TPS25942A: TPS25942A

Krishnam Raju Marupu

Prodigy 70 points

Part Number: TPS25942A

Tool/software:

TPS25942A-Power block diagram.pdf

Dear Arush and TI Team

Thank you for your support so far.

This is regarding Oring IC TPS25942A,

1. As I said earlier, these ICs are giving problems in my design. I bypassed these ICs with a strap and my board is working(Schematic and block diagram attached for your reference).

2. In a fresh card, I bypassed board load and gave these oring ICs o/p to DC load. These ICs are working fine till 2A. I increased the load to 3.2A and found that both ICs went faulty and gave only .8V output and never came up. When I mount a fresh IC it will work till 2A.

But as per data sheet these ICs should support 5A load and we mounted Resistor Rilim as 17.8K.

Could you please analyse and update.

With Regards

Krishnam Raju M

over 1 year ago

0 Arush Gupta over 1 year ago

TI__Mastermind 38335 points

Hi Krishnam Raju M,

Krishnam Raju Marupu said:
2. In a fresh card, I bypassed board load and gave these oring ICs o/p to DC load. These ICs are working fine till 2A. I increased the load to 3.2A and found that both ICs went faulty and gave only .8V output and never came up. When I mount a fresh IC it will work till 2A.

I will focus on this.

Can you test these devices without your system load, instead use rheostat or eload in CR mode to draw some current. Can you please capture waveforms when you are getting good vout and low vout. Please probe FLTb, IMON pins also.

Best Regards,
Arush

0 Krishnam Raju Marupu over 1 year ago in reply to Arush Gupta

Prodigy 70 points

Dear Arush...

1. During working conditions Vin and Vout waveform for different Loads is ok?

2. This testing was done on an electronic DC load by completely eliminating board load.

3. When I was testing with external electronic DC load, These ICs behaviour is not uniform. Sometimes these are going bad for 3A and sometimes for 4A.

Once these ICs are faulty, some cases we are getting .8V output and some cases 0V output.

4. Could you please verify the schematic once? Is it ok to use these ICs for Oring with 5A load?

With Regards

Krishnam Raju M

0 Arush Gupta over 1 year ago in reply to Krishnam Raju Marupu

TI__Mastermind 38335 points

Hi Krishnam Raju M,

Are you using CC mode or CR mode of e-load?

Are CR5,CR14 populated? If yes, can you share the part number.

Best Regards,
Arush

0 Krishnam Raju Marupu over 1 year ago in reply to Arush Gupta

Prodigy 70 points

Dear Arush

1. We have used CC mode of e-load.

2.CR5 and CR14 are not populated.

With Regards

Krishnam Raju M

0 Arush Gupta over 1 year ago in reply to Krishnam Raju Marupu

TI__Mastermind 38335 points

Can you please repeat the experiment with CR mode. CC mode is a current sink and device during current limiting mode is a current source but of different value. Connecting these in series results in unexpected and incorrect waveforms/behavior.

0 Krishnam Raju Marupu over 1 year ago in reply to Arush Gupta

Prodigy 70 points

Dear Arush

Thank you for your input. We will update you on the CR mode testing.

With regards

Krishnam Raju M

0 Krishnam Raju Marupu over 1 year ago in reply to Krishnam Raju Marupu

Prodigy 70 points

Dear Arush

In CR mode we are facing some issue. Is it ok to check in constant power mode?

With regards

Krishnam Raju M

0 Arush Gupta over 1 year ago in reply to Krishnam Raju Marupu

TI__Mastermind 38335 points

Hi Krishnam Raju M,

Can you try with a rheostat or resistor box. I have never used the CP mode of e-load so I am less familiar with it. Current drawn for a load side resistor will be determined by ohms law and in case of rheostat, you can start with maximum resistance and slowly decrease the resistance to increase the current.

Best Regards,
Arush

Power management

Power management forum

TPS25942A: TPS25942A