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TPS25926: e-fuse selection method for fans

user3991183
Prodigy 235 points
Part Number: TPS25926
Other Parts Discussed in Thread: TPS25927, TPS2595, TPS2596


E-fuse is considered to protect the power supply of rated 12V, 0.3A fan.

Protection current is about 2A.

Which is better, TPS259261 or TPS259271?

The TPS259271 data sheet says "For FAN".

The TPS259261 data sheet does not write "For FAN".

If either is OK, I want to use TPS259261.

  • 0
    TI__Guru 57737 points

    Hi,

    The major difference between TPS25926 and TPS25927 is that TPS25926 has a fixed 15V overvoltage clamp whereas TPS25927 does not have overvoltage protection.

    The reason why TPS25927 is suitable for FAN applications is because the retry delay after thermal shut down for TPS25927 is very low 100us. During startup, FANs draw huge current and can make the device hit Thermal Shutdown. If the retry timer after Thermal shutdown is low, the FAN can pickup and start after few retries. If the retry delay is more like in case of TPS25926, the FAn may have a failed startup.

     If your startup current is also less than 5A or 2A, you can consider using TPS2595 or TPS2596 respectively.  Please select a suitable device accordingly.

  • 0 in reply to Praveen GD
    Prodigy 235 points 
    Use TPS259271.
Please tell me what happens when the normal current immediately follows the inrush current in Figure 28.
For example, although C4 in FIG. 29 is I_IN, can “I_IN” and “I_OUT” be considered the same?
Even if the output stops due to a single inrush current, it is desirable to return immediately.
  • 0 in reply to user3991183
    TI__Guru 57737 points

    Hi,

    TPS259271 is a retry device and hence it keeps on trying to restart after it is turned OFF due to any fault condition.

    During Startup, Input current is the sum of current flowing into the output Caps + Current flowing into the load.

    During Short circuit condition, the input capacitance can supply high current for short period as the input capacitance has low impedance. We measure the output current before the Output capacitance as this is the current that flows into the IC and comes out.