EEVblog #90 - Linear and LDO regulators and Switch Mode Power Supply Tutorial

Just how different are linear, LDO and switching buck voltage regulators? I'm glad you asked!
You might be surprised...
It's tutorial time.

NOTE: There are many different methods of SMPS control, this is just one of the simple ones, go investigate!

The EEVblog Forum: http://www.eevblog.com/forum
The EEVblog Website: http://www.eevblog.com

Category:

Science & Technology

Tags:

• regulator
• design
• circuit
• turtorial
• linear
• ldo
• switch
• mode
• switchmode
• switching
• low
• drop
• out
• voltage
• current
• power
• lecture
• schematic
• pwm
• efficiency
• supply
• buck
• boost
• converter

[BYMYSYD]

I'm working on a project to regulate power from a 12V battery, to a 6V micro controller. Would a linear or switch mode regulator be the right choice?

[EEVblog]

@BYMYSYD Not enough data to say. Many factors are involved.

[DagGirl]

I just finished TAFE for the year (including of SMPS, which was fairly easy). I CAN FINALLY UNDESTAND THIS!

[EEVblog]

@DagGirl Awesome!, that was my hope.

[chriscchrisc]

interesting and informative, but where's the REF voltage come from?

Isn't it a bit chicken and egg?

I've used 7805 ic's countless times and just taken them for granted so its good to know some of the detail!

[EEVblog]

@chriscchrisc

Look up "Bandgap Voltage Reference". It's easy to get a 1.25V reference using the inherent properties of the silicon substrate.

[Albinorama]

THIS IS what EEVblog should be.Thank you so much.STOP the spam chat, teach us, show us.

Thanks again.

=)

[Films4You]

At last someone who explains SMPS. Thanking you 1000%.

Have you heard that some Power Supply's increase the frequency so that the power transfer is improved, reducing down that frequency back before output?

[DjRaveKing]

Well the LD1117 is a LDO that uses a NPN pass transistor .

[briefstories]

i'd just like to know how come the addition of the inductor makes it a step-down or buck regulator? what does the inductor do? thanks.

[1978Maska]

thank you, very simple, easy for beginers

[VolcanicDrum]

Really nice video, nicely explained, hands you one end of the rope so that you can pull yourself up, great accent too!

thank you.

[dpussy4u]

very informative I've learned...Can I ask a question??? I'm looking for a 1.5 dc voltage multiplier circuit..

[XTYNoLuck]

@BYMYSYD yeah....because the power needed for a micro is very much less...i would personally go with the linear ps, because it has fewer components...and it's more robust, on the other hand if you have a limited power supply(low current battery) then i would recommend an dc-dc converter....look at fairchild's offer...i like them...

[faackoof]

you explained this perfectly. although my only question is would the switch mode be more prone to wear and tear due to the constant switching on and off. both to the actual switch itself and the NPN?

[dongolahmed]

@BYMYSYD what happened to the simple voltage divider ?

[allgovsarecriminal]

and another video which i'd like to hug you for :)

[Nadrealis]

Dave when you said "So what's all this bullshit I was talking about that SMPS aren't that much different from Linear Supplies?" I nearly burst out laughing.

Cheers man, always love watching your vids.