LM5050-1: LM5050 for high current application

Wei-Hao Chen (TW-FAE)

Part Number: LM5050-1
Other Parts Discussed in Thread: TPS2411, TPS2413

Hi team,

My customer wishes to use LM5050 for high current application (250A) and faced a challenge that the MOSFET cannot be fully turn-on because the SD(REG) is rather high and Rdson is low.

In order to get 20mV of regulated forward Vsd threshold (20mV), at least 50A of current has to be applied and this generated significant amount of heat on the Oring FETs and impact efficiency severely.

Do you have any recommendation on the how to use LM5050 for high current application & low Rdson(<1mohm)? Maybe adding a depletion FET to get the little voltage drop across the drain sense pin?

Thanks.

Best Regards,

Wei-Hao

over 5 years ago

0 Karikalan Selvaraj over 5 years ago

TI__Genius 16305 points

Hello Wei-Hao Chen,

For 250A customers use multiple FETs in parallel to share the load current and power dissipation.
Is the customer using multiple FETs here?

If the operating voltage is lower than 16V and close to 12V, TPS2413 or TPS2411 which do not regulate the Vds (20mV) and can be used for high current application as it has higher gate current strength of 300uA (30uA for LM5050).

OUT pin has 3.2uA typical (8uA) maximum, so a we would need a lot of resistance through JFET or depletion FET.
Resistor divider from Drain to OUT pin and GND can work.

But we strongly recommend to use TPS2413 or TPS2411 here if the voltage level is applicable.

Could you let us know more about the customer application where 250A is required at high voltage?

Regards,
Kari.

0 Wei-Hao Chen (TW-FAE) over 5 years ago in reply to Karikalan Selvaraj

TI__Expert 3260 points

Hi Kari,

I have reply you in separate email, we can have more detailed discussion in the mail.

Thank you.

Best Regards,
Wei-Hao

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LM5050-1: LM5050 for high current application