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标题: 请教下PCB中关于电气间隙和爬电距离的要求 [打印本页]
作者: deficit    时间: 2009-12-27 11:20
标题: 请教下PCB中关于电气间隙和爬电距离的要求
有个问题一直不明白# }8 z3 U2 ]& f2 I- h% ~' G& \
根据标准中对电气间隙和爬电距离的定义，是否多层PCB板内层的走线/铜皮之间，不存在电气间隙和爬电距离的说法？- Z5 L  \; d, _! c
因为没有空气。
9 }0 X8 R/ C) s" r0 Y, T) o& ~2 _0 w5 o2 i
那么对于多层PCB来说，要设计两个高低压网络之间的电气间隙，同时这两个网络又是在PCB的内层分布的，那么要怎么做？
作者: deficit    时间: 2009-12-27 11:33
补充一下，
( z- K/ Q( b2 {3 L" T! c2 c对于PCB上电气间隙和爬电距离的设计
! |7 L# n9 R/ R# }我目前的理解是，只需要满足PCB表层网络之间电气间隙和爬电距离的设计要求。
; x+ N, i5 e- a% J: F9 {7 z  b对于PCB的内层来说，如果峰值工作电压不超过71V，则根据绝缘穿透距离的定义，没有什么要求，不需要做特殊的拉大间距的处理。
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4 ?5 H% @- P: @# N$ F不知道理解的对不对啊？
作者: ajay    时间: 2009-12-28 09:31
我认为你的理解基本正确.4 u. b6 p5 m3 G+ r4 G
PCB内层适用绝缘穿透距离的规则. 这和隔离光藕的情况查不多
作者: deficit    时间: 2009-12-28 11:03
谢谢！. T' a# x2 w* S* [
另外想问下，PCB上的走线/铜皮之间，是不是都可以认为爬电距离=电气间隙？
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. i) F) m+ {1 j因为好像导体下方不会存在沟壑的情况。
作者: ajay    时间: 2009-12-28 18:06
通常来说,我也同意在PCB的同一内层面上布线之间的爬距=间隙, 但也不排除有开槽等类似的情况.
作者: bychong    时间: 2009-12-28 21:40
不同产品的标准上都对于PBC上的爬距做了特别的说明，在实际操作过程中，我们一般是认为PCB上两个最相近的焊点间距为爬距！！
作者: freezk    时间: 2009-12-29 15:51
引用第0楼deficit于2009-12-27 11:20发表的 请教下PCB中关于电气间隙和爬电距离的要求 :
' [7 y# }& j" {/ H( g9 N6 y) E  c7 Y+ n有个问题一直不明白- [. v) m/ ~: a) y( n
根据标准中对电气间隙和爬电距离的定义，是否多层PCB板内层的走线/铜皮之间，不存在电气间隙和爬电距离的说法？
" Q0 Z1 Z! e$ S: U% I  y7 Y2 ~因为没有空气。6 O4 H( {# B3 Q* u

* Z% N1 s5 s! s3 B' V, f( e+ ~那么对于多层PCB来说，要设计两个高低压网络之间的电气间隙，同时这两个网络又是在PCB的内层分布的，那么要怎么做？
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内层走线适用于固体绝缘，对于新版本的60950，PCB要经过相应的认证否则内层的距离要求和表层是一样的；" }1 d5 Z2 X  g# H$ W% x
内层的固体绝缘除了在一些情况下要求0.4 MM要求外就要参考HI-POT测试电压对应的距离了，这个参数可以像PCB厂家询问，我们公司在收集很多家PCB厂家的参数后再加相应的余量外有个参考数据：水平方向即内层同一层之间是1.5KVRMS/1MM，垂直方向是30KVRMS/1MM
作者: ajay    时间: 2009-12-29 16:42
引用第6楼freezk于2009-12-29 15:51发表的  :; \( r) E* I" \
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. _# p% }$ ], q+ m$ W. i内层走线适用于固体绝缘，对于新版本的60950，PCB要经过相应的认证否则内层的距离要求和表层是一样的；
9 p- ]. d8 h8 g7 J; |4 o内层的固体绝缘除了在一些情况下要求0.4 MM要求外就要参考HI-POT测试电压对应的距离了，这个参数可以像PCB厂家询问，我们公司在收集很多家PCB厂家的参数后再加相应的余量外有个参考数据：水平方向即内层同一层之间是1.5KVRMS/1MM，垂直方向是30KVRMS/1MM
# [# `3 m& ?$ V) H6 ]1 {* e
请问,"对于新版本的60950，PCB要经过相应的认证否则内层的距离要求和表层是一样的" 标准哪个条款有说?
