HYPEX SMPS-400 Ripple

[Kv3audio]

Hello.

I am wondering if the ripple at the output of HYPEX-SMPS400 power supply is normal.

Oscilloscope pictures showing SMPS loaded at different loads.

Is this normal?

 

[firechief]

Tell us a little about your measurment technique. Is this a USB scope that I am looking at? Are you AC coupled or DC? What are you using for a scope probe and is it grounded?
What voltages is the power putting out, and how do you have it loaded for each of the screen shots? This looks like measurment error to me.

 

[Kv3audio]

Tell us a little about your measurment technique. Is this a USB scope that I am looking at? Are you AC coupled or DC? What are you using for a scope probe and is it grounded?
What voltages is the power putting out, and how do you have it loaded for each of the screen shots? This looks like measurment error to me.

I have taken these days ago.

Scope is 100MHZ digital Oscilloscope not a USB type.

DC Coupled.

Scope probe? x100

SMPS output without load is +-43VDC

Image 54 is 3.3Ax 81VDC
Image 57 9A x73VDC

Other cannot remember indeed. but max load was in image 57

Measure technique, scope probe connected directly at the output of the SMPS.

Scope is connected via Isolation transformer

 

[Kv3audio]

HYPEX-SMPS400

Still cannot determine if these measures are correct for HYPEX-SMPS400

 

[Th3 uN1Qu3]

Scope is connected via Isolation transformer

This is wrong. The scope must always be grounded to get proper measurements. Feed the power supply thru the isolation transformer and put the scope into a grounded outlet.

 

[Tazzz]

Not really the scope can float but you have to remember leakage currents and the safety aspect of what potential is ground for the scope. To measure ripple its better to solder on a coax and use ac coupling on the scope the resolution of 10v/div is not great with 8bit adcs

 

[Kv3audio]

Any one recognize, why HYPEX use transformer with AIR GAP, and 22uH coil in series with the transformer?


I noticed nothing new in the winding order of the transformer, only AIR GAP, in half bridge SMPS, without series capacitor!! but with 22uH coil

connected center TAP to 0.47uf caps, fed from +-320V rail

 

[hilli_billi]

On the last picture you see the 50Hz humm from the input.
This seems to be an unregulated SMPS. Just compare it to 'normal' transformer with rectifier and caps. A regulated PS removes this hum.
On the other pictures it is seen as dirt, because you trigger on the high frequency ripple

Concerning air gap and 22µH coil:
Maybe this is a resonant converter where you need series L (22µH) and perhaps another series L (stray inductance per air gap) to make it short-circuit proof.

 

[Kv3audio]

On the last picture you see the 50Hz humm from the input.
This seems to be an unregulated SMPS. Just compare it to 'normal' transformer with rectifier and caps. A regulated PS removes this hum.
On the other pictures it is seen as dirt, because you trigger on the high frequency ripple

Concerning air gap and 22µH coil:
Maybe this is a resonant converter where you need series L (22µH) and perhaps another series L (stray inductance per air gap) to make it short-circuit proof.

Thanks for answer.

I measured the inductance of the transformer, it was 390uH

I shorted ALL secondaries, inductance 370uH.

I don't know if that's normal.

That power supply, is just like any half bridge power supply, except the synchronized rectifier topology used.

Or may be LLC ?

 

[hilli_billi]

That's what I meant, a LLC resonant converter.
I assume you made like this:
Measuring primary with secondary open => main inductance
Measuring primary with secondaries shorted => stray inductance.
370µH is quite large for stray inductance ...
What controller do they use?

 

[Kv3audio]

That's what I meant, a LLC resonant converter.
I assume you made like this:
Measuring primary with secondary open => main inductance
Measuring primary with secondaries shorted => stray inductance.
370µH is quite large for stray inductance ...
What controller do they use?

Aha, that's why then


using TL494 with 4 transistors to drive GDT, one transistor at each Mosfet Gate + Zener + 1N4148.

very small heat sink for two mosfets, DT is good, TOP rounded squares, bottom is squared. that's what I noticed, not perfect squares. there is a reason for this.

Thanks