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本帖最后由 dbit 于 2011-10-7 16:40 编辑 6 N W: C9 \; p. N* O) P
123456sz 发表于 2011-10-5 00:30 ![]() ! a- W# D4 o* @. y8 K* s* F; A
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。. H6 \0 K x7 @3 c8 \7 x1 }
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所有计算依据:IPC-2221标准制定;% B2 ~2 A" z& @ y: L1 g+ f
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:. V; X9 i: ]: ^$ i* v% p" n
Generic Standard on Printed Board Design4 E$ e& f2 N$ N% n9 A# {: g
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trace width calc& V, e0 a( x2 A* m# B
Area[mils^2] = (Current[Amps]/(k*(Temp_Rise[deg. C])^b))^(1/c) 2 q! Z1 d8 v! f5 ^
Then, the Width is calculated: : q' U' K. k9 J* B/ }! r( V
Width[mils] = Area[mils^2]/(Thickness[oz]*1.378[mils/oz]) ! _0 R; n) {3 r: g0 Y, O& H9 N
For IPC-2221 internal layers: k = 0.024, b = 0.44, c = 0.725
+ y# i6 u2 F$ ^) w4 b! ^For IPC-2221 external layers: k = 0.048, b = 0.44, c = 0.725
" u' C+ r8 Y( V9 g' I0 R4 E, s4 O9 fwhere k, b, and c are constants resulting from curve fitting to the IPC-2221 curves
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PCB VIA calculator
! q1 W7 [9 N2 M9 H+ A( j; ^& V5 ~" }Resistance = Resistivity*Length/Area
. c" g& J1 p/ S" n7 x1 QArea = pi*(Inner_dia + Plating_thk)*Plating_thk
' |1 ]( ~1 Q9 W8 N' n# [Resistivity = 1.9E-6 Ohm-cm (plated copper)
# o2 I( L- y* M7 A(plated copper is much more resistive than pure copper)
! R4 _; z- s7 ~# o: Q* B6 y7 TCopper Thermal_Resistivity = 0.249 cm-K/W (at 300K) ! a, ~6 e$ n6 T+ h% S4 h, D$ U
Est_Ampacity [Amps] = k*(Temp_Rise [deg C])^b*(Area [mils^2])^c / |2 a3 u+ H) X A! y* ^
For IPC-2221 external layers: k = 0.048, b = 0.44, c = 0.725 7 b/ M2 n4 K8 U
我做的一个xls方式的计算式，可以算电流的。
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发表于 2011-7-25 09:32
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