DRV8320: Bootstrap Cap with Drv8320

Frederick Runte46

Part Number: DRV8320
Other Parts Discussed in Thread: LMR16006

´Hello,

I have a technical-question about the Bootstrapping at the DRV8320, how is this managed with only one small capacitor at "CB" do all Three swithces use the capacity only of this cap?

Can i find any application note about this? I only read the section in the 8320 datasheet,

Thanks for your Reply

over 7 years ago

0 James Lockridge19 over 7 years ago

TI__Genius 14487 points

Hi Frederick,

The bootstrap capacitor is only used by the LMR16006 regulator integrated into the DRV8320 driver. The LMR16006 regulator creates a supply rail for any external circuitry you might want to power (i.e. a microcontroller). The bootstrap capacitor is used for the FET integrated in the LMR16006. The LMR16006 datasheet will have more details about this.

The motor driver high-side gate drivers use the charge pump integrated in the DRV8320 to drive the high-side FETs.

0 Frederick Runte46 over 7 years ago in reply to James Lockridge19

Prodigy 190 points

Hey James,
thanks for your fast Reply =)
so the Chargepump only Needs one capacitor at CPL/CPHas written in Datasheet of DRV8320

Frederick

0 James Lockridge19 over 7 years ago in reply to Frederick Runte46

TI__Genius 14487 points

Frederick,

The charge pump needs two capacitors: one between VM and VCP, and one between CPH and CPL. Figures 15-17 in the datasheet show this for each device variant.

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DRV8320: Bootstrap Cap with Drv8320