Usb power and Vin Sharing
tonyp12
Posts: 1,951
On the QuickStart they are using:
a P-channel mosfet, plus two resistors and 1 cap to get softstart and also a diode for reverse current protection.
I decided to go with a Current Limiting Power Switch.
I wanted a 1.5 Amp cut-off as my micro-usb connector is rated 1.8A
Though a little pricy at $0.54 & 100 units (the 2.5A version only $0.27?)
But the above 5 parts probably cost around the same.
Diodes Inc. AP2161WG-7
http://www.mouser.com/ProductDetail/Diodes-Inc/AP2161WG-7/?qs=%2fha2pyFaduhBk7sE%252bJmSJeUNEkpLfPHIAKjVe27tPUPBXg7yRnxmGA%3d%3d
I'm using a dual color LED, red light for overcurrent flag & green part is for rx/tx
And using FTDI tool, the switch can be programmed to be turned on/off or after enumerated
I also put a small copper pour for the Drain pin to help with cooling as I think this pin is the one that get hottest.
a P-channel mosfet, plus two resistors and 1 cap to get softstart and also a diode for reverse current protection.
I decided to go with a Current Limiting Power Switch.
I wanted a 1.5 Amp cut-off as my micro-usb connector is rated 1.8A
Though a little pricy at $0.54 & 100 units (the 2.5A version only $0.27?)
But the above 5 parts probably cost around the same.
Diodes Inc. AP2161WG-7
http://www.mouser.com/ProductDetail/Diodes-Inc/AP2161WG-7/?qs=%2fha2pyFaduhBk7sE%252bJmSJeUNEkpLfPHIAKjVe27tPUPBXg7yRnxmGA%3d%3d
I'm using a dual color LED, red light for overcurrent flag & green part is for rx/tx
And using FTDI tool, the switch can be programmed to be turned on/off or after enumerated
I also put a small copper pour for the Drain pin to help with cooling as I think this pin is the one that get hottest.
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