DRV8908-Q1: Passive OLD mode control

Oba

Part Number: DRV8908-Q1

Hello,

My customer is evaluating DRV8908-Q1 and are going to use passive open load detection.

According to the datasheet, POLD is enabled by setting HBX_POLD_EN in OLD_CTRL_5, POLD_EN in CONCIG_CTRL and HBX_HS(or LS)_EN in OP_CTRL_1/2/3.

Then they are asking whether it is OK to disable and enable by just clearing and setting HBX_POLD_EN in OLD_CTRL_5 while remaining HBX_HS(LS)_EN is enabled.

I mean they want to switch to/from POLD mode directly from/to usual HS(or LS) ON by just changing HBX_POLD_EN bit.

Is it acceptable? In this case, can POLD_EN in CONFIG_CTRL be always ON?

Regards,

Oba

over 4 years ago

0 Pablo Armet over 4 years ago

TI__Mastermind 37683 points

Hi Oba,

Oba said:
Then they are asking whether it is OK to disable and enable by just clearing and setting HBX_POLD_EN in OLD_CTRL_5 while remaining HBX_HS(LS)_EN is enabled.

The answer is yes. disabling HBX_POLD_EN will re-enable the outputs and the outputs will follow HBX_POLD_EN as shown in the truth table below.

0 Oba over 4 years ago in reply to Pablo Armet

TI__Genius 17295 points

Hello Pablo,

Thanks for your reply.

Can POLD_EN in CONFIG_CTRL be always ON in this case?

Regards,
Oba

+1 Pablo Armet over 4 years ago in reply to Oba

TI__Mastermind 37683 points

Hi Oba,

POLD_EN needs to be set to "0b" to disable the passive OLD. otherwise, the outputs will remained in High-Z state. To enable the outputs, both POLD_EN and HBX_POLD_EN need to be "0b".

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DRV8908-Q1: Passive OLD mode control