I/p: 85~300 vac; o/p: 12v, 3a smps design

[nachiketsakinal]

Hello All, Can anybody help me to design SMPS with below requirements:

I/P: 85~300 VAC; O/P: 12V, 3A SMPS DESIGN

 

[alec_t]

The 12V 3A spec would be easy to meet, but have you checked if any off-the-shelf units can accept up to 300VAC? Perhaps modify the input side of an old PC supply if necessary? Perhaps a lot cheaper and easier to buy one.

 

[nachiketsakinal]

@ alec_t: Hey thanks for reply. Actually I required input voltage upto 290 vac for special purpose; that is high tolerance for that power supply. And I cant understand what you said above for modification of input side of old PC supply. Please explain in brief.

 

[ronsimpson]

Here is a design. Not 300VAC but will get you started. I could modify the design for 300V if you need.

 

[Eric911]

This is not difficult. you should supply more detail requirement, Such as efficiency, EMI and EMC requirement and so on. I remember like ST or ON have note application, maybe could help you.

 

[alec_t]

I cant understand what you said above for modification of input side of old PC supply. Please explain in brief.

A 230V AC-input PC power supply will have its input bridge rectifier, reservoir/smoothing caps, main switching device (FET or bipolar) etc rated accordingly. If those were replaced by suitable higher-rated components the input could accept 300V AC. With high (lethal) voltages present due precautions must be taken and the modification must be done by a competent person.

 

[nachiketsakinal]

@alect_t: thanks for all. But the will be increased in that case. I want some lesser size than that.
@eric911: Details are: 85 % Efficienccy, Surge / EFT : upto 2KV, ESD: Air discharge: 8 kv & contact discharge: 4 kv.High POT: 2kv for 1 min & 2.5 kv for 1 sec. Can you provide any link for that application note.
@ronisimpson: thanks for the support. How much cost will take to design for that..?

 

[ronsimpson]

@ronisimpson: thanks for the support. How much cost will take to design for that..?

Do you want to know the production cost?
Do you want to know the increase in production cost because of the 300 VAC?
Do you want to know what I charge to help you?

To work at 300 VAC we should make a better snubber in the design and maybe redesign the transformer to reduce the voltage on the IC.

ron,

 

[nachiketsakinal]

@ronisimpson: What you charge to help me..?

 

[ronsimpson]

nachiketsakinal, I sent you a private message.

 

[bountyhunter]

Your input voltage range is almost 4 : 1. That's very difficult. You could use a multi winding transformer and relays to connect different taps depending on input voltage level.

 

[bountyhunter]

Details are: 85 % Efficienccy

The app note is a pretty good flyback design, but I don't think it could possibly make 85% eff over such a wide input voltage range. Just my opinion.

 

[Eric911]

Ya, Pls reference ST or PI website.