TPS61200 - driving 4 x 3 LED matrix

Welcome to the TI forums.  I would like to ask that you put more information in your forum subject lines. This will help others in the future if they have a similar question.  Always begin the title of your post with the part number.  We have over 50 thousand part numbers, so it is key to know which ONE you are asking about.  Follow the part number with a brief description of the problem.  More detailed subject lines are very important to help others know what the forum post is about.

I am not sure about the needs of your circuit--i.e. what you are trying to do.  Please state your input voltage and output voltage and current needs.

We have many LED drivers.  If you have a need for an LED driver, just let me know and I will move this post to the LED driver forum.

Hi,

     Thanks for the replay ,my input voltage is 5V an each LED Can take 1.2V and 20mA ,The complete part number is TPS61020DRC plz find below my circuit arrangment

I suppose your circuit should work but it is not the traditional way to drive LEDs.  But first, we need to understand what the maximum voltage of your LEDs is at 20 mA.  Generally, this is about 2 V per LED.  The maximum voltage determines how much over head voltage you need to drive them.

In your configuration, I don't think you have enough drive voltage.  The TPS61200 is set to output 4.25V DC.  Even with only 1.2V across each LED, there is not enough voltage there to drive 4 of them in series.

A final question is how many LEDs you have?  Your first post said a 4 x 3 string but you show a 4 x 5 string here.