above. Further, it goes without saying that the transformer structure according to the present invention can be applied to rectifier circuits, inverter circuits, and the like having various usual circuit configurations that are not limited to the above-described embodiments. In addition, as a significant effect of the present invention, the surface mounting electronic component, at least the electrode of the electronic component having a large current capacity, can be connected to the internal copper foil layer through the through hole at the shortest, so that the mounting density can be greatly improved, and the power supply It is possible to achieve miniaturization and reduction of power loss, and more likely to connect the electrodes of many or most electronic components to the internal copper foil layer through the through holes at the shortest.
[0046]
【The invention's effect】
As described above, in the circuit board of the present invention, the plurality of main circuit wirings on the voltage fluctuation side are formed by the plurality of inner copper foil regions of the first inner copper foil layer at the first level in the circuit board. The main circuit wiring at the other stable potential is formed of a second internal copper foil layer that also acts as a shield conductor at the second level in the circuit board, and the first and second internal copper foil layers Since the secondary winding is formed on both or either side and connected by through-holes, there is no need for a connecting step by soldering the secondary winding of the transformer, and a small transformer with a large power capacity A circuit board having the same can be obtained. In addition, since there is no connection portion for the secondary winding of the transformer, high-density mounting is possible, and the adverse effects of stray capacitance and stray inductance due to circuit wiring can be reduced. If this circuit board is used, it is possible to connect to the first internal copper foil layer or the second internal copper foil layer as short as possible from the main electrode of the power electronic component through each through hole and to minimize the soldering portion. The board-type power supply can be further reduced in size, and at the same time, the electric resistance of the circuit can be reduced.
[Brief description of the drawings]
FIG. 1 is a diagram showing a basic structure of a transformer section of a circuit board according to the present invention.
FIG. 2 is a layout view for explaining one embodiment of a circuit board of the present invention.
FIG. 3 is a diagram for explaining an embodiment of a secondary winding portion of a transformer portion of a circuit board according to the present invention.
FIG. 4 is a view showing a preferred example of an internal substrate used in the present invention.
FIG. 5 is a diagram for explaining an embodiment of a secondary winding portion of a transformer portion of a circuit board according to the present invention.
FIG. 6 is a view for explaining another embodiment of the secondary winding part of the transformer part of the circuit board of the present invention.
FIG. 7 is a diagram illustrating an example of a circuit configuration of a power supply circuit.
FIG. 8 is a diagram showing one embodiment of a mounting structure of a power supply device of the present invention.
9 is a diagram showing a partial cross section of FIG. 7;
10 is a view showing another partial cross section of FIG. 7; FIG.
11 is a view showing another partial cross section of FIG. 7; FIG.
FIG. 12 is a diagram for explaining an embodiment of the power supply device of the present invention.
[Explanation of symbols]
1. Circuit board 2. First internal copper foil layer
2A, 2B ... Core of transformer 3A-3B ... Hole for core
4A ··· First primary winding portion 5A · · First secondary winding portion
6A ... Second secondary winding 7A ... Second primary winding
8A, 8B ... Through hole 9A, 9B ... Electrode pad
a1, b1, b2, c1, c2, d1, d2, T1-T10 ..Through hole
C. Capacitor L. Inductor
Tr ・ Trans

Claims

回路基板に設けられたコア穴を中心にしてそのいずれか一方又は双方の基板表面に形成されてトランスの１次巻線となる渦巻き状の１次巻線部を備える表面銅箔層と、該表面銅箔層の厚みよりも厚い肉厚をもち、基板内部における第１の平面に形成された第１の内部銅箔層と、第１の平面とは異なる第２の平面に形成された第２の内部銅箔層と、前記基板表面から前記第１、第２の内部銅箔層に延びる複数のスルーホールとを備えた回路基板であって、
前記第１の内部銅箔層は複数の個別の内部銅箔領域からなり、
前記第２の内部銅箔層は連続的に形成された広面積部と前記コア穴を中心にほぼ１タ−ン以上の前記トランスの２次巻線を形成する２次巻線部とからなり、
前記２次巻線部はその終端部又は両端部が前記スルーホールにより前記第１の内部銅箔層の個別の内部銅箔領域に接続されることを特徴とする回路基板。A surface copper foil layer having a spiral primary winding portion that is formed on one or both of the substrate surfaces around a core hole provided in a circuit board and serves as a primary winding of a transformer; A first inner copper foil layer formed on the first plane inside the substrate and having a thickness greater than the thickness of the surface copper foil layer, and a second plane formed on the second plane different from the first plane. A circuit board comprising two internal copper foil layers and a plurality of through holes extending from the substrate surface to the first and second internal copper foil layers,
The first inner copper foil layer comprises a plurality of individual inner copper foil regions,
The second internal copper foil layer is composed of a continuously formed wide area portion and a secondary winding portion that forms a secondary winding of the transformer of approximately one turn or more around the core hole. ,
The circuit board, wherein the secondary winding portion has a terminal portion or both end portions connected to individual internal copper foil regions of the first internal copper foil layer through the through holes.

