I'm trying to design some kind of backup battery charger - please see the image: enter image description here

Normally, the DC supply is ON, and provides current for load and also charges the battery. Battery should be charged to 27V or more, and maximum charging current must be limited to 4 A (when battery is fully charged up the current should automatically decrease to 0).

When DC supply is turned OFF, the battery provides current for load instead, with maximum allowed current.

I'd like to ask You for any references, circuit ideas or even some keywords to look for on internet and other sources.



1 Answer 1


keyword: power path controller, ideal diode

something like that http://www.linear.com/product/LTC4417

look also at others vendors, like TI, Fairchild, On semi

Implementation is possible with discrete components only, cheaper but less efficient.

  • \$\begingroup\$ Nice device, still need the charging part to match the OPs profile. A constant current, float voltage charger seems to fit the bill. \$\endgroup\$
    – KalleMP
    Jul 14, 2015 at 20:28
  • 1
    \$\begingroup\$ linear.com/solutions/5552 \$\endgroup\$
    – kcotton
    Jul 14, 2015 at 20:42
  • \$\begingroup\$ I'm not LT's employee, I just know their products \$\endgroup\$
    – kcotton
    Jul 14, 2015 at 20:43

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.