TSB81BA3D: Power capacity of board

richard davis

Part Number: TSB81BA3D

I am wondering if this product can handle 2 amps at 24 volts with out modifications such as removal of fusses and and jumper wires?

The power will be supplied through the FireWire cable and not through a power source.

Any feed back will be very much appreciated.

over 7 years ago

0 Richard Mourn over 7 years ago

Prodigy 140 points

Hello Richard, the TSB81BA3D IEEE-1394B Three-Port PHY requires 3.3V/1.95V supply inputs. The power from the FireWire cable (24V) will need to be regulated down to 3.3V/1.95V on the board and provided to the PHY.
Best Regards, Richard Mourn
FlightWire Technology, Inc.
(719) 338-7451

0 Elias Villegas M. over 7 years ago

TI__Guru* 76130 points

Hello,
Can you provide a block diagram of your implementation? I don't clearly understand what do you mean by "the power will be supplied through the cable..."
How are you planning to power the device up with the Vp from the cable?
Regards

0 richard davis over 7 years ago in reply to Elias Villegas M.

Prodigy 40 points

Block diagram unfortunately not. I will be powering this repeater with a FireWire cable that has 24v 2 amps of power as 1 cable will become 2 and I need to power up a 2 infrared laser's and 4 cameras running 120 frames per second a piece.

I apologize as all responses and replies are going through google translate.

0 richard davis over 7 years ago in reply to Elias Villegas M.

Prodigy 40 points

I was using unibrain repeaters but had to remove and short out fuses and solder wire from one side to other of ferrite node to keep from burning up repeater need 24v 2 amp repeater with out heavy soldering mods

0 Elias Villegas M. over 7 years ago in reply to richard davis

TI__Guru* 76130 points

Hello,
As Richard said, you will have to regulate down the 24V.

0 Richard Mourn over 7 years ago

Prodigy 140 points

Additionally, IEEE-1394 only allows 1.5A for cable power. This is based on cable gauge, voltage drop etc... In correctly implemented designs your 2A requirement will cause fuses to appropriately activate. If you want to use more than 1.5A of cable power this will require a custom non-IEEE-1394 compliant design.

0 richard davis over 7 years ago in reply to Richard Mourn

Prodigy 40 points

This is what I have been doing in current configuration is removing all fuses running 20 gauge wire in place and jumper wires across Freite connections.

Want to find alternative as I run 2 18w lasers and 2 cameras off the repeater.

0 Richard Mourn over 7 years ago in reply to richard davis

Prodigy 140 points

There is really only two concerns relative to the TSB81BA3D and cable power. 1) the CPS with ~400K resistor can support up to 30VDC. 2) When DC coupled there can only be 0.5V common mode shift. Example common mode shift: x.xx ohm DC resistance of the VP and VG path times the current (2A) must be less than 0.5V (the DC path must be less than 0.25 ohms).

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TSB81BA3D: Power capacity of board