| Electronics > Projects, Designs, and Technical Stuff |
| Usb-C 2s Liion charging Circuit |
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| ruumoo:
I'm designing a pcb for a portable aplication. I want to use a 2s liion battery as power and I would like to charge it over usb-c. This is my current plan of attack: --- End quote --- I already have a USB-C pd controller, that can deliver the full 100W, aswell as a liion charge controller and the output step downs, which aren't important to the circuit. Now I just need a fitting step up, step down converter that converts the 5-20V from the usb port to 7.4 V for charging the batteries. Now for my questions: 1. Is this a viable circuit, or does it have some giant flaw I overlooked? (Preferably, I don't want to blow up 4 18650 cells) 2. How would I go about limiting charging current? In my current cinfiguration, the batteries could draw the full 100W, if they decide to do so, which would decintigrate my PCB Gesendet von meinem LG-H930 mit Tapatalk |
| jbb:
Have a look at the bq25700 range from TI. Buck boost with: - input current, voltage limit - system output voltage *before* charge current measurement (allows proper charging current control even if system load is all over the place) - fairly accurate charge current limiting - monitor ADCs - I2C / SMBus control With the right MOSFETs, efficiencies > 90% are quite possible. Does requires chunk of support components, though. |
| ruumoo:
--- Quote from: jbb on November 30, 2018, 07:01:41 pm ---Have a look at the bq25700 range from TI. Buck boost with: - input current, voltage limit - system output voltage *before* charge current measurement (allows proper charging current control even if system load is all over the place) - fairly accurate charge current limiting - monitor ADCs - I2C / SMBus control With the right MOSFETs, efficiencies > 90% are quite possible. Does requires chunk of support components, though. --- End quote --- Sounds promising, but I will have to work through the 84 pages of datasheet first Gesendet von meinem LG-H930 mit Tapatalk |
| jbb:
--- Quote from: ruumoo on November 30, 2018, 08:08:16 pm ---Sounds promising, but I will have to work through the 84 pages of datasheet first --- End quote --- I know the feeling :-\ |
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