DRV8305: 1-PWM Mode high impedance state issue

Shashank Nambiar

Part Number: DRV8305

I was trying to configure the driver to single pwm mode.

2 of the 3 phase which are supposed have signals are working fine but the phase in which high z state is to be present is not occurring.

No matter what the GPIO input sequence is given, the co responding high z state phase high side mosfet is always turned on.

Please help,

Regards

shashank

over 8 years ago

0 Rick Duncan over 8 years ago

TI__Guru** 114905 points

Hi Shashank,

We will investigate and reply soon.

While waiting, can you provide some additional information?
What is your system voltage?
What is the voltage on the gate of the high side FET when on?

0 Shashank Nambiar over 8 years ago in reply to Rick Duncan

Prodigy 30 points

Well I was operating on 6.5v as my source. (I'm operating at such low voltage because the output is not as expected. And no motor is connected to the driver) The high side gate of the high-z phase gets a voltage around 7.1v and the current drawn by the driver is 0.04a.

0 Phil Beard over 8 years ago in reply to Shashank Nambiar

TI__Expert 4650 points

Hi Shashank,

For the high-z phase pin, the DRV8305 has a leakage path that will cause the high-z phase to float up to VM. This is not a high-current path and will not cause the phase to be incorrectly energized.

I would advise connecting a motor and trying to spin it.

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DRV8305: 1-PWM Mode high impedance state issue