2 @: I: w+ M1 o! w& a0 |( E7 MIEC60950:2005- g3 \! {# T" h/ X3 y* m4 i* r
2.10.6.3 Insulation between conductors on the same inner surface of a printed board# f8 J$ X  A" v7 j! Q% ?
On an inner surface of a multi-layer printed board (see Figure F.16), the path between any# H( p+ [, x9 [2 n
two conductors shall comply with the requirements for a cemented joint in 2.10.5.5.% R5 \! R% i1 K" H( R
标准规定的是要符合2.10.5.5 Cemented joints的要求.
作者: deficit    时间: 2009-12-29 16:52
引用第6楼freezk于2009-12-29 15:51发表的  :
4 F' a4 E8 c( s+ b" a% ^9 @
2 J$ Z3 v9 q3 s5 t7 ~
* [9 H* g5 l( H) d( {+ _4 q' V! r内层走线适用于固体绝缘，对于新版本的60950，PCB要经过相应的认证否则内层的距离要求和表层是一样的；9 k+ o; p: q+ E/ g
内层的固体绝缘除了在一些情况下要求0.4 MM要求外就要参考HI-POT测试电压对应的距离了，这个参数可以像PCB厂家询问，我们公司在收集很多家PCB厂家的参数后再加相应的余量外有个参考数据：水平方向即内层同一层之间是1.5KVRMS/1MM，垂直方向是30KVRMS/1MM
# I" Q) L0 l7 J# a7 i' A" W, \; ~
有点没看明白。。。能否再详细点说说？
作者: freezk    时间: 2009-12-29 16:56
引用第7楼ajay于2009-12-29 16:42发表的  :3 H. G7 K5 l+ \" c
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请问,"对于新版本的60950，PCB要经过相应的认证否则内层的距离要求和表层是一样的" 标准哪个条款有说?; C7 v  y. x3 X6 a! Q9 [
IEC60950:20055 a  |9 y) |2 S, T
2.10.6.3 Insulation between conductors on the same inner surface of a printed board  J' l) l) s$ X$ n9 W
.......
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对，标准里我也没发现，是AGENCY 说的，不过现在是有更多的PCB厂家、更多的型号可以满足要求。具体的你可以问AGENCY
作者: 海之未央    时间: 2009-12-29 17:28
据说还要考虑走线的~~~~暂时手头还未用新标准考虑这个问题~~~
作者: deficit    时间: 2009-12-29 17:42
有没有什么地方有给出60950新旧版本区别点的？# \, Z9 s- D4 e/ X
因为好像目前GB还是按照旧的60950
作者: 海之未央    时间: 2009-12-30 09:26
Differences between "IEC 60950-1:2001" and "IEC 60950-1:2005"
, u; Q3 x% c* `2 \7 r2 ]2 g9 Q? : Level of importance (0=not, 3=very) Page 3 of 20 Document date: 4-Apr-20068 d! [9 B) i2 S2 }; F
Subclause Change ? Comment
2 M' y! u" j, S! h( s- }( gForeword Added 0 Additional parts "22" and "23" mentioned that are planned but not published# ?. T1 o+ @- ^/ Y% i
yet (Mar-2006).9 j% V+ I/ O) \/ e6 S2 L  r) }" A
1.1.1 Clarified 2 IEC 60950-1 applies as well to components and subassemblies intended for
4 P. O8 m) H2 P+ tincorporation in ITE.0 r: X+ @8 K* s( h7 f
1.1.3 Modified 1 "Support systems" were deleted from list of excluded examples.6 ~1 M! U5 M2 ~2 Q
1.2.2.3 New 1 RATED RESTING TIME replaces subclauses 1.2.2.3~5 (CONTINUOUS OPERATION,
! V) K5 _! f% H/ R! p* nSHORT-TIME OPERATION and INTERMITTENT OPERATION).0 X- h* m) t0 |' H. \; j. \
1.2.5.3 New 0 PLUGGABLE EQUIPMENT as definition covering both pluggable equipment types* c) ~' Z. D3 K3 g; b& m
A and B.2 A1 |! Q' Q* e4 B! b$ t
1.2.8.3 New 0 MAINS SUPPLY as definition covering both AC and DC mains supply.4 q7 N) L% K. O  Z; n
1.2.9.7 New 0 RMS WORKING VOLTAGE introduced as defined term./ i+ ?' e! J' Q4 z/ J; g! g
1.2.10.4 New 0 SOLID INSULATION introduced as defined term.
# G# q8 H! _! X# @1.2.13.15 New 0 CHEESECLOTH introduced as defined term.% T* A5 \0 o, k; }
1.2.13.16 New 0 WRAPPING TISSUE introduced as defined term.
5 h5 t8 R5 S, R) T6 ?" o5 M1 k1.2.13.17 New 0 PROTECTIVE CURRENT RATING introduced as defined term which is similar to
& S" U  X7 F: qprevious term "current rating of the circuit under test" of subclause 2.6.3.4.( {# @# p1 B4 Y
