Umsebenzi wesekethe ye-liquid crystal display display power supply ikakhulukazi ukuguqula amandla amakhulu angu-220V abe amazanyana aqondile ahlukahlukene adingekayo ukuze kusetshenziswe isibonisi se-liquid crystal display, kanye nokuhlinzeka nge-voltage esebenzayo yamasekethe okulawula ahlukahlukene, amasekhethi anengqondo, amaphaneli okulawula, njll. . kusibonisi sekristalu ewuketshezi, kanye nokuzinza kwayo kokusebenza Kuthinta ngokuqondile ukuthi ngabe imonitha ye-LCD ingasebenza ngokujwayelekile yini.
1. Isakhiwo sesekhethi ye-liquid crystal display supply
Isekhethi ye-liquid display display power supply ikakhulukazi ikhiqiza i-5V, i-12V yokusebenza kwamandla. Phakathi kwazo, i-voltage ye-5V ihlinzeka ngokuyinhloko nge-voltage yokusebenza yesifunda se-logic yebhodi elikhulu kanye nezibani zezinkomba kuphaneli yokusebenza; i-voltage engu-12V ihlinzeka ngokuyinhloko amandla kagesi okusebenza ebhodini lamandla kagesi aphezulu kanye nebhodi lomshayeli.
Isifunda samandla sakhiwe ikakhulukazi isifunda sokuhlunga, isifunda sokuhlunga ibhuloho, isifunda sokushintsha esikhulu, isiguquli esishintshayo, isifunda sokuhlunga isihlungi, isifunda sokuvikela, isifunda sokuqala esithambile, isilawuli se-PWM nokunye.
Phakathi kwazo, indima yomjikelezo wesihlungi se-AC ukuqeda ukuphazamiseka kwe-high-frequency kuma-mains (isifunda sokuhlunga esiqondile ngokuvamile sakhiwe ngama-resistors, ama-capacitor nama-inductors); indima yomjikelezo wesihlungi sokulungisa ibhuloho ukuguqula i-220V AC ibe ngu-310V DC; shintsha isekethe Umsebenzi wesekethe yesihlungi sokulungisa ukuguqula amandla e-DC acishe abe ngu-310V ngeshubhu yokushintsha kanye ne-switching transformer ibe ama-pulse voltages ama-amplitudes ahlukene; umsebenzi wesekethe yesihlungi sokulungiswa ukuguqula ukuphuma kwe-pulse voltage nge-switching transformer ibe yi-voltage eyisisekelo engu-5V edingwa umthwalo ngemva kokulungiswa nokuhlunga kanye ne-12V; Umsebenzi wesekethe yokuvikela i-overvoltage ukugwema ukulimala kweshubhu lokushintsha noma ukunikezwa kwamandla okushintshwa okubangelwa umthwalo ongavamile noma ezinye izizathu; umsebenzi wesilawuli se-PWM ukulawula ukushintshwa kwe-switching tube nokulawula umjikelezo ngokuya nge-voltage yempendulo yesifunda sokuvikela.
Okwesibili, isimiso sokusebenza se-liquid crystal display power supply circuit
Isekhethi yokuphakelwa kwamandla yesibonisi sekristalu ewuketshezi ngokuvamile isebenzisa imodi yesekethe yokushintsha. Lo mjikelezo wokuphakelwa kwamandla uguqula i-AC 220V kagesi okufakwayo ibe amandla kagesi e-DC ngokusebenzisa isekethe yokulungisa nokuhlunga, bese isikwa ngeshubhu yokushintsha bese yehliswa isiguquli esinemvamisa ephezulu ukuze kutholwe i-voltage yamagagasi kanxande ephezulu. Ngemva kokulungiswa nokuhlunga, i-voltage ye-DC edingwa imojuli ngayinye ye-LCD iyaphuma.
Okulandelayo kuthatha i-AOCLM729 liquid crystal display njengesibonelo ukuchaza umgomo wokusebenza wesekethe yokunikezwa kwamandla ekristalu ewuketshezi. Isekhethi yamandla ye-AOCLM729 liquid crystal display yakhiwa ikakhulukazi isekethe yesihlungi se-AC, isifunda sokulungisa ibhuloho, isifunda esithambile sokuqala, isekethe yokushintsha okuyinhloko, isekethe yesihlungi esilungisa kabusha, isekethe yokuvikela i-overvoltage nokunye.
