INA230 - BUS Pin

Mike H Meyer

Other Parts Discussed in Thread: INA230

I've got a circuit utilizing an INA230 to monitor a 6V rail. The chip itself is powered from a 3.3V rail. We've noticed that when the 6V rail is disabled, the net is back-fed through the BUS pin. The 3.3V applied to the part results in around 2.7V on the 6V rail. Is there a way to prevent this? We're considering putting a diode in-line with the BUS pin but that affects the reading of the bus voltage.

over 10 years ago

0 Rabab Itarsiwala over 10 years ago

TI__Expert 4595 points

Hello Mike,

When you say the Bus is disabled does that mean it is floating? Is the ground connection still preset. Can you provide a schematic.

0 Mike H Meyer over 10 years ago in reply to Rabab Itarsiwala

Expert 1560 points

This is the circuit. 6V_LIM is not being purposefully driven when disabled, so I assume it would be floating.

0 Rabab Itarsiwala over 10 years ago in reply to Mike H Meyer

TI__Expert 4595 points

Hello Mike,
So when disabled is the SET resistor on the regulator shorted to ground? Is it possible for you to try this with another Supply? I am checking with the design team if this behaviour is expected.

0 Rabab Itarsiwala over 10 years ago in reply to Rabab Itarsiwala

TI__Expert 4595 points

Hello Mike,
There is an internal resistor from VBus to INA ground. So if the VBus pin is floated it should pull down to ground. If possible try a different supply and check if this behaviour could be replicated.

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INA230 - BUS Pin