Kupanga Chajara ndi Chitetezo Chafupi Cha Dera
Kuchuluka kwa zipangizo zamagetsi zonyamulika—monga mafoni am'manja, mapiritsi, makamera, zida zamagetsi, ndi zipangizo za IoT—kwapangitsa kuti pakhale kufunikira kwa ma charger othamanga kwambiri, ang'onoang'ono, komanso ogwira ntchito bwino. Komabe, mphamvu yowonjezera yochaja (kuchaja mwachangu) imawonjezeranso zoopsa zamagetsi, imodzi mwa izo ndi ma short circuits. Short circuits amatha kuchitika chifukwa cha zingwe zowonongeka, zolumikizira zonyowa, zigawo zamkati zomwe zalephera, kapena cholakwika cha wogwiritsa ntchito. Kugundako sikuti chipangizocho sichikuchaja kokha, komanso kuthekera kotentha kwambiri, kuwonongeka kwa batri, komanso ngakhale moto. Chifukwa chake, kupanga ma charger amakono kuyenera kukhala ndi njira yodalirika yotetezera short circuits.
Kumvetsetsa Ma Circuit Afupi mu Machitidwe Ochapira
Mzere waufupi ndi mkhalidwe womwe mizere yabwino ndi yoipa imalumikizidwa ndi kukana kochepa kwambiri, zomwe zimapangitsa kuti mphamvu yamagetsi ikwere kwambiri. Mu ma charger, ma circuit afupi amatha kuchitika kumbali yotulutsa (mwachitsanzo, nsonga za cholumikizira cha USB zikakhudza, chingwe chimachotsedwa), kapena kumbali yolowera (kuwonongeka kwa gawo loyamba kapena zigawo zokonzanso). Mu machitidwe amagetsi, kuwonjezeka kwadzidzidzi kwa mphamvu yamagetsi kumayambitsa mavuto awiri akuluakulu: (1) kutentha kwakukulu mu zigawo - makamaka ma MOSFET, ma diode, ma transformer osinthira, ndi zingwe; (2) kuchepa kwa magetsi komwe kungayambitse kugwedezeka kolamulira, zomwe zimapangitsa kuti dongosolo likhale losakhazikika.
Kuti izi zitheke, chitetezo cha short-circuit chiyenera kupangidwa kuti chiyankhe mwachangu, kuchepetsa mphamvu, ndikubwezeretsa (kuyambitsanso zokha) popanda kuwononga zigawo. Izi zimafuna kuphatikiza njira za hardware ndi firmware (ngati chojambuliracho chikuyendetsedwa ndi digito), komanso kusankha zigawo zoyenera zotetezera.
Mfundo Zoyambira Zoteteza Ma Circuit Short mu Chargers
Kawirikawiri, chitetezo cha short-circuit mu ma charger chimamangidwa pa mfundo za kuchepetsa mphamvu ndi kutseka kwa magetsi. Kusankha kwa kapangidwe kake kumadalira pa topology ya charger (linear, switching buck, flyback SMPS) ndi cholinga chogwiritsa ntchito mphamvu (5–120 watts kapena kuposerapo). Chitetezo chabwino nthawi zambiri chimaphatikiza zigawo zingapo kuti zitsimikizire chitetezo pazochitika zosiyanasiyana zolephera.
Nazi mfundo zina zomwe zimagwiritsidwa ntchito kwambiri:
1. Kuzindikira kwa overcurrent
Mphamvu yotulutsa imayang'aniridwa pogwiritsa ntchito shunt resistor, Hall sensor, kapena RDS(on) MOSFET (yopanda kutayika kwa mphamvu yamagetsi). Mphamvu yamagetsi ikadutsa malire, wowongolera amachepetsa kayendedwe ka ntchito, amachepetsa mphamvu yamagetsi, kapena azimitsa switch.
2. Hiccup mode (yesaninso yokha)
Pamene dawunilodi yochepa yapezeka, charger imazimitsa kwakanthawi mphamvu yotulutsa mphamvu kenako imayesa kuyiyatsanso nthawi ndi nthawi. Ngati dawunilodi yochepa yapitirira, charger imazimanso. Njira iyi imachepetsa mphamvu yotulutsidwa kuti zinthu zisatenthe kwambiri.
3. Kuchepetsa kwa mphamvu ya foldback
Pamene mphamvu yotulutsa mphamvu yatsika pansi pa mtengo winawake, mphamvu yotulutsa mphamvu yamagetsi imatsika. Njira imeneyi imalepheretsa mphamvu yotulutsa mphamvu yamagetsi kupitiriza kupereka mphamvu yamagetsi yayikulu ikachepa.
4. Chitetezo cha kutentha (kutseka kutentha)
Ngakhale mphamvu yamagetsi ili yochepa, kutentha kwa zinthu kumatha kukwerabe. Zosensa zamkati za kutentha, ma IC, ma NTC, kapena ma switch a kutentha zimatha kutseka makinawo kutentha kukapitirira malire.
