TPS2388: Discrepancy

Marvn Arcangel

Part Number: TPS2388

Hi Experts,

Our customer notice a discrepancy between the provided tps2388x example code and the tps23881x provided GUI (for the eval board).

The customer is trying to configure the chip to limit its power allocation for a particular channel and the documentation says that it can only be done on 1 port "pair" but the source code shows:

typedef enum
{
_2P_15W_15W = 0x00,
_2P_4W_4W = 0x01,
_2P_7W_7W = 0x02,
_2P_30W_30W = 0x03,
_2P_7W_15W = 0x04,
_2P_15W_7W = 0x05,
_2P_15W_30W = 0x06,
_2P_30W_15W = 0x07
} TPS238x_2P_Power_Allocation_t;

Can you help clarify?

Regards,

Marvin

over 3 years ago

0 Penny Xu over 3 years ago

TI__Genius 15685 points

Hi Marvin,

I will need to double check with FW team on this. BTW, I am curious to know why your customer would need to set the power allocation to different values on different channel. Thanks.

Best regards,

Penny

0 Marvn Arcangel over 3 years ago in reply to Penny Xu

TI__Genius 14120 points

Hi Penny,

Thanks for the help. The application is classified, unfortunately. But the big picture is that they want to limit the total power consumption of the device. They have different kinds of devices connected to each port and would want to allocate different amounts of power to every port as a result.

I hope this information helps.

Regards,

Marvin

0 Penny Xu over 3 years ago in reply to Marvn Arcangel

TI__Genius 15685 points

Hi Marvin,

Actually TPS23881 sets the power limit to ports based on the classification of PD already. For example, if the power allocation is 30W, and you have a class 3 PD connected to the port, then the PSE sets the power limit to 15W to that port.

If you set power allocation to 15W to a specific port, the port can't supply 30W if a class 4 PD is connected to the port even you have enough power supply at system level.

If you only want to manage the power consumption at system level to make sure the total power consumption is not exceeded, I think you should set the port power allocation at the max level based on the 2 pair/ 4 pair HW configuration and then use the system FW to manage the port power based on priorities and power budget.

Thanks,

Penny

0 Marvn Arcangel over 3 years ago in reply to Penny Xu

TI__Genius 14120 points

Hi Penny,

Thank you for the information. Just to clarify is it possible to limit the power per port or not?

0 Penny Xu over 3 years ago in reply to Marvn Arcangel

TI__Genius 15685 points

Hi Marvin,

I am out of office in trainings today. I will get back to you by end of this week. Thanks.

Best regards,

Penny

0 Marvn Arcangel over 3 years ago in reply to Penny Xu

TI__Genius 14120 points

Hi Penny,

Thank you. I am hoping for your response.

Regards,

Marvin

+1 Penny Xu over 3 years ago in reply to Marvn Arcangel

TI__Genius 15685 points

Hi Marvin,

I checked on bench this is not implemented in the SRAM. Can you clarify which source code has this? Thanks.

Best regards,

Penny

0 Marvn Arcangel over 3 years ago in reply to Penny Xu

TI__Genius 14120 points

Hi Penny,

I will check this with the customer. I will get back to you soon.

Regards,

Marvin

0 Penny Xu over 3 years ago in reply to Marvn Arcangel

TI__Genius 15685 points

Thanks, Marvin.

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TPS2388: Discrepancy