TPS7A74: TPS7A7401 OCP hiccup and inrush current issue

Hailiang Zhang

Part Number: TPS7A74
Other Parts Discussed in Thread: TPS74901

Hi Team,

Customer report that when the load (electronic load) is set to CC mode 2.7A, the device restarts repeatedly and the peak output current is as high as about 8A. This appears to be due to thermal shutdown being triggered.

Power consumption

(3.3V-1.8V)*2.7A = 4.05W

Expected temperature rise

4.05*49.3(JEDEC) = 199.7℃

4.05*34.9(EVM) = 141.3℃

Can you please help analyze and suggest whether the high inrush peak current is expected? Can it be verified on EVM?

waveform

Regards，
Hailiang

over 1 year ago

0 Juliette over 1 year ago

TI__Mastermind 18466 points

Hello Hailiang,

does this problem persist when a resistive load is used instead of an e-load? We see issues of the E-load negatively interacting with the internal compensation network of the LDO.

What is your ambient temperature?

Best,

Juliette

0 Hailiang Zhang over 1 year ago in reply to Juliette

TI__Genius 10840 points

Hi Juliette,

We will try and back to you. But customer also use TPS74901, it worked as expected. Here is the waveform.

Regards,
Hailiang

0 Juliette over 1 year ago in reply to Hailiang Zhang

TI__Mastermind 18466 points

Hello Hailiang,

are the set-up otherwise the same?

have they changed any of the parts on the EVM?

Best,

Juliette

0 Hailiang Zhang over 1 year ago in reply to Juliette

TI__Genius 10840 points

Hi Juliette,

The set-up is the same.

And customer test TPS7A7401 on their board, not on EVM;

Pls provide Iout, Vin, Vout waveform measured on EVM when OCP and OTP is trigged. It will be helpful. Thanks in advance.

Regards,
Hailiang

0 Juliette over 1 year ago in reply to Hailiang Zhang

TI__Mastermind 18466 points

The TPS7A7401 is a 1.5 A part. When I apply the 2.7A resistive load, my device turns off and I cannot replicate your waveform

Power management

Power management forum

TPS7A74: TPS7A7401 OCP hiccup and inrush current issue