Support method and apparatus for printed circuit board
AssigneeHitachi, Ltd.
InventorsHideki OSAKA, Yutaka Uematsu
Life of this patent
Estimating the term…
Abstract
An orthogonal array is formed by performing electromagnetic field analysis only once and determining a range by using the mount position and type of a capacitor and the number of capacitors as parameters to perform circuit analysis a small number of times. An estimation equation is formed by using as an index a result of the absolute value of the calculated power source impedance, and a capacitor is disposed to reduce noises by using the estimation equation.
Claims8
A printed circuit board design support apparatus for determining arrangement of a semiconductor device and a decoupling capacitor connected to the semiconductor device on a printed circuit board, comprising:
- printed circuit board information inputting means for inputting layer structure information and outer shape information on the printed circuit board;
- component information inputting means for inputting power source ground information of the semiconductor device, electric characteristic information on a capacitor component of each type as a candidate for the decoupling capacitor, and the number of decoupling capacitors on the printed circuit board;
- component arrangement inputting means for inputting arrangement of the semiconductor device and the decoupling capacitor on the printed circuit board;
- electromagnetic field analyzing means for performing electromagnetic analysis in accordance with the layer structure information and outer shape information on the printed circuit board;
- calculating means for calculating inductance parameters from inductance network information obtained by said electromagnetic field analyzing means;
- parameter set calculating means for forming an orthogonal array from the calculated inductance parameters, type information of the decoupling capacitor and the number of mounted decoupling capacitors;
- evaluation index calculating means for calculating an electric characteristic index by using analysis results by said electromagnetic field analyzing means and the parameter sets of the orthogonal array formed by said parameter set calculating means;
- and
- calculating means for calculating an evaluation equation of a polynomial equation representing the electric characteristic index calculated by said evaluation index calculating means by using combinations of the parameters of the orthogonal array,
- wherein an electric characteristic is evaluated even for an unknown combination of the parameters by using the calculated evaluation equation of a polynomial equation.
A printed circuit board noise calculating method of calculating a power source noise of a printed circuit board mounting a semiconductor device and a decoupling capacitor by using CAD, comprising steps of:
- dividing the printed circuit board into a mesh shape;
- calculating an inductance matrix of all mesh positions on the printed circuit board through electromagnetic field analysis;
- calculating an inductance existing between an arrangement position of the semiconductor device and an arrangement allowable position of the decoupling capacitor by using the inductance matrix;
- forming an orthogonal array by using as parameters the inductance, a type of a capacitor component to be adopted as the decoupling capacitor, and the number of decoupling capacitors on the printed circuit board;
- calculating parameter sets including the inductance, type of the decoupling capacitor and the number of decoupling capacitors on the printed circuit board, from the formed orthogonal array;
- calculating a power source noise evaluation equation by using a power source noise of each parameter set as an index, through circuit analysis of the printed circuit board corresponding to each parameter set;
- and
- designating a change in at least one of the arrangement position of the decoupling capacitor, the type and the number of decoupling capacitors,
- wherein a power source noise corresponding to rearrangement of the decoupling capacitor caused by the change is calculated by using the calculated power source noise evaluation equation.
Dependencies are inferred from the claim text.