Hello

I am experimenting with LM2576 HV to convert 48 VDC to 15 Volt.

Circuit is working well. But when batteries are under charge Vin approaches 55 Volt (regulated by a PWM Morningstar microcontrolled device). That is dangerously close to 60 V, the max Vin rated.

So a couple of times The 2576 burned out. Both tries the circuit lasted more than a month, working 24/24.

I can reduce the input V connecting some diodes in series, and sacrificing efficiency.

But I suppose there are better solutions. I browsed for higher voltage ICs, but did not find.

Output C is standard electrolytic, not ESR. Can that harm ?

Thanks for your time !

Kind regards, Horacio

 

Output C is standard electrolytic, not ESR. Can that harm ?

The higher the ESR of the cap the greater will be the ripple voltage.

 

Hello

I am experimenting with LM2576 HV to convert 48 VDC to 15 Volt.

Circuit is working well. But when batteries are under charge Vin approaches 55 Volt (regulated by a PWM Morningstar microcontrolled device). That is dangerously close to 60 V, the max Vin rated.

So a couple of times The 2576 burned out. Both tries the circuit lasted more than a month, working 24/24.

I can reduce the input V connecting some diodes in series, and sacrificing efficiency.

But I suppose there are better solutions. I browsed for higher voltage ICs, but did not find.

Output C is standard electrolytic, not ESR. Can that harm ?

Thanks for your time !

Kind regards, Horacio

Pretty close.
What you might try is to use only 3 batteries to power it and see how it does. This will unbalance your batteries a little, but probably not bad if they are big ones.

 

the genuine HV have no problem with 60V ! and his maximum is 63V

http://www.ti.com/lit/ds/symlink/lm2576.pdf

maybe you have a counterfeit product...

 

Ive used external MOSFET and gate drive transformer with this IC.
It worked for high voltage, but extremly sensible for EMI when triggering photo flash the IC would latch off.

You need to build a discrete converter there are not many ICs for high voltage.