UCC27710: Bias resistor for H bridge gate driver

akssas atmane

Prodigy 10 points

Part Number: UCC27710

hello comunity,

is there any equation on how to define the exact value of the bias resistor.

The driver is supplied by a 12V voltage regulator 400mA max load current.

over 2 years ago

0 Ethan Galloway over 2 years ago

TI__Mastermind 30705 points

Hello Akssas,

That resistor is there to act as an RC filter for the driver. It slows down the dv/dt. The datasheet recommends 10 ohms.

Best Regards,
Ethan Galloway

0 akssas atmane over 2 years ago in reply to Ethan Galloway

Prodigy 10 points

Hello, thank you for the answer, I agree but it cuses a drop as well for the bootstrap during the low battery voltage.
How we can calculate the exact resistor value for a defined voltage?

0 Ethan Galloway over 2 years ago in reply to akssas atmane

TI__Mastermind 30705 points

Hello Akssas,

You need to make sure the VDD ramp up time is larger than 20 us. I think you can calculate the rise time by using the RC network equation and plugging in the VDD voltage.

I've got a few questions to ask about the circuit.

How is the circuit not working? How low of a battery voltage are you seeing? How large of a voltage drop are you seeing on RBias?

Best Regards,
Ethan Galloway

Power management

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UCC27710: Bias resistor for H bridge gate driver