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Yep, there is a voltage doubler on the board. It is labled A3_3V. The output seems to be the center pin between the other two. Right now I am trying to steal from it and run some lights, but I don't think I can pull more than around 50mA or so without the noise interfering with the RF stuff and IC.
The reason the N channel works is because there is 3 volts coming from the IC. The Source is connected to ground and so Vgs=3v. We normally want more but you know... The upper side of the H-bridge is diffrent. Assuming no voltage less than ground, we would need 6volts to the gate, that is because the motor would take 3volts away from the Source. That is if we used and N channel mosfet. A P channel one would need either 3volts on the Source (meaning running the motor at 3v) or putting -1.5v on the gate. Either could be done if someone wanted to.
I think the upper transistors are PNP because it looks like the intention of the circuit was when one side of the motor went to ground, that would pull down the gate of the transistor on the other side. And since that is the other transistor we want to be turned on I think it is a PNP type.
Also there is somthing funny about the current going to the PNP transistors. Even with 10ohms instead of the 68ohms I still don't get the power I do when I short the resistor out. I am going to try a PNP darlington and see what happens.
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