Inductors for EMC are different ?

[eem2am]

i wish to use small outline inductors for differential mode filtering in battery powered (12V) SMPS.

is it correct that such inductors can NOT be the same type as the inductor that i use as the switched current inductor in the boost converter?

...since the inductors used in the differential mode EMC filter should have a very very high self resonance frequency and are not the same type of inductors as the type that get used as switching inductors in boost converters etc ?

 

[cristivasilache]

the iductors which you mention about, for boost smps, have Al low, they are with so called distribuited airgap (yellow torids with white side, or ligt green with red side, amng most used) you need a hi-permeability one (grey or green color toroid) and for differential mode, two identical windings winded opposite. the ones which are winded together are for common mode.

 

[eem2am]

Thankyou,

do you believe automotive EMC test is harder to pass than other EMC tests eg for domestic equipment?

Do you think car companies first install Linear regulator style power supplies to get the product out to market, then work on an EMC passing power supply thats switch mode totally......then release the product with that in ?

that is , is passing automotive EMC standards horrendously, hideously difficult?

i cant see why, a car is an "isolated unit" and doesnt exactly interfere with other cars.