Difference between revisions of "Reverse Protection Diodes"

From OpenCircuits
Jump to navigation Jump to search
 
(52 intermediate revisions by 34 users not shown)
Line 1: Line 1:
[http://agenzialignano.hyndres.info/ Agenzia lignano] [http://dominatrix.gerbinu.info/ Dominatrix strapon] [http://artascii.grekles.info/ Art ascii] [http://agenziacomunicazione.hyndres.info/ Agenzia comunicazione] [http://hotelbelgio.hpirale.info/ Hotel belgio] [http://tetteabbronzate.hequila.info/ Tette abbronzate] [http://hawaishopping.hpirale.info/ Hawai shopping] [http://albergopamplona.hyndres.info/ Albergo pamplona] [http://inailit.hpirale.info/ Inail it] [http://mappapolitica.gittose.info/ Mappa politica spagna] [http://jenavevejolie.gittose.info/ Jenaveve jolie free video] [http://vacanzatrentino.hequila.info/ Vacanza trentino] [http://albergobagheria.hyndres.info/ Albergo bagheria] [http://bancaditalia.grekles.info/ Banca d italia] [http://corriereannunci.goxasi.info/ Corriereannunci it] [http://hotelanacapri.hpirale.info/ Hotel anacapri] [http://testconnessione.hequila.info/ Test connessione adsl] [http://dormiremadrid.gerbinu.info/ Dormire madrid] [http://fotomammetettone.hpirale.info/ Foto mamme tettone] [http://charmsbracelet.goxasi.info/ Charms bracelet] [http://ristorantespiaggia.ipnerka.info/ Ristorante spiaggia rimini] [http://sfondopcmare.ipnerka.info/ Sfondo pc mare spiaggia tropicali] [http://contatti.goxasi.info/ Contatti msn transex] [http://zoccolenere.hyndres.info/ Zoccole nere] [http://sessoincontro.ipnerka.info/ Sesso incontro cosenza] [http://videlporno.flowake.info/ Videl porno] [http://creampie.goxasi.info/ Cream pie] [http://insonnia.gittose.info/ Insonnia] [http://sailormoonporn.ipnerka.info/ Sailor moon porn] [http://ricettapanettone.ipnerka.info/ Ricetta panettone] [http://brownstocking.goxasi.info/ Brown stocking tease] [http://studenteit.hequila.info/ Studenteit] [http://lubahegre.gittose.info/ Luba hegre] [http://pontedilegno.hunchoxi.info/ Ponte di legno] [http://wordecdlsimulazioni.flowake.info/ Word ecdl simulazioni] [http://commercialisti.goxasi.info/ Commercialisti] [http://tennisracchetta.hequila.info/ Tennis racchetta] [http://fototroienere.hpirale.info/ Foto troie nere] [http://hotelegitto.hpirale.info/ Hotel egitto] [http://mymovies.hunchoxi.info/ Mymovies archivio] [http://mutuoagevolato.hunchoxi.info/ Mutuo agevolato tasso fisso] [http://pitone.hunchoxi.info/ Pitone] [http://script.flowake.info/ script] [http://willisbruce.hyndres.info/ Willis bruce film] [http://niscemi.hunchoxi.info/ Niscemi] [http://fatetribali.gerbinu.info/ Fate tribali] [http://gadgetpersonalizzati.hpirale.info/ Gadget personalizzati] [http://kittimfenici.gittose.info/ Kittim fenici] [http://installatori.gittose.info/ Installatori impianto climatizzazione] [http://quizesegnali.ipnerka.info/ Quiz e segnali stradali] [http://ragazzedell.ipnerka.info/ Ragazze dell est] [http://arzachena.grekles.info/ Arzachena] [http://angelodemone.grekles.info/ Angelo demone] [http://troiefighe.hequila.info/ Troie fighe bocchini] [http://temamanzoni.hequila.info/ Tema manzoni] [http://50enniporche.flowake.info/ 50enni porche] [http://homosapiens.hpirale.info/ Homo sapiens sapiens arma ed utensile] [http://figarotta.gerbinu.info/ Figa rotta] [http://bpuit.goxasi.info/ Bpu it] [http://pezziricambio.hunchoxi.info/ Pezzi ricambio scarabeo aprilia] [http://porteasoffietto.hunchoxi.info/ Porte a soffietto] [http://vestiarioantinfortunistica.flowake.info/ Vestiario antinfortunistica] [http://incontricalabria.hpirale.info/ Incontri calabria] [http://contrattoaffitto.goxasi.info/ Contratto affitto] [http://eserciziosnellire.gerbinu.info/ Esercizio snellire gamba] [http://virgiliotesi.hyndres.info/ Virgilio tesi on line gratis] [http://henrymorgan.hpirale.info/ Henry morgan roatan] [http://evamendes.gerbinu.info/ Eva mendes] [http://infoltimento.hpirale.info/ Infoltimento capello] [http://thelemameditazione.hequila.info/ Thelema meditazione] [http://geova.hpirale.info/ Geova] [http://oroscopo2003.hunchoxi.info/ Oroscopo 2003 vergine] [http://giocattolo.hpirale.info/ Giocattolo per bambini] [http://wwwdonnecom.flowake.info/ Www donne com] [http://vacanzamare.hequila.info/ Vacanza mare sicilia] [http://vehiclewarranty.hyndres.info/ Vehicle warranty] [http://extremesex.gerbinu.info/ Extreme sex] [http://openpussy.hunchoxi.info/ Open pussy] [http://gioiellododo.hpirale.info/ Gioiello dodo] [http://bigcocksex.grekles.info/ Big cock sex] [http://fotosborrate.hpirale.info/ Foto sborrate in mano] [http://lottolotteria.gittose.info/ Lotto lotteria] [http://videojessica.hyndres.info/ Video jessica fiorentino] [http://videolesbo.flowake.info/ Video lesbo gratis] [http://trilli.hequila.info/ Trilli] [http://wwwvereporche.hyndres.info/ Www vereporche it] [http://indonesiabugil.hpirale.info/ Indonesia bugil] [http://borsaitaliana.goxasi.info/ Borsaitaliana it] [http://tesinainglese.hequila.info/ Tesina inglese ulisse joyce] [http://sfondidisney.flowake.info/ sfondi disney] [http://bancadati.grekles.info/ Banca dati] [http://lurlodimunch.gittose.info/ L urlo di munch] [http://videocensure.flowake.info/ Video censure casalinga vogliosa] [http://vivimilano.hyndres.info/ Vivimilano] [http://fibrosicistica.gerbinu.info/ Fibrosi cistica soluzione ipertonica] [http://professionedottore.hunchoxi.info/ Professione dottore commercialista] [http://sexcartoni.ipnerka.info/ Sex cartoni] [http://imballaggioplastica.hpirale.info/ Imballaggio plastica] [http://vinomalvasia.flowake.info/ Vino malvasia] [http://speziacalcio.hequila.info/ Spezia calcio] [http://tessagelisio.hequila.info/ Tessa gelisio] [http://fanfictionlady.gerbinu.info/ Fanfiction lady oscar] [http://fotomontaggio.hpirale.info/ Fotomontaggio sexy vip piu spinti] [http://accompagnatrici.grekles.info/ Accompagnatrici ventenni] [http://auricolaresony.grekles.info/ Auricolare sony ericsson] [http://pastasfoglia.hunchoxi.info/ Pasta sfoglia online] [http://valturpollina.hequila.info/ Valtur pollina] [http://giapponeristorante.hpirale.info/ Giappone ristorante] [http://misssixty.gittose.info/ Miss sixty shoes] [http://sexinsana.ipnerka.info/ Sex insana] [http://portocervo.hunchoxi.info/ Porto cervo hotel] [http://fotopalestrati.hpirale.info/ Foto palestrati] [http://convenzione.goxasi.info/ Convenzione mutuo banca intesa] [http://oroscopouomo.hunchoxi.info/ Oroscopo uomo bilancia] [http://freebondanime.hpirale.info/ Free bondanime] [http://fumettilesbo.hpirale.info/ Fumetti lesbo] [http://smsdamore.ipnerka.info/ Sms damore] [http://aviomarscuola.grekles.info/ Aviomar scuola volo] [http://muranobicchiere.gittose.info/ Murano bicchiere] [http://poltrona.hunchoxi.info/ Poltrona frau] [http://videotettone.flowake.info/ Video tettone pompini] [http://hotelgrosseto.hpirale.info/ Hotel grosseto] [http://videosextrans.flowake.info/ Video sex trans] [http://wwwvideosex.hyndres.info/ Www videosex it] [http://arcatoncom.grekles.info/ Arcatoncom] [http://catalogotattoo.goxasi.info/ Catalogo tattoo] [http://aeroportolondra.hyndres.info/ Aeroporto londra stansted] [http://culturiste.gerbinu.info/ Culturiste] [http://tettonegalerie.hequila.info/ Tettone galerie gratis] [http://sardiniaferris.ipnerka.info/ Sardinia ferris] [http://amateurwife.grekles.info/ Amateur wife] [http://fotodiavolita.gerbinu.info/ Foto diavolita] [http://disegnifarfalle.gerbinu.info/ Disegni farfalle] [http://affittomolise.grekles.info/ Affitto molise] [http://orologioatomico.hunchoxi.info/ Orologio atomico] [http://lettereingotico.gittose.info/ Lettere in