LM5170-Q1：Constant Current Source

Chun Hung Chen

Intellectual 590 points

Part Number: LM5170-Q1
Other Parts Discussed in Thread: LM5170,

Hi I'Andy

Could LM5170 output 0V/25A??

Thanks

over 6 years ago

0 Chun Hung Chen over 6 years ago

Intellectual 590 points

I'm Andy

We want to use LM5170-Q1 in a new project.

There are 2 versions in this project.

Version1

The high voltage side is voltage range of 35V, the low voltage side is programmed power source 0V/20A-32V/6A.

Version2

The high voltage side is voltage range of 70V, the low voltage side is programmed power source 0V/10A-60V/3.5A.

I think the question is could LV works under 3V even 0V?

Thanks

0 Youhao Xi over 6 years ago in reply to Chun Hung Chen

TI__Guru* 78630 points

Hi Chun,

Thank you for reaching out. The short answer to you is yes the LM5170 can achieve this.

Note that the LM5170 can easily achieve a current source which is proportional to ISETA signal. It is just not very clear from you post:

whether you need the solution to output a 200W fixed power when Vout is between 10 to 32V or 20to 60V,
or the power can vary but you want the max power limit at voltage to not exceed 200W?

The implementation will be different.

Thanks,

Youhao

0 Chun Hung Chen over 6 years ago in reply to Youhao Xi

Intellectual 590 points

Hi Youhao

whether you need the solution to output a 200W fixed power when Vout is between 10 to 32V or 20to 60V,
Yes, it needs.
or the power can vary but you want the max power limit at voltage to not exceed 200W?

YES

Do you have any idea?

Thanks

0 Youhao Xi over 6 years ago in reply to Chun Hung Chen

TI__Guru* 78630 points

Your replies just confused me. Is it a fixed 200W, or the power cannot exceed 200W?

0 Chun Hung Chen over 6 years ago in reply to Youhao Xi

Intellectual 590 points

Hi Youhao

The power can vary but you want the max power limit at voltage to not exceed 200W.

It is not a fixed watts power supply.

0 Chun Hung Chen over 6 years ago in reply to Chun Hung Chen

Intellectual 590 points

I think the question is could LV works/output 3V/20A even 0V/20A in Buck mode when HV is 60V?

0 Youhao Xi over 6 years ago in reply to Chun Hung Chen

TI__Guru* 78630 points

The answer is YES. Like I mentioned, the LM5170 in the buck mode can implement the current source. See the EVM test results for output short circuit (Buck mode). The current after short is proportional to the ISETA signal. If you use single phase, set the ISETA=1V, and use 1mOhm resistor, you will limit the current to 20A no matter the output voltage.

If you use dual phase, reduce the ISETA by 2.

Thanks,

Youhao

0 Chun Hung Chen over 6 years ago in reply to Youhao Xi

Intellectual 590 points

Thank you

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LM5170-Q1：Constant Current Source