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TPS2493: Selection of hot swap controller for bi-directional current limit

Part Number: TPS2493
Other Parts Discussed in Thread: LM5069, , TPS25940, LM5060-Q1, TPS2492

Hi,

I would like to select a switch controller for a two 50V 100 A batteries. These battery will be in parallel and require-

  • birectional current
  • un-symmetrical current limit for charging and discharging
  • Or-ing of the two

The figure 24 in http://www.ti.com/lit/an/slva948/slva948.pdf gives a good idea about the architecture. However, I would like to have different current limits in both the directions. The TPS2493/ LM5069 should be able to do it. The same file SLVA948 gives an indication that this is possible.

If I am right that TPS25940 does these functions but only with symmetrical current limit and at lower voltages.

I am right is understanding that the TPS2493 can achieve the requirements? Also, would it be an advantage to use the LM5050 Or controller if I can compromise with currrent limit?

Thanks in advance.

LM5069
  • Hi Tarun,

    Welcome to E2E!

    Do you need ORing between the two batteries ? means that both batteries powering a common load at a given time? If yes - under that scenario, do you need load current sharing between the sources ?

    Can you share top level system block diagram to understand the requirements.

    Regards, Rakesh

  • Hi Rakesh!

    Yes, I do need load current sharing but this is not actively controlled.

    I only need the current limit to protect against external short circuits. The operation is idicated below

    On a side note, for unidirectional current, can we use a hot-plug IC as an OR-ing IC if we connect the Mosfet's source facing Vin? This will provide current limit in addition to OR-ing as well. Or should we use a hot plug IC in series with an Or-ing IC to achieve the same?

  • Hi Tarun,

    OR-ing circuit provides reverse current blocking but no current limit during overload or short circuit where as Hot-swap circuit provides inrush current management, overload + short circuit protection.

    As you need current flow in both directions (charging and discharging), OR-ing circuit does not allow to do that. So, you may have to go with back to back connected switch such as Figure-22 or Figure-24 in http://www.ti.com/lit/ds/symlink/lm9061-q1.pdf

    With another controller LM5069 http://www.ti.com/lit/an/snva683/snva683.pdf  or Auto-grade device LM5060-Q1

    Regards, Rakesh

  • Thanks for that info Rakesh,

    I would to like to clarify the usage of TPS24932 /3. This is intersting as it provides an analog current read. How would you compare its accuracy to an external current sensor like a hall effect sensor?

  • Hi Tarun,

    In TPS2492/3, thecurrent monitor output has a voltage equal to 48 times the voltage across RSENSE (VVCC-SENSE). So, any variation due to process, temperature in (VVCC-SENSE) will affect the IMON. The (VVCC-SENSE) has +/-10% accuracy. 

    I guess, there are options in hall effect sensors to get better accuracy but may be expensive. 

    Regards, Rakesh

  • Thanks Rakesh, that clarifies my queries.