回路基板に設けられたコア穴を中心にしてそのいずれか一方又は双方の基板表面に形成されてトランスの１次巻線となる渦巻き状の１次巻線部を備える表面銅箔層と、該表面銅箔層の厚みよりも厚い肉厚をもち、基板内部における第１の平面に形成された第１の内部銅箔層と、第１の平面とは異なる第２の平面に形成された第２の内部銅箔層と、前記基板表面から前記第１、第２の内部銅箔層に延びる複数のスルーホールとを備えた回路基板であって、
前記第１の内部銅箔層は前記コア穴を中心に一方向にほぼ１タ−ン以上で形成される２次巻線部と複数の個別の内部銅箔領域とからなり、
前記第２の内部銅箔層は連続的に形成された広面積部からなり、
前記２次巻線部はその終端部が前記スルーホールにより前記第２の内部銅箔層に接続されることを特徴とする回路基板。A surface copper foil layer having a spiral primary winding portion that is formed on one or both of the substrate surfaces around a core hole provided in a circuit board and serves as a primary winding of a transformer; A first inner copper foil layer formed on the first plane inside the substrate and having a thickness greater than the thickness of the surface copper foil layer, and a second plane formed on the second plane different from the first plane. A circuit board comprising two internal copper foil layers and a plurality of through holes extending from the substrate surface to the first and second internal copper foil layers,
The first internal copper foil layer is composed of a secondary winding portion formed by approximately one turn or more in one direction around the core hole and a plurality of individual internal copper foil regions,
The second internal copper foil layer is composed of a continuously formed wide area portion,
The circuit board according to claim 1, wherein a terminal portion of the secondary winding portion is connected to the second internal copper foil layer through the through hole.

回路基板に設けられたコア穴を中心にしてそのいずれか一方又は双方の基板表面に形成されてトランスの１次巻線となる渦巻き状の１次巻線部を備える表面銅箔層と、該表面銅箔層の厚みよりも厚い肉厚をもち、基板内部における第１の平面に形成された第１の内部銅箔層と、第１の平面とは異なる第２の平面に形成された第２の内部銅箔層と、前記基板表面から前記第１、第２の内部銅箔層に延びる複数のスルーホールとを備えた回路基板であって、
前記第１の内部銅箔層は前記中央穴を中心に一方向にほぼ１タ−ン以上で形成される第１の２次巻線部と複数の個別の内部銅箔領域とからなり、
前記第２の内部銅箔層は連続的に形成された広面積部とこの広面積部から伸びて前記コア穴を中心に逆方向にほぼ１タ−ン以上で形成される第２の２次巻線部とからなり、
前記第１と第２の２次巻線部はそれぞれの終端部と相手の始端部を通る前記スルーホールにより互いに直列接続されて、ほぼ２ターン以上の巻数のトランス２次巻線を形成することを特徴とする回路基板。A surface copper foil layer having a spiral primary winding portion that is formed on one or both of the substrate surfaces around a core hole provided in a circuit board and serves as a primary winding of a transformer; A first inner copper foil layer formed on the first plane inside the substrate and having a thickness greater than the thickness of the surface copper foil layer, and a second plane formed on the second plane different from the first plane. A circuit board comprising two internal copper foil layers and a plurality of through holes extending from the substrate surface to the first and second internal copper foil layers,
The first internal copper foil layer is composed of a first secondary winding portion formed by approximately one turn or more in one direction around the central hole and a plurality of individual internal copper foil regions,
The second internal copper foil layer is a continuously formed wide area portion and a second secondary layer extending from the wide area portion and formed in about 1 turn or more in the opposite direction around the core hole. Consisting of winding part,
The first and second secondary winding portions are connected in series with each other by the through-holes passing through the respective end portions and the mating start end portion to form a transformer secondary winding having approximately two or more turns. A circuit board characterized by.

