Boost convertor design simulation(Ltspice)

Irving

Joined Jan 30, 2016
2,308
And somehow you expect the laws of physics to give instant results? You have capacitors to charge, magnetic fields to establish, control loops to stabilise. A 100mS+ startup time is pretty reasonable I'd say...
 

Papabravo

Joined Feb 24, 2006
17,242
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A reference like Basso, Switch-Mode Power Supplies, (2014) will explain all of this in more detail.
 
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Papabravo

Joined Feb 24, 2006
17,242
I didn't get to look at the design as away from PC at the moment, but sounds like this could benefit from a cockroft multiplier on the output.
He still has the problem of having 100 ma of output current. The more stages you have the more difficult it is to maintain and regulate the output voltage because it is load dependent. I think he will have better results with a transformer in the mix. This does complicate the actual design in terms of complexity and cost. I don't see the current approach being feasible at all.
 

ronsimpson

Joined Oct 7, 2019
1,630
Things not right:
M2 has 4.9 ohms resistance when turned on. Need higher current part! The poor little part can not take that current and would explode in a real world.
The Gate signal is only 8 volts which is a little low.
R7 is very small.
Frequency 445khz which is very fast. But with only 10uH of L1 maybe that is ok.
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I changed the MOSFET out for a 250V 0.425 ohm part and it works much better.
 

Papabravo

Joined Feb 24, 2006
17,242
Things not right:
M2 has 4.9 ohms resistance when turned on. Need higher current part! The poor little part can not take that current and would explode in a real world.
The Gate signal is only 8 volts which is a little low.
R7 is very small.
Frequency 445khz which is very fast. But with only 10uH of L1 maybe that is ok.
---------------------------------------------------
I changed the MOSFET out for a 250V 0.425 ohm part and it works much better.
It pays to read the datasheet(s) with some level of precision and attention to detail.
 
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