DRV8307: Duty cycle

Annie Liu

Part Number: DRV8307

Hi Team,

Customer would like to know

what is the duty cycle of the minimum input 20kpwm waveform of drv8307 to have drive waveform output? He tested that a duty cycle greater than 4% was required to output a waveform to drive the motor.

He uses the 5V power supply made by the dc_dc chip for the power supply of the Hall sensor. Why does the drv8307 heat up?

How should the RSVD signal be handled better?

Thanks,

Annie

over 4 years ago

0 Matt Hein over 4 years ago

TI__Mastermind 21805 points

Hi Annie,

I don't think we specify a minimum duty cycle, but I think 2us is the normal minimum input time accepted. However this time could be 2.5us across process, voltage, and temperature.

Please read section 7.3.1 of the DRV8307 datasheet, which describes how the Hall Comparators can be used. In the last paragraph in the section, the datasheet describes that the Hall inputs should not be driven by external voltages in standby mode.

We recommend RSVD pins 8-10 to be left floating (not connected). RSVD pins 11-15, & 23 can either be left floating or connected to GND.

Thanks,

Matt

0 Annie Liu over 4 years ago in reply to Matt Hein

TI__Genius 10295 points

Hi Matt,

The hall signal of the customer's motor is a voltage of more than 10V, so the power supply is used. He wants to confirm that is it unable to connect like this?

Thanks,

Annie

0 Matt Hein over 4 years ago in reply to Annie Liu

TI__Mastermind 21805 points

Hello Annie,

The inputs to the DRV8307 are rated up to VREG. If the hall inputs exceed VREG, it will exceed the abs max rating of the DRV8307.

Thanks,

Matt

0 Matt Hein over 4 years ago in reply to Matt Hein

TI__Mastermind 21805 points

Hello Annie,

Do you need any further help on this thread?

Thanks,

Matt

0 Matt Hein over 4 years ago in reply to Matt Hein

TI__Mastermind 21805 points

Hi Annie,

I'll go ahead and close this thread.

Thanks,

Matt

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DRV8307: Duty cycle