Power over I2C (something like PoE)

[ROVguy]

Hello.

I'm looking at using PCA9615 (or PCA9614) to run a 4 wire bus for I2C. Is it possible to setup a power insertion on one of these two IC's the way one can on a (PoE) Ethernet line?
Thanks

David

[cabletie]

Hi,  Your question is interesting; however, you may be missing the intent of I2C.

By definition: (source credit: en.wikipedia.org) I2C = Inter Integrated Circuit, and is a synchronous serial bus capable of multi-master and multi-slave communication over a data line and a clock line.

  The length of the bus is limited to a maximum of a couple of feet;  its' usefulness is limited to basically

chips located on the same circuit board (close proximity).  It may, or not, be possible to use the

data/clock line with some sort of low power charge pump circuit but this seems redundant as

power must be available within the distance to which the I2C bus is limited in order to use it.

[ROVguy]

The question was based on going longer distances, few to 10s of meters, it was also with the assumption that a 4 wire hot-swap buffer like the PCA9615 would be used. The purpose of the power is not to use it as a supply but a dead man switch holding a relay closed for emergency shutdown without affecting the I2C bus or the PWR supply and still have noise immunity and limited number of wires (6).

Maybe I should look at a different protocol.

Thanks