5. Chitetezo cholowera (fuse, MOV, NTC, TVS)
Mafunde afupiafupi kumbali yoyamba kapena kukwera kwa magetsi kuchokera ku gridi yamagetsi ayenera kuyendetsedwa ndi ma fuse, varistors (MOVs), NTC inrush resistors, ndi TVS pamalo ena.
Kapangidwe ka Charger ndi Chitetezo cha Dera Lalifupi: Gawo Lalikulu
Kupanga chojambulira chokhala ndi chitetezo cha ma circuit afupi nthawi zambiri kumafuna zinthu zotsatirazi:
1) Cholowetsa cha AC/DC (cha chojambulira cha adaputala)
Mu adaputala ya SMPS, mbali yolowera ya AC imadutsa mu fyuluta ya EMI, chosinthira magetsi, ndi capacitor yayikulu. Zigawo zodzitetezera ndi izi:
– Fuse: imasiya kugwira ntchito kwamuyaya ngati pali mphamvu yochulukirapo. Iyi ndi "gawo lomaliza" loletsa moto.
– MOV: imapirira kukwera kwa magetsi kuchokera ku gridi yamagetsi.
– NTC inrush limiter: imachepetsa mphamvu yoyambira pamene bulk capacitor ikuchaja.
Ma circuit afupiafupi kumbali yoyamba nthawi zambiri amakhala oopsa chifukwa amakhudza ma voltage ambiri. Chifukwa chake, ubwino wa insulation ya transformer ndi kapangidwe ka PCB (creepage/clearance) zimathandizanso mwanjira ina kuteteza.
2) Kusintha kwa Conversion Block ndi Current Control
Ma adapter amakono amagwiritsa ntchito flyback kapena LLC topology yokhala ndi chowongolera cha PWM. Chowongolera cha IC nthawi zambiri chimakhala ndi zinthu zotsatirazi:
- Malire a mphamvu yamagetsi ya cycle-by-cycle kudzera mu resistor ya mphamvu yamagetsi mu njira ya MOSFET.
- Chitetezo cha shortcircuit chomwe chimagwira ntchito pamene feedback ikusonyeza kuchepa kwa mphamvu yotulutsa.
- Njira yolumikizira mkati kuti muchepetse kutentha.
Kumbali ya DC-DC (monga ma charger agalimoto, ma power bank, kapena ma USB-C PD modules), ma buck/boost topologies amafunika kuyeza molondola mphamvu yamagetsi yotuluka. Ma shunt resistors ang'onoang'ono (monga 10–20 mΩ) ndi ma current-sense amplifier nthawi zambiri amagwiritsidwa ntchito kuti azindikire mwachangu komanso molondola.
3) Cholepheretsa Chotulutsa: eFuse/Load Switch ndi TVS
Kumbali yotulutsa, opanga mapulogalamu nthawi zambiri amawonjezera:
– eFuse / load switch: IC yomwe imatha kuletsa mzere wotulutsa ikafupikitsidwa, yokhala ndi yankho la microsecond-millisecond. Ma eFuses ena amapereka soft-start, reverse current blocking, komanso malire osinthika a current.
– TVS diode: imateteza ku ESD ndi kukwera kwa magetsi pa cholumikizira cha USB.
– Polyfuse (PTC resettable fuse): njira yotsika mtengo yochepetsera mphamvu yamagetsi, ngakhale kuti yankho lake limakhala lochedwa ndipo limakhudzidwa ndi kutentha.
Chotulutsa ichi chimagwira ntchito bwino kwambiri pa ma circuit afupi omwe amayambitsidwa ndi zingwe kapena ogwiritsa ntchito, makamaka pazida zomwe nthawi zambiri zimalumikizidwa ndi kutulutsidwa.
Njira Yopangira Chitukuko: Kuchokera ku Zofotokozera mpaka Kutsimikizira
Kupanga chojambulira chokhala ndi chitetezo cha ma circuit afupi si nkhani yongowonjezera zinthu zoteteza. Njirayi iyenera kukhala yofanana komanso yoyezeka:
1) Kutsimikiza kwa Mafotokozedwe a Chitetezo
Zitsanzo za magawo omwe ayenera kukhazikitsidwa:
– Mphamvu yapamwamba kwambiri (monga 3 A) ndi mphamvu yoteteza (monga 3.3–4 A).
- Nthawi yoyankha chitetezo (monga nthawi yobwezera). < 5 ms).
- Njira yobwezeretsa: latch-off (iyenera kuchotsedwa) kapena kuyesanso yokha.
- Malire a kutentha kwa zigawo (monga kutsekedwa pa mphambano ya 140°C).
Mafotokozedwe awa amadalira miyezo yachitetezo, gulu la malonda, ndi momwe amagwiritsidwira ntchito.
