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I have a 6V 3AMP power supply and I wanted to reduce the voltage output to 5V 3AMP.

I saw buck converted on ebay of the following spec. Can i use it to step down 6V to 5V without losing Ampere? or any suggestion, how i can step down 6V to 5V while keeping 3AMP.

DC-DC Buck Step Down Converter Regulator Power Supply Module 9V 12V 24V to 5V 3A.

Mini DC-DC Step Down Converter

Input voltage 7V~28V

Output voltage 5V(Precision 1%）

Output current 3A(max),long time work within 1.5A

Conversion efficiency 96%(max)

Output ripple <30mV

Switching frequency 1.5MHz(max), Typical 1MHz

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    \$\begingroup\$ Not just can, you must. DC/DC will reduce voltage, while power on both sides will be almost the same, so disregarding it's own limitations output current may be even a little more. But pay attention, they say continuous current is 1.5A, meaning with 3A it will overheat. Maybe you will want to use some heatsink or choose more powerful DC/DC. Ah, and minimum voltage is higher than yours. Maybe it will work, but you can never know. \$\endgroup\$
    – user76844
    Commented Jun 21, 2017 at 18:54

3 Answers 3

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It says that the input voltage is a minimum of 7 volts and this means that it won't work correctly if the input voltage drops below 7 volts. Don't ask what might happen if you do run it at 6 volts because I won't be able to answer you. There are devices out there that should do what you want. Keep looking.

It also says that the peak current that can be delivered is 3 amps but the wording implies to me it can only deliver 1.5 amps continuously.

Here's a design from Linear technology that can do what you want with what looks like apparent ease: -

enter image description here

There is also this device too: -

enter image description here

And this: -

enter image description here

So, in conclusion, there are designs around and maybe you can find someone vending this as a finished PCB. There are similar offerings from Texas Instruments as well.

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  • \$\begingroup\$ Thank you very much. since using this buck converter is out of question, I might go for DIY - I have this old power supply with a rating of 6V 3AMP, what is the theory behind stepping down it to 5V and 3AMP. Any DIY project you can help me with? thanks a ton! \$\endgroup\$
    – marc Katz
    Commented Jun 21, 2017 at 19:20
  • \$\begingroup\$ Try googling buck converters. Basically if you switch some thing on and off rapidly, you lower the average voltage but end up with a square wave. If you filter it with an inductor and capacitor, you restore the shape to a dc representation of the average voltage. Switching, theoretically involves no power loss hence buck converters are efficient. Linear technology have a website feature where you can enter the input voltage range, the output voltage and current and they pick a list of suitable devices. \$\endgroup\$
    – Andy aka
    Commented Jun 21, 2017 at 19:31
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Don't be too hasty to buy Two buck converters ($2 or $1.97ca)

Your question indicates "9V 12V 24V to 5V 3A." but only rated for 1.5A peak not continuous.

Keep shopping , not just here..

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you can just use the single or two diodes in series of about 6A or 10A (6A10) for droping 0.7V for each diode. at the output.without using buck converter.

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  • \$\begingroup\$ Thanks. If my need is 5 v and I use two diodes to drop 1.4 v, the resulting voltage will be 4.6V. Can this be used in 5V microcontroller projects? In this process will the Amp remain at 3 Amp, which is the input current? \$\endgroup\$
    – marc Katz
    Commented Jun 22, 2017 at 9:55
  • \$\begingroup\$ the 6V battery voltage is about 6.5V at full charge \$\endgroup\$
    – Zahid Abbas
    Commented Jun 30, 2017 at 9:41

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