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Thermal Dissipation and Efficiency

Posted by: aliaykan on

Hi,

Is this a good approach for minimizing the thermal dissipation and increasing efficiency?

1. Optimizing the available largest device by forcing the efficiency to %99, R Ilimit settings and optimizing primary to secondary ratio.

2. Attached files shows the heatsink requirements just 1/5 of the default PI Expert results. It seems very good.

So I want to learn is there any disadvantage or restriction; especially in light loads or using with secondary side controllers in CC mode? Should I pay attention for any other issue?

 

Best regards,

 

Files

Attachment Size
TOP262EN-24V-4.2A.uds 754 KB
TOP271KG-43V-1.4A.uds 848 KB

Comments

Submitted by PI-Neela on 09/01/2016

Using over sized device could reduced the IC temperature due to smaller Rdson. However, it could also increase the switching related loss due to the larger charges. It needs verification on bench.  99% of efficiency is hard to meet becuase the loss is not only on IC, it is system total loss.another concern of oversized device is that Ilim is higher. Your transformer design has to based on higher Ilim, may result in bigger size.

Not clear about your question of :using secondary controller in CC mode.

 

Submitted by aliaykan on 09/01/2016

Dear Neela,

I also do not hope %99 eff in practice. It's just forcing the PI Expert for using the largest device.

Could you give me any advice for attached PI Expert designs? Do you see any problem with optimization?

I meant with secondary side controllers; CC/CV controllers like Sea05. You can ignore this question. I think bench tests will answer this. 

Regards,

Submitted by PI-Neela on 09/12/2016

I suggest you start with 66kHz design. I may resutls in higher efficiency.