DRV8800 internal PWM frequency

NAOKI AOYAMA

Guru 11215 points

Other Parts Discussed in Thread: DRV8800

Hello,

Our customer uses the DRV8800.

He wants to estimate the switching loss.

How about the frequency of internal PWM?

Regards,

Naoki Aoyama

over 9 years ago

0 Wilson Zuo over 9 years ago

TI__Mastermind 26065 points

Hi Naoki

We will look for it in design side and get back later.

Note that the switching loss of normal running should more depend on external PWM frequency as the internal PWM only presented when current limit is meet at start or stall condition.

Best regards,

0 NAOKI AOYAMA over 9 years ago in reply to Wilson Zuo

Guru 11215 points

Hi Wilson,

Thank you for your fast reply.
I will wait for your answer.

Best Regards,
Naoki Aoyama

0 Wilson Zuo over 9 years ago in reply to NAOKI AOYAMA

TI__Mastermind 26065 points

Hi Naoki,

DRV8800 was in a different way that when current trip level is reached.

As shown in figure 5 of datasheet, when tripped for more than 3us(Tdeg), the device shuts down output for 1.2ms(Tocp). This is only designed for abnormal output short condition and the current will set to a very low level.

So there is no internal PWM scheme in DRV8800.

Best regards,

0 NAOKI AOYAMA over 9 years ago in reply to Wilson Zuo

Guru 11215 points

Hi Wilson,

Thank you for your reply.
I understood there is no internal PWM.
I will feedback the customer this information.

Thanks,

Naoki Aoyama

0 NAOKI AOYAMA over 9 years ago in reply to Wilson Zuo

Guru 11215 points

Hi Wilson,

May I ask one more question?
The customer wants to know the switching time of the output.
How about the rise time and fall time?

Regards,

Naoki Aoyama

0 Wilson Zuo over 9 years ago in reply to NAOKI AOYAMA

TI__Mastermind 26065 points

Hi Naoki,

It is normally <500ns rising/falling time of the outputs. You can use that as a worst case.

Best regards,

0 NAOKI AOYAMA over 9 years ago in reply to Wilson Zuo

Guru 11215 points

Hi Wilson,

Thank you for your fast reply.
I will feedback the customer this information.

Thanks,

Naoki Aoyama

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DRV8800 internal PWM frequency