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Hi friends pls help me about lm2572 ic

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Antonyraj

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Hi friends pls help me about lm2575 ic

In my lm2575 ic im getting the output of 4amps ,, wat is problem in that,, i checked with lot of ic but the same problem is there pls help me
 
Last edited:

Re: Hi friends pls help me about lm2575 ic

cameo_2007 said:
what do you mean by "getting 4Amps" ?

Where is the output of 2575 connected to?
Click to expand...

it is connected to the ammeter to check amperes
 
Last edited:

Antonyraj said:
it is connected to the ammeter to check amperes
Click to expand...

what is your load i mean for which output circuit you using this IC?

post your circuit here if possible for you.
 

ud23 said:
what is your load i mean for which output circuit you using this IC?

post your circuit here if possible for you.
Click to expand...

i will connect my output to the white leds ,,, i need a output of one amps but im getting 4 amps in lm2575ic
 

Antonyraj said:
i will connect my output to the white leds ,,, i need a output of one amps but im getting 4 amps in lm2575ic
Click to expand...

which value inductor you using?
 

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I think he shorts the output of the regulator with an ammeter and he gets a rating of 4A 8-O
 

ud23 said:
which value inductor you using?
Click to expand...

i just use the inductor value more than 330 micro henries

- - - Updated - - -

alexan_e said:
I think he shorts the output of the regulator with an ammeter and he gets a rating of 4A 8-O
Click to expand...

ya ya your right then how to check the output amps

- - - Updated - - -

cameo_2007 said:
Measure the voltage level at the output of the IC. How much is it?
Click to expand...

the output voltage is 5 volt,,, i used the fixed voltage version
 

An ammeter has a resistance of less than 0.1 ohm so basically the result is the same as shorting the output of the regulator.
The ammeter should be use in conjunction with a load, for example you use a 5 ohm resistor with a 5v regulator (the resistor in series with the ammeter) and you read the current that flows through the load.

What kind of supply are you making?
If it is a constant voltage supply then the current will change according to the load, for example 5v /5 ohm 1Amp , 5v/ 10 ohm 0.5v , if you connect a load that needs 5v 1A then that is the current that the regulator will provide , it will not force high current in a load that "requests" a lower current.

If you are trying to make a constant current source then the regulator changes the output voltage in order to keep the current of the load constant and in the set rating.

So which type did you make?
Are you trying to make a constant current source for the led?
 

- - - Updated - - -

alexan_e said:
An ammeter has a resistance of less than 0.1 ohm so basically the result is the same as shorting the output of the regulator.
The ammeter should be use in conjunction with a load, for example you use a 5 ohm resistor with a 5v regulator (the resistor in series with the ammeter) and you read the current that flows through the load.

What kind of supply are you making?
If it is a constant voltage supply then the current will change according to the load, for example 5v /5 ohm 1Amp , 5v/ 10 ohm 0.5v , if you connect a load that needs 5v 1A then that is the current that the regulator will provide , it will not force high current in a load that "requests" a lower current.

If you are trying to make a constant current source then the regulator changes the output voltage in order to keep the current of the load constant and in the set rating.

So which type did you make?
Are you trying to make a constant current source for the led?
Click to expand...
can i use lm2575 to drive leds

- - - Updated - - -

alexan_e said:
An ammeter has a resistance of less than 0.1 ohm so basically the result is the same as shorting the output of the regulator.
The ammeter should be use in conjunction with a load, for example you use a 5 ohm resistor with a 5v regulator (the resistor in series with the ammeter) and you read the current that flows through the load.

What kind of supply are you making?
If it is a constant voltage supply then the current will change according to the load, for example 5v /5 ohm 1Amp , 5v/ 10 ohm 0.5v , if you connect a load that needs 5v 1A then that is the current that the regulator will provide , it will not force high current in a load that "requests" a lower current.

If you are trying to make a constant current source then the regulator changes the output voltage in order to keep the current of the load constant and in the set rating.

So which type did you make?
Are you trying to make a constant current source for the led?
Click to expand...

ya ya i want to drive leds
 

LM2575 can be used with a ground referenced 1.2 ohm shunt and respective feedback connection as a 1 A current source. But the efficiency won't be good due to shunt power dissipation.
 

Connect a 1.5 Ohm 5 Watt resistor between the lm2575 output and the white LED.
 

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