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I have a requirement to convert 54 V battery output to 5 V. My battery's positive terminal is grounded. I tried the connection as mentioned in the datasheet which is attached here, but as soon as I connected to my 54 V positive grounded battery the LM2576HV got burnt. Please suggest what should be done.

LM2576 HV connection

Here is what I have used in the circuit: enter image description here

enter image description here

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    \$\begingroup\$ Does the output need to be referenced to the battery ground? If not you can simply ignore the battery grounding and hook positive to Vin and ground to negative. If you need the output to be referenced to battery ground then a buck converter isn't going to work. \$\endgroup\$
    – user1850479
    Commented Dec 27, 2022 at 17:51
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    \$\begingroup\$ High much current do you need? \$\endgroup\$
    – Bruce Abbott
    Commented Dec 28, 2022 at 3:19
  • \$\begingroup\$ @user1850479 output need not be referenced to battery ground. When I connected positive ground battery to vin it got damaged \$\endgroup\$
    – Nikhil Pandya
    Commented Dec 28, 2022 at 3:25
  • \$\begingroup\$ @BruceAbbott my current requirements is 0.5 Amp \$\endgroup\$
    – Nikhil Pandya
    Commented Dec 28, 2022 at 3:26
  • \$\begingroup\$ In that case, you can simply build the circuit in Figure 8-3 of the datasheet, which is a buck converter with up to 60V input and 5/12V output. You have a 48V battery, so you're good to go. \$\endgroup\$
    – user1850479
    Commented Dec 28, 2022 at 3:43

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The LM2576HV expects the battery's positive terminal on the input and the negative on GND. As such it can't make a voltage higher than the battery's positive terminal.

Try a boost regulator like the LM5001 instead. Feedback is going to be a bit sketchy, you may need to arrange a special feedback circuit.

Measured from -48 V, +5 is 53V - so a boost topology is needed. The tricky part is that the 48 V is probably not 48.0 V but the 5 V probably should be 5.0 V so you can't just make a 53 V output boost converter; the 5 V needs to be measured against the supply positive (AKA ground).

Maybe something like this (modified version of LM5001 datasheet figure 20):

enter image description here

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  • \$\begingroup\$ The datasheet suggest one such case where it boost (-5 to -12 Volt) input to -12 V output. But i need +5 volt \$\endgroup\$
    – Nikhil Pandya
    Commented Dec 28, 2022 at 3:28
  • \$\begingroup\$ Tthat's the LM2676 datasheet right? that part only makes voltages more negative than the positive supply. to make them more positive you need a boost converter. \$\endgroup\$
    – Jasen Слава Україні
    Commented Dec 28, 2022 at 4:11
  • \$\begingroup\$ Sorry but could not understand it. \$\endgroup\$
    – Nikhil Pandya
    Commented Dec 28, 2022 at 7:02
  • \$\begingroup\$ updated picture \$\endgroup\$
    – Jasen Слава Україні
    Commented Dec 28, 2022 at 10:40
  • \$\begingroup\$ Though I want to use 2576 only, I will try it as well. \$\endgroup\$
    – Nikhil Pandya
    Commented Dec 29, 2022 at 5:38

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