TMUX6209: Current Measure of 9V rail through TUX6209

Aakash Dey

Part Number: TMUX6209
Other Parts Discussed in Thread: TMUX4827

Hi,

I want to measure the current flowing through the 9V power rail. I have connected a Sense resistor in series of the rail and both end of the resistor is connected to S1A & S1B terminal of TMUX. Below is the rough diagram of my conncetion.

In this case, S1A is connected to 9V power rail directly and S1B is connected to Load (approx 9V only). But, supply voltage VDD is 5V. Is the schematic is correct? Or Shall I need to provided more than 9V to VDD pin of TMUX6209 IC?

Please confirm.

over 2 years ago

0 Clemens Ladisch over 2 years ago

Guru 318050 points

The absolute maximum ratings forbid I/O voltages above the supply.

0 Aakash Dey over 2 years ago in reply to Clemens Ladisch

Intellectual 300 points

Hi Clemens,

Thanks for your reply.

Though its showing that I have connceted the 9V to TMUX6209 with VDD=5V, But I have connected it in a diffential line (S1A and S1B), the the voltage across the sense resistor will be always less than 5V. This means in any cases, the voltage between S1A and S1B will be always less than 5V. So, is my understanding is wrong?

If yes, should I need to change my VDD voltage to 12V in that case?

0 Clemens Ladisch over 2 years ago in reply to Aakash Dey

Guru 318050 points

Only the absolute voltage (relative to GND) matters. 9 V is larger than 5 V. You must increase V_DD to 9 V or more.

0 Aakash Dey over 2 years ago in reply to Clemens Ladisch

Intellectual 300 points

Hi Clemens,

Thanks for the confirmation.

0 Stephen Scheramic over 2 years ago

TI__Intellectual 1176 points

Hi Aakash,

I was going to make 1 other suggestion, you could also use our TMUX4827 which supports up to +/-12V inputs on a 5V supply rail. That might help simplify your design.

Thanks,

Stephen

0 Aakash Dey over 2 years ago in reply to Stephen Scheramic

Intellectual 300 points

Hi Stephen,

I have 12V power supply in my design and also we got some samples of TMUX6209 from TI. So, we would like to test the TMUX6209 first. If this doesn't fulfill our requirement, then will definatly try with TMUX4827 as per your advice.

Thanks for your valuable inputs.

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TMUX6209: Current Measure of 9V rail through TUX6209