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I am developing small board with MCU, lithium battery and USB OTG and I am wondering what is the simplest way to power up the whole thing?

Basically:

  1. If USB cable is connected - PMIC detects type of the charger(from PC / wall charger) and charges battery with maximum available current. Also stable 3v3 should be provided for MCU.
  2. If charger is removed - PMIC supply 3v3 output for MCU.
  3. If USB OTG cable connected - PMIC supply 3v3 for MCU and 5v to USB.

So I've found RT9460, which does not provide stable output. External DC-DC is needed. There is LTC3576 with 3 programmable power outputs, but that's a bit overhead for me. Maybe there is a simpler solution?

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  • \$\begingroup\$ What about ti.com/product/BQ24298? or perhaps ti.com/product/BQ24140? \$\endgroup\$
    – Victor S
    Jul 24 '18 at 13:04
  • \$\begingroup\$ Looks good, but neither of this chips can provide stable output voltage - so DC-DC or LDO IC is still needed. \$\endgroup\$ Jul 24 '18 at 13:48
  • \$\begingroup\$ There is no simplest way. If your expected volume is 10,000 per week, you go with custom PMIC. If less, use TI/Linear/Maxim PMIC and add a DC-DC to whatever voltage you need. \$\endgroup\$ Jul 24 '18 at 17:02
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From having a look on Digikey I found the following Texas Instruments part that seems to fit your needs. I found this component by looking in the PMIC(Battery Chargers) section of the Digikey search.

BQ24090DGQR

https://www.digikey.com/product-detail/en/texas-instruments/BQ24090DGQR/296-38875-6-ND/5143531

http://www.ti.com/lit/ds/symlink/bq24092.pdf

(Couldn't leave this as a comment as I don't have enough reputation, sorry.)

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  • \$\begingroup\$ There is no embedded boost converter for USB OTG, like in RT9460 \$\endgroup\$ Jul 24 '18 at 13:56

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