DRV8837C: Discrete vs motor driver IC

Hi Mason,

I have a couple questions:

• How are you driving the motor with the discrete circuit?
• How are you driving the motor with the DRV8837C?

Drive current can be affected by the way the driver is configured. If I know how you have configured and drived the motor in both cases, I might be able to find the cause for the current increase.

Hi Pablo,

• How are you driving the motor with the discrete circuit?

            : I've attached a schematic.

• How are you driving the motor with the DRV8837C?

            : I've tested with DRV8837CEVM without MSP430.

Hello,

Thank you for sending the information. I will take a look at it and figure out what could be causing the rise in current. 

You can expect an answer by tomorrow.

Hello Mason,

I think the higher increase in current is due to the lower power consumption of the FETs in the DRV8837C compared to the discrete circuit. Having less power consumed by the FETs will increase the voltage being delivered to the output terminals which will increase the output current (because same motor resistance). 

The DRV8837C has a very low MOSFET on-resistance : HS + LS of 1Ω. This means that for the same VM, there will be a higher current in the DRV8837C.

I hope this answers your question.