一.SPEC
1.电解电容零件工程规格书中之StandardRating表格,其中规定了不同规格的电解电容RatedRipple Current值,例如:Sharp机种PWPCC904(滤波电容) 67L215L-820-15N (CNN公司KXG Series)
VDC V |
Cap. uF |
Case size ∮D*L mm |
tanδ
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|
L.C. uA |
Rated Ripple Current mA rms/105℃ |
||||
1min |
5min |
120Hz |
100KHz |
||||||
450 |
82 |
18*35.5 |
0.24 |
1576 |
763 |
715 |
1785 |
2.此电容用于电源输入端滤波,因此采用120Hz时的RatedRipple Current规格715mA。
3.而用于评估电解电容RippleCurrent之Spec要依据以下公式:
SPEC=Spec(component)×频率系数(FM)×温度系数(TM)
注:FM/TM取值方法见附表
4.OTPV 评估电解电容Ripple Current的Derating规格为85%,因此 测试值<SPEC×85% 时判定OK。
二.Test Method
将电解电容接地端吸开串联一导线,直接用电流计探头测试该导线电流的有效值(rms),测试时要调整输入电压值(90V~264V)达到纹波电流最大。见图示:
三.附表(FM&TM取值方法):NCC公司产品为例
1.MultiplyingFactors on KMG Series(radial lead type)
Frequency Multipliers
Range |
50Hz |
120Hz |
300Hz |
1KHz |
10KHz |
100KHz |
~3.3uF |
0.65 |
1.00 |
1.35 |
1.75 |
2.30 |
2.50 |
4.7uF~33uF |
0.75 |
1.00 |
1.25 |
1.50 |
1.75 |
1.80 |
47uF~1000uF |
0.80 |
1.00 |
1.15 |
1.30 |
1.40 |
1.50 |
2200uF~ |
0.85 |
1.00 |
1.03 |
1.05 |
1.08 |
1.08 |
Temperature Multipliers
Temp(℃) |
55 |
65 |
75 |
85 |
105 |
Multipliers |
2.23 |
2.23 |
2 |
1.73 |
1 |
2. MultiplyingFactors on KY Series
Frequency Multipliers
Range |
120Hz |
1KHz |
10KHz |
100KHz |
~180uF |
0.40 |
0.75 |
0.90 |
1.00 |
220uF~560uF |
0.50 |
0.85 |
0.94 |
1.00 |
680uF~1800uF |
0.60 |
0.87 |
0.95 |
1.00 |
2200uF~3900uF |
0.75 |
0.90 |
0.95 |
1.00 |
4700uF~ |
0.85 |
0.95 |
0.98 |
1.00 |
TemperatureMultipliers
Temp(℃) |
55 |
65 |
75 |
85 |
105 |
Multipliers |
2.23 |
2.23 |
2 |
1.73 |
1 |
3. MultiplyingFactors on KXG Series
Frequency Multipliers
Range |
120Hz |
1KHz |
10KHz |
100KHz |
~100uF |
1.00 |
1.75 |
2.25 |
2.5 |
120uF~ |
1.00 |
1.67 |
1.75 |
2.25 |
Temperature Multipliers
Temp(℃) |
55 |
65 |
75 |
85 |
105 |
Multipliers |
2.23 |
2.23 |
2 |
1.73 |
1 |
*Temperature multipliers shows the guide limits of themaximum available ripple current at each of the temperature,of which the lifetime at the rated maximum operating temperature is expected.
四.电解电容寿命评估测试方法
1.Calculation Formula:
电容寿命LifeTime= Life(spec)×2(Ts-Tt)/10
Life(spec):指spec中标明的寿命值
Ts:电容最高使用温度值
Tt:电容本体温度测试值
2.判定方法:以上计算得出之寿命值与整机MTBF目标值比较,若大于目标值则判定OK。
3.例如:SHARP机种C904 Life(spec)=10000Hrs,Ts=105℃,Tt=52.6℃,。SHARP MTBF目标50000Hrs。
Life Time=10000×2(105-52.6)/10=377917Hrs>50000Hrs OK