DRV8814: DRV8814

Hi Ian,

What are the four signals in the image?

Assuming channel 3 and 4 are inputs, please provide images of the output voltages instead.

Where is the current being measured?

Please zoom in further to the area where the current is reversing?

Hi Sir,

As shown below:

2 channel (FEED ECHY) and 4channel (Pick ECHY) are the signals fed back by the dc motor to the MCU.

1channel  (FEED Motor current, BOUT1 signal of DRV8814PWPR ) and 3 channel  (Pick Motor current, AOUT2 signal of DRV8814PWPR) output to control

different dc motors. We want to know why the reverse current is generated when the dc motor stops.

Pls kindly help to explain why scope got reserve current when motor STOP? 

Thanks, Ian.

Hi Rick,

Excuse for push, may I have your comments?

This is super urgent issue due to production is stop now, pls kindly help us for questions. Thanks.

Hi Ian,

I really need the zoomed in voltages at the point where the current switches from positive to negative.

Please request these from the customer.

Also, please find out where the current is measured.

Hi Ian,

We still need a closer look at what is happening at the outputs.

Please zoom in much closer and provide the voltages at both outputs. We do not need the +24VM.

Have the inputs changed during the requested zoom in area?

Hi Rick,

(1)     As shown below ,channel 1 is the voltage of Bridge B output 1, channel 2 is the voltage of Bridge B output 2, channel 4 is the current of Bridge B output 1(Feed motor current).

(2)     Attached is the original drawing;

Thanks, Ian.

Hi Ian,

I can see that something is changing at the outputs but I cannot determine what is causing the change.

I have highlighted the area.

In this area, the voltage at BOUT1 is shifting up by a little. The peak is now higher and the bottom also is a little higher.

I am assuming the inputs may have changed to cause this.

What is changing in the system to create this higher voltage?

What is the DECAY setting?

A new scope capture of 2ms/div that shows the outputs shifting up, plus understanding how the inputs have changed will help.