12v in 50v out boost converter for pulsed discharge application

Hello David,

Possibly this reference design might be a good starting point: 

Thanks but that's far too complex for little ol me, it doesn't have to be commercially viable, just a simple and dirty prototype for pulsed output only, I could use a large capacitor bank supplied from a bench supply at 50v but I'd rather not risk having them short out and make a big scary bang.

Is it too much power for a single phase to supply for 1ms?

Hello David,

You could use LM5156 as single phase boost converter with less output power and have a medium size capacitor bank to reduce the voltage drop during the 1ms. So from the maximum voltage drop you allow and the maximum capacitor bank you want to have, you could calculate back, how much current the converter needs to deliver and then design one that gets into current limit for the 1ms when the 16A are drawn and then only re-charge the output caps during the time when no current is drawn.

But here it depends on the voltage drop and capacitor bank you allow.

That sounds like a good idea, how do I implement a current and voltage limit at the same time?

Hello David,

If the input voltage is not varying too much, the converter itself has a switch current limit implemented. The voltage regulation via the feedback resistor will be the voltage limit.

I'm trying to make a webench design but it cant create the design with the LM5156 with the following parameters:

Input voltage: 20-25 DC

Output: 50v 10A(max for the LM5156)

Min package size: 0805

Use ceramic capacitors: on

Hello David,

Let me forward you request to the expert of this device. In the meantime you might check your application with the LM5155 boost quickstart Excel sheet: 

The LM5155 is WSON, I cant solder packages like that.

Hi David,

You don't need to use LM5155 IC. You can just use its tool for your calculation as LM5155 and LM5156 can be calculated the same way.

Please let me know if you have any questions.

Thanks,

Yinsong

At what voltage does the LM5156 drive the MOSFET gate?

It's driven by the VCC voltage.

Thanks,

Yinsong

One slight problem is the LM5156H is so new I cant find it in stock anywhere.

Please check the link https://www.ti.com/product/LM5156-Q1#order-quality 

I can add it to cart here.

Thanks,

Yinsong

I referenced the LM5156H because that comes in a package I know I can solder, I assume its the same.

I'm looking at using the CSD19532KTT‎ as the switcher as it looks like a very efficient MOSFET, do you think that is suitable? If so what resistor/ferrite bead will I need for the gate if any?

It looks ok to me. You can have the placeholder for gate resistor/ferrite bead on the PCB layout and add if it is needed based on your EMI requirement.

Thanks,

Yinsong