Umsebenzi wesekethe yonikezelo lwamandla ekristale elulwelo kukuguqula amandla amakhulu angama-220V abe yimisinga ethe ngqo eyohlukeneyo efunekayo ukuze kusebenze umboniso wekristale yolwelo, kunye nokubonelela ngombane osebenzayo kwiisekethe zolawulo ezahlukeneyo, iisekethe ezinengqondo, iiphaneli zolawulo, njl. kumboniso wekristale yolwelo, kunye nokuzinza kwayo Ichaphazela ngokuthe ngqo ukuba i-LCD monitor inokusebenza ngokuqhelekileyo.
1. Ulwakhiwo lwesekethe yonikezelo lwamandla ekristale elulwelo
Umbane obonisa umbane wekristale uvelisa ikakhulu i-5V, i-12V yombane osebenzayo. Phakathi kwabo, i-voltage ye-5V inikezela ngokuyinhloko i-voltage yokusebenza kwisekethe ye-logic yebhodi ephambili kunye nezibane zesalathisi kwipaneli yokusebenza; i-voltage ye-12V inika ubukhulu becala amandla ombane osebenzayo kwibhodi ene-voltage ephezulu kunye nebhodi yomqhubi.
Isiphaluka samandla siqulunqwe kakhulu kwisekhethi yokucoca, i-bridge rectifier filter circuit, isiphaluka esikhulu sokutshintsha, i-switch switching, i-rectifier filter circuit, isiphaluka sokukhusela, isiphaluka sokuqala esithambileyo, isilawuli se-PWM njalo njalo.
Phakathi kwabo, indima ye-AC filter circuit kukuphelisa ukuphazamiseka kwe-high-frequency in the mains (i-linear filter circuit ngokubanzi iqulethwe ngabaxhamli, i-capacitors kunye ne-inductors); indima yesihluzi sokucoca ibhulorho kukuguqula i-220V AC ibe yi-310V DC; tshintsha isiphaluka Umsebenzi wesiphaluka sokucoca ukucoca kukuguqula amandla e-DC malunga ne-310V ngetyhubhu yokutshintsha kunye ne-transformer yokutshintsha kwi-pulse voltages of amplitudes ezahlukeneyo; umsebenzi wesiphaluka sokucoca isihluzo kukuguqula i-pulse voltage output nge-switching transformer kwi-voltage esisiseko ye-5V efunwa ngumthwalo emva kokulungiswa kunye nokucoca kunye ne-12V; Umsebenzi wesiphaluka sokukhusela i-overvoltage kukuphepha umonakalo we-tube yokutshintsha okanye ukunikezelwa kwamandla okutshintsha okubangelwa ngumthwalo ongaqhelekanga okanye ezinye izizathu; umsebenzi womlawuli we-PWM kukulawula ukutshintshwa ityhubhu yokutshintsha kunye nokulawula isiphaluka ngokwe-voltage yempendulo yesiphaluka sokukhusela.
Okwesibini, umgaqo wokusebenza we-liquid crystal display power supply circuit
Isiphaluka sonikezelo lwamandla lomboniso wekristale yolwelo ngokuqhelekileyo lwamkela imowudi yesekethe yokutshintsha. Le sekethi yonikezelo lwamandla iguqula i-AC 220V igalelo lombane kwi-DC yombane ngokusebenzisa i-rectification and filtering circuit, ize isikwe ngetyhubhu yokutshintsha kwaye yehliswe yi-high-frequency transformer ukufumana i-high-frequency rectangular wave voltage. Emva kokulungiswa kunye nokucoca, i-voltage ye-DC efunwa yimodyuli nganye ye-LCD iyaphuma.
Oku kulandelayo kuthatha i-AOCLM729 liquid crystal display njengomzekelo wokuchaza umgaqo wokusebenza we-liquid crystal display circuit circuit. Isiphaluka samandla se-AOCLM729 i-crystal display ye-liquid crystal iqulunqwe kakhulu yi-AC filter circuit, i-bridge rectifier circuit, i-soft start circuit, i-switch switch, i-rectifier filter circuit, i-overvoltage protection circuit njalo njalo.
