Without any load (i.e. no phone attached), the output voltage of my MintyBoost is 5.0V (+/- 0.03V or so) and the voltage on the D+ and D- pins is 2.0V. Since my iPhone wouldn't charge--I initially get the chime indicating it's charging, but then immediately I get the "This accessory may not be supported" message--I did some troubleshooting using a 15 ohm resistor as a load. With the resistor attached the output voltage of the MintyBoost drops to 3.1V even it I supply the MintyBoost 3.0V from a regulated bench power supply.
I checked and double-checked component placement and solder joints. Any suggestions on what to do next?
MintyBoost voltage drops under load
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- adafruit_support_bill
- Posts: 88099
- Joined: Sat Feb 07, 2009 10:11 am
Re: MintyBoost voltage drops under load
What is the current rating of the bench supply? Measure the actual input voltage to the Minty under load.even it I supply the MintyBoost 3.0V from a regulated bench power supply
If you post photos of the front and back of the board we can check over the assembly.
- vizzini
- Posts: 2
- Joined: Thu Mar 06, 2014 9:45 pm
Re: MintyBoost voltage drops under load
The bench supply is rated for 2.0A continuous. Voltage at the supply measures 3.01V powering only the MintyBoost; 2.99V with Minty under load.
- adafruit_support_bill
- Posts: 88099
- Joined: Sat Feb 07, 2009 10:11 am
Re: MintyBoost voltage drops under load
2A should be plenty on the input side, and the voltage drop is minimal Your assembly looks excellent too. I suspect either a bad chip or a marginal inductor. If you contact [email protected] with a link to this thread we can send you a replacement MintyBoost kit.
Please be positive and constructive with your questions and comments.