Current issue on an IC REG BOOST Part number: LM2622MM-ADJ/NOPB

Ariana Ni

I have used this part to convert a 5V input to a 12V output but the highest current I get is about 120mA. Any ideas on why I am not able to get a higher current?

over 7 years ago

0 Jasper Li over 7 years ago

TI__Mastermind 46905 points

1. could you confirm the input voltage at the VIN pin of the IC is 5V?
2. do you select the correct inductor?
3. what about the layout

0 Ariana Ni over 7 years ago in reply to Jasper Li

Prodigy 90 points

The Vin is 5V.
The inductor I used was 4.7uH which I got from the datasheet.

The layout is a bit different, but I would think I would get the right current for a very short time (unitl the IC reaches a specific temperature.)
The resistors are placed closer to the IC than the layout suggests.

0 Jasper Li over 7 years ago in reply to Ariana Ni

TI__Mastermind 46905 points

Hi Ariana,

Could you detail the issue you see when the output current is higher than 120mA, and share the VIN, SW and VOUT waveform. The waveform could help us to analyze what is happening.

Is it possible that you can share the image of the layout?

0 Ariana Ni over 7 years ago in reply to Jasper Li

Prodigy 90 points

Here I have images of waveforms when there is no load, 40.5 ohm load and 154ohm load. Waveforms of SW, Vin and Vout. Also there's is an image of the schematic, layout and part numbers for the inductor and diode I'm using. PB.zip

0 Jasper Li over 7 years ago in reply to Ariana Ni

TI__Mastermind 46905 points

Hi Ariana

The saturation current of the inductor is only 0.27A, which is too small. please select an inductor with >1A saturation current.

0 Jasper Li over 7 years ago in reply to Jasper Li

TI__Mastermind 46905 points

Hi Ariana,

I closed the post as no further feedback. The post opens again if you reply.

0 Ariana Ni over 7 years ago in reply to Jasper Li

Prodigy 90 points

I switched to another inductor (This: CBC3225T4R7MR)
I am still getting the same issue.

0 Jasper Li over 7 years ago in reply to Ariana Ni

TI__Mastermind 46905 points

Hi Ariana,

Keep using inductor "CBC3225T4R7MR"
In the waveform 6, named "6 Vin 40.5 ohm load shut off", the input is lower than 2V. So you need a stronger power supply, and the cable between the power supply and the boost converter should be short and strong.

Power management

Power management forum

Current issue on an IC REG BOOST Part number: LM2622MM-ADJ/NOPB