Umfanekiso webhodi yesekethe yamandla:
Umzobo weSchematic wesekethe yamandla:
- I-AC filter circuit
Umsebenzi we-AC filter circuit kukucoca ingxolo evezwe ngumgca wegalelo we-AC kwaye ucinezele ingxolo yempendulo eyenziwa ngaphakathi kokunikezelwa kwamandla.
Ingxolo ngaphakathi konikezelo lwamandla ikakhulu ibandakanya ingxolo yemowudi eqhelekileyo kunye nengxolo eqhelekileyo. Kwinqanaba elinye lonikezelo lwamandla, kukho iingcingo ze-AC ezi-2 kunye ne-1 yocingo olusezantsi kwicala lokufaka. Ingxolo eyenziwa phakathi kweentambo zombane ezimbini ze-AC kunye nocingo olusemhlabeni kwicala lokufakwa kwamandla yingxolo eqhelekileyo; ingxolo eyenziwa phakathi kweentambo zombane ezimbini ze-AC yingxolo eqhelekileyo. I-AC filter circuit isetyenziswa ikakhulu ukuhluza ezi ndidi zimbini zengxolo. Ukongeza, ikwasebenza njengokhuseleko lwesekethe ye-overcurrent kunye nokukhuselwa kwe-overvoltage. Phakathi kwabo, i-fuse isetyenziselwa ukukhuselwa kwe-overcurrent, kwaye i-varistor isetyenziselwa igalelo lokukhusela i-voltage overvoltage. Lo mzobo ungezantsi ngumzobo weskimu sesekethe yesihluzi se-AC.
Kulo mzobo, i-inductors L901, L902, kunye ne-capacitors C904, C903, C902, kunye ne-C901 zenza i-EMI filter. Ii-Inductors L901 kunye ne-L902 zisetyenziselwa ukuhluza ingxolo ephantsi eqhelekileyo; I-C901 kunye ne-C902 zisetyenziselwa ukuhluza ingxolo yesiqhelo ephantsi; I-C903 kunye ne-C904 zisetyenziselwa ukuhluza ingxolo ephezulu eqhelekileyo kunye nengxolo eqhelekileyo (i-high frequency electromagnetic interference); i-resistor yokukhawulela yangoku i-R901 kunye ne-R902 isetyenziselwa ukukhupha i-capacitor xa iplagi yamandla ikhutshiwe; I-inshurensi ye-F901 isetyenziselwa ukhuseleko olugqithisiweyo, kwaye i-varistor NR901 isetyenziselwa igalelo lokukhusela i-voltage overvoltage.
Xa iplagi yamandla yomboniso wekristale yolwelo ifakwe kwi-socket yamandla, i-220V AC idlula kwi-fuse F901 kunye ne-varistor NR901 ukukhusela impembelelo yokunyuka, kwaye idlula kwisekethe eyenziwe ngama-capacitors C901, C902, C903, C904, resistors R901, R902, kunye inductors L901, L902. Ngenisa i-bridge rectifier circuit emva kwe-anti-interference circuit.
2. Umjikelo wokucoca ibhulorho
Umsebenzi wesekethe yokucoca ibhulorho kukuguqula i-220V AC ibe ngumbane we-DC emva kokulungiswa kwamaza apheleleyo, emva koko uguqule umbane ube kabini umbane oyintloko emva kokucoca.
Isihluzo sokucoca ibhulorho ikakhulu yenziwe sisilungisi sebhulorho iDB901 kunye necapacitor ye-C905..
Kulo mfanekiso, ibhuloho yokulungisa ibhuloho iqulethwe ngama-4 e-rectifier diode, kunye ne-filter capacitor yi-400V capacitor. Xa i-220V AC mains ihluzwa, ingena kwisilungisi sebhulorho. Emva kokuba isilungisi sebhulorho senze ulungiso lwamaza agcweleyo kwimibhobho ye-AC, iba ngumbane weDC. Emva koko amandla ombane e-DC aguqulwa abe yi-310V DC yombane ngokusebenzisa i-capacitor ye-C905 yokucoca.
