TPS61169: TPS61169

JIJESH P

Part Number: TPS61169

Hi Team,

We are planning to use TPS61169 as a IR LED driver in our design. The requirement are as follows,

Input voltage : 5V
Output voltage : 18.6V
Output Current : 100mA

In datasheet, Its shown that the inductor value is 4.7-10 uH. But in my calculation, for our requirement more that 22uf is need to minimize the ripple current below 40%.

So please let me know if i can follow the design with 10uH.

Please find the snapshot of my design below,

Please reply ASAP

over 2 years ago

0 Yuting Shao over 2 years ago

TI__Genius 13001 points

Hi,

It seems that these two pictures are broken, pls. upload again.

BR,

Robin

0 JIJESH P over 2 years ago

Prodigy 100 points

0 JIJESH P over 2 years ago in reply to JIJESH P

Prodigy 100 points

0 Yuting Shao over 2 years ago in reply to JIJESH P

TI__Genius 13001 points

Hi,

You can utilize more than 10uH.

BR,

Robin

0 JIJESH P over 2 years ago in reply to Yuting Shao

Prodigy 100 points

Hi Yuting Shao,

Thanks for your support.

Have one more doubt to clarify here, Can I design for 18.8V @ 100mA from a 5V supply with TPS61169? Also please suggest suitable inductor value for this design. Please note that the design is for IR LED driver application.

0 Yuting Shao over 2 years ago in reply to JIJESH P

TI__Genius 13001 points

Hi,

Yes, as for inductor design, it depends on your requirements such as current ripple, rated current, saturation current and Rdc and so on.

BR,

Robin

0 JIJESH P over 2 years ago in reply to Yuting Shao

Prodigy 100 points

Hi,

Understood.

the application is for IR LED powering. In these conditions, how much current ripple we select normally? As my calculation the rated current is 400mA So the saturation current= 1.25x400mA=500mA. Only the doubt is with howmuch ripple we can take in this condition. While i designed with 10 uf, i got peak to peak ripple as 300mA witch is about 80% of rated current. Is this is a issue on these condition?

Also the IC featurre is for led driver and they given the recommended inductor value as 4.7uH to 10uH. This makes me confusion such that the ripple is not a concern. Please help me here.

0 Yuting Shao over 2 years ago in reply to JIJESH P

TI__Genius 13001 points

Hi,

The inductor value in datasheet is typical value under some certain test conditions, and you can design inductor according to your design requirement.

80% ripple is a little large, it's recommended below 40%.

BR,

Robin

0 JIJESH P over 2 years ago in reply to Yuting Shao

Prodigy 100 points

Thanks for your support.

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TPS61169: TPS61169