DRV8332,Load Current drawn by bldc motor dips around 1A when subjected to step cmd.

Hi Ujwla,

Can you provide more information?
Is this your own board?
Where is the current measured?
What is your PVDD voltage?
What do you mean by the current dips, and what is a step command?
How much current device drawn before the step command?

hi,

 we have designed an application for motion  control where pid and pwm is used. alegro AC764 I2C is  put is put in series with DRV8332 to measure load current as recommended . Then we  commanded the one degree step command to the controller which drives faulhabver 3564024B . Three phase BLDC motor. motor has  response time of 50 msec to achieve  one degree deflection. Around 15 msec to nearby load current drawn by driver IC drops to 2A  for around 10 msec time  and again raises to 8A. whereas full load current shown is around 8A.  overcurrent threshold is set to 9.7A. 

 we are trying to find why current dips to 2A level when demand for current to achieve is around 8A?

regards

Hi Ujwla,

Have you examined the output voltages (OUT_x) for clues. These voltages will provide an indication of what the motor is seeing.
If the output voltages do not make sense, then check the input voltages and the FAULT and OTW pins.

Hi,

yes these are 28v pulses.

input voltage is 28v

OTW and FAULT is stable during  during those 60 msec response time. so IC is not shutting down even though in these 60 msec time , load current dips for 6 msec and from 8A to 1.5A and again builds.

I think you can ask your FAE to visit my place. we have spend one lakh rupees on procuring drv kits and have developed cards using drv 8332 ic by spending 20lakh rupees.

regards

Hi Ujwla,

Do the DRV8332 EVMs work properly? If so what is different about your card?

Can you provide scope captures of the motor current and output voltages for both the DRV8332 EVM and your card?
Can you provide the schematic and layout?