Amp consumption before and after a step down voltage converter?

Thread Starter

newbienick

Joined Sep 4, 2019
3
sorry newbie question..

If I have a power supply capable of 24v @2 amps max, and I use a step down converter to go down to 12 volts, does the amp pull off that 24v power supply still max out at 2 amps or does it double to 4amps?

i.e. for a LED application, i can run a 48watt led off the 24v supply directly, if I step down to 12v can I still run a 48watt 12v led or does it go down to 24 watts?
 

KeithWalker

Joined Jul 10, 2017
1,144
sorry newbie question..

If I have a power supply capable of 24v @2 amps max, and I use a step down converter to go down to 12 volts, does the amp pull off that 24v power supply still max out at 2 amps or does it double to 4amps?

i.e. for a LED application, i can run a 48watt led off the 24v supply directly, if I step down to 12v can I still run a 48watt 12v led or does it go down to 24 watts?
It depends on the type of step down converter. Check it's spec sheet.
 

Thread Starter

newbienick

Joined Sep 4, 2019
3
thank you keith for the crazy fast response.

this is the one i am looking at on amazon

5A DC-DC Adjustable Buck Converter 4~38v to 1.25-36v Step Down Power Supply High Efficiency Voltage Regulator Module

Product Features

This product is a 180 KHz fixed frequency PWM buck (step-down) DC/DC module,capable of driving a 5A load with high efficiency, low ripple and excellent line and load regulation.

Parameters:
Input Voltage: DC 4-38V, error ±0.1V
Output Voltage: DC 1.25V to 36V
Output Current: 5A(MAX) It is recommended to use under 4.5A (NOTE: When using high power, add a heat sink to the power supply chip)
Size: 5.4x2.3x1.8CM
Weight: 16g

Fuction:
1.Built in over-temperature protection function
2.Built in current limit function
3.Built in output short-circuit protection function

How to use
1.Access the power supply (4-38V), the power indicator light, the module is working properly.
2.Adjust the blue potentiometer knob (usually clockwise rotation boost, counterclockwise rotationStep-down) and monitor the output voltage with a multimeter to reach the required voltage.
3.A customer reflects the module output voltage can not be adjusted, always equal to the input voltage. When you encounter this problem, please first counterclockwise rotation potentiometer 10 laps above, and then use the module can be normal adjustment of the voltage.
 

MrChips

Joined Oct 2, 2009
21,658
Check the efficiency of the converter.
Your power supply is good to 48W.
If the converter is 85% efficient then it will supply 40W from a 48W supply.

It is never a good idea to run power devices at max rated power.
 

Alec_t

Joined Sep 17, 2013
11,520
Both the power supply and the converter need to be rated for a good bit more than 48W if you want them to have a long life.
 
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