LMZ31710: Necessary External Clock in Parallel Mode

Hirotsugu Kobayashi

Mastermind 8485 points

Part Number: LMZ31710

Hi, team.

When using LMZ31710 in parallel mode, is external clock necessary?

When Master is used by a RT mode, what kind of problem forms?

Best Regards,

over 5 years ago

0 Jimmy Hua over 5 years ago

TI__Mastermind 47060 points

Hi Hirotsugu Kobayashi-san,

To use the LMZ31710 in parallel mode the external clock is necessary. Internal discussion with the design team show that the clock must be synchronized to the same period. Otherwise, the two oscillators are free-running and asynchronous. For peak current mode control, the oscillator sets the HS FET turn-on event, and the COMP signal sets the HS FET turn-off event. If the oscillators are not sync’d, then the peak currents are not the same. So the current sharing is off between two modules.

Regards,

Jimmy

0 J Arrigo over 5 years ago

TI__Mastermind 28020 points

When paralleling multiple LMZ31710 devices, they must be synchronized to the same frequency. This can be done by applying an external clock or by using the SYNC_OUT signal from the master.

0 Hirotsugu Kobayashi over 5 years ago in reply to J Arrigo

Mastermind 8485 points

If SLAVE is operated with master SYNC_OUT, will MASTER be OK in either RT mode or CLK mode?

0 J Arrigo over 5 years ago in reply to Hirotsugu Kobayashi

TI__Mastermind 28020 points

Yes, the Master frequency can be set by either RT mode or external clock. The Slave device(s) can get their clock signal from the SYNC_OUT of the Master, ensuring synchronization.

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LMZ31710: Necessary External Clock in Parallel Mode