Good day everybody. This is my first question on this site so bare with me :) .

I am working on general purpose driver using TBD62083 (replacement of darlington array ULN2803). As you can see the circuit is realy simple:

enter image description here

The only problem that I foreseen is reversing polarity on POW1 connector. Analysing the internal diagram of the driver I came with this solution: enter image description here

Of course that on 24V the resistor must be rated to at least 5W. I don't have room on PCB for such big resistor so I was also thinking to add a resetable fuse in series with resistor.

So, my questions are:

Will this setup affect in normal operation (in case of using an inductive load) the clamp diode?

Did anyone tried a better solution?

Is this device suitable for paralleling the outputs (no reference found in datasheet)?

Thank you in advance for your answers.

  • \$\begingroup\$ I don't understand what you are asking for? What's the purpose of 100 ohm resistor and resetable fuses? \$\endgroup\$ – Marko Buršič Jun 15 '19 at 7:27
  • \$\begingroup\$ Is it correct that you simply want to add reverse polarity protection to POW1? \$\endgroup\$ – hekete Jun 15 '19 at 8:02
  • \$\begingroup\$ Hi. When you will reverse power supply this circuit via Pow1 connector, the diode that it is tied to ground will start conducting because "COMMON" is tied now to GND. Same for parasitic diode. Because the parasitic diode it is conducting then the clamp diode will conduct as well. If no load on "COMMON" then the device will be destroyed. Now, on 24V with 100 ohms resistor the power on it will be ~5W. I do not have enough room for it so I was thinking to Adding a small resistor and a polyfuse. \$\endgroup\$ – Petrescu Cristian Jun 15 '19 at 8:02
  • \$\begingroup\$ @hekete Yes it is correct. I know that it can be done with a diode or a P channel mosfet in series but at this moment I cannot use those solutions. \$\endgroup\$ – Petrescu Cristian Jun 15 '19 at 8:08
  • \$\begingroup\$ Can you explain why none of the standard reverse polarity protection methods are suitable for this purpose? \$\endgroup\$ – hekete Jun 15 '19 at 8:10

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