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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
9 e9 g0 m6 ^# H* `$ |' H$ Y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？
& |, p2 E  N3 |5 C8 _' s因为没有空气。/ m( d$ I$ I- ~3 X/ L
4 Z7 u: p) o2 `6 {: C
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，
2 S9 S5 c! C  c) [( X1 V对于PCB上电气间隙和爬电距离的设计+ e  W( n# i8 U7 }' v5 q
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。
! S& G! w5 i# X$ w9 _' w0 @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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  A1 _" ^" o( ]& t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.5 ~" \+ e$ z! A) l. P
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！
% }* D8 l7 t% z2 c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？
+ [7 R8 r; Y. J; {
) Y2 S& y9 V/ _5 z, T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 :
6 Y. G) L9 h! @1 [  R" X有个问题一直不明白
! V' [6 x) v. p6 ~! D) |9 M4 C! |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？
2 J: d8 S% K' ~* d5 ^% V因为没有空气。, U) S$ n4 F% F( E5 m
6 |* L- k& q+ N# `1 X
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？
& T# ]$ ?- o0 H1 L# M  b
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；* w6 H( d+ l4 f+ Y' K% o) z* s0 I
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  :
& P2 @$ ~; q8 U$ S$ V/ g8 Y+ I0 w1 {2 i

/ W6 y5 f% Y; Q: q, L" |# ^' V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；
* ~) Q! t8 M, F3 L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
! `8 C" h: `0 U: a7 Q
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?
8 d8 Z$ o$ d' A  V! mIEC60950:2005) E/ D2 w3 I& a# g* B- ]
2.10.6.3 Insulation between conductors on the same inner surface of a printed board
* K" X) n8 T! G/ V3 T4 f' k0 w0 oOn an inner surface of a multi-layer printed board (see Figure F.16), the path between any# f! X( \+ N- H4 g- w" [
two conductors shall comply with the requirements for a cemented joint in 2.10.5.5.
! v1 C% r# I. a. D. L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  :) l& e. p  ?$ t  v
* b- z8 q! H* x# ~* y8 q# W
* b% n4 Z6 H( C/ f) W7 P( Y% 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；! o: ~- K$ @6 a2 [4 r
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

& N2 x% S5 Z/ Q, B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  :, e  O# b9 I+ l8 P# k/ j
- I3 d* F1 Q+ T0 ]4 w

2 U" K0 M, C' B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?
8 v8 E4 d4 m3 ^. v3 f. y/ k* }IEC60950:2005
) k# N, r. s, l8 F: }5 z2.10.6.3 Insulation between conductors on the same inner surface of a printed board
9 q7 m( C7 s6 I. o. T. `& ?6 [; m0 z.......

