TPS2456: Power Design Review

Hi Ashish,

Thanks for using TPS2456 and reaching out to us. There is an integrated ORing + Hot Swap solution, TPS25947. It'll be well suited for your application. Please have a look on TPS25947 and kindly let us know your feedback. 

Hi Avishek,

Thanks for the reply and suggesting  TPS25947 . We will be using TPS2456 .Kindly provide the feedbacks regarding  our schematic design.

Regards,

Ashish

Hi Ashish,

I'll get back to you tomorrow. 

Hi Ashish,

Please see the observations on the schematic.

1) What is the purpose and the part number of CR5 and CR6?

2) A Schottky diode at OUTA/B is always recommended to clamp the transient energy and limit the negative voltage excursion during fast turnoff of the Hot Swap Controller.

3) The board should use a single point ground scheme. The current return path for both channels should be isolated from each other as much as possible and tie together at a single point. Also, sensitive analog grounds (such as the ground connections of RMONx and CTx) should be run separate from the power path grounds. Please refer to the section "LAYOUT CONSIDERATIONS" in the datasheet for more detail and try to incorporate all the suggestions mentioned there.

4) R44 and R109 can be made DNP components. 

5) May I know why is a 100 V MOSFET selected for 12 V application? Any specific reason?

6) Please share the value of maximum output capacitance and the information regarding the load during startup if any to compute the MOSFET SOA margin during startup. This is very important to know if PG\ is not used to enable the down stream loads.

Hi Avishek ,

Thanks for the detailed review.

Please find the reply below

1.These are reference board TPS2456EVM parts  used for Zener protection mechanism.

2.Can you suggest suitable part for it

3.Have changed the ground scheme as per datasheet layout guidelines

4.R44 and R109 are now DNP

5.We wanted to reduce BOM.Could you please suggest any  cheaper alternate ??

6.The max. O/P capacitance is 44uF.The load is 12V to 3.3V convertor working in auto-enable mode.

Regards,

Ashish

HI Ashish,

Thanks for the feedback.

1) MBRM140G can be used as Schottky diodes. Please place two Schottky diodes, one at output of the channel 1 and another at channel 2 as shown in EVM schematic (D1 and D6). 

2) CSD16403Q5A might be cheaper than BSC0802LSATMA1. 1ku price of CSD16403Q5A and BSC0802LSATMA1 are $0.852 and $1.72 respectively at www.mouser.in. CSD16403Q5A comes with much lesser R_DSON as compared to BSC0802LSATMA1. 

3) May I know what's the power rating of the 12 V to 3.3 V converter or the part number of this converter? 

Hi Avishek,

Thanks for suggestions.

For 12v to 3v3 conversion we are using MPM3630GQV-Z.

Regards,

Ashish