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本帖最后由 dbit 于 2011-10-7 16:40 编辑
5 l- P* J1 R. x$ E( S123456sz 发表于 2011-10-5 00:30 ![]()
9 t# A1 Q" u. }+ N更改铜厚没有反应
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谢谢你帮忙查出问题，另外过孔不需要铜厚，我已去掉，线宽的公式中，没有除铜厚，现修正。- h4 y0 }1 n- L, J6 ~( R; s. P% M6 Z
/ e' T* h8 l! Y) Q' X* ~( A所有计算依据:IPC-2221标准制定;$ u0 x6 L1 U* _
IPC-2221标准描述:是由IPC组织制定的关于PCB设计的通用标准,英文名为:4 E" S/ G$ Y' s8 q( z) k
Generic Standard on Printed Board Design
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1 O) H3 U. J; I+ {! X6 Ntrace width calc
. S9 a' s$ W- D6 e: fArea[mils^2] = (Current[Amps]/(k*(Temp_Rise[deg. C])^b))^(1/c) . t+ I3 B2 P) C( D: Y) f7 p
Then, the Width is calculated:
% X, p. Q: I9 O7 P6 K# PWidth[mils] = Area[mils^2]/(Thickness[oz]*1.378[mils/oz])
+ k: d* e% R" M3 jFor IPC-2221 internal layers: k = 0.024, b = 0.44, c = 0.725 % Q, O* H, R% ]
For IPC-2221 external layers: k = 0.048, b = 0.44, c = 0.725 * y! N6 {8 ^" c( {3 N
where k, b, and c are constants resulting from curve fitting to the IPC-2221 curves
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, X0 T }+ r) |2 U, Y( t- R8 zPCB VIA calculator }5 [# x( `: g5 S' o( h( w+ p
Resistance = Resistivity*Length/Area $ p: v0 b' P$ M& G# `9 u2 B. s0 `6 T
Area = pi*(Inner_dia + Plating_thk)*Plating_thk " l( R: m' { {& l4 L4 Z
Resistivity = 1.9E-6 Ohm-cm (plated copper) 9 L* n9 D9 Y# `
(plated copper is much more resistive than pure copper)
9 J) h2 w/ ], Z$ g5 Q2 _6 q6 z( iCopper Thermal_Resistivity = 0.249 cm-K/W (at 300K)
: j8 i" i0 S! X$ P5 V/ PEst_Ampacity [Amps] = k*(Temp_Rise [deg C])^b*(Area [mils^2])^c
: l; {- ]. V$ {$ cFor IPC-2221 external layers: k = 0.048, b = 0.44, c = 0.725
$ e3 M' \- W0 J* V2 C/ [+ e6 t我做的一个xls方式的计算式，可以算电流的。: ~9 x' [0 r$ o& T( `5 r
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楼主
发表于 2011-10-7 23:04
