SLVAF24 April   2021 TPS65988

 

  1.   Trademarks
  2. 1Automatic RDO for Explicit Contracts in SINK Role
    1. 1.1 Autonegotiate Sink Register (0x37)
    2. 1.2 Automatic PDO Selection as a Sink
    3. 1.3 Autonegotiate PDO Selection Flow
    4. 1.4 Autonegotiate Behavior Examples
  3. 2Multi Port Source Policy Management
    1. 2.1 Multi Port Source Policy Management Flow
  4. 3Multiport Sink Policy Management
  5. 4Revision History

1.4 Autonegotiate Behavior Examples

SL No.

Source PDO Set

Sink PDO Set

Offer Priority

Autocompute Sink Min Power

Computed / Set Min Power

RDO Position

RDO Power / Current / Voltage

Cap Mismatch

Remarks

1

Fixed: 5 V @ 3 A

Fixed: 5 V @ 3 A

Power

Yes

40 W

4

45 W

FALSE

Perfect match

Fixed: 9V @ 1 A

Variable: 5–20 V @ 2 A

Fixed: 15 V @ 1 A

Fixed:15 V @ 3 A

2

Fixed: 5 V @ 3 A

Fixed: 5 V @ 3 A

Power

Yes

40 W

3

15 W

TRUE

PDO #3 provides highest power

Fixed: 9 V @ 1 A

Variable: 5–20 V @ 2 A

Fixed: 15 V @ 1 A

Fixed: 20 V @ 0.5 A

3

Fixed: 5 V @ 3 A

Fixed: 5 V @3 A

Current

Yes

40 W

4

4 A

FALSE

Ignore Offer Priority since Minimum Power Requirement has been met

Fixed: 9 V @ 4 A

Variable: 5–20 V @ 2 A

Fixed: 15 V @ 1 A

Fixed: 20 V @ 2 A

4

Fixed: 5 V @ 3 A

Fixed: 5 V @ 3 A

Voltage

Yes

40 W

4

20 V

TRUE

PDO #4 provides highest voltage

Fixed: 9 V @ 4 A

Variable: 5-20 V @ 2 A

Fixed: 15 V @ 2.5 A

Fixed: 20 V @ 1 A

5

Fixed: 5 V @ 3 A

Fixed: 5 V @ 3 A

Power

Yes

40 W

4

45 W

FALSE

Ignore Offer Priority since Minimum Power Requirement has been met. SRC PDO #4 power computed :: 15 V@ 3 A = 45 W

Fixed: 9 V @ 4 A

Variable: 5–20 V @ 2 A

Fixed: 15 V @ 2.5 A

Variable: 15–20 V @ 3 A

6

Fixed: 5V @ 3 A

Fixed: 5 V @ 3 A

Power

No

30 W

3

37.5 W

FALSE

PDO #3 provides highest power SRC PDO #4 power computed :: 5 V@ 3 A = 15 W

Fixed: 9V @ 4 A

Variable: 5–20 V @ 2 A

Fixed: 15 V @ 2.5 A

Variable: 5–20 V @ 3 A

7

Fixed: 5V @ 3 A

Fixed: 5 V @ 3 A

Power

Yes

40 W

4

1.8 W

TRUE

PDO #4 provides highest power Source Current cannot exceed cable limit of 3 A

Fixed: 9 V @ 1 A

Variable: 5–20 V @ 2 A

Fixed: 15 V @ 1 A

Battery: 15–20 V @ 75 W

Example Scenarios:

Some of the examples have been discussed below:

  • Example #1: Minimum Power value, i.e. the maximum power the Sink requires is determined by AutoComputeSinkMinPower. Hence, of the two Sink PDOs, PDO #2 (5–20 V @ 2 A) results in a Minimum Power value of 40 W. The PD controller hence chooses PDO #4 (15 V @ 3 A) which can deliver 45 W. Capability mismatch is not set.
  • Example #2: AutoComputeSinkMinPower = 1. Therefore, Sink PDO #2 (5–20 V @ 2 A) results in a Minimum Power value of 40 W. However, the Source PDO list has the highest offerable power of 15 W. This would be a capability mismatch and the PDO selection would now be dependent on the OfferPriority setting. In this example, the offer priority is set to Highest Power, so PDO #3 (15 V @ 1 A) would be selected.
  • Example #4: AutoComputeSinkMinPower = 1. Therefore, Sink PDO #2 (5–20 V @ 2 A) results in a Minimum Power value of 40 W. However, the Source PDO list has the highest offerable power of 37.5 W (Source PDO #3–15 V @ 2.5 A). PDO #4 (20 V @ 1 A) would be chosen since the OfferPriority setting is set to Highest Voltage. Capability mismatch is set since there isn't a perfect match to the Minimum Power requirement.
  • Example #6: AutoComputeSinkMinPower = 0, which means the Minimum Power value is not autocomputed by the PD controller, but is directly taken as the value entered in the field ANSinkMinRequiredPower (30 W). Source PDO #2 (9 V @ 4 A) and Source PDO #3 (15 V @ 2.5 A) meet the criteria. The PDO selected would be the latest iterated matching source PDO, i.e. PDO #3 (15 V # 2.5 A). Capability mismatch bit is not set.