回路基板に設けられたコア穴を中心にしてそのいずれか一方又は双方の基板表面に形成されてトランスの１次巻線を形成する渦巻き状の表面銅箔層と、該渦巻き状の表面銅箔層の厚みよりも厚い肉厚をもち、基板内部における第１の平面に形成された第１の内部銅箔層と、第１の平面とは異なる第２の平面に形成された第２の内部銅箔層と、前記基板表面から前記第１、第２の内部銅箔層に延びて接続される複数のスルーホールとを備えた回路基板であって、
前記第１の内部銅箔層は前記コア穴を中心に一方向にほぼ１タ−ン以上で形成される第１の２次巻線部と、複数の個別の内部銅箔領域とからなり、
前記第２の内部銅箔層は連続的に形成された広面積部とこの広面積部から伸びて前記コア穴を中心に前記第１の巻線部と同方向にほぼ１タ−ン以上で形成される第２の２次巻線部とからなり、
前記第１と第２の巻線部はそれぞれの終端部と相手の始端部を通る前記スルーホールにより互いに並列接続されて、ほぼ１ターン以上の巻数のトランス２次巻線を形成し、
たことを特徴とする回路基板。A spiral surface copper foil layer that forms a primary winding of a transformer formed on one or both substrate surfaces around a core hole provided in a circuit board, and the spiral surface copper foil A first internal copper foil layer formed on a first plane inside the substrate and having a thickness greater than the thickness of the layer, and a second internal formed on a second plane different from the first plane A circuit board comprising a copper foil layer and a plurality of through-holes extending from and connected to the first and second internal copper foil layers from the substrate surface;
The first internal copper foil layer is composed of a first secondary winding portion formed in approximately one turn or more in one direction around the core hole, and a plurality of individual internal copper foil regions.
The second internal copper foil layer has a wide area portion formed continuously, and extends from the wide area portion, and has approximately one turn or more in the same direction as the first winding portion around the core hole. A second secondary winding portion to be formed,
The first and second winding portions are connected to each other in parallel by the through-holes that pass through the respective end portions and the other end portion, thereby forming a transformer secondary winding having a number of turns of approximately one turn or more.
A circuit board characterized by that.

回路基板に設けられたコア穴を中心にしてそのいずれか一方又は双方の基板表面に形成されてトランスの１次巻線を形成する渦巻き状の表面銅箔層と、該渦巻き状の表面銅箔層の厚みよりも厚い肉厚をもち、基板内部における第１の平面に形成された第１の内部銅箔層と、第１の平面とは異なる第２の平面に形成された第２の内部銅箔層と、前記基板表面から前記第１、第２の内部銅箔層に延びて接続される複数のスルーホールとを備えた回路基板であって、
前記第１の内部銅箔層は複数の個別の内部銅箔領域と、該内部銅箔領域の一つである第１の内部銅箔領域から延びる、前記コア穴を中心に一方向にほぼ１タ−ン以上で形成される第１の２次巻線部とからなり、前記内部銅箔領域は一方の巻線端子を構成し、また前記個別の内部銅箔領域の他の一つである第２の内部銅箔領域が他方の巻線端子の役割を行い、
前記第２の内部銅箔層は連続的に形成された広面積部とこの広面積部とは分離して形成され、かつ前記コア穴を中心にほぼ１タ−ン以上で形成される第２の２次巻線部とからなり、
前記第１の巻線部の終端部と前記第２の巻線部の一方の端部は前記スルーホールにより接続され、前記第２の巻線部の他方の端部は前記スルーホールにより前記第２の個別の内部銅箔領域に接続されてほぼ２ターン以上の巻数のトランス２次巻線を形成し、
たことを特徴とする回路基板。A spiral surface copper foil layer that forms a primary winding of a transformer formed on one or both substrate surfaces around a core hole provided in a circuit board, and the spiral surface copper foil A first internal copper foil layer formed on a first plane inside the substrate and having a thickness greater than the thickness of the layer, and a second internal formed on a second plane different from the first plane A circuit board comprising a copper foil layer and a plurality of through-holes extending from and connected to the first and second internal copper foil layers from the substrate surface;
The first internal copper foil layer extends from a plurality of individual internal copper foil regions and a first internal copper foil region which is one of the internal copper foil regions, and is approximately 1 in one direction around the core hole. The inner copper foil region constitutes one winding terminal, and is another one of the individual inner copper foil regions. The second inner copper foil region serves as the other winding terminal,
The second inner copper foil layer is formed by separating the wide area portion formed continuously and the wide area portion, and is formed by approximately one turn or more around the core hole. Secondary winding part,
The terminal portion of the first winding portion and one end portion of the second winding portion are connected by the through hole, and the other end portion of the second winding portion is connected by the through hole. Connected to two separate internal copper foil regions to form a transformer secondary winding with more than two turns,
A circuit board characterized by that.

請求項１、請求項３ないし請求項５のいずれかにおいて、
前記第２の内部銅箔層に形成された２次巻線部は前記広面積部に囲まれていることを特徴とする回路基板。In any one of Claim 1 and Claim 3 thru | or 5,
A circuit board, wherein a secondary winding portion formed on the second internal copper foil layer is surrounded by the wide area portion.