' G( W5 Z; f9 }0 D6 c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？9 T5 ?* o* L* H+ F( K1 J
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"3 p7 }) l$ ]$ B* J6 Z4 K
? : Level of importance (0=not, 3=very) Page 3 of 20 Document date: 4-Apr-20068 T5 |) D  E2 K* h
Subclause Change ? Comment6 l/ M# j+ F" W: _1 @
Foreword Added 0 Additional parts "22" and "23" mentioned that are planned but not published. M' l- Y5 i! ^/ J7 ~; a* q
yet (Mar-2006).
6 r$ H8 @; m4 R. q) G( q1 M. @1.1.1 Clarified 2 IEC 60950-1 applies as well to components and subassemblies intended for* C: Z; O" C/ D, f- P! v3 @  ?- g
incorporation in ITE.
6 \6 b' C, W1 G2 C1.1.3 Modified 1 "Support systems" were deleted from list of excluded examples.
% f! ?5 Y6 D) [) {, e1.2.2.3 New 1 RATED RESTING TIME replaces subclauses 1.2.2.3~5 (CONTINUOUS OPERATION,; _1 ~' K! ]2 O1 G( [! s
SHORT-TIME OPERATION and INTERMITTENT OPERATION).
* l6 ?( K, e* j! e- h+ ?" N1.2.5.3 New 0 PLUGGABLE EQUIPMENT as definition covering both pluggable equipment types8 c# b9 E6 y' `5 V9 v+ c+ m
A and B.2 s" P) m" V% ?- s. [" j0 {
1.2.8.3 New 0 MAINS SUPPLY as definition covering both AC and DC mains supply.+ z- g* B( u- }2 {/ V
1.2.9.7 New 0 RMS WORKING VOLTAGE introduced as defined term.( m3 F! q. k1 w! K1 _, n
1.2.10.4 New 0 SOLID INSULATION introduced as defined term.
& b9 i) T3 m" [) H: q$ V4 n1.2.13.15 New 0 CHEESECLOTH introduced as defined term.
4 x( i; U- ]* o1.2.13.16 New 0 WRAPPING TISSUE introduced as defined term.
; k+ |$ W* Q0 H4 E1.2.13.17 New 0 PROTECTIVE CURRENT RATING introduced as defined term which is similar to+ k5 V2 Q' y" |3 }  C* n+ c2 Q
previous term "current rating of the circuit under test" of subclause 2.6.3.4.
1 P1 U& E0 }, B& k1 b1 V3 y1.3.3 Clarified 1 If the test voltage is not specified in a test item the rated voltage or any value
. b8 @& K9 i! q. o6 [3 qin the rated voltage range shall be used for test.; u( [, R# T( J+ C- O) x. R
1.4.8 Modified 1 "Note 2" added for additional requirements of USA and Canada for/ f' }$ u2 k$ b' ^5 F' P
overvoltage protection of TNV circuits.* O" z' I, R3 M! ^5 ^5 a
1.4.14 Clarifi ed 1 Adding to third paragraph: "The failure of functional insulation is only
- C$ e2 g* E1 ]6 Gsimulated when required by 5.3.4 c)" (risk of fire, risk of electric shock).
% \+ R/ h0 d- R1.5.1 Modified 0 Adding "Note 3" (Switzerland does not allow mercury switches) and deleting$ t9 Q  S3 m/ b9 i! E- [
second paragraph and old "Note 3"., \* G4 T2 ^" R, r
1.5.6 Modified 0 Complete change of subclause by adding information from IEC 60384-14.0 p. y- w: \, W. {8 I
However, application principle of X- and Y-capacitors not changed.
7 A7 L2 W* T$ N2 e$ P' J9 v1.5.7 Complete change and concept for bridging resistors. Detailed requirements) M' Q# f4 K" E
for:
/ i. g& n0 ?7 S* ]; P·  Resistors bridging functional/basic/supplementary insulation (1.5.7.1). u  I4 u' g; U* \4 D" i
·  Resistors double/reinforced functional insulation (1.5.7.2)
' ]* h( ]1 A" T·  Resistors double/reinforced functional insulation – Special- @0 d) Q" j9 K9 l3 I
requirements when connected to antenna/coaxial cable (1.5.7.3)2 k5 t" W9 u( ?, S
1.5.7.1 Only subclauses 2.10.3 and 2.10.4 (distances) apply to such resistors.3 h2 x/ O) H9 w: R
1.5.7.2 Very different concept:
( y3 L6 A. b6 k7 {' ?; p·  Single resistor is acceptable if it passes "Resistor test"
$ g! ]' Y1 V& J# F; R/ H·  Group of resistors must either pass "Resistor test" or pass subclauses
: ^% [) L  `  B  F2 S2.10.3 and 2.10.4 (distances) with each resistor short-circuited in turn
" L* Q6 D) J" H& S! z6 W8 v$ I4 I0 p"Resistor test":
& x$ n$ J% u6 a& {) R$ r# h6 ^Damp heat test of IEC 60068-2-78 plus impulse test and resistance
* r! r/ v$ y% ~! i; b! c4 Wmeasurement.7 o& ~0 M( r1 q& O/ Q' S) V- H) S
1.5.7.3
( s) c3 n/ [( }6 tModified 2
7 g$ D$ \9 }3 @8 B6 TSame as 1.5.7.2 above but with different impulse generator for circuits with2 H' ^" |  n$ O1 u. I
coaxial cable connection.! @4 P) p" ^( |  E9 C
1.5.9 Requirements for varistors (VDR) specified.
/ c/ U9 Z! }# B. C4 ?$ j  j1 |  d/ p1.5.9.1 Secondary circuit surge suppressors: any suitable component allowed
& Q8 Y* [6 N+ _Primary circuit surge suppressors: only VDR allowed., F6 C' o- g- X8 A* ~0 P. [
1.5.9.2 An interrupting means must be provided for protection of the VDR in series.
1 r& i* a1 o: d* w1.5.9.3 It is allowed to bridge functional insulation by VDR, no additional& V6 E+ U$ [0 j8 B5 y
requirements.
5 ~- c! ]+ V3 l! o6 q) T  \# Q! ~. |1.5.9.4 It is allowed to bridge basic insulation by VDR with additional requirements:( ?0 Z1 f  O& u& t; E: Y
·  one side of the VDR must be earthed
! u1 }1 s, j0 P·  only possible for pluggable equipment type B or permanently. M( h/ F7 P- \* U
connected equipment or equipment with permanently connected- v( X* W, b; C. a2 g# L
earthing conductor
7 L  Z: Y+ S4 n1 k·  more restrictions for countries FI, NO, SE$ b4 i- W: b) N% g( b
1.5.9.5: X2 N" @7 H( W  U/ n5 I: I
New 2
- F( }2 \4 l6 H, \7 ~It is not allowed to bridge supplementary/double/reinforced insulation by) _1 p# n: ]/ b4 z0 a) {
VDR.) L- a. v% d7 K, l2 h) H+ d
1.6.1 Modified 0 "Note" for Australian national difference was deleted.* h8 m/ v3 S2 }+ W3 o: K* [
1.7.1 Clarified 0 Clarification for the use of the Class II symbol.  f0 N% {$ t$ |; H
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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