DRV8432 Shunt Resistor Between PVDD

ALbert Tello

Intellectual 735 points

We using only 0.125 Ohms 1% shunt resistor on top of the bridge but we use one per bridge .

I would like to ask WHY need to use one per PVDD_A,B,C,D .

Our schematics is as follows:

MOTOR_PWR_CD-------<ShuntRES>--- LT6103(INA+INA-)_____> PVDD_D,PVDD_C } this tow pins are connected together.

MOTOR_PWR_CD-------<ShuntRES>--- LT6103(INB+INB-_____>PVDD_A,PVDD_B } this tow pins are connected together.

I need to know if this configuration is recommended or According to TI where is the Current Reading configuration

Regards

Albert Tello

over 13 years ago

ALbert Tello over 13 years ago

Intellectual 735 points

Hello , is any body can help me with questions.

Albert

Ryan Kehr over 13 years ago in reply to ALbert Tello

TI__Guru 55655 points

Albert,

For 3-phase applications, you may want to measure current independently in each phase. For DC motor applications, then you only need 2 current sense assuming you are connecting 2x DC motors to the 8432.

Not sure why you are using a LT amplifier since TI has plenty of options here. :) One is listed below:

http://www.ti.com/lit/ds/symlink/ina193.pdf

ALbert Tello over 13 years ago in reply to Ryan Kehr

Intellectual 735 points

Hi Ryan,

We will use Drv8432 with Stepper .

We would like to support motors from 1 to 4 Amp , software adjustable. Can use one shunt resistor High Side for PVDD_A and PVDD_B (Both pins are connected together) ,and another Resistor for PVDD_C PVDD_D (Both pins are connected together) ,

My question : can be connected in this topology for feedback current .

Albert

Ryan Kehr over 13 years ago in reply to ALbert Tello

TI__Guru 55655 points

Albert,

No problem with this configuration.

Penn Linder over 13 years ago in reply to Ryan Kehr

Expert 1035 points

Ryan,

When using the DRV8432 with high side current sense resistors, where would you recommend the ceramic PVDD bypass capacitors go? Should the entire current path be bypassed (i.e., bypass capacitors between Power Supply and Ground as per U2 in attached), or just the PVDD pins (i.e., capacitor between PVDDx and GVDDx as per U1 in attached)?

2251.DRV8432_Bypass_Options.pdf

Thanks!

Motor drivers

Motor drivers forum

DRV8432 Shunt Resistor Between PVDD