INA180-Q1: Pspice model (INA180A2) behaviour

Stani Bell Ngoufack Tchoufack89

Intellectual 2020 points

Part Number: INA180-Q1
Other Parts Discussed in Thread: INA138, TINA-TI, INA180

Hello,

my customer is using INA180A2QDBVRQ1 (current sense amplifier) in their project.While using this model in SIMetrix 8.3 for simulation work, with PWM signal input the output voltage is decreasing if the current load starts to consume (see images below):

In other to do a cross check the same simulation with the same circuit was done with INA138 current sense amplifier; as can be seen in the image below the voltage is increasing from 0 to some extent for its respective current load consumption

Could you please verify was is happening with the first simulation and let us know the reason for this simulation result?

What could be done to have a correct simulation result?

Can this be related to the Pspice model itself (downloaded on ti.com)?

Best regards,

Stani

over 4 years ago

0 kai klaas69 over 4 years ago

Guru 140200 points

Hi Stani,

I would recommend to run the INA180 TINA-TI Reference Design (Rev. A)

TINA-TI is a free simulator.

Kai

0 Stani Bell Ngoufack Tchoufack89 over 4 years ago in reply to kai klaas69

TI__Intellectual 2020 points

Hi Kai,

thanks for your reply.

The customer uses Simetrix for simulation in the whole company and they are not allowed to install/use another tool for simulation.

What could be the reason for the observed behaviour? Is there another alternative than having to download TINA-TI?

Best regards,

Stani

0 Ian Williams over 4 years ago in reply to Stani Bell Ngoufack Tchoufack89

TI__Mastermind 27715 points

Hello Stani,

I don't see anything wrong with the INA180A2 model - it's doing exactly what you are asking it to. The differential input voltage (INP - INN) is equal to 68mOhms * 452mA = 30.7mV. The output of the amplifier should be 30.7mV * 50V/V = 1.54V, and it is. The long decay of VOUT is simply due to the time constant of the RC filter placed on the output.

Keep in mind that the INA180A2 is not affected much by the common-mode voltage set by your source V2. Changing that voltage will only cause small variations in input offset voltage by the INA180's common-mode rejection ratio spec. If you want to see the output voltage change, you must modulate your input current I1.

Best regards,

Ian Williams
Applications Manager
Current Sensing

0 kai klaas69 over 4 years ago in reply to Stani Bell Ngoufack Tchoufack89

Guru 140200 points

Hi Stani,

could you help to "translate" the parameter line of "V2", so that we can carry out a TINA-TI simulation?

Kai

0 Ian Williams over 4 years ago in reply to kai klaas69

TI__Mastermind 27715 points

Hi Kai,

It's a pulse with the following settings:

V1 = 0V
V2 = 5V
Time delay = 0
Rise time = 10.245902 us
Fall time = 10.245902 us
Pulse width = 1.0245902 ms
Period = 2.0491803 ms

However I have already duplicated the circuit in PSpice and saw the same behavior.

Best regards,

Ian Williams

0 kai klaas69 over 4 years ago in reply to Ian Williams

Guru 140200 points

Thanks, Ian :-)

Kai

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INA180-Q1: Pspice model (INA180A2) behaviour