Welcome to Synthiam!

Program robots using technologies created by industry experts. ARC is our free-to-use robot programming software that makes features like vision recognition, navigation, and artificial intelligence easy.

Get Started
Netherlands
Asked — Edited

7,5A Servo External Power Supply

Hi all!
i've been a bit busy with practicing my pcb design skills, and designed a 7,5A servo PSU.

specs:
7,5A max out
8-18VDC in power in (ideal for a car batery:) 9-15V recommended)
power supply out: 5,05V (@8V in)
power supply out: 5,21V (@12Vin)
power supply out: 5,24V (@15Vin)

pcb dimensions: 2 inch x 1 inch

needed parts list:
1x 5k6 resistor
1x 33k resistor
1x 22k resistor
1x 1k resistor
1x 100nf cap
2x tip47 transistors (or other NPN transistors)
1x 2sc5200 transistor (or any other NPN one with a high current capability~)
1x 6,2V zener diode
a way to make your pcb (be it etched, on a expirimental pcb or another way)
a heatsink (standard 60w cpu heatsink should work if it has a solid aluminium base large enough to fit all 3 transistors)
and of course your servos!:)

optional parts:
screw terminals for on your pcb.

approx costs of the parts (excl pcb and servos): around $10

i hope this is usefull for the community to make powerfull power supplies
here is the schematic:

User-inserted image


and how to wire it up:


User-inserted image


the pcb with it's components:

User-inserted image



and finally, the pcb itself (non-mirrored!) on a non-scale:

User-inserted image



important!: i am not responsible for design errors or anything, i just want others to know how they need to make this sort of stuff!:)


ARC Pro

Upgrade to ARC Pro

Harnessing the power of ARC Pro, your robot can be more than just a simple automated machine.

AI Support Bot
Related Content
Synthiam
Based on your post activity, we found some content that may be interesting to you. Explore these other tutorials and community conversations.
#1  
I don't know if you started already started but I was going to make a suggestion. Servos put out a lot more power when the appropriate voltage is supplied. Standard RC servos take 6 volts in and operate cooler when voltage is correct. Many High torque servos ( if not most) accept 7 volts DC. Undervolting servos reduces power significantly. Just food for thought when you do your next one:) so 6 volts standard and 7 for high power/ high torque servos.
#2  
i didn't know that honestly~ and the answer is simple: to get an higher output voltage, you could simply replace the zener diode with one with a higher voltage (i used a 6,2V one in the schematic, you could use a 6,8v one for around 0.4V more power);)
United Kingdom
#3  
What advantages would this have over an LDO voltage regulator circuit?
#4  
at least that i had something to do which i like, which is pcb designing x)

maybe for other users: a soldering practice, something to be proud of because they made it themselfs?

and i honestly don't know what a LDO is.. :o

____

edit, i searched it up, and found out that the 78xx and 79xx are LDO's:P

which i have a 10A schematic laying around of it.:P

User-inserted image
United Kingdom
#5  
An ldo regulator still needs a PCB, perhaps your next project:)

LDO is a low drop out regulator, basically it has less losses and produces less heat etc. One of them, a couple of capacitors and some resistors and you're done. Google it and you'll see schematics I'm sure.
#6  
updated my post above *blush*
and made a pcb for it.
7,5A max, 6V out based on a 7806 LDO regulator and a 2sc5200 transistor
same pcb dimensions, 1 inch x 2 inch~

User-inserted image
#7  
hi all, there's a new version of my psu, for those interested.
this time it's a 20A one (maybe even more)
it is based on a lm7805 (or lm7806 for 6V output) and 2 TIP36C transistors.
the input voltage is: 9-14V, and the output is 5V (if you use a lm7805) with 20A
note: if you want to use this psu in your robot, be sure your battery or power supply can handle at least ~30A of continous load (when fully used)

there are a few reasons why i choose this design:
you can easily upgrade it from 5V to 6V out, simply by switching the volt regulator,
you can easile add more transistors for greater power
also: it is cheaper to upgrade it, because 1084 ic's aren't that cheap, and one TIP36C can handle more than 10A out continous (equals 2 1084ic's)

there are also a few things why you shouldn't use this:
when you need a compact power supply (it is a bit large)
or when you have a low input volt of lower than 9V with less than 30A out continous.


note: this is really only usefull for advanced robots with ALOT of servos (say more than 30) and too high input voltage or for robots which have current-consuming servos (like digital servos)

use at your own risk and USE FUSES in case of short circuit or what ever, oh and also use >10mm2 for the wiring because of the current draw.:)

pcb design in the zip