TPS65987DDJ: Power Management

Toshiro Imi

Part Number: TPS65987DDJ
Other Parts Discussed in Thread: TPS65987D, TIDA-050012

Hello,

When I have checked the TPS65987DDJ datasheet 8.3.2 Power Management session, do I understand VIN_3V3 is first prioritized rather than VBUS1 or VBUS2.

If my understanding is correct, could you also let me know if we cannot use VIN_3V3 input. Are there any side effect is happened.

If it is available, could you please let me know if it is available VIN_3V3 left open.

best regards,

over 6 years ago

0 Eric Beljaars over 6 years ago

TI__Mastermind 36756 points

Hi Toshiro-san,

There is no power sequencing needed for TPS65987D. If VBUS is applied first, the PD controller will boot in dead battery mode. If VIN_3V3 is applied first, the PD controller will boot in regular operation. Here are some more details on dead battery mode: http://www.ti.com/lit/an/slvae65/slvae65.pdf

Thanks,
Eric

0 Toshiro Imi over 6 years ago in reply to Eric Beljaars

TI__Expert 7390 points

Thank you very much. If a customer do not use VIN_3V3 power supply, VIN_3V3 pin leaves open. In this case, TPS65987DDJ power up from VBUS power supply only.

Is my understanding correct.

best regards,

0 Eric Beljaars over 6 years ago in reply to Toshiro Imi

TI__Mastermind 36756 points

Hi Toshiro-san,

Yes, the TPS65987DDJ can be powered from VBUS only. However, in that use case, the TPS65987DDJ would never be able to source power. It would only be able to sink power. TIDA-050012 is an example of a sink-only design that has no VIN_3V3 supplied to it.

Thanks,
Eric

0 Toshiro Imi over 6 years ago in reply to Eric Beljaars

TI__Expert 7390 points

Hi Eric-san,

Thank you very much. I understood. TPS65987DDJ can start up from VBUS but this is sink only. It is OK because we are thinking sink only.

best regards,

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TPS65987DDJ: Power Management