DRV8832: Motor drivers forum

Dev_Ninja

Part Number: DRV8832

Hello TI,

Hope all is well.

I'm using the DRV8832 in a new application. I've limited ISET to 1A using 0.2Ohms on the ISENSE pin to ground. VSET is set to 3.0V and 4.2V<VCC<3.0V. The motor consumes about 0.7A maximum but in-rush current can go as high as 1.5A in some situations.

Few questions:

1- Motor current at OUT1/2 is limited to 1A internally, however in the first page of the datasheet shows 1.3A peak to the motor, see picture below. What's the true maximum current that can be supplied to the motor?

2- Looking at the Iocp ratings, 3.0A<Iocp<1.3A, FAULTn is triggered when Iout>Iocp, is there a way to limit Iocp? To avoid FAULTn triggered because of in-rush current, it is desirable to set Iocp to 2.0A, is that possible?

3- Would an external 10uF capacitor on OUT1/2 (in parallel with motor), help on the in-rush current?

Look forward to your feedback.

Thanks

over 3 years ago

0 Pablo Armet over 3 years ago

TI__Mastermind 37683 points

Hi Dev,

Dev_Ninja said:
1- Motor current at OUT1/2 is limited to 1A internally, however in the first page of the datasheet shows 1.3A peak to the motor, see picture below. What's the true maximum current that can be supplied to the motor?

1-A peak is the recommended maximum value. However, the 1.3A is the absolute maximum peak current before OCP fault is triggered.

Dev_Ninja said:
2- Looking at the Iocp ratings, 3.0A<Iocp<1.3A, FAULTn is triggered when Iout>Iocp, is there a way to limit Iocp? To avoid FAULTn triggered because of in-rush current, it is desirable to set Iocp to 2.0A, is that possible?

Unfortunately, the OCP threshold value cannot be adjusted. However, you can set the current limit to below 1.3A (preferably 1-A or lower), to prevent OCP. However, if the motor requires higher in-rush current to start spinning, then you'll need a motor driver with higher current. You'll need to experiment with your motor if this will work. I recommend using the DRV8832EVM for evaluation.

Dev_Ninja said:
3- Would an external 10uF capacitor on OUT1/2 (in parallel with motor), help on the in-rush current?

That may help. I would also check the datasheet of the motor you are using to check if there is an internal capacitor. Sometimes, capacitors are placed inside the motors which are meant to help with EMI noise. These capacitors will generate high in-rush currents.