current sense and low ripple

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#1
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hi
i want a IC that can sense from 0 to 3 amp with 10mA or better resolution
and i want a regulator that its output current max can be 5A and its max voltage is 13 V .
the important thing is ripple should be lower than 20 mV ;
please help :)
i failed one time crying  and i cant fail again
help crying

Last Edited: Wed. Jan 6, 2016 - 12:17 PM
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Lets see now....

 

Current sensing - is that AC or DC? I'll assume it's DC.

 

You want a range of 3 A with a resolution of 10 mA

So assuming we can pass that current through a shunt resistor, and get a voltage that varies from 0V for (0mA) to (say) 2.5V for 3 A that would be a 0.833 Ohm Resistor.

Power is then a factor, 3 A through 0.833 Ohms would dissipate about 7.5W - that's going to get hot!

What exactly are you trying to do? Do you really need a 10mA resolution on something that draws up to 3 AMPs? 

 

Then you also want a low ripple high current power supply. I have no idea what "its max voltage is 13 V" means. Is that input or output?

Try here for the PSU design.

SpiderKenny
@spiderelectron
www.spider-e.com

 

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Since I'm in  a good mood today, here are some 12V 5A Power supplies with ripple "less than 1.0% of VOUT"

SpiderKenny
@spiderelectron
www.spider-e.com

 

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navidrct wrote:
help

I think it would be better if you tell us what you are trying to build rather than a few specs of a few pieces of it.

It might be better (cheaper, simpler, more reliable), for example, to build something that can handle ripple, rather than design it out of the PSU. I can't believe something that draw 5A would care about 20mV ripple!

 

SpiderKenny
@spiderelectron
www.spider-e.com

 

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Hi.

if your power (CPU) is 5V ACS712 , it is a type 5A or +-5A , it is a hall element, that means you can read where you want and the output is isolate from the measure wire.

if you have only 3V3 (CPU) ACS711 but I think it is only +-12A minimum. 

Thierry

Thierry Pottier

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Not enough information! It sounds like the OP is talking about two devices: a regulator and a current sensor. 

 

Regulator:

Max voltage = 13 but what is minimum?

Max ripple = 20mV. Is that switcher ripple or line ripple?

Maximum output current = 5A. Continuous or transient? And, what is the minimum output current? 0.000 Amps?

Regulator linear or switcher?

Can you tolerate heat sink?

What is the input source and its voltage range?

 

Current Sense:

AC or DC current?

Analog or digital output?

3A max with 20mA resolution. Do you mean resolution or precision or both?

 

navidrct - you say that you "failed" once. What did you do and what did not work? Does this have anything to do with AVRs or is it a general electronics question?

 

Jim

Jim Wagner Oregon Research Electronics, Consulting Div. Tangent, OR, USA http://www.orelectronics.net

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ka7ehk wrote:

Not enough information! It sounds like the OP is talking about two devices: a regulator and a current sensor. 

 

Regulator:

Max voltage = 13 but what is minimum?

Max ripple = 20mV. Is that switcher ripple or line ripple?

Maximum output current = 5A. Continuous or transient? And, what is the minimum output current? 0.000 Amps?

Regulator linear or switcher?

Can you tolerate heat sink?

What is the input source and its voltage range?

 

Current Sense:

AC or DC current?

Analog or digital output?

3A max with 20mA resolution. Do you mean resolution or precision or both?

 

navidrct - you say that you "failed" once. What did you do and what did not work? Does this have anything to do with AVRs or is it a general electronics question?

 

Jim

thanks everybody

Regulator:

Max voltage = 13 but what is minimum? its output range between 4 V and 13V

Max ripple = 20mV. Is that switcher ripple or line ripple? voltage ripple in output . i think it be line ripple

Maximum output current = 5A. Continuous or transient? Continuous

And, what is the minimum output current? 0.000 Amps? 300 mA

Regulator linear or switcher? switcher

Can you tolerate heat sink? no

What is the input source and its voltage range? input source is a battery 24V - 28V

 

Current Sense:

AC or DC current? DC

Analog or digital output? does not matter

3A max with 20mA resolution. Do you mean resolution or precision or both? resolution

 

thanks for everything

im not pro but i want be

thanks alot

 

Last Edited: Thu. Jan 7, 2016 - 10:54 AM
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Would you please change the colour of your text? it really bothers us to read it.

"One's value is inherent; money is not inherent"

 

Chuck, you are in my heart!

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Amin,

 

I do not agree with your request to change the colour of his answers. It is clear that he is answering each question.

 

Cheers,

 

Ross

 

Ross McKenzie ValuSoft Melbourne Australia

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No Ross, he has changed the colour of his text now. at first he used this colour:

 

Ross

 

Now it's better.

"One's value is inherent; money is not inherent"

 

Chuck, you are in my heart!

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Ohh... apologies Amin. I did not see his green version. Black or blue are fine, but green... hard on my eyes.

 

Cheers,

 

Ross

 

Ross McKenzie ValuSoft Melbourne Australia

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For the power supply - have you tried Webench? It's an online power supply design tool from TI.

Here's a link to it: http://www.ti.com/lsds/ti/analog/webench/overview.page?DCMP=analog_power_mr&HQS=webench-pr

 

SpiderKenny
@spiderelectron
www.spider-e.com

 

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navidrct -

 

What have you already tried, and how did it fail?

 

Jim

Jim Wagner Oregon Research Electronics, Consulting Div. Tangent, OR, USA http://www.orelectronics.net

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ka7ehk wrote:

navidrct -

 

What have you already tried, and how did it fail?

 

Jim

i used ACS712 for current sensing

its output does not change alot to sense it with ADC . it change but its less than ripple

that trans is for switching of and on when its over current

ac

and TPS54331 for output voltage

its output has ripple like 80mV and i want less than 20mV

 

Last Edited: Sun. Jan 10, 2016 - 10:38 AM
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you used "ASC712" and failed ? what  is failed ? 

ripple --> just problem with filter & capacitor wrong type? 

Thierry

 

Thierry Pottier