Isithombe esibonakalayo sebhodi lesekhethi yamandla:
Umdwebo wohlelo lwesekhethi yamandla:
- Isekhethi yesihlungi se-AC
Umsebenzi wesekethe yesihlungi se-AC uwukuhlunga umsindo owethulwa ulayini wokufaka we-AC futhi ucindezele umsindo wempendulo okhiqizwa ngaphakathi kwendawo yamandla.
Umsindo ongaphakathi kwamandla kagesi ikakhulukazi uhlanganisa umsindo wemodi evamile nomsindo ovamile. Ngokunikezwa kwamandla esigaba esisodwa, kunezintambo zamandla ezingu-2 AC kanye nentambo yaphansi engu-1 ohlangothini lokokufaka. Umsindo okhiqizwa phakathi kwezintambo ezimbili zamandla e-AC kanye nentambo yaphansi ohlangothini lokufakwa kwamandla umsindo ovamile; umsindo okhiqizwa phakathi kwezintambo ezimbili zamandla e-AC umsindo ojwayelekile. Isekhethi yesihlungi se-AC isetshenziswa kakhulu ukuhlunga lezi zinhlobo ezimbili zomsindo. Ngaphezu kwalokho, iphinde isebenze njengokuvikelwa kwe-overcurrent wesifunda kanye nokuvikelwa kwe-overvoltage. Phakathi kwazo, i-fuse isetshenziselwa ukuvikelwa kwe-overcurrent, futhi i-varistor isetshenziselwa ukuvikela i-voltage overvoltage input. Isibalo esingezansi siwumdwebo wohlelo lwesekethe yesihlungi se-AC.
Emfanekisweni, ama-inductors L901, L902, nama-capacitor C904, C903, C902, kanye ne-C901 enza isihlungi se-EMI. Ama-Inductors L901 kanye ne-L902 asetshenziselwa ukuhlunga umsindo ovamile ovamile; I-C901 ne-C902 isetshenziselwa ukuhlunga umsindo ovamile ovamile; I-C903 ne-C904 isetshenziselwa ukuhlunga imvamisa ephezulu yomsindo ojwayelekile nomsindo ojwayelekile (ukuphazanyiswa kwe-electromagnetic high frequency); i-current limiting resistor R901 kanye ne-R902 isetshenziselwa ukukhipha i-capacitor lapho ipulaki yamandla inqanyuliwe; umshwalense u-F901 usetshenziselwa ukuvikela i-overcurrent, futhi i-varistor NR901 isetshenziselwa ukuvikela i-voltage overvoltage okokufaka.
Lapho ipulaki yamandla yesibonisi sekristalu ewuketshezi ifakwe kusokhethi yamandla, i-220V AC idlula ku-fuse F901 kanye ne-varistor NR901 ukuvimbela umthelela wokuhlinzwa, bese idlula kumjikelezo owenziwe ngama-capacitor C901, C902, C903, C904, resistors R901, R902, kanye inductors L901, L902. Faka isekethe yokulungisa ibhuloho ngemva kwesekhethi yokulwa nokuphazamiseka.
2. Isekhethi yesihlungi sokulungisa ibhuloho
Umsebenzi womjikelezo wesihlungi sokulungisa ibhuloho ukuguqula i-220V AC ibe amandla kagesi e-DC ngemva kokulungiswa kwegagasi eligcwele, bese uguqula i-voltage ibe yi-voltage ephindwe kabili yama-mains ngemva kokuhlunga.
Isekhethi yesihlungi sokulungisa ibhuloho ikakhulukazi yakhiwe isilungisi sebhuloho i-DB901 kanye ne-filter capacitor C905..
Emfanekisweni, isilungisi sebhuloho sakhiwe ngama-diode angu-4 okulungisa, futhi i-capacitor yokuhlunga iyi-400V capacitor. Uma i-220V AC mains ihlungwa, ingena kusilungisi sebhuloho. Ngemuva kokuthi isilungisi sebhuloho senze ukulungiswa kwegagasi eligcwele kumapayipi amakhulu e-AC, liba amandla kagesi e-DC. Bese i-voltage ye-DC iguqulwa ibe amandla kagesi angu-310V DC nge-capacitor yesihlungi C905.
