LM5176: LM5176 boot technology consult

Bill Xu

Prodigy 50 points

Part Number: LM5176

how LM5176 charge boot1 capacitor during boost mode and boot2 capacitor during buck mode? in boost mode, the 8.3.14 of datasheet said, in boost mode LDRV2 and HDRV2 are switched while HDRV1 remains continously on. it is easy understand that boot2 capacitor was charge during LDRV2 switched on in boost mode and the charge loop is VCC-->Diodes-->LDRV2 MOSFET. what's the charge loop for HDRV1 MOSFET boot capacitor in boost mode since HDRV1 continously on in boost mode according datasheet? thanks.

over 6 years ago

0 Garrett Roecker over 6 years ago

TI__Mastermind 21720 points

Hi Bill,

Thanks for reaching out with your question.

In the LM5176 there is internal circuitry that keeps the boot capacitor charged when the 100% duty cycle is required for one of the high-side MOSFETs.

Thanks,

Garrett

0 Bill Xu over 6 years ago in reply to Garrett Roecker

Prodigy 50 points

how this circuit running? could you please explain a little detailed? thanks.

0 Garrett Roecker over 6 years ago in reply to Bill Xu

TI__Mastermind 21720 points

Bill,
I cannot share detailed information on this circuit. The basic idea is that since on leg is switching the other boot strap capacitor can be charged for this with a circuit internal to the LM5176.
Thanks,
Garrett

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LM5176: LM5176 boot technology consult