LM5069: LM5069 -- Power limit

delun kao

Part Number: LM5069

HI TI,

When my condition is 19~24V, a total of 100W, Rsns set as 0.007ohm, how can I set PWR resistor? What is the difference between current limit and Power limit?

Does the Power limit have a typical recommended setting range? If I set the current limit to 1.3 times of the maximum current, and set the power limit to 1.2 times, Is it achievable to avoid transient currents?

BR, Delun

over 6 years ago

0 Rakesh over 6 years ago

TI__Guru** 105361 points

Hi Delun,

Thanks for reaching us on E2E!
What is the max. load current?
The design calculator helps us in arriving the final parameters. It is available under www.ti.com/.../toolssoftware . Please input your system specs and send me for review.
Also we have models to run simulation to understand the device behavior.

Best Regards,
Rakesh

0 delun kao over 6 years ago in reply to Rakesh

Intellectual 270 points

HI TI,

My config :Vin 19~24V (+-10%), Total power 130W, Iout=6.5A

Which can last longer for protection? What if I want to set the current limt to 6.5A and the Power limit to 6A?

Thanks,

BR, Delun

0 Rakesh over 6 years ago in reply to delun kao

TI__Guru** 105361 points

Hi Delun,

Power limit function is active only during startup to limit the SOA stress on the external FET. Once the Vout reaches Vin, power limit function become inactive.

For example, if you set power limit at 50W using PWR resistor, the inrush current profile will follow 50W/Vds. The inrush current starts from 50W/19V and increases as Vds decreases.
Go through the datasheet example and videos in the design calculator and let me know if you have any questions.

Best Regards,
Rakesh

0 delun kao over 6 years ago in reply to Rakesh

Intellectual 270 points

HI Rakesh,

When PWR-RES is 21.5K , what is the limit power?Can you teach me that?

thanks.

0 delun kao over 6 years ago in reply to delun kao

Intellectual 270 points

The current setting, can't 5A to boot?

0 Rakesh over 6 years ago in reply to delun kao

TI__Guru** 105361 points

Power limit will be ~24W for PWR-RES = 21.5K

0 Rakesh over 6 years ago in reply to delun kao

TI__Guru** 105361 points

Hi,

Please make use of the attached design calculator to verify your design. There are tutorial links in the tool which helps you what to enter in each STEP.

Let me know if you have any questions on the tool.

5001.LM5069_Design_Calculator_REV_C.xlsx

Best Regards,

Rakesh

Power management

Power management forum

LM5069: LM5069 -- Power limit