600W Boost Converter Step-up / LM2596S / Others...

[HumbleBumble]

Hello! So the thoughts are, for those of us who are on a tight budget, will these supplies do the business? I suspect they might. Just getting started out, I'm not entirely sure of their limitations, such as ripple currents, overshoots, inefficiencies and the like. Would love Dave to dedicate a video investigating these "wonhanlows", for us hobbiest. Who at the moment would be better off in the short term skimping in this area!

http://www.aliexpress.com/item/Free-shipping-2pcs-lot-LM2596S-LM2596-LM2596-ADJ-DC-DC-Step-down-module-5V-12V-24V/1966206183.html?
http://www.aliexpress.com/item/Mini-360-DC-DC-Buck-Converter-Step-Down-Module-4-75-23V-to-1-17V-for/32436860547.html
http://www.aliexpress.com/item/5A-DC-to-DC-CC-CV-Lithium-Battery-Step-down-Charging-Board-Led-Power-Converter/32345253824.html?
http://www.aliexpress.com/item/350W-12V-Small-Volume-Single-Output-Switching-power-supply-for-LED-Strip-light/628585980.html?

[uncle_bob]

Hello! So the thoughts are, for those of us who are on a tight budget, will these supplies do the business? I suspect they might. Just getting started out, I'm not entirely sure of their limitations, such as ripple currents, overshoots, inefficiencies and the like. Would love Dave to dedicate a video investigating these "wonhanlows", for us hobbiest. Who at the moment would be better off in the short term skimping in this area!

http://www.aliexpress.com/item/Free-shipping-2pcs-lot-LM2596S-LM2596-LM2596-ADJ-DC-DC-Step-down-module-5V-12V-24V/1966206183.html?
http://www.aliexpress.com/item/Mini-360-DC-DC-Buck-Converter-Step-Down-Module-4-75-23V-to-1-17V-for/32436860547.html
http://www.aliexpress.com/item/5A-DC-to-DC-CC-CV-Lithium-Battery-Step-down-Charging-Board-Led-Power-Converter/32345253824.html?
http://www.aliexpress.com/item/350W-12V-Small-Volume-Single-Output-Switching-power-supply-for-LED-Strip-light/628585980.html?

Hi

You have a bunch of parts there, each has it's own little plusses and minuses. Rather than dig into each one of them it's easier to simply talk about them as a group. Since you don't mention an application, there is no real way to evaluate them against a specific need.

For their intended use at the specific voltage they are actually designed for (as opposed to the numbers you see in the ads), yes they work. They are a great thing to burry down inside a prototype and forget forever and ever. They are noisy as all get out, so they will work fine for driving an LED array or charging a battery. Some, (possibly with some mods) are ok to run an MCU board off of. I would avoid them for anything that needs even a modestly quiet supply.

If you are looking for a general purpose lab or bench supply .... this is not what you want.

Bob

[station240]

The problem is there is no way to know what the actual specifications of these devices are, without testing them yourself.

In general though:
1. Quoted efficiency is always the maximum, eg 90%, instead of a range 70-90%
2. The inductors are too small, not enough core material to avoid over saturation.
3. Heatsinking is too small, or non existent.
4. Due to #2 and #3, claimed wattage rating is not achievable for more than a few minutes.

[uncle_bob]

The problem is there is no way to know what the actual specifications of these devices are, without testing them yourself.

In general though:
1. Quoted efficiency is always the maximum, eg 90%, instead of a range 70-90%
2. The inductors are too small, not enough core material to avoid over saturation.
3. Heatsinking is too small, or non existent.
4. Due to #2 and #3, claimed wattage rating is not achievable for more than a few minutes.

Hi

The reason for all of that is: The modules you see listed as "48 V to 5V input to 20V to 1 V output 10 A to 0.1 A" regulators were not put together to do all of that. Somebody sat down and said:

I need to start at 24V, that's inside the 48 to 5V range.

I need 3.3V out, that's inside the 20V to 1V range.

I need 1A out, that's inside the 10A to 0.1 A range.

They then picked a set of parts that worked to provide 3.3V at one amp off of a 24V supply. The IC on the board can do a lot of things, the rest of the parts were all picked for the intended application. If you want it to do more, you will need to change the parts on the board. You also will need to heatsink things if you increase the power. When you do all that  ... the parts likely will not fit on the board.

====

So back to the start:

Why did these parts get picked out in the first place?

What is the intended use?

Bob

[nowlan]