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I want to use boost converter to to supply higher voltage to LED .I have confusion about which smps power supply to use on input side. From specs. I am unable to understand why input current limitation is given?? and what happens if higher input current supply used?? Some websites blogs saying that in electonics devices donts consume power more than that they requires. and What about linear voltage regulators??In datasheet of regulators they also mention input current limitations.

Below is of details of my project and spec: 1)SMPS spec.=12V 20 amps 2)led spec =35v 4 amps I am using this boost converter https://www.newegg.com/Product/Product.aspx?Item=2S7-00MH-02G82 boost converter spec:

  1. Input voltage : DC8.5V-48V []Input current : 10A (MAX) exceeds 8A please enhance heat dissipation []Output voltage : 10-50V continuously adjustable 12-80V fixed output [Output current] : 10A MAX exceed 6A please enhance heat dissipation

PLZ SEE BELOW IMAGE:enter image description here

Nikhil P
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The specs give you a set of limits you must not exceed. Input current is one of those limits. It is not something you choose directly: it is a result of the input voltage (which you select), the efficiency (which you don't select, but can probably be found elsewhere in the documentation) and the output power, which is determined by the output voltage(s) (which you select) and the output current(s) (which are set by the things you connect to the outputs).

Wouter van Ooijen
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Input voltage : DC8.5V-48V

Output Voltage : at least 2V more than input 50V max

Output current: [ Constant ] range : 0.2-8 A ( adjustable )

Input power: at least 5% more than output power V*I
e.g. 35V * 4A = 140 Watts + 7W loss.(5%) so I suggest heatsink.

Is this clear now?

Tony Stewart EE75
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Let's do the sums for your application.

LEDs = 35v at 4A. That's a load of 140 watts.

Boost converter efficiency. That data sheet says 'up to' 96%, but you can expect lower, with the large change in voltage. 90% might still be optimistic, but we'll go with that. 140W output would then need 155W input.

155W input from a 12v source requires 13A. This exceeds your boost converter spec by a comfortable (uncomfortable??) margin. So you cannot use the boost converter to supply your LEDs from this 12v supply.

If your supply was the same power capability, but delivered a higher voltage, say 24v, then your input current would be lower, and within specification for your boost converter.

As your supply is adjustable to 15v, you might, just, maybe, get away with increasing it to its max (which would probably be slightly more than 15v) and hoping that the boost converter efficiency was better than 90%, and its input could handle the required 10.something amps. Programming the LEDs to take less than 4A would get you inside specification though, I doubt you would see much difference between 4A and 3.5A.

Neil_UK
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