How smps provide current ?

[arecssor]

hi,

I am using A 24V 10 A SMPS to power my project work, it consumes different current rating in different intervals , i want to know how the smps provide current to the load,
if i connect a LOAD that require 12 v 600 MA is that possible to use 12 v 10 A smps here , is there is any chance to damage the load ?
i want to know whether the following statement is technically correct or not .

normally smps provide current as per the requirement of the load,in this case the smps will provide only 600 Ma and there is no chance to damage the load due to excess current from the smps .

 

[treez]

the smps, if output voltage regulated, will simply provide whatever current the load draws.....if the load draws too much current, then the smps will not be able to maintain its vout.

 

[chuckey]

Some SMPSs require a minimum load, such as the cheap ones that power small halogen lights, if the load does not draw enough current the voltage remains LOW !!
It is extremely unlikely that your one suffers from this problem.
Frank

 

[arecssor]

the smps, if output voltage regulated, will simply provide whatever current the load draws.....if the load draws too much current, then the smps will not be able to maintain its vout.

my question is , whether the smps provide output current as per the requirement of the load or not m simply smps out put current is consonant or not basically, if it is not constant then my idea will work i need only 12 v , 3.5 A max at any instant during the operation , since am providing the smps with 13 v (adjustable ) 10 A it is capable to provide the required power am i right ?

 

[Audioguru]

You need to understand Ohm's Law and basic electricity to see how much current is used. The rated current of a power supply is the maximum current it is allowed to provide. It does not provide that much current all the time.

Ohm's Law says that the current is the voltage divided by the resistance. You have a load that uses 600mA when the voltage is 12V so its resistance is 12V/0.6A= 20 ohms. Then 12V/20 ohms= 0.6A which is 600mA. If the voltage changes then the current also changes. If the resistance changes then the current also changes.

The battery in my car can provide 500A to the starter motor when the engine is very cold in winter but the clock is running all the time day and night and is using only about 5mA (0.005A) or less. The clock does not use all the current (500A or more) that the battery can provide. If it did then there will be a nice hot fire.

EDIT: Your power supplies have a constant output voltage. Then the current is determined by the resistance of the load. If you have a power supply with a constant output current then its voltage must change a lot for its current to be constant.
Example: If a constant current power supply produces 1A all the time then the voltage across a load resistance of 1 ohm must be 1A x 1 ohm= 1V. If the load resistance is 10 ohms then the output voltage must be 1A x 10 ohms= 10V. if the load resistance is 10k ohms then the voltage must be 10,000V. If the load resistance is infinite (nothing is connected to the output of the constant current power supply) then the voltage must be infinite and produce big long sparks in the air with a current of 1A.

 

[BradtheRad]

my question is , whether the smps provide output current as per the requirement of the load

For a given load resistance, you must adjust the duty cycle, to obtain a desired voltage.

Suppose you increase load resistance, but make no other changes. Then output voltage will rise. This could be bad for the load. In that case you must reduce the duty cycle.