I'm attempting to interface a TPS61235P boost converter to an Arduino Pro Mini (3.3V Vcc), and while I can get it to turn on, I can't for the life of me get it to turn back off.
I currently have a 1M resistor pulling it down, and a 10k resistor to an output on the Arduino.
Before driving the pin high, the converter is (correctly) disabled. When I make the pin go high, it turns on just fine. But when I turn the pin low, figuring it'd pull it to ground combined with the 1M resistor, the converter stays on. On top of that, my code indicates the OUTPUT pin state is high as well, despite me setting it low (I have an OLED display on the Arduino).
The enable pin stays at 5.15V constant, despite originally only supplying it with 3.3V. Its almost like it feeds itself, because not even the Arduino can drive it low, I must ground it with a wire and then it stays low, even after disconnecting the jumper wire.
If I disconnect the enable pin from the Arduino, the output pin switches as it should to low. It reads high again the moment I plug it back onto the enable pin of the converter.
Even with jumpering resistors to the enable pin, the only way I can get this thing to turn off is to jumper it to ground with a wire, no resistors.
What's going wrong?
simulate this circuit – Schematic created using CircuitLab
Best Answer
It sounds like you have a connection between the boost converter's Vout pin and the Enable pin. If so, the converter's output is driving its own Enable pin high. This is collaborated by the comment you attached to your question. Perhaps your pullup resistor is in the wrong place?
In any case, the Arduino output pin may get damaged by the overvoltage condition. It sounds like it's still working (so far), but something to keep in mind.