3. Isiphaluka sokuqala esithambileyo
Umsebenzi wesiphaluka sokuqala esithambileyo kukuthintela impembelelo yangoku kwi-capacitor ukuqinisekisa ukusebenza okuqhelekileyo nokuthembekileyo kokunikezelwa kwamandla okutshintsha. Kuba amandla ombane okuqala kwi-capacitor ingu-zero ngeli xesha isekethe yegalelo iqhutywa, kuya kwenziwa i-inrush yangoku enkulu kwangoko, kwaye lo mjelo uya kuhlala ubangela ukuba i-fuse yegalelo ivuthelwe, ngoko ke isekethe ethambileyo kufuneka zibekwe. Umjikelo othambileyo wokuqala wenziwa ikakhulu ngabaxhathisi bokuqala, iidiode zokulungisa, kunye neecapacitors zokucoca. Njengoko kubonisiwe kumzobo ngumzobo weskimu wesekethe yokuqala ethambileyo.
Kulo mzobo, i-resistors R906 kunye ne-R907 i-resistors elinganayo ye-1MΩ. Ekubeni ezi zixhasi zinexabiso elikhulu lokumelana, ukusebenza kwazo kuncinci kakhulu. Xa unikezelo lwamandla okutshintsha lusanda kuqaliswa, ukuqala kokusebenza ngoku okufunwa yi-SG6841 kongezwa kwi-terminal yokufaka (iphini 3) ye-SG6841 emva kokuhla nge-300V DC yombane ophezulu ngokusebenzisa i-resistor R906 kunye ne-R907 ukuqonda ukuqala okuthambileyo. . Nje ukuba ityhubhu yokutshintsha ijike ibe yimeko yokusebenza eqhelekileyo, amandla ombane aphezulu asekwe kwi-transformer yokutshintsha alungiswe kwaye ahluzwe yi-diode yokucoca i-D902 kunye ne-capacitor yokucoca i-C907, emva koko ibe ngumbane osebenzayo we-chip SG6841, kunye nesiqalo- inkqubo up iphelile.
4. main switch circuit
Umsebenzi wesiphaluka esiphambili sokutshintsha kukufumana i-high-frequency wave rectangular wave voltage ngokutshintsha ukunqunqa ityhubhu kunye ne-high-frequency transformer step-down.
Isiphaluka esisisiseko sokutshintsha ikakhulu siqulunqwe ityhubhu yokutshintsha, isilawuli se-PWM, i-transformer yokutshintsha, isiphaluka sokukhusela i-overcurrent, isiphaluka sokukhusela umbane ophezulu kunye nokunye.
Kulo mzobo, i-SG6841 isilawuli se-PWM, eyona nto ingundoqo yokunikezelwa kwamandla okutshintsha. Inokuvelisa isignali yokuqhuba kunye ne-frequency esisigxina kunye nobubanzi be-pulse eguquguqukayo, kunye nokulawula imeko yokucima i-tube yokutshintsha, ngaloo ndlela ilungelelanisa i-voltage ephumayo ukufezekisa injongo yokuzinzisa umbane. . I-Q903 yi-tube yokutshintsha, i-T901 i-switching transformer, kunye nesekethe ehlanganiswe ne-voltage regulator tube ZD901, i-resistor R911, i-transistors Q902 kunye ne-Q901, kunye ne-resistor R901 yisekethe yokukhusela i-overvoltage.
Xa i-PWM iqala ukusebenza, i-pin ye-8 ye-SG6841 ikhupha i-wave ye-pulse ye-rectangular (ngokuqhelekileyo i-frequency ye-pulse output yi-58.5kHz, kwaye umjikelezo womsebenzi yi-11.4%). I-pulse ilawula i-tube yokutshintsha i-Q903 ukwenza isenzo sokutshintsha ngokuhambelana nokusebenza kwayo. Xa i-tube yokutshintsha i-Q903 ivuliwe ngokuqhubekayo / ivaliwe ukwenza i-oscillation yokuzimela, i-transformer T901 iqala ukusebenza kwaye ivelise i-oscillating voltage.
