DRV8703-Q1: SO pin output

By the way,R(sense) = 4mR

Give me 24 hours to look into this and get back to you.

Best,

Keerthi

Sorry,PWM is 25%HIGH 

Hi Huan,

The offset and the peak values of the waveform look correct and match the numbers that you have sent. How is the shunt resistor hooked up?

Is it low side? Are you going from forward into high-z or slow decay?

What application will this be used in?

Best,

Keerthi 

Hi Keerthivasan,

The shunt resistor is between SN and SP.

"Are you going from forward into high-z or slow decay?" : forward into slow decay.MODE = 0,and IN2 is PWM.If PWM is high , it will be forward.Else it will be slow decay.

This will be used to brush DC motor drive.

I hope you will find this helpful,and I want to reconfirm that the waveform is correct.

BR,

Huan Yin

Hi Huan,

Part of it looks correct. I will capture the waveform on my side as well to correlate. I will give update tomorrow.

Best,

Keerthi

Hi  Keerthivasan,

Because the application scenario is brushed DC motor, I also want to know whether the SO output waveform includes the ripple current signal of the motor.

Whether the spike in the SO waveform represents the ripple signal generated when the motor is commutated.

BR,

Huan Yin

Hi Huan,

Have you looked at any of our other devices that feature IPROPI like the DRV824x family of devices:
DRV8243-Q1 Automotive H-Bridge Driver with Integrated Current Sense and Diagnostics datasheet (Rev. C)

Are you trying to do some kind of ripple counting with the current ripples? We do have an industrial version of this device that integrates ripple counting:

DRV8234 2-A Brushed DC Motor Driver with Ripple Counting, Stall Detection, and Speed Regulation datasheet

I will update you once I perform the bench testing tomorrow.

Best,

Keerthi

Hi  Keerthivasan,

Sorry, the device we use cannot be changed. So I want to know if the current waveform phenomenon is correct.

BR,

Huan Yin

Hi Huan,

The waveforms don't match what I would expect for the configuration you have set. Here is what I measured with the EVM:

Blue - OUT1

Red - SO

Yellow - Current

Can you send me the full schematic or are you using an EVM?

Best,

Keerthi

Hi  Keerthivasan,

This is the application circuit diagram of drv8703.I hope you find this useful.

IN1 controls the direction and IN2 inputs PWM.

Hi Huan,

I need the full schematic with the FET connections as well as the shunt resistor connection. This only shows the pins being broken out into headers.

Best,

Keerthi

Hi  Keerthivasan,

The FET schematics have been added.R5 is sampling resistor.

Hi Huan, 

Can you measure the voltage at SP whiles going from forward to brake?

Can you also try capturing VREF?

Can you also try with a lower gain value (20) ?

Best,

Keerthi

Hi  Keerthivasan,

I'm so sorry it's taken so long.The problem has been solved.

Thank you very much again.

BR,

Huan Yin

Hi Huan,

Can you tell me what the resolution was?

Best,

Keerthi