gotico] [http://vacanzacervia.flowake.info/ Vacanza cervia] [http://gemelli.hpirale.info/ Gemelli] [http://fatinetatoo.gerbinu.info/ Fatine tatoo] [http://cazzinericuli.goxasi.info/ Cazzi neri culi bianchi] [http://figagrossa.gerbinu.info/ Figa grossa] [http://tankavillage.hequila.info/ Tanka village] [http://screensaver.ipnerka.info/ Screensaver stereogramma] [http://voliperucraina.hyndres.info/ Voli per ucraina] [http://borsametalli.goxasi.info/ Borsa metalli] [http://addobbipalloncini.grekles.info/ Addobbi palloncini] [http://webmarketing.hyndres.info/ Webmarketing b2b] [http://uscirecn.hequila.info/ Uscire cn amico] [http://autosfondo.grekles.info/ Auto sfondo] [http://letteradimissioni.gittose.info/ Lettera dimissioni preavviso modelli] [http://tornio.hequila.info/ Tornio] [http://shakespeare.ipnerka.info/ Shakespeare amleto] [http://cancelliautomatici.goxasi.info/ Cancelli automatici] [http://divafutura.gerbinu.info/ Divafutura com] [http://trisit.hequila.info/ Trisit] [http://pornogiapponesi.hunchoxi.info/ Porno giapponesi] [http://studioszante.hequila.info/ Studios zante] [http://stokkevariable.hequila.info/ Stokke variable] [http://prestitodonore.hunchoxi.info/ Prestito donore mutuo prima casa] [http://scaleferro.ipnerka.info/ Scale ferro battuto ringhiera] [http://coloralewinx.goxasi.info/ Colora le winx] [http://cavoottico.goxasi.info/ Cavo ottico] [http://fotologlesbian.hpirale.info/ Fotolog lesbian kiss] [http://lisbonavoli.gittose.info/ Lisbona voli aereo] [http://culiporno.gerbinu.info/ Culi porno] [http://dentistamilano.gerbinu.info/ Dentista milano] [http://dragonballhentai.gerbinu.info/ Dragonball hentai fumetti] [http://nokian91.hunchoxi.info/ Nokia n91] [http://fucilibenelli.hpirale.info/ Fucili benelli] [http://videotroia.hyndres.info/ Video troia gratis] [http://temisull.hequila.info/ Temi sull amicizia] [http://medicinafisica.gittose.info/ Medicina fisica riabilitazione] [http://wwwomageil.flowake.info/ Www omageil de] [http://grassone.hpirale.info/ Grassone troia] [http://windvdkeygen.flowake.info/ Windvd keygen] [http://sessocoppia.ipnerka.info/ Sesso coppia] [http://wwwputtaneit.flowake.info/ Www puttane it] [http://analfuck.grekles.info/ Anal fuck] [http://manichinovirtuale.gittose.info/ Manichino virtuale abbigliamento] [http://notebookoccasione.hunchoxi.info/ Notebook occasione] [http://arcisamarcanda.grekles.info/ Arci samarcanda] [http://tavoli.hequila.info/ Tavoli] [http://peternorth.hunchoxi.info/ Peter north] [http://trasportoaereo.hequila.info/ Trasporto aereo cane] [http://hotwifesfucked.hpirale.info/ Hot wifes fucked on line] [http://filmatiincesti.gerbinu.info/ Filmati incesti gratis] [http://albergomirabilandia.grekles.info/ Albergo mirabilandia] [http://lefotoharddi.gittose.info/ Le foto hard di stefania sandrelli] [http://donnebagnate.gerbinu.info/ Donne bagnate] [http://indicedi.hpirale.info/ Indice di massa corporea] [http://aiutotesitorino.grekles.info/ Aiuto tesi torino] [http://matureass.gittose.info/ Mature ass] [http://forumanalisi.gerbinu.info/ Forum analisi tecnica] [http://vedeteporno.hyndres.info/ Vedete porno italiane] [http://malvasia.gittose.info/ Malvasia lipari] [http://normanni.hunchoxi.info/ Normanni] [http://audiusataroma.grekles.info/ Audi usata roma] [http://designarredamento.gerbinu.info/ Design arredamento salotto] [http://trasportiroma.flowake.info/ Trasporti roma] [http://canottiera.goxasi.info/ Canottiera uomo] I feel like a complete blank.
+
{| align=right
That's how it is.
+
|-
I can't be bothered with anything recently.  
+
|
 +
[[Image:PG31-PowerSupply.jpg|300px|TPS Voltage Regulator]]
 +
|}
 +
<b>Description:</b><br> These large current, high voltage diodes can be used for a multitude of purposes. Really, we just use them for reverse polarization protection.  
  