3. Isifunda esithambile sokuqala
Umsebenzi wesifunda sokuqala esithambile ukuvimbela umthelela osheshayo wamanje ku-capacitor ukuqinisekisa ukusebenza okuvamile nokuthembekile kokunikezwa kwamandla okushintsha. Njengoba i-voltage yokuqala ku-capacitor inguziro ngesikhathi isekethe yokufaka ivuliwe, kuzokwakhiwa i-inrush current enkulu esheshayo, futhi lokhu kwamanje kuzovame ukubangela ukuthi i-fuse yokufaka iphume, ngakho-ke isekethe eqala kancane idinga zibekwe. Isifunda esithambile sokuqala sakhiwe ikakhulukazi izinqamuleli zokuqala, ama-diode okulungisa kabusha, nama-capacitor okuhlunga. Njengoba kuboniswe emfanekisweni umdwebo wohlelo lwesekethe yokuqala ethambile.
Emfanekisweni, ama-resistors u-R906 no-R907 alingana no-1MΩ. Njengoba lezi ziphikisayo zinenani elikhulu lokumelana, ukusebenza kwazo kuncane kakhulu. Lapho ugesi oshintshwayo usanda kuqaliswa, ugesi oqala ukusebenza odingwa yi-SG6841 ungezwa endaweni yokugcina okokufaka (iphinikhodi 3) ye-SG6841 ngemva kokwehliswa amandla kagesi aphezulu angu-300V DC ngama-resistor u-R906 no-R907 ukuze kuqalwe kahle. . Lapho ishubhu elishintshayo seliphendukela esimweni esivamile sokusebenza, i-voltage ephezulu-frequency esungulwe kusiguquli esishintshayo iyalungiswa futhi ihlungwe yi-rectifier diode D902 kanye ne-filter capacitor C907, bese iba amandla okusebenza we-chip ye-SG6841, kanye nesiqalo- up inqubo isiphelile.
4. main switch circuit
Umsebenzi wesekethe yokushintsha eyinhloko ukuthola i-voltage yamagagasi angunxande we-high-frequency ngokushintsha ukunqunywa kweshubhu kanye nesitebhisi se-high-frequency transformer siyehla.
Isifunda esishintshayo esiyinhloko sakhiwe ikakhulukazi i-switching tube, isilawuli se-PWM, i-switching transformer, i-overcurrent protection circuit, i-high voltage protection circuit nokunye.
Emfanekisweni, i-SG6841 isilawuli se-PWM, okuwumgogodla wokushintshwa kwamandla kagesi. Ingakwazi ukukhiqiza isignali yokushayela ene-frequency engaguquki kanye nobubanzi be-pulse obushintshwayo, futhi ilawule isimo sokucisha seshubhu yokushintsha, ngaleyo ndlela ilungise ugesi ophumayo ukuze kuzuzwe injongo yokuqiniswa kwe-voltage. . I-Q903 iyishubhu yokushintsha, i-T901 iyisiguquli esishintshayo, futhi isifunda sakhiwe nge-voltage regulator tube ZD901, resistor R911, transistors Q902 kanye ne-Q901, kanye ne-resistor R901 iyisekhethi yokuvikela i-overvoltage.
Uma i-PWM iqala ukusebenza, iphinikhodi yesi-8 ye-SG6841 ikhipha igagasi lokushaya kwe-rectangular (ngokuvamile imvamisa ye-pulse ephumayo ingu-58.5kHz, futhi umjikelezo womsebenzi ngu-11.4%). I-pulse ilawula ishubhu yokushintsha i-Q903 ukwenza isenzo sokushintsha ngokuya ngemvamisa yokusebenza kwayo. Lapho ishubhu yokushintsha i-Q903 ivuliwe/ivaliwe ngokuqhubekayo ukuze yakhe i-oscillation yokuzithokozisa, i-transformer i-T901 iqala ukusebenza futhi ikhiqize i-voltage e-oscillating.
