INA199: Multiplexed Measurement Using Logic Signal for Power

Przemysław Pietrzyk

Prodigy 20 points

Part Number: INA199
Other Parts Discussed in Thread: INA138

Hello, sorry for the same question, I would like to seperate them for different parts.

Can I use INA199 with multiple loads and multiplexing as ilustrated bellow?:

it's from INA138/168 datasheet:

https://www.ti.com/lit/ds/symlink/ina138.pdf?ts=1659265251390

Chapter 8.2.6

over 3 years ago

0 kai klaas69 over 3 years ago

Guru 140200 points

Hi,

the output signal of the INA138 is a current and is converted into a voltage by the voltage drop across RL. So the voltage drop across the isolation diode 1N4148 will not harm here.

But when using the INA199 in this circuit, the voltage drop across the isolation diode will cause a massive error because the INA199 has a voltage output.

Kai

0 Guang Zhou over 3 years ago in reply to kai klaas69

TI__Mastermind 34140 points

Hi,

Kai is correct. The diagram needs slight modification in order to work with INA199. For example, each INA199 output could be connected to an individual MUX input, all diodes can be removed, as well as RL.

Regards, Guang

0 Przemysław Pietrzyk over 3 years ago in reply to Guang Zhou

Prodigy 20 points

thank you

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INA199: Multiplexed Measurement Using Logic Signal for Power