So I'm designing a battery charger circuit. It has two connectors in, a main power source and then a powerbank can be connected through a USB C port. I understand that there are various IC's to handle this.

However, since my main power source is not a USB C port, I want to be able to use the USB C port to also power the circuit sometimes, using a standard USB C power source that you can plug into the wall. This is handy when testing the system in a controlled environment. But I'm unsure how to handle this, wont the charging IC sometimes try to "charge" the power outlet? Or is this automatically handled.


  • \$\begingroup\$ What is the 'main power source'? "wont the charging IC sometimes try to "charge" the power outlet?" - which charging IC? \$\endgroup\$ – Bruce Abbott Feb 11 at 23:21
  • \$\begingroup\$ The main power source is just a standard DC socket capeable of handling 5-36V inputs. A typical charging IC would be this: ti.com/product/BQ24721C \$\endgroup\$ – stackman82 Feb 12 at 7:29
  • \$\begingroup\$ That IC has an AC adapter operating range of 8V–28 V, and is designed to work with 3S or 4S Lithium batteries. It will not work with a 5V supply. Your powerbank puts out 5V, right? What battery will this circuit be charging? \$\endgroup\$ – Bruce Abbott Feb 12 at 19:26

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