[http://www.gb-x.de/gbuch.php?forum_id=76268 ladyboys thai katy] |
+
Most systems that we play with are DC based - whatever board requires 'X' voltage (3.3V for example). The board expects the DC voltage in a certain way. VCC in one spot, ground in another. If you reverse this (attaching VCC where GND should be, etc) ''BAD'' things happen. If you're lucky, there will be a massive short somewhere and nothing major will smoke. If you're unlucky, the board will go up in smoke and some things might explode. In practice, most things heat up (no smoke or explosion), but are instantly killed. So now you've got a board that doesn't work but it can be very hard (nye, nearly impossible) to tell what is damaged and what can be fixed.
[http://securitye.www2.prexon.nl/ ladyboy bars in bangkok] |
+
 
[http://www.guestbook.at/gb/gast/index.php?buchid=physiologyjnb thai ladyboy thumbs] |  
+
Obviously there must be a way to prevent this from happening. Enter diodes...
[http://www.gb-x.de/gbuch.php?forum_id=76267 ladyboy cocksucking]
+
 
 +
These pieces of silicon allow current to flow in one direction only. Quite simply, VCC is allowed through but GND is not. Why don't we put a diode on every VCC? Well a diode can cause a 0.7V drop (that's what they teach you in silly eng school at  least) on the power line. So if you are dealing with a really low-power system, 0.7V drop can be too much.
 +
 
 +
There are other ways to protect against reverse polarization like polarized connectors and certain voltage regulators have protection built in. But it you're designing something for mass-market where you don't know who will be connecting what, a reverse protection diode is cheap and easily designed into a board.
 +
 
 +
[[Image:PG31-PowerSupply-Schematic.jpg]]
 +
 
 +
Here you can see the diode D3 in place, directly connected to the [[Barrel Power Jack]].
 +
 
 +
These type diodes can also be used, four at a time, in an [http://en.wikipedia.org/wiki/Diode_bridge bridge rectifier] configuration. I don't have a good image (now you do), but an bridge rectifier takes an AC signal and rectifies it to a DC signal (neat trick actually). A bridge rectifier circuit will also work with a DC supply.  This allows the "reverse protection" trick to become an "I don't care" trick -- whichever way the polarity of the input voltage is, the circuit will still work.  The downside is that you lose 2 diode drops or about 1.3V.  NOTE -- you have to disconnect the input power from ground to make this work.
 +
 
 +
Diodes come in all shapes and sizes. For this posting, we only care about cheap, bulky, large current diodes. These diodes can handle 1-2A each and are cheap. For some our mass designs, we prefer the surface mount diodes (MBRA140). The MBRA140 comes in an SMA package (hopelessly confused with the SMA antenna connector - who came up with this?!). Many other diodes come in axial packages perfect for bread boarding. They all work the same - there is an anode and a cathode. I was always told to remember the <b>a</b>node is the <b>a</b>rrow, the bar is the cathode, and current flows in the direction of the arrow. Cool huh?
 +
 
 +
We like the MBRA140 cause it's cheap and can handle up to 1A. One amp is overkill for most applications, but that's why it's good, it'll work with most applications. If you need something less burly, Digikey/Mouser has more than plenty. Be sure to get a diode that is current rated for the max current draw of your system. If the diode is too small, it'll heat up and eventually burn out.
 +
 
 +
Dropping 0.7V is wasteful, and it becomes more significant the lower the power supply. If the design will operate on batteries, then dropping 0.7V might not even allow the circuit to work. What do you do in this case? There are two options:
 +
 
 +
1. Use Schottky diodes instead of standard ones. A Schottky will only drop around 0.3V and there are some than can drop even less voltage than that. Cheap, simple!<br>
 +
2. When even 0.3V won't do it, then use a transistor! Use a P-mosfet and control the base using either discrete components or an LTC4412 for only 20mV of voltage drop. The pitfall with this is the added power consumption of the LTC4412 and the cost, but for most cases the 28uA are insignificant.:<br>
 +
 
