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PMP21529: Tweak to 48V and high side sensing

Part Number: PMP21529
Other Parts Discussed in Thread: UCD3138

I am looking at PMP21529 and am considering basing a new design off of it. 

A few questions:

- It talks about max VIN and VOUT being 60V. I'm hoping that by tweaking R1, R2, R9 and R10 I could have a 48V bus voltage exchanging power with a 12V lead acid battery voltage. Please confirm.
- I see it uses low side current sensing. Any comments on why this was chosen? I would need high side sensing so that the systems have a common ground.

This will work for a PoC of the product. Eventually I will need an isolated bi-directional buck boost.  Do you have any reference designs for isolated, bi-directional buck boosts? (48V<->12V, 100W to 500W range)


  • Yes you can change R1 R2 R9 and R10. The code for PMP21529 is for Li-On battery, you need to change the code for lead acid battery.

    You can do high side current sensing, but it is high voltage signal, you need to bring the signal down to less than 2.5V, then connect to UCD3138

    We have non-isolated bi-directional buck boost, I don't know if there is any isolated reference design.

  • Thanks!

    Yes, can put the lead acid profiles in the code as well as move to high side current sensing.

    I guess we will cross the isolation bridge when we get to it.