Xa i-terminal ephumayo ye-pin 8 ye-SG6841 ikwinqanaba eliphezulu, ityhubhu yokutshintsha i-Q903 ivuliwe, kwaye emva koko i-coil ephambili ye-transformer yokutshintsha i-T901 inomgudu ojikelezayo kuyo, eyenza i-voltages efanelekileyo kunye nembi; ngexesha elifanayo, i-second of transformer ivelisa i-voltages efanelekileyo kunye nengalunganga. Ngeli xesha, i-diode D910 kwisibini inqunyulwe, kwaye eli nqanaba liyinqanaba lokugcina amandla; xa i-terminal yemveliso ye-pin 8 ye-SG6841 ikwinqanaba eliphantsi, i-tube yokutshintsha i-Q903 inqunyulwe, kwaye yangoku kwi-coil ephambili ye-transformer yokutshintsha i-T901 itshintsha ngokukhawuleza. yi-0, amandla e-electromotive eprayimari asezantsi e-positive kunye ne-negative ephezulu, kwaye amandla e-electromotive aphezulu kunye ne-negative esezantsi enyanzelwa kwinqanaba lesibini. Ngeli xesha, i-diode D910 ivuliwe kwaye iqala ukukhupha i-voltage.
(1) Isekethe yokhuseleko lwangoku
Umgaqo wokusebenza wesekethe yokukhusela i-overcurrent ngolu hlobo lulandelayo.
Emva kokuba i-tube yokutshintsha i-Q903 ivuliwe, i-current iya kuhamba ukusuka kwi-drain ukuya kumthombo we-tube yokutshintsha i-Q903, kwaye i-voltage iya kuveliswa kwi-R917. I-Resistor i-R917 yinto ekhoyo yokukhangela i-resistor, kwaye i-voltage eveliswa yiyo yongezwa ngokuthe ngqo kwi-terminal ye-non-inverting input ye-overcurrent yokubona uthelekiso lwe-PWM yomlawuli we-SG6841 chip (okuthiwa i-pin 6), nje ukuba umbane udlula i-1V, iya kwenza isilawuli se-PWM i-SG6841 yangaphakathi Isiphaluka sokukhusela samanje siqala, ukwenzela ukuba i-pin ye-8 iyeke ukukhupha amaza e-pulse, kunye ne-tube yokutshintsha kunye ne-transformer yokutshintsha ukuyeka ukusebenza ukuze kuqaphele ukukhuselwa kwangoku.
(2) Isiphaluka sokukhusela umbane ophezulu
Umgaqo osebenzayo wesekethe yokukhusela umbane ophezulu ngolu hlobo lulandelayo.
Xa i-voltage yegridi inyuka ngaphaya kwexabiso eliphezulu, i-voltage ephumayo ye-coil yempendulo ye-transformer nayo iya kwanda. I-voltage iya kudlula i-20V, ngeli xesha i-voltage regulator tube i-ZD901 iphukile, kwaye ukuhla kwamandla kwenzeka kwi-resistor R911. Xa i-voltage drop yi-0.6V, i-transistor Q902 ivuliwe, kwaye ke isiseko se-transistor Q901 siba kwinqanaba eliphezulu, ukwenzela ukuba i-transistor Q901 nayo ivuliwe. Ngelo xesha, i-diode D903 nayo ivuliwe, ibangela ukuba i-4th pin yesilawuli se-PWM i-SG6841 chip ibekwe phantsi, ibangele i-short-circuit current yangoku, eyenza ukuba umlawuli we-PWM SG6841 acime ngokukhawuleza ukuphuma kwe-pulse.
Ukongeza, emva kokuba i-transistor Q902 ivuliwe, i-voltage ye-reference ye-15V ye-pin 7 yomlawuli we-PWM SG6841 isekelwe ngokuthe ngqo kwi-resistor R909 kunye ne-transistor Q901. Ngale ndlela, i-voltage ye-terminal yonikezelo lwamandla ye-PWM yesilawuli se-SG6841 chip iba yi-0, isilawuli se-PWM siyayeka ukukhupha amaza e-pulse, kunye ne-tube yokutshintsha kunye nokutshintsha i-transformer ukuyeka ukusebenza ukuphumeza ukhuseleko lwe-voltage ephezulu.
