New HDPLEX 200W LPS

[oneguy]

Why is the ripple voltage so high at 1 millivolt when a sigma11 LPS is around 10 microvolts. Is there something I am missing?

[oneguy]

12 minutes ago, rickca said:

Good question. Can you please provide a link to your referenced 10 microvolt measurement on a sigma11 LPS?

 

From memory this eBay listing references 10 microvolts and a quick google search found someone else referencing 12 microvolts in the second post on this page. 

 

Both of these could very well be erroneous. Your thoughts?

[oneguy]

4 minutes ago, rickca said:

I would want to make sure that we're talking about an actual measurement (not something off a spec sheet) and that we're measuring exactly the same thing so that the results are comparable.  

I think the only way to accomplish this is a side-by-side test using the same methods since as far as I know there is no standard of testing methods. I don’t believe anyone has done this yet especially because the new HDPLEX LPSU hasn’t been released. 

[oneguy]

2 hours ago, Karin said:

Hello oneguy,

 

In general a ripple voltage of +/- 1mV for a (non-audio) linear power supply is not so bad at all. The LT3045 family however is capable of showing ripple and noise figures of < 10uV in real-live design.

 

The relatively "high" ripple of HDPlex is caused by the pre-regulation circuits, market in red. These are switching DC/DC converters and are necessary to achieve an adjustable voltage from 15V to 3.3V @ 2A.

 

In a full blow linear power supply design the LT3045 regulators would need to dissipate about 24W (=6W per LT3045) extra in heat, when the power supply is set from 15V @ 2A to 3.3V @ 2A. Unnecessary to mention that this is from a technical point of view simply not possible without proper heatsink(s).

 

Regards,

Karin

 

   

Karin,

 

Thank you for the reply. 6w of heat per LT3045 in that for factor would be a lot to dissipate in that form factor. Damn engineering trade offs!

 

-oneguy