Boost Converter Tutorial?

Feb 11, 2012 65 Replies

In the past I have designed boost converters in burst mode, with peak current control, but never with a PWM-controlled loop.



Outputs: +5 @ 25mA, -5V @ 20mA



Can someone point me to a tutorial?



Thanks!



[Don't point me to an off-the-shelf part. This has to go into a _custom_ chip... just a little thing... 1mm x 25mm :-] ...Jim Thompson

-- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at

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| 1962 | I love to cook with wine. Sometimes I even put it in the food.


Hmm, an inch long and a millimeter wide--it's for a robotic cockroach, right?

Cheers

Phil Hobbs

Nope. It goes in something that virtually every person owns :-) ...Jim Thompson

| James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.

=A0 =A0 ...Jim Thompson

=A0 =A0| =A0 =A0mens =A0 =A0 |

=A0 | =A0 =A0 et =A0 =A0 =A0|

=A0|

=A0 =A0 =A0 |

Twenty questions!

Is it for a tracking chip that goes into people's necks?

So you decided to take someone's advice about what to do with your design?

Cheers

Phil Hobbs

Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

TI app notes?

The 3525 has been around for a long time... Maybe DN-62 has what your looking for.

cheers

What is the power source? I don't think they make batteries that thin.

This is but a small portion of the whole chip. As I said, I have no experience (*) with PWM'd boost converters, though lots of those with low output current, running burst mode (they have little or no stability issues).

As Larkin would snark, If you've got something technical to say, then say it, otherwise STFU :-{)

(*) Unlike some posters lurking here, I readily admit areas of which I have little or no expertise. Then I listen, learn and ultimately become the expert ;-) ...Jim Thompson

| James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.

Thanks, Martin! I owe you another sip or two or...

Though probably at some other location than Long Island. I sent those horse's-asses in Huntington (and only you will appreciate why I say that) an E-mail, "As I sit here in Rochester, in my _office_ (with a _door_), looking out my _window_ at the melting snow, with a _door-pass_ badge hanging around my neck, and with my laptop sitting there connected to the customer's _network_ and the _Internet_, I was thinking of you fellows at @#$%... >:-} "

I doubt they'll invite me back ;-) Though you never know... I was the only one who could convey to Cadence what was needed with the "w-real" modeling. ...Jim Thompson

| James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.

2.3-5V Battery. ...Jim Thompson
| James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

That'll be a watch then....

I was going to say a tooth brush but, I've been in parts where that maybe not be true :)

Jamie

No. Think teenagers... what are they never seen without ?:-) ...Jim Thompson

| James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.

Actually, I'd go looking at off-the-shelf parts to snag ideas from.

Efficiency? Regulation bounds? % of total product cost that'll be taken up by the converter?

Unless the above answers are "low, loose, and low", I think your biggest challenge won't be the silicon, it'll be finding small, economical & high performance inductors, designing the thing to take advantage of them, and dancing around the inevitable unstable zero in the boost converter.

Are you planning on paying for the 0.3V drop of a Schottkey on each supply, or the time & trouble to drive the extra two switches & make it synchronous?

Tim Wescott Control system and signal processing consulting www.wescottdesign.com

Decent clothes ? lol U seen the ones in the UK where their pants crotch comes down to their knees .... PMSL

Doh that dreaded thumb rattling Mobile :( Got any good designs for a blocker ????

He's a real tease.. probably got all that sorted already....

Well, I would hope so. But you could do everything he's asking for with a couple of charge pumps followed by linear regulators, if you didn't mind the inefficiency.

Tim Wescott Control system and signal processing consulting www.wescottdesign.com

No blocker. But I understand that new movie theater installs in the US are shielded sufficiently that cell phones don't function in the auditorium portion of the facility. I know that at least one theater I frequent requests that doctors leave their cell phones and pagers at the front desk if they're "on-call"... an usher will come and notify them as needed. ...Jim Thompson

| James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.

As high as practical.

Loose. Lots of compensating innards for power supply variation.

They've already committed to external switch(es)

The inductor _is_ a problem. They're already at their height limit and their present implementation (at lower current) is just pushing into saturation :-(

That's up for debate.

But this client is no onesy-twosy outfit... they just shipped their BILLIONETH chip! ...Jim Thompson

| James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.

Try 32 Ohm "bumps" and you see another aspect of the problem :-( ...Jim Thompson

| James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.

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