EMC of eight parallel mini switch mode current regulators.

[eem2am]

current regulators

hello,

I am making a LED lamp using eight 300mA LEDs.

It will run off a battery with voltage 13.5V.

I dont want all the LEDs to simply come on all at once,
-i want them to come on in succession, LED "chaser" style.

Therefore, i have designed the following circuit, which uses 8 parallel mini switch mode current regulators (one for each LED).
(I will control each LEDs on/off with a PIC interfaced to each of the current regulators)

https://i27.tinypic.com/1z1zsi1.jpg

These will all be paralleled across the 13.5V input.

My question is.................

Will this cause a Bad EMC problem?,

-since eight switchers (albeit ~one Watt each) will be switching away and may "beat" with each other or something, causing bad EMC problems.?

(These mini current regulators are not synchronized and i may end up using a different (constant frequency) controller than ZXLD1362, which is hysteretic mode.)

 

[FvM]

emc switchmode

Unsynchronized switchers can be expected to broaden the EMC interference lines and thus cause lower peak levels in emission measurements. If there would be a synchronisation option, the phase should be shifted between individual switchers.

The commutated current between D2 (VIN node) and GND should be bypassed with minimum inductance.

 

[eem2am]

FvM,

what you say appears to make good sense, but my place synchronize the converters for EMC reasons.

Are they wrong?