1.3.3 Clarified 1 If the test voltage is not specified in a test item the rated voltage or any value
4 F8 W7 ~2 \/ u8 e+ Uin the rated voltage range shall be used for test.
7 C# W3 u' S. A3 H1.4.8 Modified 1 "Note 2" added for additional requirements of USA and Canada for" b% N" E& M& ^/ d; y: r
overvoltage protection of TNV circuits.% _4 S* P0 U) D# m
1.4.14 Clarifi ed 1 Adding to third paragraph: "The failure of functional insulation is only6 J: r# ^; K) q- V% b9 ~0 f4 j4 B
simulated when required by 5.3.4 c)" (risk of fire, risk of electric shock).# c0 V$ I7 k/ V# Q0 m' J
1.5.1 Modified 0 Adding "Note 3" (Switzerland does not allow mercury switches) and deleting
/ C& B6 \& r6 P9 R8 [second paragraph and old "Note 3".) y- G' X0 H) Y/ B. a
1.5.6 Modified 0 Complete change of subclause by adding information from IEC 60384-14.
( I1 O' C9 I, K( {- g* Y8 t) j3 bHowever, application principle of X- and Y-capacitors not changed.( O; H8 B" _6 Z: w
1.5.7 Complete change and concept for bridging resistors. Detailed requirements# v/ |9 c- S% J5 W2 P
for:& l6 c, X/ [2 n! g, D
·  Resistors bridging functional/basic/supplementary insulation (1.5.7.1)3 s: W2 H* u3 D) S& \
·  Resistors double/reinforced functional insulation (1.5.7.2)
* f$ V& P* X- r: R* E·  Resistors double/reinforced functional insulation – Special
0 u# U9 ]8 ?% ?" J/ c& brequirements when connected to antenna/coaxial cable (1.5.7.3)
: |& s1 L3 l8 u) \/ S. M6 @1.5.7.1 Only subclauses 2.10.3 and 2.10.4 (distances) apply to such resistors.. S. X( X/ Y' Z# l( G& ^- _
1.5.7.2 Very different concept:
6 s: g- b0 m. j& P' G·  Single resistor is acceptable if it passes "Resistor test"
' \. J  A' Q0 H$ t  E9 j! Y) @·  Group of resistors must either pass "Resistor test" or pass subclauses
4 C- ^' T% ?" l! |# L  d2.10.3 and 2.10.4 (distances) with each resistor short-circuited in turn6 I' ?' o9 e$ ^2 u; _+ z, J1 T
"Resistor test":% ^  j5 D/ k, a
Damp heat test of IEC 60068-2-78 plus impulse test and resistance% O: x( Y' |  Q/ W0 p
measurement.
9 C& Z$ I# X9 V9 b- q' h1.5.7.3! d6 O/ J$ `$ ~2 v( j- t
Modified 2  P- x" M* t! N: `5 _
Same as 1.5.7.2 above but with different impulse generator for circuits with# Z$ s% K! T: d
coaxial cable connection.
; y  w2 r; W. i. {+ {6 }1.5.9 Requirements for varistors (VDR) specified.# @: g4 Z2 b+ i" u" }4 F
1.5.9.1 Secondary circuit surge suppressors: any suitable component allowed9 M) c4 b' j7 V  r; Z1 o) q# k5 u
Primary circuit surge suppressors: only VDR allowed.
5 [1 F( E/ y/ A& O$ p, S' A. u1.5.9.2 An interrupting means must be provided for protection of the VDR in series.
' q$ b; n* M/ C: o- V3 c5 ]8 ^1.5.9.3 It is allowed to bridge functional insulation by VDR, no additional
; Z9 C* o+ o( Qrequirements.1 n8 p" d: n% L" `  W
1.5.9.4 It is allowed to bridge basic insulation by VDR with additional requirements:3 p) R. c' _1 G; f) M" m: j! A8 x
·  one side of the VDR must be earthed
$ `3 N7 r6 y) N% \·  only possible for pluggable equipment type B or permanently
5 C1 [+ B" [  N# u2 o  I1 r: Q0 z4 gconnected equipment or equipment with permanently connected. I; Y5 k# E9 |1 t6 s6 t* X; I
earthing conductor+ w2 E! Q5 F. ^/ d- c  ~, [
·  more restrictions for countries FI, NO, SE. B  s. l2 T% L- K/ \
1.5.9.5
" t; E3 ^/ A$ Y2 H7 D2 C+ d* e% ?New 2
; a: o: I- K, o  iIt is not allowed to bridge supplementary/double/reinforced insulation by+ O3 ^" v: @4 }6 v
VDR.
6 l) z( N" v$ @) S: I' e1.6.1 Modified 0 "Note" for Australian national difference was deleted.- p& @3 I1 T, f* @
1.7.1 Clarified 0 Clarification for the use of the Class II symbol." F; U; m1 C4 r' L1 L2 A
1.7.2 Modified 0 Re-arranging of content of subclauses 1.7.2, 1.7.10 and 1.7.16.
作者: deficit    时间: 2009-12-30 09:53
太感谢了！



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