TPS40170: A bootstrap capacitor

Shuji Ishiwata

Part Number: TPS40170
Other Parts Discussed in Thread: LM5145

Hi All,

I have a question about a bootstrap capacitor.

The recommended capacity value is 0.1uF to 0.22uF, but is it possible to connect 0.47uF?

It also states that the ripple voltage of a bootstrap capacitor should be limited to less than 250 mV.
Is there a solution if it exceeds 250 mV?

Best Regards,
Ishiwata

over 2 years ago

0 Timothy Hegarty over 2 years ago

TI__Guru 59117 points

Hi Shuji-san,

0.1uF to 0.47uF should be fine. A higher cap value is acceptable if the FET has high gate charge. Not a big deal if the BOOT ripple exceeds 250mV - this is just a guideline.

By the way, I recommend using the LM5145 over the TPS40170 - better performance and lower cost.

Regards,

Tim

0 Shuji Ishiwata over 2 years ago in reply to Timothy Hegarty

Mastermind 6430 points

Hi Tim-san,

Thank you for your reply.
I give advice to customers.

Best Regards,
Ishiwata

0 Timothy Hegarty over 2 years ago in reply to Shuji Ishiwata

TI__Guru 59117 points

Ok, thank you.

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TPS40170: A bootstrap capacitor