Problem regarding voltage regulator.

[ycho]

Hi Guys,

I am using LM 2575 HVT 5.0 as the step down voltage regulator from 12v to 5v.
below is the schematic that i used.
**broken link removed**

The problem is the inductor are very hot. It cause the LCD not function properly.
What i need to do?

 

[ronv]

Is the inductor sized for the load?

 

[davenn]

Hi Guys,
The problem is the inductor are very hot. It cause the LCD not function properly.
What i need to do?

what sort of LCD ? what is its current drain ? maybe you are asking more of the regulator than it can handle ?
if the inductor ( and its the correct one for the cct) is getting hot, thats inferring a large current flowing through it

Dave

 

[MrAl]

Hi,

What is the part number of the inductor?
Also, what is your maximum input voltage?
If you measure the efficiency you can tell if the inductor is saturating. If the inductor saturates, it will cause all sorts of problems.
When an inductor saturates its core domains are all flipped so there are none left to flip. At that point it acts like a big resistor and eats up power. This is easily detected on a scope with a current probe as a big spike in current, but also shows up as decreased efficiency by quite a bit in most cases. An inductor with a larger core would solve the problem, and this would be one with a higher saturation current rating.