UCC2818A-Q1: synchronization to external clock

Dongbao Zhou

Part Number: UCC2818A-Q1
Other Parts Discussed in Thread: UCC2818

Hi team,

Just to double confirm if it's possible to synchronizing to an external clock, customer is not satisfied with the switching frequency accuracy.

If so, do you have any parameters recommendation for fig.7 in the d/s? Besides, any suggestion for a 68kHz PWM generator circuit?

Thanks

Dongbao

over 4 years ago

0 Dongbao Zhou over 4 years ago

TI__Expert 4000 points

Hello,

Any feedback on this request?

Thanks

Dongbao

0 Teng Feng over 4 years ago in reply to Dongbao Zhou

TI__Genius 13660 points

Hi Dongbao,

There is an application note explaining how to synchronize the device which can be found at the following link.

https://www.ti.com/lit/an/slua245/slua245.pdf?ts=1591099102076

Regards,

Teng

0 Dongbao Zhou over 4 years ago in reply to Teng Feng

TI__Expert 4000 points

Hi teng，

What am I trying to clarify is"is it possible to achieve higher switching frequency accuracy by using synchronizing to external clock "?

Dongbao

0 Peter Meaney over 4 years ago in reply to Dongbao Zhou

TI__Mastermind 31580 points

Hi Dongbao,

For proper synchronization, it is important to select the UCC2818 timing components to set up the oscillator to run at a frequency that is20−30% less than the external sync signal.

The accuracy of the switching frequency once the UCC2818 is synchronised to the external sync signal is then dependent on the frequency tolerance of the external signal.

So if the external sync signal comes from a tight tolerance signal source then the switching frequency of the UCC2818 will also have the same tolerance.

Regards

Peter

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UCC2818A-Q1: synchronization to external clock