DRV8876: Spread spectrum clocking

Shoo Saga

Part Number: DRV8876

Hi Team,

Regarding to the datasheet, This device has SSC function. however I cannot find the detail of it.This function is spread as a percentage of the external PWM clock freqency in PWM mode? Am I understanding correct?

Thanks,

Shoo

over 1 year ago

+1 Pablo Armet over 1 year ago

TI__Mastermind 37683 points

Hi Shoo,

The spread spectrum applies to the internal digital clock. The clock is spread or "dithered" around its center frequency so that its fundamental frequency and subsequent harmonics are spread out and thus lowering EMI. I hope this answers your questions.

Regards,

Pablo Armet

0 Shoo Saga over 1 year ago in reply to Pablo Armet

TI__Intellectual 1456 points

Hi Pablo,

The output frequency is affected by internal digital clock?

only improve EMI from digital core ?

Thanks,

Shoo

0 Pablo Armet over 1 year ago in reply to Shoo Saga

TI__Mastermind 37683 points

Hi Shoo,

The spread spectrum only applies to the the digital clock which is in the MHz range. The output PWM frequency will not be affected by spread spectrum.

Regards,

Pablo Armet

0 Shoo Saga over 1 year ago in reply to Pablo Armet

TI__Intellectual 1456 points

Hi Pablo,

Got itThanks for your prompt reply.

then do we have the motor driver that improves EMI noise of the output frequency?

Regards,

Shoo

+1 Pablo Armet 12 months ago in reply to Shoo Saga

TI__Mastermind 37683 points

Shoo,

Let me clarify a previous statement: The spread spectrum is applied on the internal digital oscillator which impacts the other circuits on the IC that depend on the internal clock. For example the charge pump frequency. For the output switching frequency, slowing down the edge rises is critical for reducing the EMI noise. This is not possible with the DRV8876 but we have other drivers such as the DRV8706 (gate driver) that is capable.

If the customer wants to use the DRV8876, the edge rise/falls can be slowed down by adding a resistor with capacitor to add some time constant and slow down the voltage rise/fall.

Regards,

Pablo Armet

0 Shoo Saga 11 months ago in reply to Pablo Armet

TI__Intellectual 1456 points

Hi Pablo,

Thanks for clarification!

Regards,

Shoo

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DRV8876: Spread spectrum clocking