LM25116: Instant current issue

Yue TANG

Part Number: LM25116
Other Parts Discussed in Thread: CSD18563Q5A

Hi,

My customer have used LM25116 in a 24V in 5V10A out design. so far, they are doing test. recently, they found the boot up of their CPU will cause a extra 10A peak instant current, added this ,their system will experience a 20A peak instant current, they are worried about the temperature rise of the MOS.

so far, they are using CSD18563Q5A for both high side and low side. they found the low side MOS can't passed the stress test when they increased the load current to 16A for a short time, the temperature of low side MOS increase dramatically. so far, They don't have good solution and want us to suggest a MOS which can better deal with this situation. looking forward to your suggestion. thanks.

over 4 years ago

0 Neal Zhang over 4 years ago

TI__Expert 4720 points

Hi,

This is a FET problem and I will change to their org.

0 John Wallace1 over 4 years ago in reply to Neal Zhang

TI__Mastermind 29535 points

Hi Yue Tang,

Thanks for the inquiry. Can you please provide additional information about the application. What is the switching frequency, output inductor and amount of time the output current jumps up to 20A. What is the pass/fail criteria for the stress test that the low side failed when the customer increased the load current to 16A? How long did they keep the output current at this level? We can look at an alternative low side FET but would first need to know more about their design. If possible, can you send me the schematic at my TI.com email address.

0 Yue TANG over 4 years ago in reply to John Wallace1

TI__Expert 8485 points

John,

Please see my feedback , thanks.

1. switching frequency is 250Khz.

2. Inductor is 3uH

3. They only keep 16A output for a few seconds, MOS temperature rise more than 100°C

Actually, their design is for 10A full load, using a electronic load to test, it works fine under 10A load. MOS temperature is 60 to 70 ℃，but sometimes they can observe a 10A peak [40~100ms] current when boot up or stress test, stress test here mean CPU run performance test program。and this is not under a full load condition. so, they think this may be a problem.

4. I have send the schematic to your e-mail, please check.

0 John Wallace1 over 4 years ago in reply to Yue TANG

TI__Mastermind 29535 points

Hi Alex,

Thanks for the information. I will review the schematic and respond to you via email. I am going to close this thread.

0 Yue TANG over 4 years ago in reply to John Wallace1

TI__Expert 8485 points

Thanks for the reply. it's helpful.

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LM25116: Instant current issue