Is 200mA DC regulator ok for a board with nominal currect of 180mA?

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Is 200mA DC regulator ok for a board with nominal current of 180mA?

Is there any standard regarding this issue?

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At this point it's all about heat.  If a linear reg, the wattage (waste) will be approx 0.18*(Vin-Vout)  .....This can be quite a bit, but you neglected to mention your voltages. 

Is it a TO-220 mount?  Surface mount?....you need to allow for the proper heatsinking (pcb copper or actual heatsink).  Super small smd packages can't handle much heat...so take that into consideration.

If Vin is too close to Vout, you will lose your proper Vout regulation....Low dropout types (LDO) are then the choice.

 

For linear type efficiency is approx Vout/Vin (neglecting meager current needed to run the reg).

 

Why cut it so close??...there are 23487 regulators with higher ratings, you could prob get a 300ma or 500ma reg for the same price & have more margin ...but again it's the heat to look at. 

 

Provide more details & you can get more answers!

 

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

Last Edited: Tue. Jul 9, 2019 - 07:08 AM
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LOSTISLAND wrote:

Is 200mA DC regulator ok for a board with nominal current of 180mA?

Is there any standard regarding this issue?

Look at the data sheets. 

If that is nominal 180mA, what is the maximum ?

Also check what margin the regulator has on the 200mA, over temperature. 

 

What voltage is the regulator ?

These days, regulator rated up to 1.2A are quite cheap and small, as that current is more of a peak value, than one they expect it to sustain.

See post above about thermal.

 

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Thanks

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And if Vin is much more than Vout, go with a switching regulator so you don't generate the heat.

The largest known prime number: 282589933-1

It's easy to stop breaking the 10th commandment! Break the 8th instead. 

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Sometimes all you need is a mA.

Control of high dV SMPS can be difficult though more are appearing in distributor catalogs some of which have internal compensation.

Demand may be due to EV and hybrids (start-stop, 48Vdc is here now); maybe not so much e-bike but e-motorcycle and more.

Another demand is for PV (panel strings into a microverter or inverter)

 

"Dare to be naïve." - Buckminster Fuller

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One of the really important things is to actually READ the spec sheet for that "200mA regulator". In particular, what does that number of 200mA refer to? Often, it refers to an internal, preset, current limit. You also need to check on whether "200mA" is minimum, maximum, or typical. If it is typical or maximum, what is the minimum?

 

Then, determine what happens when that number is exceeded? Does the output voltage start to drop? If so, at what rate? 

 

Then, what ever are the answers to these important questions, CAN YOUR APPLICATION TOLERATE THIS BEHAVIOR?

 

The answer to THAT question will be the answer to "Is 200mA DC regulator ok"?

 

None of us can provide you that answer.

 

Jim

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

Last Edited: Tue. Jul 9, 2019 - 09:55 PM
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LOSTISLAND wrote:

Is 200mA DC regulator ok for a board with nominal current of 180mA?

Is there any standard regarding this issue?

theoretically, yes it is ok.

your values : 180mA (nominal load), 200 (absolute max rating) will be fine up to +-5% tolerance. will fail at +-6% tolerance.

 

I have a %80 rule of thumb for myself for absulute max rating of electronic parts.

in your project, I would prefer a regulator with absolute max rating greater than 225mA (180/0,80 = 225)

 

 

Majid

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m.majid wrote:

LOSTISLAND wrote:

Is 200mA DC regulator ok for a board with nominal current of 180mA?

Is there any standard regarding this issue?

theoretically, yes it is ok.

 

Or not. The OP says a nominal current of 180mA. What about start-up currents? What about switching transients? What happens if the regulator's 200mA is the point at which it starts hard current limiting. What happens to the output voltage?

 

As usual with this sort of question there are many many things that need to be specified before the answer can be given. Let's start with...

 

Q1) Part number of the regulator?

Q2) Load characteristics of the connected device?

Q3) Characteristics of the unregulated supply?

Q4) Physical environment?

 

 

#1 This forum helps those that help themselves

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#3 How have you proved that your chip is running at xxMHz?

#4 "If you think you need floating point to solve the problem then you don't understand the problem. If you really do need floating point then you have a problem you do not understand." - Heater's ex-boss

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Brian Fairchild wrote:
As usual with this sort of question there are many many things that need to be specified before the answer can be given. Let's start with...

I agree.

 

then maybe Q0 is : are we talking about voltage regulator or current regulator?

Majid