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I am requesting help to create a battery charger and load sharing circuit with the following specifications:

  • 3s Lithium Ion battery
  • 12 V at 2 Amps to power TPA3128D2 Class-D Amplifier (this is for max volume. Possible to lower the voltage/current to accommodate design constraints)
  • 2.7 V at 50 mA, low noise to power STM32F4 microcontroller as well as external DAC and analog circuitry
  • Charging done via USB Micro-B port with USB 2.0 (5 V at 500 mA or 1.5 A)

I am currently considering this design:

  • Power Circuit Module to handle battery charging and balancing.
  • BQ25713 to handle the load sharing/power path management as well as 12 V boost converter
  • TPS62125 to output the 2.7 V from the BQ25713 power path
  • BQ24392 to handle USB charge detection/enumeration

I would appreciate any help on confirming or denying the viability of this design as well as any suggestions on any improvements that can be made for simplicity.

Edit: Simple block diagram as requested. Block Diagram

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    \$\begingroup\$ What design? This is a list of resistors and a bag of ICs. Please outline the general connectivity of your thoughts at block level at least. \$\endgroup\$ – Ale..chenski Mar 14 at 20:08
  • \$\begingroup\$ @Ale..chenski Thank you for the suggestion. I've added a block diagram \$\endgroup\$ – D Haze Mar 14 at 20:50
  • \$\begingroup\$ I think the BQ25713 is hooked incorrectly. Battery shouldn't be connected to Vsys. Otherwise the rest looks good to me, provided that you will never run your amplifier when charging the battery - uB port won't be able to provide 5A on primary 5V side to run the booster. \$\endgroup\$ – Ale..chenski Mar 14 at 21:24
  • \$\begingroup\$ And what about "power Path management" block? How do you envision to match 12V Vsys with 5V Vbus? \$\endgroup\$ – Ale..chenski Mar 14 at 21:32
  • \$\begingroup\$ So if you take a look at the first page of the BQ25713 datasheet the power path management is apart of the design of the IC. It uses power MOSFETs along with outputs from the IC to maintain a 12V Vsys by pulling from the USB port or discharging from the battery. The BQ25713 has an internal Buck/boost converter to help with this. \$\endgroup\$ – D Haze Mar 14 at 21:48

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