Lapho i-terminal ephumayo ye-pin 8 ye-SG6841 isezingeni eliphezulu, ithubhu yokushintsha i-Q903 ivuliwe, bese ikhoyili eyinhloko ye-switching transformer T901 ine-current egeleza kuyo, ekhiqiza ama-voltages amahle namabi; ngesikhathi esifanayo, i-secondary ye-transformer ikhiqiza izintambo ezinhle nezimbi. Ngalesi sikhathi, i-diode D910 yesibili inqanyuliwe, futhi lesi sigaba yisiteji sokugcina amandla; lapho i-terminal ephumayo ye-pin 8 ye-SG6841 isezingeni eliphansi, ishubhu yokushintsha i-Q903 iyanqanyulwa, futhi yamanje kukhoyili eyinhloko ye-switching transformer T901 ishintsha ngokushesha. ingu-0, amandla e-electromotive of the primary aphansi anegethivu nangaphezulu, futhi amandla e-electromotive aphezulu avumayo kanye nenegethivu ephansi afakwa kwesesibili. Ngalesi sikhathi, i-diode D910 ivuliwe futhi iqala ukukhipha i-voltage.
(1) Isekhethi yokuvikela yamanje
Umgomo wokusebenza wesekethe yokuvikela i-overcurrent umi kanje.
Ngemva kokuba ishubhu yokushintsha i-Q903 ivuliwe, i-current izogeleza isuka ku-drain iye emthonjeni weshubhu yokushintsha i-Q903, futhi i-voltage izokwenziwa ngo-R917. I-Resistor R917 iyisivikeli sokubona samanje, futhi i-voltage ekhiqizwa yiso yengezwa ngokuqondile endaweni yokokufaka engaguquki yesiqhathanisi sokutholwa okudlulele kwe-chip yesilawuli se-PWM SG6841 (okuyi-pin 6), inqobo nje uma i-voltage idlula i-1V, iya izokwenza isilawuli se-PWM i-SG6841 yangaphakathi Isekethe yamanje yokuvikela iqala, ukuze iphinikhodi yesi-8 iyeke ukukhipha amagagasi e-pulse, futhi ishubhu yokushintsha kanye ne-switching transformer iyeke ukusebenza ukuze ibone ukuvikeleka kwamanje.
(2) Isifunda sokuvikela amandla kagesi aphezulu
Umgomo wokusebenza wesekethe yokuvikela amandla kagesi aphezulu kanjena.
Lapho i-voltage yegridi ikhuphuka ngaphezu kwenani eliphakeme, i-voltage ephumayo yekhoyili yempendulo ye-transformer nayo izokhuphuka. I-voltage izodlula i-20V, ngalesi sikhathi i-voltage regulator tube ZD901 iphukile, futhi ukwehla kwe-voltage kwenzeka ku-resistor R911. Lapho ukwehla kwe-voltage kungu-0.6V, i-transistor Q902 ivuliwe, bese isisekelo se-transistor Q901 siba yizinga eliphezulu, ukuze i-transistor Q901 nayo ivuliwe. Ngasikhathi sinye, i-diode D903 nayo ivuliwe, okubangela ukuthi iphinikhodi yesi-4 yesilawuli se-PWM i-SG6841 chip ibekwe phansi, okuholela ekubeni khona kwesekethe esifushane, okwenza isilawuli se-PWM i-SG6841 sivale ngokushesha ukuphuma kwe-pulse.
Ngaphezu kwalokho, ngemva kokuvulwa kwe-transistor Q902, i-voltage eyireferensi engu-15V yephinikhodi 7 yesilawuli se-PWM SG6841 isekelwe ngokuqondile nge-resistor R909 kanye ne-transistor Q901. Ngale ndlela, i-voltage yetheminali yokuphakelwa kwamandla ye-chip yesilawuli se-PWM i-SG6841 iba ngu-0, isilawuli se-PWM simisa ukukhipha amagagasi okushaya kwenhliziyo, futhi ishubhu yokushintsha nokushintsha i-transformer kuyayeka ukusebenza ukuze kuzuzwe ukuvikelwa kwamandla kagesi aphezulu.
