Why SMPS output inductors *not* coupled?

eem2am · 2nd January 2012, 09:50 AM

The SPS30 SMPS is a +/-58V, 4A bridge or forward type SMPS with output inductors which are *not* coupled..........-the two outpout inductors are seen in the picture on page 1 of the datasheet (the two red coils)

https://www.coldamp.com/store/media/...tasheet_en.pdf

I would think that the SPS30 was a current mode controlled SMPS, because current mode gives quicker transient response than voltage mode...and is just easier to control....so i assume that they chose current mode control

Page 3 , part 5 of the following clearly states that output inductors should be coupled with current mode converters.....

http://www.ti.com/lit/an/slua119/slua119.pdf

So does any reader know why the output inductors of SPS30 are not coupled?

Kv3audio · 2nd January 2012, 11:42 AM

Wish to see EMI measurements for the same SMPS

sawreyrw · 2nd January 2012, 02:19 PM

The reference you gave says "coupled inductors are required for good cross regulation." Note that the regulation of the SPS30 is extremely poor, so obviously, they wouldn't care about coupled inductors.

ssanmor · 3rd January 2012, 11:56 AM

The photos you are seeing are not updated.
Check here:

SPS30:
https://www.coldamp.com/store/sps30.html

SPS80:
https://www.coldamp.com/store/sps80.html

SPS80HV:
https://www.coldamp.com/store/sps80hv.html

Sonora Combo (integrated PSU):
https://www.coldamp.com/store/sonora-combo-2s300.html

Since three years ago or so all our SMPS have coupled ouptut inductors for better cross regulation.
In fact, SPSXX regulation is extremely good, why do you say that, sawreyrw?
This reminds me that we need to update some datasheet photographs! Thanks!

sawreyrw · 3rd January 2012, 03:02 PM

Duh, I misunderstood that the output is adjustable, and instead thought it was regulation. Sorry.

2nd January 2012, 09:50 AM	#1
eem2am diyAudio Member Join Date: Jun 2011	*Why SMPS output inductors not* coupled?** The SPS30 SMPS is a +/-58V, 4A bridge or forward type SMPS with output inductors which are not coupled..........-the two outpout inductors are seen in the picture on page 1 of the datasheet (the two red coils) https://www.coldamp.com/store/media/...tasheet_en.pdf I would think that the SPS30 was a current mode controlled SMPS, because current mode gives quicker transient response than voltage mode...and is just easier to control....so i assume that they chose current mode control Page 3 , part 5 of the following clearly states that output inductors should be coupled with current mode converters..... http://www.ti.com/lit/an/slua119/slua119.pdf So does any reader know why the output inductors of SPS30 are not coupled?

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2nd January 2012, 11:42 AM	#2
Kv3audio diyAudio Member Join Date: Sep 2011	Wish to see EMI measurements for the same SMPS

2nd January 2012, 02:19 PM	#3
sawreyrw diyAudio Member Join Date: Apr 2006 Location: Minnesota	The reference you gave says "coupled inductors are required for good cross regulation." Note that the regulation of the SPS30 is extremely poor, so obviously, they wouldn't care about coupled inductors.

3rd January 2012, 11:56 AM	#4
ssanmor diyAudio Member Join Date: Jan 2002 Location: Madrid	The photos you are seeing are not updated. Check here: SPS30: https://www.coldamp.com/store/sps30.html SPS80: https://www.coldamp.com/store/sps80.html SPS80HV: https://www.coldamp.com/store/sps80hv.html Sonora Combo (integrated PSU): https://www.coldamp.com/store/sonora-combo-2s300.html Since three years ago or so all our SMPS have coupled ouptut inductors for better cross regulation. In fact, SPSXX regulation is extremely good, why do you say that, sawreyrw? This reminds me that we need to update some datasheet photographs! Thanks!

3rd January 2012, 03:02 PM	#5
sawreyrw diyAudio Member Join Date: Apr 2006 Location: Minnesota	Duh, I misunderstood that the output is adjustable, and instead thought it was regulation. Sorry.

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