 +
<b>Documents:</b><br>
 +
[[Media:Mbra140tr.pdf|MBRA140 Datasheet]]
 +
 
 +
<b>Footprints:</b><br>
 +
[[SFE_Footprint_Library|SFE Footprint Library]]
 +
 
 +
FP Name: SMA-Diode
 +
 
 +
<b>Manufacturer Info:</b><br>
 +
International Rectifier # : MBRA140TR<br>
 +
 
 +
<b>Supplier Info:</b><br>
 +
Digikey part # : MBRA140CT-ND<br>
 +
Single Piece Price : $0.45
 +
 
 +
<b>Related Items:</b><br>
 +
 
 +
[[Category:Components]]

Latest revision as of 11:47, 17 November 2011

TPS Voltage Regulator

Description:
These large current, high voltage diodes can be used for a multitude of purposes. Really, we just use them for reverse polarization protection.

Most systems that we play with are DC based - whatever board requires 'X' voltage (3.3V for example). The board expects the DC voltage in a certain way. VCC in one spot, ground in another. If you reverse this (attaching VCC where GND should be, etc) BAD things happen. If you're lucky, there will be a massive short somewhere and nothing major will smoke. If you're unlucky, the board will go up in smoke and some things might explode. In practice, most things heat up (no smoke or explosion), but are instantly killed. So now you've got a board that doesn't work but it can be very hard (nye, nearly impossible) to tell what is damaged and what can be fixed.

Obviously there must be a way to prevent this from happening. Enter diodes...

These pieces of silicon allow current to flow in one direction only. Quite simply, VCC is allowed through but GND is not. Why don't we put a diode on every VCC? Well a diode can cause a 0.7V drop (that's what they teach you in silly eng school at least) on the power line. So if you are dealing with a really low-power system, 0.7V drop can be too much.

There are other ways to protect against reverse polarization like polarized connectors and certain voltage regulators have protection built in. But it you're designing something for mass-market where you don't know who will be connecting what, a reverse protection diode is cheap and easily designed into a board.

PG31-PowerSupply-Schematic.jpg

Here you can see the diode D3 in place, directly connected to the Barrel Power Jack.

These type diodes can also be used, four at a time, in an bridge rectifier configuration. I don't have a good image (now you do), but an bridge rectifier takes an AC signal and rectifies it to a DC signal (neat trick actually). A bridge rectifier circuit will also work with a DC supply. This allows the "reverse protection" trick to become an "I don't care" trick -- whichever way the polarity of the input voltage is, the circuit will still work. The downside is that you lose 2 diode drops or about 1.3V. NOTE -- you have to disconnect the input power from ground to make this work.

Diodes come in all shapes and sizes. For this posting, we only care about cheap, bulky, large current diodes. These diodes can handle 1-2A each and are cheap. For some our mass designs, we prefer the surface mount diodes (MBRA140). The MBRA140 comes in an SMA package (hopelessly confused with the SMA antenna connector - who came up with this?!). Many other diodes come in axial packages perfect for bread boarding. They all work the same - there is an anode and a cathode. I was always told to remember the anode is the arrow, the bar is the cathode, and current flows in the direction of the arrow. Cool huh?

We like the MBRA140 cause it's cheap and can handle up to 1A. One amp is overkill for most applications, but that's why it's good, it'll work with most applications. If you need something less burly, Digikey/Mouser has more than plenty. Be sure to get a diode that is current rated for the max current draw of your system. If the diode is too small, it'll heat up and eventually burn out.

Dropping 0.7V is wasteful, and it becomes more significant the lower the power supply. If the design will operate on batteries, then dropping 0.7V might not even allow the circuit to work. What do you do in this case? There are two options:

1. Use Schottky diodes instead of standard ones. A Schottky will only drop around 0.3V and there are some than can drop even less voltage than that. Cheap, simple!
2. When even 0.3V won't do it, then use a transistor! Use a P-mosfet and control the base using either discrete components or an LTC4412 for only 20mV of voltage drop. The pitfall with this is the added power consumption of the LTC4412 and the cost, but for most cases the 28uA are insignificant.:

Documents:
MBRA140 Datasheet

Footprints:
SFE Footprint Library

FP Name: SMA-Diode

Manufacturer Info:
International Rectifier # : MBRA140TR

Supplier Info:
Digikey part # : MBRA140CT-ND
Single Piece Price : $0.45

Related Items: