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Phone charger Y connector

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xmen_xwk

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I'm building a Y cable type connector, that will charge phone and power OTG keyboard and mouse. Like this.

Actual Charger > Y connector > Phone, keyboard, mouse.


Its quite simple but since I want to digitally turn off the phone charging and it became little problematic, I thought of using a p-mosfet in charger and VBus that is going to phone. But the problem is, when the mosfet is off and phone is no longer charging, then the current will flow back because phone is being host for other devices. And the diode inside PMosfet will let the current go in the rest of the circuit. The problem can be solved by placing an external diode so current only flows in one direction.

But another problem, since my phone charger is rated 3A output, I believe my phone is consuming around 2.5A, thats why they gave 3A charger, right ? Now if that much current is going through a diode, the forward voltage drop will become high like 1V. So the phone will have 4V, thats not enough to charge it. There are some very low Vf diodes for solar panel, but they are expensive. Is there any other way to fix this ? or a good diode ?
 

Hi,

Connecting a second component to the line will be a bad idea as you suggested.

I assume you've found a low Vds P-Channel MOSFET with a reasonable price, so maybe you can use two switches instead of one, one to the phone and other to the OTG by connecting their gates together, so that you will never face this issue.

Actually there are MOSFET array chips with seperate P-Channel MOSFETs and common gate P-Channel MOSFETs, which may be cheaper.
 

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