2) Topology ndi Kusankha Zigawo Ngati cholinga chake ndi 5V/3A USB charger, kapangidwe kake kangagwiritse ntchito buck converter yokhala ndi eFuse. Pa USB-C PD (mpaka 20V), kulamulira ndi kuteteza PD komwe kumagwirizana ndi mgwirizano wa magetsi ndikofunikira. Apa ndi pamene kusankha IC yoyenera kumakhala kofunika kwambiri: ma PD IC ena ali kale ndi OCP/OVP/OTP ndi chitetezo chachifupi mu VBUS.
3) Kapangidwe ka PCB ndi Kusamalira Kutentha Nthawi zambiri kulephera kwa chitetezo sikuchitika chifukwa cha lingaliro lolakwika, koma chifukwa cha kapangidwe koyipa: - Njira zamphamvu zamagetsi ziyenera kukhala zazikulu, zazifupi, komanso zokhala ndi njira yosokera.
- Chotsukira cha shunt chiyenera kuyikidwa pafupi ndi sense IC kuti muchepetse phokoso.
- Kugawa koyenera kwa malo olumikizirana ndi mphamvu kuti mupewe zoyambitsa zabodza.
- Sinki yotenthetsera, kuthira mkuwa, ndi mpweya wotuluka (pa mphamvu yayikulu) zimathandiza kuti OTP isayambe kugwira ntchito pafupipafupi.
4) Kuyesa ndi Kutsimikizira Kuyesa chitetezo cha fupifupi kumaphatikizapo: - Kufupikitsa kutulutsa mwachindunji (0 Ω) pamagetsi osiyanasiyana ogwirira ntchito.
- Kukana kwakanthawi kochepa (monga kukana pang'ono). 50–200 mΩ) kuti muwone kusintha.
- Yesani kutentha kwapamwamba komanso kotsika.
- Yesani zingwe zazitali/zoyipa zomwe zimawonjezera kutsika kwa magetsi.
- Kuyesa kwa ESD pa cholumikizira (IEC 61000-4-2) ndi surge (ya adaputala ya AC).
Kupambana sikuti "chaja sichimaphulika" kokha, komanso kusinthasintha: kaya chimabwerera bwino, kaya kutentha kuli bwino, komanso ngati zigawo zake sizimawonongeka pambuyo pobwerezabwereza.
Mavuto Ofala ndi Mayankho Othandiza Mavuto ena omwe nthawi zambiri amabuka popanga ma charger okhala ndi chitetezo cha ma circuit afupi: 1. Choyambitsa cholakwika chifukwa cha phokoso losinthasintha Yankho: kusefa pa njira yomvera (RC filter), kapangidwe kabwino, ndi kusankha mtengo woyenera wa shunt.
2. Chitetezo chochedwetsa kuti zigawo zitenthe kaye Yankho: gwiritsani ntchito malire a cycle-by-cycle pa controller + eFuse pa output kuti muyankhe mwachangu.
3. Kuyesanso kokha kumapangitsa chipangizocho "kuthwanima" ndipo n'chosasangalatsa. Yankho: chepetsani vuto la ntchito, kapena gwiritsani ntchito latch-off pa ntchito zina (monga mafakitale).
4. Kusinthanitsa mtengo ndi chitetezo: khalani ndi OCP + OTP + TVS osachepera. Pazinthu zambiri, eFuse ikhoza kukhala yowonjezerapo chifukwa imawonjezera chitetezo ndikuchepetsa zopempha za chitsimikizo.
Kutsiliza Kupanga ma charger okhala ndi chitetezo cha short-circuit ndikofunikira kwambiri panthawi ya zida zochapira mwachangu komanso zonyamulika. Chitetezo chabwino cha ma short circuit chiyenera kukhala chachangu, chokhala ndi zigawo zambiri, chokhala ndi mphamvu yolamulira kutentha, komanso choyesedwa pansi pa zochitika zosiyanasiyana zenizeni. Mwa kuphatikiza njira monga kuchepetsa mphamvu zamagetsi, hiccup mode, eFuse/load switch, ndi chitetezo cha kutentha ndi cholowera, chochaja chingakhalebe chotetezeka ngakhale mutakumana ndi cholakwika cha wogwiritsa ntchito kapena kulephera kwa gawo. Pomaliza, kapangidwe kotetezeka sikuti kokha kakukwaniritsa zofunikira, komanso kuonetsetsa kuti kudalirika kwa nthawi yayitali ndikuteteza ogwiritsa ntchito ku zoopsa zomwe sizikuoneka.
Ngati mukufuna, nditha kupitiriza ndi chitsanzo cha kapangidwe ka bolodi la chojambulira cha 5V/3A kapena USB-C PD chokhala ndi malangizo a zigawo ndi zochitika zoyesera zazifupi.
