DRV3204E-Q1: the value of passive device for motor current sense

Takao Yamamoto

Genius 4135 points

Dear all,

Could you answer following two questions?

■Question 1; Are there some concern to use following value of resistor to set Vgain?

I want to set Vgain to x30. You recommend R21=R22=30kΩ, R11=R12=1kΩ at Figure 15.

However I want to use E6 line resistor.

So I think that R21=R22=33kΩ、R11=R12=1kΩ or R21=R22=47kΩ、R11=R12=1.5kΩ.

I am able to think that changing of Vgain, but are there some other concern?

And which is the value recommended?

■Question 2; Are there some trade-off to use 0.1uF capacitor for C2?

You recommend 10nF for C2 at Figure 15.

However I think to use 0.1uF to get more stability.

Are there some trade-off things to increase capacitance?

Best regards,

over 8 years ago

0 Wilson Zuo over 8 years ago

TI__Mastermind 26065 points

Hi Takao,

Our expert will be noticed and get back to you later.

Best regards,

0 Takao Yamamoto over 8 years ago in reply to Wilson Zuo

Genius 4135 points

Dear all,

How is this going?
I would like to know about this.

Best regards,

0 William Toth over 8 years ago in reply to Takao Yamamoto

TI__Expert 3555 points

Hi Yamamoto-san,

With the E6 line resistor you can expect +/-20% variation, is this true for the components you are selecting?

The recommendation would be to use the closest values, as you said is R21=R22=33kΩ, R11=R12=1kΩ

The concern is on the Vgain. A large mismatch on the gain resistors will have a huge impact on the output of the amplifier, and with +/-20% accuracy, the worst case gain main cause the output to saturate the ALV output even at low current.

For Question #2 we are still working on this, however this may take some time.

Regards,
Will Toth

Motor drivers

Motor drivers forum

DRV3204E-Q1: the value of passive device for motor current sense