go_away

Author Topic: Voltage Regulator for Axon  (Read 2337 times)

0 Members and 1 Guest are viewing this topic.

Offline KirkTopic starter

  • Jr. Member
  • **
  • Posts: 44
  • Helpful? 2
Voltage Regulator for Axon
« on: May 17, 2009, 10:16:52 PM »
Dear Admin or other knowledgeable folk,
Some time ago I saw a post about the voltage regulator used on the Axon vs. the one on the Arduino.  My searches failed to reveal the old post.

What regulator is used in the Axon? Or perhaps a better question, What regulator should I use as a replacement for my Arduinos?  Digikey has an amazing array of regulators but I did not find one that met the advertized specs for the Axon

Thanks

Kirk

PS. The problem that I have is that the Arduino regulator goes into thermal shutdown when I use 19.2V on my robot.  It works fine on 9.6V but my 24V motors want more! 

Offline SmAsH

  • Supreme Robot
  • *****
  • Posts: 3,959
  • Helpful? 75
  • SoR's Locale Electronics Nut.
Re: Voltage Regulator for Axon
« Reply #1 on: May 17, 2009, 11:51:58 PM »
uhhh, if i was you i would use your current supply for the motors only and just get a
9V battery to power the arduino...
im not sure on specifics of the axon regulator but just know that it is an ldo regulator.
just look for a regulator that meets your specs.
Howdy

Offline billhowl

  • Supreme Robot
  • *****
  • Posts: 375
  • Helpful? 32
  • Your success is in your hands.
Re: Voltage Regulator for Axon
« Reply #2 on: May 18, 2009, 03:42:19 AM »
Linear regulators are great for powering very low powered devices. They are easy to use and cheap, and therefore are very popular. However, due to the way they work, they are extremely inefficient.

A linear regulator works by taking the difference between the input and output voltages, and just burning it up as waste heat. The larger the difference between the input and output voltage, the more heat is produced. In most cases, a linear regulator wastes more power stepping down the voltage than it actually ends up delivering to the target device!

With typical efficiencies of 40%, and reaching as low as 14%, linear voltage regulation generates a lot of waste heat which must be dissipated with bulky and expensive heatsinks. This also means reduced battery life for your projects.

Even the new LDO (low drop-out) regulators are still inefficient linear regulators; They just give you more flexibility with input voltage drops.

A switching regulator works by taking small chunks of energy, bit by bit, from the input voltage source, and moving them to the output. This is accomplished with the help of an electrical switch and a controller which regulates the rate at which energy is transferred to the output (hence the term “switching regulator”). Switching regulators are complex circuits to design, and as a result they aren’t very popular with hobbyists.

With high input voltages, driving loads over 200mA with a linear regulator becomes extremely impractical. Most people use a separate battery pack in these situations, so they have one battery pack for high voltage devices and one for low voltage devices. This means you have twice as many batteries to remember to charge, and twice the hassle! A switching regulator can easily power heavy loads from a high voltage, and save you from splurging on an additional battery pack.

Where can you find more information on switching regulators?
Try searching for “buck converter”, “boost converter” or “dc-dc converter” and you should find some good tutorials.

I'm using LM2575-5 which have 5 pin T-220 only need 4 external components and supply 5V 1 Amp.

or you can use Hobbywing 5V/6V 3A Switch-Mode Ultimate BEC from dealextreme.com it cost USD$9.27 with Input: 5.5V-23V
http://www.dealextreme.com/details.dx/sku.15149



Offline Razor Concepts

  • Supreme Robot
  • *****
  • Posts: 1,856
  • Helpful? 53
Re: Voltage Regulator for Axon
« Reply #3 on: May 18, 2009, 03:44:02 AM »
Also the Axon's voltage regulator has a maximum input rating of 10 volts.

Offline KirkTopic starter

  • Jr. Member
  • **
  • Posts: 44
  • Helpful? 2
Re: Voltage Regulator for Axon
« Reply #4 on: May 24, 2009, 06:35:25 PM »
Well I found a part LM2940 that is a drop in replacement for the regulator on the arduino (SOT-223 package)  5.6 to 23 V input 1 A out.
Thanks for all your help.
Kirk

Offline Admin

  • Administrator
  • Supreme Robot
  • *****
  • Posts: 11,658
  • Helpful? 169
    • Society of Robots
Re: Voltage Regulator for Axon
« Reply #5 on: May 25, 2009, 05:58:06 PM »
This is why the Axon is more expensive than the Arduino series of products. They use the cheapest parts with not so great specs. For the Axon I used the one with the best specs, no matter the cost.

The Axon voltage regulator is the L4940V5.

1.5 A current
0.5 V dropout at 1.5A (0.2V at 0.5A)
reverse polarity protection
thermal shutdown

The maximum input voltage to the regulator is 30V, but other components on the Axon limit it to 10V. I suspect you'll find a similar problem with the Arduino.

Compare those specs to that of the Arduino's regulator, and you'll see why the Arduino is so cheap ;D

And remember, you can always put voltage regulators in parallel, and put heatsinks on them too, to stay cool.

Offline SmAsH

  • Supreme Robot
  • *****
  • Posts: 3,959
  • Helpful? 75
  • SoR's Locale Electronics Nut.
Re: Voltage Regulator for Axon
« Reply #6 on: May 26, 2009, 12:50:56 AM »
 :o i thought 10v sounded a bit low...
Howdy

 


Get Your Ad Here

data_list