5. Umjikelezo wesihlungi sokulungisa
Umsebenzi wesifunda sokuhlunga ukulungisa ukulungisa nokuhlunga i-voltage ephumayo ye-transformer ukuze uthole i-voltage ye-DC ezinzile. Ngenxa yokuvuza kokuvuza kwe-switching transformer kanye ne-spike okubangelwa ukuhlehla kokubuya kwe-diode ephumayo, zombili zakha ukuphazamiseka okungaba khona kukazibuthe kagesi. Ngakho-ke, ukuze uthole ama-voltages ahlanzekile we-5V kanye ne-12V, i-voltage ephumayo ye-switching transformer kufanele ilungiswe futhi ihlungwe.
Isekhethi yesihlungi esilungisa kabusha yakhiwa ikakhulukazi ama-diode, izihlungi ezimelana nezihlungi, ama-capacitor okuhlunga, ama-inductors okuhlunga, njll.
Emfanekisweni, umjikelezo wesihlungi se-RC (i-resistor R920 kanye ne-capacitor C920, i-resistor R922 ne-capacitor C921) exhunywe ngokuhambisana ne-diode D910 kanye ne-D912 ekupheleni kokuphuma kwesibili kwe-switching transformer T901 isetshenziselwa ukumunca i-voltage yokuqhuma ekhiqizwa kugesi. i-diode D910 kanye ne-D912.
Isihlungi se-LC esakhiwe i-diode D910, i-capacitor C920, i-resistor R920, i-inductor L903, i-capacitor C922 ne-C924 ingahlunga ukuphazamiseka kwe-electromagnetic kokuphuma kwamandla ka-12V nge-transformer futhi ikhiphe i-voltage engu-12V ezinzile.
Isihlungi se-LC esakhiwe i-diode D912, i-capacitor C921, i-resistor R921, i-inductor L904, i-capacitor C923 ne-C925 ingahlunga ukuphazamiseka kozibuthe we-voltage ephumayo engu-5V ye-transformer futhi ikhiphe i-voltage engu-5V ezinzile.
6. Isifunda sokulawula isilawuli se-12V/5V
Njengoba amandla amakhulu angu-220V AC eshintsha phakathi kwebanga elithile, lapho amandla amakhulu enyuka, i-voltage ephumayo ye-transformer kumjikelezo wamandla nayo izokhuphuka ngokufanele. Ukuze uthole ama-voltage azinzile angu-5V no-12V, isekethe yesilawuli.
Isekethe yesilawuli se-voltage engu-12V/5V yakhiwa ikakhulukazi isilawuli se-voltage enembile (TL431), i-optocoupler, isilawuli se-PWM, kanye nesihlukanisi se-voltage.
Esithombeni, i-IC902 iyi-optocoupler, i-IC903 iyisilawuli samandla kagesi esinembayo, futhi ama-resistors u-R924 no-R926 angama-voltage divider resistors.
Lapho isifunda sokuphakela amandla sisebenza, i-voltage ye-DC engu-12V ephumayo ihlukaniswa ngabaphikisi i-R924 ne-R926, bese i-voltage ikhiqizwa ku-R926, engezwe ngokuqondile kusilawuli se-voltage enembile i-TL431 (kutheminali ye-R). Ingaziwa kusukela kumapharamitha wokumelana kusekethe Le voltage yanele ukuvula i-TL431. Ngale ndlela, i-voltage engu-5V ingageleza nge-optocoupler kanye nesilawuli se-voltage esinembile. Lapho okwamanje kugeleza ku-optocoupler LED, i-optocoupler IC902 iqala ukusebenza futhi iqedele isampula ye-voltage.
Lapho i-voltage eyinhloko engu-220V AC ikhuphuka futhi i-voltage ephumayo ikhuphuka ngokufanele, yamanje egeleza nge-optocoupler IC902 nayo izokhuphuka ngokufanele, futhi ukukhanya kwe-diode ekhipha ukukhanya ngaphakathi kwe-optocoupler nakho kuzokhuphuka ngokufanele. Ukumelana kwangaphakathi kwe-phototransistor nakho kuba kuncane ngesikhathi esifanayo, ukuze izinga lokuqhuba le-terminal phototransistor nalo lizoqiniswa. Lapho izinga lokuqhuba le-phototransistor liqiniswa, i-voltage yephinikhodi 2 yesilawuli samandla se-PWM i-SG6841 chip izokwehla ngesikhathi esifanayo. Njengoba le-voltage yengezwa kokokufaka okuguquguqukayo kwe-amplifier yephutha yangaphakathi ye-SG6841, umjikelezo womsebenzi we-pulse okukhiphayo we-SG6841 ulawulwa ukuze unciphise i-voltage ephumayo. Ngale ndlela, iluphu yempendulo yokuphuma kwe-overvoltage iyakhiwa ukuze kuzuzwe umsebenzi wokusimamisa okukhiphayo, futhi i-voltage ephumayo ingaqiniswa cishe ekuphumeni okungu-12V kanye no-5V.
