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Low voltage, high current supply - 1.3V/60A

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certino

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Hello all,

I'm new here. Electronics is my hobby and consumes most of my free time. Now I have big problem with IR diode. Diode need 1.3V/60A and I need regulate current in range 5-60A (5A - threshold current), so this isn't a simple matter (parameters). I'm searching all time internet but I don't have any precised idea. I will be grateful for some hints, etc.
 

mtwieg

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What source do you have to work with? Battery, AC mains, etc?

There are lots of specialized ICs for controlling low voltage, high current supplies, mainly for providing supply rails for CPUs. You should look at using such a controller for your purpose, though the operation of these controllers is often pretty sophisticated.

Does the voltage need to be negative, or can you just work with a +1.3V supply with the diode reversed?
 

tpetar

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Hello all,

I'm new here. Electronics is my hobby and consumes most of my free time. Now I have big problem with IR diode. Diode need 1.3V/60A and I need regulate current in range 5-60A (5A - threshold current), so this isn't a simple matter (parameters). I'm searching all time internet but I don't have any precised idea. I will be grateful for some hints, etc.
Sorry for asking what is purpose of that IR diode 1,3V 60A ?

Where this diode is used ?

Did you miss "m" in front of "A" and want to say mA (miliamperes) instead A (amper)?
 

mtwieg

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High power laser diodes are very useful in industry and research. 100W is not an unreasonable power level at all.
 

tpetar

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Ok for laser diode but he write IR. I assume IR is Infra Red.

If this is IR Laser Diode this power is not small.
 

BradtheRad

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Suppose you can provide a regulated reference voltage...
then you can vary it through a potentiometer...
then you can current control a mosfet.

To illustrate:



I do not know specifically what volt level needs to be on the gate, in order to send 60A through your load.

I just picked 170 V because it is easy to obtain from 120 VAC mains.

Nor do I know what supply voltage will be sufficient to push 60A through load and mosfet combined. Of course it will be easier on the mosfet if you apply the lowest supply voltage that will do the job.

The mosfet will need to be rated (and heat-sunk) to carry the amps.
 

certino

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Hello all,
First of all thank You very much for answers. This is laser IR diode and this is 60 amps, not mA.
Sorce at this point is labolatory supply (0-30VDC). I tried with LTC3738 (65A Power Supply for VRM10, page 30 in datasheet), but this system was damaged at 10 amps (probably transistors). I need only positive voltage.
I thought about transformer and transistor (PWM) but now I want exclude transformer. Pulse converter will be better.




Suppose you can provide a regulated reference voltage...
then you can vary it through a potentiometer...
then you can current control a mosfet.

To illustrate:



I do not know specifically what volt level needs to be on the gate, in order to send 60A through your load.

I just picked 170 V because it is easy to obtain from 120 VAC mains.

Nor do I know what supply voltage will be sufficient to push 60A through load and mosfet combined. Of course it will be easier on the mosfet if you apply the lowest supply voltage that will do the job.

The mosfet will need to be rated (and heat-sunk) to carry the amps.
I need 1.3 V.
 

jochez

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First a transformer then ac-dc and after that a http://www.ericsson.com/ourportfolio/products/pmm-series-50-60a-pola-interoperable

That might work?!
 

KerimF

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Should the laser IR diode be driven with DC current (60A) or be pulsed?
 

certino

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My schematic shows 60 A through a 0.022 ohm load. That makes 1.3 V across the load.
Ok, my mistake.
But I will prefer something with labolatory supply. For transformer I have to wait about two weeks and is to expensive for me in this moment.

I read about atx supply, I have one - 200w with ka7500b IC.
It's possible to use this supply ?
 

tpetar

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I read about atx supply, I have one - 200w with ka7500b IC.
It's possible to use this supply ?
Definitely not, this supply is weak for this job. You need at least 1000W PC PSU or stronger, this supply have on 12V rail 80A. That 200W psu have at 12V rail around 12A and on 5V around 5A.
 

mtwieg

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Hello all,
First of all thank You very much for answers. This is laser IR diode and this is 60 amps, not mA.
Sorce at this point is labolatory supply (0-30VDC). I tried with LTC3738 (65A Power Supply for VRM10, page 30 in datasheet), but this system was damaged at 10 amps (probably transistors). I need only positive voltage.
I need 1.3 V.
Well a supply like the LTC3738 is basically the best solution in terms of performance and efficiency. Did you actually build that circuit yourself, or get an evaluation kit? Did you set it up to regulate output current or output voltage? Were you testing it with the actual IR diode as the load at the time?

So are you looking for an alternative to a SMPS? You certainly could get a linearly regulated current source, but it will be pretty inefficient. Just get some high power transistor modules, a good sense resistor, and the rest can be done with op amps and other basic components.
 

certino

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I built this circuit myself base on datasheet. Voltage I set by combination beetwen VID0 - VID5. I tested this circiut with resistors - 0,2 ohm. Circuit worked about 1 minute, after this I saw smoke.
 

mtwieg

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I built this circuit myself base on datasheet. Voltage I set by combination beetwen VID0 - VID5. I tested this circiut with resistors - 0,2 ohm. Circuit worked about 1 minute, after this I saw smoke.
There are tons of possible explanations for the failure. Mainly I would be very cautious about using a voltage regulated output on a diode. It's possible that it had a high Vf temperature coefficient, causing thermal runaway.

I actually have a friend who did almost the exact same project (but he wanted to be able to modulate the diode current with a high bandwidth), and he also used a three phase buck controller from linear tech. It's definitely doable, though you really want a current regulated output.
 
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iop95

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You may use ATX psu but need some modifications. Check if there are transformer window space to add 1+1 litz wire or Cu sheet (calculated for 60A); if not space, may try to remove original seconday windings. Remove all outputs components after TR, add a 80-100A double diode connected to those 1+1 wire, some low ESR caps and "construct" feedback voltage with 5V standby (1.3V is below 2.5V IC reference, or better modify IC reference also to 1.3V) for KA7500b IC (TL494). Sure, much beter is a psu with multi-phase IC controller and corresponding power switchs if you need high BW modulation.
 

certino

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You may use ATX psu but need some modifications. Check if there are transformer window space to add 1+1 litz wire or Cu sheet (calculated for 60A); if not space, may try to remove original seconday windings. Remove all outputs components after TR, add a 80-100A double diode connected to those 1+1 wire, some low ESR caps and "construct" feedback voltage with 5V standby (1.3V is below 2.5V IC reference, or better modify IC reference also to 1.3V) for KA7500b IC (TL494). Sure, much beter is a psu with multi-phase IC controller and corresponding power switchs if you need high BW modulation.

Ok, I'm thinking about atx psu but I have one ambiguity. How control ?? Transistor and PWM ??
 

DeepOne

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May be is better use PC PSU without any changes with PWM system from motherboard, such as based on IRU3055
 
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certino

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Ok, but what is the relationship between voltage and current in this case ?

I see only codes for voltage control. This circuit is a current source ?
 

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