Power!!!

[Dragon Tamer]

i need a power supply! I have looked but i am having trouble finding what i want. this is the closest thing that i found Power supply even though he is very detailed, it is still not what i am looking for. i want a dual rail power supply that can put out at least 10 Amps from rail to rail. there are also some nice touches to the what i have desighned so far. if i can get the regulated power circuit from use guys then i will show it to you. Thanks!

(also if i could also get advice on how to hook up voltage regulators for high current, the ones that i have are only rated for 1A and they get really hot. i want to boost their current.

 

[crutschow]

If you want to minimize power dissipation at high currents you may need to consider a switching regulator. With a linear regulator the power dissipated is proportional to the output current and the difference between the input unregulated voltage and the output voltage.

 

[smanches]

(also if i could also get advice on how to hook up voltage regulators for high current, the ones that i have are only rated for 1A and they get really hot. i want to boost their current.

The circuits in your link show the way you beef up a linear regulator to handle more current. That's what the additional transistors are for on the output.

 

[caster.cp]

It'll be difficult to manage 10A with linear regulators. Switching is the way to go. If you're not intending to use that to power an analog design.

If you do, why not use a transformer with a full bridge rectifier? It's nice to project those kind of power-supplies. Ever heard of the Schade's Curves? Deprecated but really cool =D

 

[Sceadwian]

So you need 5 positive amps and 5 negative amps, what is your voltage requirement?

Linear regulator datasheets generally contain complete schematics for serializing AND paralleling their chips for higher voltage or higher current. Read the datasheet. A 5 amp positive and 5 amp negative supply should not be too much of an issue, depending on your voltage requirements which you didn't list.

 

[Dragon Tamer]

So you need 5 positive amps and 5 negative amps, what is your voltage requirement?

10Amps in respect to ground, voltages i would like are; +15, +12, +5, +variable (a fixed +9 regulation would be nice too), ground (obviosly), -5 (ditto with -9), -12, -15, and -inverting

 

[Sceadwian]

You're going to be hard pressed to find a single power supply with all of those values, especially at the current you want, the supply would cost hundreds of dollars. I'd try a website like mpja.com and look through some of their supplies. You're going to need more that one. You can find +12 +5 -5 and -12 as well as 3.3 on a PC supply, though the negative rails don't supply much current the + rails supply well more than what you need, then just buy an inexpensive variable supply.

 

[MikeMl]

I have a 19" rack-mounted linear LAMBDA supply which puts out 0-32V at 100A. (Boat Anchor).

I have a home-built 10A linear supply that uses a Variac ahead of the input transformer. This lets me set the unregulated voltage ahead of the pass transistors to a value to just keep the regulator from dropping-out. This minimizes the regulator dissipation, especially when the supply is set to deliver a low voltage like 3V.

 

[Dragon Tamer]

I have a 19" rack-mounted linear LAMBDA supply which puts out 0-32V at 100A. (Boat Anchor)

lol

so someone correct me if i'm wrong, but if you put a certain voltage into the base of a trasistor, then won't you get the same (or close to the same) voltage at the emiter?

 

[crutschow]

so someone correct me if i'm wrong, but if you put a certain voltage into the base of a trasistor, then won't you get the same (or close to the same) voltage at the emiter?

For a bipolar transistor the emitter voltage will be a diode drop (about 0.65V for silicon) below the base voltage.

 

[Sceadwian]

Keep in mind Dragon Tamer you have to consider power dissipation. At the currents you want linear power supplies have to dissipate huge amounts of power, all as heat. If you want a relativly high voltage and high currenty supply you could be talking hundreds of watts at lower voltage settings.

 

[Dragon Tamer]

so then a circuit like this could be used to increase the current output?

 

[Dragon Tamer]

sorry, i can't post the image, my computer is acting weird, yes it's a windows (it's starting to act like windows ME) but the circuit is the output of Vreg going into the base of the 3055 with a 100 ohm resistor to limit the current.

 

[Dragon Tamer]

Ripple Ok so i got to pondering eirlier, couldn't MOSFETS or SCRs be used instead of 3055? i also found a circuit in a link to another site that is suposed to get rid of the current ripple (i guess it hapens when the capacitor discharges in the filter section). you can hear the effect when you hook up a cheap power supply to some types of amps. my questions are simple, can a circuit like this be applied to the negative rail? and ditto for the current limiter in my first post. And, what is the PNP equivalent of the 3055? (if the MOSFETs don,t work)

 

[Dragon Tamer]

isn,t anyone going to reply?

 

[Nsxvtec]

Does anyone know what this is called?

I desoldered it from a Gateway laptop "Power Switch"

Thank You in advance.

 

[Dragon Tamer]

the image is too fuzzy to tell what it is, can you try taking another picture? if i were to take a guess, i would say that it's a push button.


For everyone else, this is the link to the ripple circuit that i was talking about, sorry it took me so long; Clean Power

and also, i was using multisim to simulate my power supply and i was getting some weird signals from the output of the transformer.

 

[Dragon Tamer]

your non-responsiveness is painfull please, you are the only people that understand what i'm trying to say. on that note, i think that i have another circuit to add, a function generator! the problem is that i have been trying for a long time to find a reliable function generator, and i have been unsuccess full. can show me a reliable circuit?

 

[Dragon Tamer]

is this post really that boring? all i want is to discuss my power supply ideas

 

[Diver300]

and also, i was using multisim to simulate my power supply and i was getting some weird signals from the output of the transformer.

Those sort of waveforms are what I would expect. The resistance of the transformer is often large compared to the resistance of the capacitor and the diodes, so when current it taken, there is a lot of voltage drop on the transformer. The diodes only conduct near peak voltage, so that is when the current is taken and the waveform is reduced from a sinewave.

I don't think you've realised how big and expensive a +/-10 A 0 - 15 V supply is. If you make it linear, you are looking at something that will produce up to about 400 W of power.

A switch-mode supply will produce a lot less heat but is a lot more difficult to design.

A compromise is an unregulated linear power supply (transformer - rectifier - capacitor) followed by something like this https://docs-europe.electrocomponents.com/webdocs/0228/0900766b80228ba5.pdf