Somebody help me to solve the current problem

[hankeong]

how to solve current problems

I have 1 Power supply output 700mA
and 2 string LED board

Now I connector power supply to 2 string LED board.
Each string 350mA.

My problem :

1. Cannot get the same current (350mA) for each LED board.
- I have add 1 resistor 10 ohm to each LED board.
The different around 30mA.

Somebody can let me know, the current from power supply can automatic
seperate to parellal on the same current?

I already add a resistor to control the current, why still over the current.

Somebody can help me.

Thanks

 

[okireinaldi]

why dont you try add resistor to 1 path that trough current more high(to make ballance),cause resistor is current limiter also.

 

[betwixt]

If you rely only on the characteristics of the LEDs you will find that happens. They are not manufactured to very tight tolerances and when you use them in a chain, the differences add together.

The only solution is to use constant current drives to them.

Brian.

 

[vipinsaini]

Dear hankeong
u can use Variable regulator in both led strings to fix the current in every current.

Thanks & Regards
Er.VIPIN SAINI

 

[senthilkumar.b]

give me the circuit and mention the modification and its effect.

then we can exatly give solution for your issue.

bye

 

[reyhur]

use potenciometers to fix the currents

 

[eng.behzad]

you can use current source or use potenciometer