DRV8301: OC @ no load

Kees Esser

Other Parts Discussed in Thread: DRV8301

Hello,

We found out that skipping the motor driver's load (resistance or DC motor) from the output leads to driver OVER-CURRENT state.It looks like the driver needs a minimum load.

Is this a known feature, and if so, what's that minimum load value ?

Thanks in advance.

Kees

over 10 years ago

0 Nicholas Oborny over 10 years ago

TI__Mastermind 21305 points

Hi Kees,

What OVER_CURRENT mode are you in? How are you driving the half bridges when this event occurs?

The comparator simply measures the Vds voltage and compares to the register value. If no current is flowing through the FET no voltage should be generated. So overcurrent should not trip if a motor is not connected as far as I know.

0 Kees Esser over 10 years ago in reply to Nicholas Oborny

Prodigy 20 points

Hi Nick,

- We're driving 2 DC-motors with the DRV8301 chip: 1 per half bridge side. (see picture)

- Low side FET's Q2 and Q4 always "off" -> used as "free-wheel diodes" in Q1/Q3 off state

- Overcurrent in latch mode.

Kees

0 Nicholas Oborny over 10 years ago in reply to Kees Esser

TI__Mastermind 21305 points

Hi Kees,

You should not be experiencing an over current condition if you disconnect the motor. Can you obtain some scope shots of the Vds when the FAULT occurs. You should just be seeing leakage current through the high side FET when it is on.

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DRV8301: OC @ no load