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标题: UL8750电容短路测试 [打印本页]
作者: 琥珀流云    时间: 2016-10-11 11:21
标题: UL8750电容短路测试
有哪位高手懂UL8750 LED driver的! C/ k/ p0 Q% v: j
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我们有一款LED driver，使用两个大电容串联，在短路其中一个电容的时候，另外一个电容喷液了，我们的电源内部全部灌胶，如果耐压测试通过是否可以？
作者: jsspace    时间: 2016-10-11 11:34
漏液不可以接受，不管是否灌胶。
作者: fasten    时间: 2016-10-11 12:39
jsspace 发表于 2016-10-11 11:34 ' j) i( d# F, n0 R
漏液不可以接受，不管是否灌胶。
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2 _& s7 v. S/ x4 m' e. G8.7.1.2 After ultimate results have been obtained for each test, the sample shall be permitted to cool to
% v7 [+ ]7 r' q. e: Q' }room temperature and the dielectric voltage withstand test of 8.6 shall be repeated.5 Q$ P3 o' t; V$ r1 F* u1 E
8.7.1.3 A risk of fire or electric shock is considered to exist with any of the following results:
9 g% Q, |6 t, D- f! {& L$ Fa) Opening of the ground fuse,
2 N  `) t9 Y( nb) Charring of the cheesecloth or tissue paper,
7 {4 K& N  N. u5 \3 ~c) Emission of flame or molten material from the unit,
1 t  {/ g2 P2 D) L% A) v& P3 ad) Ignition or dripping of a compound from the unit,( P5 r* D% `4 p/ w
e) Exposure of live parts that pose a risk of electric shock under the requirements for, C7 ^% O$ p; {- k. _: f
accessibility of 7.2, or1 s: _+ }# Z% B5 C4 E, v0 O& o$ n
f) Breakdown during the subsequent dielectric voltage withstand test.7 l, h% Y3 q; |, c" B* v! i
Opening of the 20A time delay fuse is acceptable provided none of the other conditions noted in (a)5 H/ b* n& [- [2 a# A' O
through (f) occurs.) a& j6 F; z5 W% J& C0 A4 m
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  F1 w+ J: P) ]  Y* [; k, J8.7.2 Component failure test
; B  F- {2 q) ^# V  E- b' C- m3 p: K; r8.7.2.1 A unit having components such as resistors, semiconductor devices, capacitors, and the like shall
) ]" ?& x$ b. d2 G# }* M8 @( Enot exhibit a risk of fire or electric shock when a simulated short circuit or open circuit is imposed. In
" S2 ]7 `$ P9 e, Spreparation for component failure tests, the equipment, circuit diagrams, and component specifications- S* |) l) U( n1 |
are examined to determine those fault conditions that might reasonably be expected to occur. Examples
8 y! g7 r# m5 f! ?( Ninclude: short-circuits and open circuits of semiconductor devices and capacitors, faults causing open
2 v5 v" H# r" d7 z6 T* q8 }circuits of resistors and internal faults in integrated circuits.: X3 p5 n* ?. s1 o# W: q
Exception No. 1: Circuits in which maximum power levels have been determined to not exceed 50 W need1 \9 [5 U+ c3 D; ?4 j
not be evaluated for component failure.
, z" }/ e# [$ E1 s: [. p; {Exception No. 2: Devices supplied by a source operating within the limits for risk of fire and electric shock
3 g0 [+ p- L9 G- d- @need not be subject to this test.
" q3 e# J4 X5 U8 U; ~8 U9 G8.7.2.2 Each component is to be short circuited or open circuited, one at a time (one fault per test). Each- s1 m1 c* j# H) F: q2 J% ^5 U
test shall continue until either the unit is no longer operable, or until conditions are obviously stable (as& p) x4 S, c& h! J& d- o# |3 d3 ]( e
determined by no visual.
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- Q4 G# m9 q" p0 ^- M7 ?/ E1 S3 Y再核对一下标准看有没有答案？
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作者: jsspace    时间: 2016-10-11 14:16
本帖最后由 jsspace 于 2016-10-11 14:30 编辑 0 z3 y; h6 E* j; M3 `
fasten 发表于 2016-10-11 12:39
5 w4 K" b) n' \7 I6 U8.7.1.2 After ultimate results have been obtained for each test, the sample shall be permitted t ...
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但奇葩的是UL内部有很多工程判断8 X: ^2 T* i7 A+ H8 h9 m
这个问题，我刚刚发邮件跟UL重新确认了一下，现在的做法是如果漏液没有益处到外壳外面，且耐压测试通过，可以接受。
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作者: 琥珀流云    时间: 2016-10-11 16:12
非常感谢，我问的UL 工程师是说不行~~，这个标准也很烂，工程师判断也不一样~·~麻烦·~~
作者: jsspace    时间: 2016-10-11 17:02
琥珀流云 发表于 2016-10-11 16:12
0 A% d7 |' X2 G* n非常感谢，我问的UL 工程师是说不行~~，这个标准也很烂，工程师判断也不一样~·~麻烦·~~
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你在问问吧，我今天问的，他说可以



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