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Powering board with 3.3V and 5V


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Hey guys, I need some help with debugging an existing circuit that's supplying 3.3V and 5V. Attached is a photo of the schematic in which the green numbers are the measured voltages. The LiPo charger is partially based on @bluehash's LiPo charger. 

 

In this circuit, 5V is supplied via USB to the LiPo battery charger. The output battery voltage is then passed into a 5V booster to supply the components that are using 5V. This 5V is then lowered to 3.3V via a LDO. The 5V components use a maximum of 25mA, 3.3V components maybe a maximum of 150-200mA. This circuitry was suggested to me because it was the cheapest option with components coming from element14. 

 

I'm not sure what I did wrong and it would be awesome if I can get some help getting proper 5V and 3.3V output.

 

 

post-32777-0-41636100-1408895034_thumb.png

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From your measurements, The 0.7v drop across the tps61222 looks suspicious. perusing the datasheet shows that there is an integrated forward pass diode from L to Vout, paired with a FET.

 

It looks like the device isn't starting up for some reason. Are you sure that all the pins are properly soldered?  SC-70 packages can be very fun sometimes.

 

 

 

It's also strange that your LDO isn't running either. Can we see the area of the routed board? Because I'm looking at the datasheet for the RT9030 LDO, and according to your numbering it's not wired correctly.

post-274-0-95055200-1408932261_thumb.png

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