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Power supply from USB wall adapter...some works...some doesn't

atomosrl

Apr 22, 2024
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Hello!

I've two battery powered board with onboard charger.
Here some detail
  1. Board1 has fast charger (needs 15V from wall adapter) and I've a power delivery IC to request correct voltage from the power supply
  2. Board2 has linear charger (needs 5V), there's not power delivery IC in this case
I can charge batteries of Board1 with all kind of power adapter (QC compliant) I have.
I can charge batteries of Board2 only with some adapter, not all.

Question: in your opinion (and knowledge)...with quick charge adapter I've also to request 5V voltage?

how to recognize an adapter compliant with no power delivery IC board?

Thanks
Stefano
 

Harald Kapp

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with quick charge adapter I've also to request 5V voltage?
As far as I know: no.
This kind of adapter starts at 5 V and only delivers more if the power delivery IC at the other end requests more.

I can charge batteries of Board2 only with some adapter, not all.
A standard USB interface delivers only 100 mA at startup. After handshake with the USB device current can go up to 500 mA. At least that's the standard. Many USB power suources ignore this standard. But if you happen to have a compliant power source, the initial 100 mA may not suffice to power the charger.
Do you have a USB tester (example) to check voltage and curent at the output of the various USB power sources?
 

atomosrl

Apr 22, 2024
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As far as I know: no.
This kind of adapter starts at 5 V and only delivers more if the power delivery IC at the other end requests more.


A standard USB interface delivers only 100 mA at startup. After handshake with the USB device current can go up to 500 mA. At least that's the standard. Many USB power suources ignore this standard. But if you happen to have a compliant power source, the initial 100 mA may not suffice to power the charger.
Do you have a USB tester (example) to check voltage and curent at the output of the various USB power sources?
Hello Harald, thanks for reply.
Also as I far as I know the adapters starts at 5V then drives larger voltages following a request on CC1 and CC2....but...

I've 4 adapter: three adapter are USBC-USBC (my boards have USB-C connectors) and one USBA-USBC.
All adapters charge my smartphone with "Fast Charge" anda all adapters charge my board with power delivery IC onboard.

....but....only USBA-USBC adapter presents 5V on my board without PD IC. Other adapters present 0V (I've a red led on 5V rail).

I continue my investigation....if I'll get some new I'll back here.
Regards
Stefano
 

Delta Prime

Jul 29, 2020
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I believe the moderator, Mr.Harald Kapp nailed it!
You just repeated what he has stated.
I've two battery powered board with onboard charger.
Here some detail
Make,model number,link of your two battery powered boards with onboard charger?
 

atomosrl

Apr 22, 2024
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I believe the moderator, Mr.Harald Kapp nailed it!
You just repeated what he has stated.

Make,model number,link of your two battery powered boards with onboard charger?
There's no model/link. Boards are made by me. If you want some number

QC adapters can deliver much more current then needed at 5V, but may be limited to 100mA like Harald suggest if it's not present PD ICs.

Tomorrow I'll do some current measure
bye
Stefano
 

atomosrl

Apr 22, 2024
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Then supply the circuit diagrams of each and a photo of each side of each board.
Why do you need diagrams and photos of the boards?
what are you looking for? each board works fine and it hasn't problem.
bye
Stefano
 

Harald Kapp

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You have two candidates for failure:
  1. the USB power supply
  2. your linear regulator (without PD chip)
Check both independently:
  1. Does the failing USB power supply(ies) deliver 5 V without load or with a small load?
  2. What is the output voltage of the failing USB power supply when you draw more than 100 mA or more than 500 mA (use a resistor to simulate the load).
  3. Does your circuit operate as expected when supplied with a 5 V power supply with enough amperage (output current)? I suspect it will as it works with the USB-A power source.
What do the data sheets of the failing power supplies say about requirements for the connected device? Your cable may require additional resistors, read e.g. this article.
 
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