Malaki86

On your current design, does it have regulated 12v now? If so, what is the power output on that?

I'm in the planning stages of a carpc setup in my 18-wheeler. I would only need the switched power for the lcd monitor in the sleeper of the truck.

The regulated 5v is perfect for the usb hub. I have 2 in the truck (currently running off a laptop). I have one powered and one unpowered and it's all working great with that setup.

The main thing I'm wanting to do is to get rid of all of my power inverters (I have 2 - 1 75watt and 1 400watt).

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drutort

so why not buy the cheap or decent regular usb hubs... they all require ac to dc adaptors... in which case you can use a regular 1-5A 5v voltage regulator... you can simply buy a 1A at radio shack for like 2 bucks... and other electronic places have them up and above 5A

so at the end you would have a 12v to 5v hub... and you can buy a few...

also can use a 12v regulator to stabilize voltage for say touchscreen

these voltage regulators can cost from $.89 to over 30+

i can see were noise could be an issue but thats a different story.

I also do not understand were you are getting that a device can pull 2A a USB one... i thought i read some place that the max is something of .5a hence why most 4 port hubs have a rating in put of 5v and 2A

Beehphy

I have designed a new model that provides 12V@2A, 5V@5A, and Switched unregulated 12 outputs, with the same USB and simple wire enable inputs as the current model.

From my conversations with people and online research, it looks like most 7” LCD's that need regulated input draw about 1A, so 2A sould be enough to run larger ones. To validate this, I checked mp3car’s online store and it looks like the 10.4’s draw, at max 12V@2A.

I still have to build and validate the design. Coming soon.


I assume your talking about generic cell phone and iPod chargers. Those cheap power adapters operate at lower frequencies, usually within the audible range. I have a car charger for my iPod that I cannot use while playing music because there is an awful hum generated by the power adapter that booms through all the speakers.

In my system the M2 power supply in the computer does the same thing. The audio outputs from the computer have a ton of noise from the PSU. In order to get around this a USB sound card is generally used. And it really helps to have a very clean 5V power source for the audio source.


For 0.89$ you must be talking about just the regulator chip. Not the supporting circuitry, board, case etc.

Because the cars power system is close to 12V you cannot depend on a simple linear voltage regulator (cheap ones) to regulate a 12V source. A worst case event would be a rainy night, while using the headlights and wipers, the alternator can’t keep its 12V system above 13V (required for a linear regulator to function) and your underpowered LCD gets damaged (bricked).

This situation is exactly why cheap audio amplifiers die so easily and often. The power regulation stage of the amp is not adequate to keep up with the output stage when conditions are not ideal (real life). The output try’s to drive the speaker like you have told it to, but the input cant keep up, the output over exerts itself and blows up. Not because it couldn’t have driven the speaker at that power level, but because it was starved.

My new 12&5V design takes that into account. It uses a SEPIC switching regulator, allowing it to create a constant 12V source with the input ranging from 9-20V. The 5V also has the same input range.

http://en.wikipedia.org/wiki/SEPIC_converter.

This design should be tested some time in January.


Exactly, each USB device is limited to 0.5A. So a 4port hub could draw 2A. Most people also have 2 or more hubs in the system. My design allows for simplicity; one self contained and protected power supply for all 5V accessories.

An Update from Spiro:

That’s what I like to hear!

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drutort

i understand the issue with the 12v but i fail to see the reason for the 5v? why does a simple 5v voltage regulator isnt sufficient? i have seen some range from 1-5A i believe.

and for the 12v why not step it up and then use a regular linear regulator? 12v is used for the LCD's and at max need 2A

anyway...

i dont know i was just searching around and found that linear tech has some nice things... its way over my understanding

http://www.linear.com/pc/productDeta...3,C1042,P39304

Beehphy

There are many reasons for choosing a switching regulator, including higher input noise immunity, more accurate regulation, but main reason is efficiency. Because of the significantly improved performance of switchers, they produce far less heat, and they make better use of the battery while the engine isn't running.

As a simple exercise we'll run through a simple 5V@1A linear Vs. experimental data from my device.

Primer:
A linear regulator works by passing the required current to the load while wasting the excess voltage between the input and output. It acts kind of like a large automatic variable resistor. The regulator also uses some current itself to operate. The system follows this equation: Iout + Iregulator = Iin.

A switching regulator uses a transistor as a switch to connect the input to the output for very short periods of time. An inductor is used to maintain the electron momentum at the output and steady the pulses of power coming from the switch. While the switch is off the circuit is consuming no power, even though the output is still providing power.

Linear:
This assessment will neglect the power used to operate the linear regulator, the actual efficiency will be lower than this prediction.
Pin = 12 * 1A = 12W
Pout = 5V * 1A = 5W
Efficiency = Pout/Pin = 5W/12W = 41.67%
With a linear regulator, 7Watts is wasted as heat while 5Watts are being used.

Switcher:
Experimental (measured) data from the ACPPS v1:
Pin = Vin * Iin = 12V * 2.112A = 5.68W
Pout = Vout * Iout = 5V * 1A = 5W
Efficiency = Pout/Pin = 5W / 5.86 = 88%
With the ACPPS, 0.68Watts is wasted as heat while 5Watts are being used.

7W wasted Vs. 0.68W wasted. The ACPPS wastes 1/10 the power for the same load. And the ACCPS efficiency continues to improve as the output current increases. It is above 92% from 2A to 5A.

