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Flex 6400 usb +5V current

phase2682
phase2682 Member
edited December 2019 in FLEX-6000 Signature Series
How much current can the usb port supply?  I want to detect that the flex 6400 has turned on by monitoring the usb voltage which turns on/off with power up/down.  plan to use an optoisolator to protect the flex and need 10 to 20 mA .

Answers

  • Neal_K3NC
    Neal_K3NC Member ✭✭
    edited March 2019
    The spec for USB2 (and 1) is 500ma.
  • Mike-VA3MW
    Mike-VA3MW Administrator, FlexRadio Employee, Community Manager, Super Elmer, Moderator admin
    edited April 2019
    If you use a Opto, which is very high impedance, then you will only be drawing as much current as a good voltmeter.    

    If you check the hardware reference manual, Section 7.3.5  you'll see that Pin 9 of the 15 pin accessory connector does provide +5VDC at up to 500ma and it has a resetable fuse.  This would be a much safer way to do it.

    If this is for a remote station, I would also recommend that you add a remote Relay for Pin 14 PTT in.  You may need this for a remote registration for SmartLink.

    Mike
  • Ted  VE3TRQ
    Ted VE3TRQ Member ✭✭✭
    edited December 2019
    USB 1, as I recall, would only deliver 100ma, and USB 2 boosted that to 500ma. Also, there was always a negotiation step to allow full current delivery on USB 2. A device could depend on 100ma, but had to negotiate with the bus driver for higher current. There was also an aggregate limit for the bus.

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