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TPS2117: current consumption

Nam, Dino
Expert 6235 points
Part Number: TPS2117
Other Parts Discussed in Thread: LM66100,

Dear team, 

My customer would like to use below concept. Their main concern is current consumption of battery < 1uA. Please review below concept and let me know your opinion. 

<Case 1> normal operation. no load

1. VIN1(Primary) : 3.3V system voltage 

2. VIN2(Secondary) : 2 ~ 3.3V battery voltage 

At above condition, upper FET is turn on, lower FET is turn off . 

In case of this configuration, what is current consumption of VIN2 battery?  Max 0.08uA , VIN2 standby current(red box). is it right? 

<case 2> system voltage lost , no load 

1. VIN1(Primary) : 0V system voltage 

2. VIN2(Secondary) : 2 ~ 3.3V battery voltage 

At above condition, upper FET is turn off, lower FET is turn on. 

In case of this configuration, what is current consumption of VIN2 battery?  max 4.5uA , VIN2 quiescent current(Green box). is it right?

 If the current consumption is over 1uA under both case, the customer can't use this concept. Is there any recommend concept to satisfy customer requirement? 

Thank you. 

  • 0
    TI__Prodigy 550 points

    Hey Nam,

    Thank you for reaching out. 

    For case 1, that's correct. you will have a current of 0.08uA.

    For case 2, Vin1 should be between 1.6V and 5.5V. Setting Vin1 to 0V would be outside recommended operating conditions. If used outside the Recommended Operating Conditions but within the Absolute Maximum Ratings, the device may not be fully functional, and this may affect device reliability, functionality, performance, and shorten the device lifetime. If Vin1 is set to at least 1.6V then it would be 4.5uA+any Load current.

    If you are okay with the larger supply being chosen, I would recommend using 2 lm66100s for lower quiescent current draw.

    Thanks,

    Sam

  • 0 in reply to Sam Isaac
    TI__Expert 6235 points

    Hello Sam, 

    Thank you for your comment. 

    Sam Isaac said:
    If you are okay with the larger supply being chosen, I would recommend using 2 lm66100s for lower quiescent current draw.

    What do you mean the larger supply? TPS2117 has Imax 4A but LM66100 has Imax 1.5A. Which one is the larger supply? 

    And I already requested similar question regarding LM66100 in other post like below but I didn't get feedback yet. 

    https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1354894/lm66100-shut-down-or-leakage-current 

    Please review and let me know your opinion. 

    Thank you. 

  • +1 in reply to Nam, Dino
    TI__Prodigy 550 points

    Hello Nam,

    What I meant by larger supply being chosen was that if you only need to prioritize the supply with greater voltage compared to the other then the LM66100 would be a good option.

    Thanks,

    Sam