At 1A output the linear wastes 7watts. All that heat is generated from one component that will require a heat sink to keep from overheating. At 5A the linear regulator would be wasting 35W of power as heat, requiring a large heat sink and fan. Just think about how hot a 35W soldering iron gets.

At 8A output the ACPPS is ~90% efficient, wasting only 4.44W as heat spread across 5 separate components, none of witch requires a heat sink. The copper on the PCB is enough to cool everything.


In order to step it up, requires a switching regulator.


That chip would be WAY nice to use, unfortunately I don’t have the equipment to solder it. It only comes in a BGA (ball grid array) package. Way too small for my comfort.

Also the ACPPS v2 (5&12) uses a very similar type of circuit; it just requires a few more parts.

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drutort

is it possible IF people wanted to get some company to solder the chip on a socket something more easier to solder? or are there any socket adaptors that could work?

anyway im solving my problem with simply a bigger psu going with the dsatx so i could run my screen, hubs and other stuff from it directly :/ the m2 wont be enough and seems that cranking could be a problem, currently the car that i have has old bat, that isnt too bad only dropped to 10.2-10.5 while cranking... not sure if my VM registered it good enough... cold start wasnt that cold heh 50F-60F and other starts were similar results... im guessing that a really good bat would work real well in my car.

But since ppl had/have issues with m2 not working right, and the dsatx i havent heard anyone have issues while crank

Btw I googled it and some place stated that nice chip would run about 18 bucks or more.


you explained to me why the simple things such as dropping 12v to 5v for a cpu fan the volt regulator would get so warm, i always thought why would that be such a big task now i understand, thx

Vitorio

Hello

I Interested to buy the USB 5 Volt power supply waht is the best way to contact you

Thanks

S4Per

Sorry if this has been asked before in this thread: I use standby on my PC, and my mobo keeps voltage supplied to the USB bus while in standby. Because of this, I had to rig my hubs up to only draw power from the power cable, not the USB cable itself (someone figured out you need to cut just one trace on a certain model hub I have).

Will the sync'ing with the computer, as you describe, still work, or will your device think the PC is still on since it's using USB as its trigger and my USB bus stays powered?

Thanks much!

-Per

MP3Car.com

 

Beehphy

The ACCPSv1, using the USB port as the enable signal, will be turned on whenever there is 5V comming from the computer. In your case it would stay on.

The remote enable input available on the ACPPS would allow you to continue using whatever signal source you are currently using to switch power to the USB hub.

How do you have the 5V supply to the hub controlled now? Do you put the computer in standby manually or does your PS controller send a power button singal that is configured as standby in the OS?

If you are sending the computer to standby manually, you could connect the ACPPS to the accessory ingnition signal. and it would turn on and off with the car/key. and you would just have to remember to go to standby before turning the key off.

In any setup you 'could' connect the usb power supply to the accessory signal in the car, switching with the key. In doing so, you run the risk of damaging the drivers for those USB devices that require ejecting before disconnecting.

The only other thing I can think of; would be adding some logic controller with a delay to wait for the computer to get to standby before cutting power to the USB system.
If the ps controller is set for no shutdown delay, it could be as simple as a 1 minute delay for USB shutdown after the key is turned off.

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S4Per

The Carnetix 5v PS does it. Instead of doing the default install of that which uses a trigger on the carnetix itself (I use the 2140) I elongated the trigger wire and use a 5v line running to one of the Molex connectors. This way, power only gets shut off once the Hard drive is powered down vs. when ignition is turned off. It works well.

Can you tell me about this remote enable input? Sounds like what I'd need to use.

Beehphy

I have spoken with Victor and it sounds like he is going to be using the remote enable input in his install since he doesn't want to use one of the two USB ports his computer has. He is also going to be using the accessory output to provide power to his screen. (it takes 10-20V input).

Vitorio bought an ACPPSv1 last night and he is also using the carnetix 2140 in his install. S4per, you guys might want to talk about how this could best be hooked up using that power supply and report back.

The Remote enable works exactly the same as the USB enable. when 5-20V are applied to this pin the ACPPS will turn on the 5V and the accessory (12V unregulated) outputs.

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Beehphy

UPDATE 1/6/08

I just dropped a load of money on the first run of 10. I ordered the parts and circuit boards just now.

A couple people have contacted me reserving one for thier system. PM or email me if you are interested.

I also ordered the parts and prototype circuit board for two ACPPSv2 (5&12V regulated).

For the next week, while I'm waiting on the parts I'll be building the chassis for the first run.

Visit the first post in this thread for up to date information and ordering info.

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Beehphy

UPDATE 1/14/08

I built what I could over the weekend. Some of the components i ordered were on backorder with delivery expected ~1/23/08. 6 of 10 are complete but are untested as of yet. The other 4 should be available shortly after parts arive.

I painted the chassis last night but the paint requires 7 days to fully cure. I should be able to finish assembly next sunday on the 6 that are complete. Then they will be ready for delivery, slightly earier than expected.

I built 2 ACPPSv2 at the same time. They too are untested as of yet. I built them with subtle differences in parts to determine what makes them most stable and accurate. I should be able to test them soon. Once I am happy with thier performance they'll be available. It is possible they could be ready to ship by the end of February or mid March.

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dmistry

sweet, i've already signed up for a pre-order

Beehphy

Bump!!

6/10 of the first run have been sold!
Just waiting for the paint to dry before final assembly!!!

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