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I need to step down from 53V to anywhere between 36V to 48V. Because of space constrains, I want to build a DIY solution. I have searched a lot but i cannot find any schematic/project that meets my requirements ant that i could follow (I am a relatively inexperienced DIYer). Can anyone point me in the direction of a project/schematic that i could use? thanks!

use case:

  • Subwoofer power amp. The built in PSU provides 53VDC. I need to change the stock amplifier and the amplifier i want to use cannot accept more than 48V. Any voltage from 36V to 48V will work. My preference is to stay as high as possible withing this range.

Requirements:

  • The normal power consumption will be between 6 and 20 W. But it should be capable to stand peaks up to 300 W that will be seldom, maybe never, reached.
  • Efficiency as high as possible: the subwoofer is sealed. The amp plate is metallic and acts as heat sink. Overheating was not a problem at all with the stock PSU and amp, so i think it will not be a problem after my modification, but to stay on the safe side i prefer the buck converter to be as efficient as possible.
  • I prefer to build my own PCB to make it fit to the space available and with the existing screws.
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    \$\begingroup\$ Buy a 48 V power supply? Crack open the existing one and adjust down the output voltage? \$\endgroup\$
    – winny
    Commented Feb 25 at 13:00
  • \$\begingroup\$ What is the anticipated range of input supply voltages. It can't be (never is) fixed at 53 volts so, how low can it droop and how high can it peak. What peak current do you want the circuit to be able to deliver? What is an acceptable maximum level of output ripple? Are their any requirements for EMI compatibility or, switching frequencies that must be avoided? \$\endgroup\$
    – Andy aka
    Commented Feb 25 at 13:02
  • \$\begingroup\$ If it's a switching PSU you can adjust the voltage by changing a resistor value, it's close enough. \$\endgroup\$
    – bobflux
    Commented Feb 25 at 13:04
  • \$\begingroup\$ TI has a "Power Designer" tool. As an inexperienced DIYer, what chip packages are you able to solder? \$\endgroup\$
    – CL.
    Commented Feb 25 at 13:08
  • \$\begingroup\$ @Andyaka the PSU supplies 53V. I don't have the possibility to check how much it will drop under load but 53V is too much for my amp, so i need to bring it down a bit anyways. Current: worst case scenarion 300W at 36V : ca. 8 amps. I am sure i could do with less. Ripple within reason but i am not too concerned, the amp has some fileters in the input. I don't think switching frequency will be a problem. \$\endgroup\$
    – MrRamone
    Commented Feb 25 at 13:14

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