ukusikisela:
I-optocoupler isebenzisa ukukhanya njengendlela yokudlulisa amasignali kagesi. Inomphumela omuhle wokuzihlukanisa kumasignali kagesi okufakwayo nokuphumayo, ngakho-ke isetshenziswa kabanzi kumasekethe ahlukahlukene. Njengamanje, isiphenduke enye yemishini ye-optoelectronic ehluke kakhulu futhi esetshenziswa kabanzi. I-optocoupler ngokuvamile iqukethe izingxenye ezintathu: ukuphuma kokukhanya, ukwamukela ukukhanya, nokukhulisa isignali. Isignali kagesi efakiwe ishayela i-light-emitting diode (LED) ukuthi ikhiphe ukukhanya kwe-wavelength ethile, etholwa i-photodetector ukuze ikhiqize i-photocurrent, ethuthukiswayo futhi ikhiphe. Lokhu kuqeda ukuguqulwa kukagesi-okubona-kagesi, ngaleyo ndlela kudlala indima yokokufaka, okukhiphayo, nokuhlukanisa. Njengoba okokufaka nokuphuma kwe-optocoupler kuhlukanisiwe komunye nomunye, futhi ukudluliswa kwesignali kagesi kunezici ze-unidirectionality, kunekhono elihle lokuhlukanisa ugesi kanye nekhono lokulwa nokuphazamiseka. Futhi ngenxa yokuthi isiphetho sokufakwayo se-optocoupler siyisici esine-impedance ephansi esisebenza kumodi yamanje, sinamandla okulahla imodi evamile. Ngakho-ke, ingathuthukisa kakhulu isilinganiso sesignali-kuya-kumsindo njengento yokuhlukanisa isiphetho ekudlulisweni kolwazi lwesikhathi eside. Njengedivaysi yokusebenzelana yokuhlukanisa isignali ekuxhumaneni kwedijithali yekhompuyutha kanye nokulawula isikhathi sangempela, ingakhuphula kakhulu ukwethembeka komsebenzi wekhompyutha.
7. Isekethe yokuvikela i-overvoltage
Umsebenzi wesekethe yokuvikela i-overvoltage ukuthola i-voltage ephumayo yesekethe yokuphumayo. Lapho i-voltage ephumayo ye-transformer ikhuphuka ngokungavamile, ukuphuma kwe-pulse kuvaliwe isilawuli se-PWM ukuze kuzuzwe inhloso yokuvikela umjikelezo.
Isekhethi yokuvikela i-overvoltage ikakhulukazi yakhiwa isilawuli se-PWM, i-optocoupler, kanye neshubhu lokulawula i-voltage. Njengoba kukhonjisiwe kulesi sithombe esingenhla, ishubhu yesilawuli se-voltage ZD902 noma i-ZD903 kumdwebo wohlelo lwesekethe isetshenziselwa ukuthola i-voltage ephumayo.
Lapho i-voltage yesibili ephumayo ye-switching transformer ikhuphuka ngokungavamile, ishubhu lesilawuli se-voltage ZD902 noma i-ZD903 izophulwa, okuzokwenza ukukhanya kweshubhu elikhipha ukukhanya ngaphakathi kwe-optocoupler kukhule ngendlela engavamile, kubangele iphinikhodi yesibili yesilawuli se-PWM. ukudlula ku-optocoupler. I-phototransistor ngaphakathi kwedivayisi isekelwe phansi, isilawuli se-PWM sinqamula ngokushesha ukuphuma kwe-pulse ye-pin 8, futhi ishubhu yokushintsha kanye ne-switching transformer iyeka ukusebenza ngokushesha ukuze kuzuzwe inhloso yokuvikela umjikelezo.
Isikhathi sokuthumela: Oct-07-2023