5V Voltage Regulator

[tane]

Recently I had to change my 5.0V power supply. I found one 5V lying around (by the way, made in China) and after turn on the Atari (by the way, my arrowhead machine), immediately I realized the colors were not the same, it was a bluish tonality. After that, I was heavily worried for some minutes, and then I tested the voltage resulting in 5.34V.

 

So I was thinking what about to install a voltage regulator. Making a research, I though it should have been easily to find an option, since that many devices use 5V. Even thought there are several regulators, not too many accomplish the required features:

• Step-up (boost converter) to 5V
• Step-down (buck) to 5V
• Automatic process, but many of them are manual with a potentiometer.
• Enough amps for machines with lots of upgrades. Without testing I'm guessing 4A would be ok. (What is the maximum current consumption of a heavily upgraded machine?).
• Good accuracy to 5.0V.
• A converter should be better than a linear voltage regulator, according to this video.

 

 

After researching, not to many options for the job:

 

Pololu 5V Step-Up/Step-Down Voltage Regulator S18V20F5

 

• Maximum output current: 2A
• 4% accuracy
• Input voltage: 2.9V to 32V
• USD 14.95

 

 

 

Pololu 5V Step-Up/Step-Down Voltage Regulator S9V11F5

 

• Maximum continuous output current: 1.5A
• +5/-3% accuracy
• Input voltage: 2V to 16V
• USD 5.95

 

 

However with the above devices I'm not fully happy. They have a wide input voltage resulting in few accuracy (ex: 5V * 1.05 = 5.25V). I think the proper one should be something in the range of an input of 4-6V, with an accuracy of less than 2%, and an output over 4A.

 

Has anyone tested any of the Pololu regulators or any other?

 

[archeocomp]

You want to install switching regulator in between output of your linear power supply and Atari? If so it is not good idea. Better fix your linear ps.

[tane]

2 minutes ago, archeocomp said:

You want to install switching regulator in between output of your linear power supply and Atari? If so it is not good idea.

Why not?

 

2 minutes ago, archeocomp said:

Better fix your linear ps.

The idea is to install a protection and not to be worried about the quality of the power supply, for anyone who wants to plug the device.

[archeocomp]

Regulator will worsen already bad efficiency of linear ps, that means it will be even hotter, because it will have to supply even more current. Ripple and noise of switching regulator is worse that that of linear one, that means more noise in video.

[+DrVenkman]

This isn't nearly as complicated as the OP seems to think. An Atari will rarely need more than 1.5A, even loaded up with an Ultimate 1MB, a UAV, etc. Completely reliable, low-noise switching PSUs in this range are dirt cheap. If you want to rig up your own circuit, these work extremely well (I have one of them inside my 1088XLD, per Mytek's design).

 

https://www.digikey.com/products/en/power-supplies-board-mount/dc-dc-converters/922?k=TPSM84205

 

 

[archeocomp]

27 minutes ago, tane said:

 

The idea is to install a protection and not to be worried about the quality of the power supply, for anyone who wants to plug the device.

That's clear. Better replace your dodgy linear 7805 (IIRC that is already third one) with that TPSM84205 or a TRACO TSR 2-2450 or a Murata and done. Cool and safe.

[+bob1200xl]

I think what you want is called a 'crowbar'. (in the old, old days, they would throw an iron crowbar across the bussbar, tripping the circuit breaker, if the power regulator ran away )

 

It watches the output voltage and blows the fuse if it gets too high. 

 

If you use an LM340-5 as your regulator, it really isn't necessary.

 

Bob

[Kyle22]

Bob is great! A good heavy duty crowbar type zener will blow the Ingot before it can damage the computer.

:)