Capacitor Charger LT3750

Thread Starter

MGPERF

Joined Jun 8, 2021
77
I am fairly certain the layout is designed per the datasheet maximum current of 10A on the primary. Even the datasheet proposed layout for the LT3750 could run into problems if you try to push it up to 20A which is probably why the LT3751 has a different layout to handle higher currents. I would recommend if using the LT3750 to simply set the primary at maximum 10A. I know you wanted 20A but I don't think it is achievable with that part. Also I would not use the LT3751 recommended 2.5uH transformer with the LT3750. Sure it may 'look' like it works in sim, but could damage parts because it is not recommended on the datasheet. The LT3751 allows lower inductances to 2.5uH but the LT3750 allows a minimum inductance for proper operation of 10uH on the primary.
You are correct to be concerned about to much current. It exceeds datasheet recommendations. I would not do it. If this circuit requires high reliability over the long run there is no guarantees after you step outside the boundaries of the datasheet.
Ok sounds good, I am thinking I can charge a smaller cap to a higher voltage to reduce amps on the primary yet get the same energy.
 

Thread Starter

MGPERF

Joined Jun 8, 2021
77
Could I just do 2 transformers and 2 mosfets in parralel but only 1 LT3750? I am thinking
Ok sounds good, I am thinking I can charge a smaller cap to a higher voltage to reduce amps on the primary yet get the same energy.
Update, linear says go ahead and use the 20 amp transformer. Cool!
 

dcbingaman

Joined Jun 30, 2021
1,065
Could I just do 2 transformers and 2 mosfets in parralel but only 1 LT3750? I am thinking

Update, linear says go ahead and use the 20 amp transformer. Cool!
That is good news. Glad you got the input from LT if the designers of the chip are ok with it, should work fine :)
 

Thread Starter

MGPERF

Joined Jun 8, 2021
77
Any ideas for if I wanted to make a simpler power supply? I need 300 plus volts out with 12 volts in and a peak draw of about 10 amps. I also want to use an offer the shelf transformer.
 

Thread Starter

MGPERF

Joined Jun 8, 2021
77
Ron, thanks I was thinking maybe a royer oscillator as I’ve used those successfully in the past but this will be much more compact, have better voltage regulation, and I can use an off the shelf compact transformer :)
 

ZJUshine

Joined Jan 15, 2022
1
MGPERF,帖子:1671034,成员:797285 said:
我可以在并联中只做 2 个变压器和 2 个 MOSFET 但只有 1 个 LT3750?我在想

更新,线性说继续使用 20 安培变压器。凉爽的!
[/引用]
我发现类似的问题是充电速度很慢(75V/s 4400uF)。你有什么建议可以加快充电速度吗?我目前的想法是将R的电阻降低到4mΩ。我想知道你最后是如何改变你的电路的。
如果您能回答我,我将不胜感激。
 
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