請求項１ないし請求項６のいずれかにおいて、
前記渦巻き状の表面銅箔層が双方の前記基板表面に形成される場合には、それぞれの前記渦巻き状の表面銅箔層の終端部から他方の前記渦巻き状の表面銅箔層に延びる前記スルーホールにより互いに直列接続されることを特徴とする回路基板。In any one of Claims 1 thru | or 6,
When the spiral surface copper foil layer is formed on both the substrate surfaces, the through-holes extending from the terminal portions of the respective spiral surface copper foil layers to the other spiral surface copper foil layer A circuit board characterized by being connected in series with each other by holes.

請求項１ないし請求項６のいずれかにおいて、
前記渦巻き状の表面銅箔層が双方の前記基板表面に形成される場合には、それぞれの前記渦巻き状の表面銅箔層の終端部から他方の前記渦巻き状の表面銅箔層に延びる前記スルーホールにより互いに並列接続されることを特徴とする回路基板。In any one of Claims 1 thru | or 6,
When the spiral surface copper foil layer is formed on both the substrate surfaces, the through-holes extending from the terminal portions of the respective spiral surface copper foil layers to the other spiral surface copper foil layer A circuit board characterized by being connected in parallel to each other by a hole.

請求項１ないし請求項８のいずれかにおいて、
前記回路基板は、前記渦巻き状の表面銅箔層と前記内部銅箔層の前記第１の巻線部と第２の巻線部の両外側で、かつ前記コア穴を通る直線上にコア用の別の穴を備えたことを回路基板。In any one of Claims 1 thru | or 8,
The circuit board is used for a core on a straight line passing through the core hole on both outer sides of the first winding portion and the second winding portion of the spiral surface copper foil layer and the inner copper foil layer. Circuit board with another hole in it.

請求項９において、
前記コア穴及び前記コア用の別の穴にコアのそれぞれの磁脚が挿入され固定されていることを特徴とする回路基板。In claim 9,
A circuit board, wherein the magnetic legs of the core are inserted and fixed in the core hole and another hole for the core.

請求項１ないし請求項１０のいずれかの回路基板において、
前記スルーホールに跨がって前記回路基板上に形成された前記電極パッドに所定の電子部品を接続し、前記第２の内部銅箔層の前記広面積部は安定電位に接続されることを特徴とする電源。The circuit board according to any one of claims 1 to 10,
A predetermined electronic component is connected to the electrode pad formed on the circuit board across the through hole, and the wide area portion of the second internal copper foil layer is connected to a stable potential. Features a power supply.

請求項１ないし請求項１０のいずれかの回路基板を用い、前記スルーホールを通して前記第１の内部銅箔層における前記第１の巻線部と前記個別の内部銅箔領域との間に前記電極パッドを介して電子部品が接続されることを特徴とする電源。 The circuit board according to any one of claims 1 to 10, wherein the electrode is provided between the first winding portion and the individual internal copper foil region in the first internal copper foil layer through the through hole. A power supply characterized in that an electronic component is connected through a pad.

請求項１ないし請求項１１のいずれかの回路基板を用い、前記スルーホールを通して前記第１の内部銅箔層の前記個別の内部銅箔部と前記第２の内部銅箔領域との間に前記電極パッドを介して電子部品が接続されることを特徴とする電源。 The circuit board according to any one of claims 1 to 11, wherein the individual internal copper foil portion of the first internal copper foil layer and the second internal copper foil region are formed through the through hole. A power supply characterized in that an electronic component is connected through an electrode pad.

請求項５の回路基板に整流用ＦＥＴを表面実装してなる同期整流式の電源において、
前記整流用ＦＥＴのドレイン電極とソース電極をそれぞれ前記スルーホールを通して前記第１の内部銅箔層における前記第１の個別の内部銅箔領域と前記第２の個別の内部銅箔領域に接続したことを特徴とする電源。In the synchronous rectification type power supply in which the rectifying FET is surface-mounted on the circuit board of claim 5,
The drain electrode and the source electrode of the rectifying FET are connected to the first individual internal copper foil region and the second individual internal copper foil region in the first internal copper foil layer through the through holes, respectively. Power supply characterized by.

請求項５の回路基板にフリホイーリング用ＦＥＴ又はダイオードを表面実装してなる同期整流式の電源において、
前記フリホイーリング用ＦＥＴ又はダイオードを、前記第１の内部銅箔層の第１の個別の内部銅箔領域と前記第２の内部銅箔層の広面積部との間に前記スルーホールを通して接続したことを特徴とする電源。In the synchronous rectification type power supply formed by surface mounting a freewheeling FET or diode on the circuit board of claim 5,
The freewheeling FET or diode is connected through the through hole between a first individual inner copper foil region of the first inner copper foil layer and a large area portion of the second inner copper foil layer. A power supply characterized by