5. Isihluzo sokucoca isiphaluka
Umsebenzi wesiphaluka sokucoca ukulungiswa kukulungisa kunye nokucoca i-voltage yemveliso ye-transformer ukufumana i-voltage ye-DC ezinzileyo. Ngenxa yokuvuza kwe-inductance ye-switching transformer kunye ne-spike ebangelwa kukubuyisela umva ngoku kwi-diode ephumayo, zombini zenza ukuphazamiseka okunokubakho kwe-electromagnetic. Ngoko ke, ukufumana i-5V ecocekileyo kunye ne-12V yombane, i-voltage ephumayo ye-switching transformer kufuneka ilungiswe kwaye ihluzwe.
Umjikelo wokucoca ukucoca ubukhulu becala wenziwe ngeediode, izixhasi zokucoca, ii-capacitors zokucoca, ii-inductors zokucoca, njl.
Kumzobo, i-RC filter circuit (i-resistor R920 kunye ne-capacitor C920, i-resistor R922 kunye ne-capacitor C921) idityaniswe ngokuhambelana ne-diode D910 kunye ne-D912 ekupheleni kwesiphumo sesibini se-switching transformer T901 isetyenziselwa ukufunxa amandla ombane wokunyuka owenziwe kwi-voltage. diode D910 kunye D912.
Isihluzi se-LC siqulunqwe yi-diode D910, i-capacitor C920, i-resistor R920, i-inductor L903, i-capacitors i-C922 kunye ne-C924 inokucoca ukuphazamiseka kwe-electromagnetic ye-voltage ye-12V yemveliso yi-transformer kunye ne-voltage ezinzileyo ye-12V.
Isihluzi se-LC esine-diode D912, i-capacitor C921, i-resistor R921, i-inductor L904, i-capacitors i-C923 kunye ne-C925 inokucoca ukuphazamiseka kwe-electromagnetic ye-5V ye-voltage yemveliso ye-transformer kunye ne-voltage ezinzileyo ye-5V.
6. I-12V / 5V yokulawula isiphaluka solawulo
Ekubeni i-220V AC itshintsha amandla amakhulu phakathi koluhlu oluthile, xa amandla ombane ephakama, i-voltage ephumayo ye-transformer kwisiphaluka samandla nayo iya kunyuka ngokufanelekileyo. Ukuze ufumane i-voltages ye-5V kunye ne-12V ezinzileyo, isiphaluka se-Regulator.
I-12V / 5V ye-voltage regulator circuit ikakhulukazi iqulunqwe ngumlawuli we-voltage echanekileyo (TL431), i-optocoupler, isilawuli se-PWM, kunye ne-voltage divider resistor.
Kumzobo, i-IC902 yi-optocoupler, i-IC903 sisilawuli sombane esichanekileyo, kunye ne-resistors i-R924 kunye ne-R926 zi-resistors ze-voltage divider.
Xa isiphaluka sonikezelo lwamandla sisebenza, i-voltage ye-DC ye-12V ephumayo yahlulwe ngabachasi be-R924 kunye ne-R926, kwaye i-voltage iveliswa kwi-R926, eyongezwa ngokuthe ngqo kwi-TL431 yokulawula umbane ochanekileyo (kwi-terminal R). Iyakwazi ukwaziwa kwiiparamitha zokuchasana kwisekethe Lo mbane wanele nje ukuvula i-TL431. Ngale ndlela, i-voltage ye-5V inokuhamba nge-optocoupler kunye ne-precision voltage regulator. Xa ikhoyo ngoku ihamba nge-optocoupler LED, i-optocoupler IC902 iqala ukusebenza kwaye igqibezela isampuli yombane.
Xa i-voltage ye-220V AC iphakama kwaye i-voltage ephumayo inyuka ngokufanelekileyo, i-current flowing kwi-optocoupler IC902 nayo iya kunyuka ngokufanelekileyo, kunye nokukhanya kwe-diode ekhupha ukukhanya ngaphakathi kwe-optocoupler kuya kwanda ngokufanelekileyo. Ukuchasana kwangaphakathi kwe-phototransistor kwakhona kuba yincinci ngexesha elifanayo, ukwenzela ukuba i-degree conduction ye-terminal phototransistor nayo iya kuqiniswa. Xa i-degree conduction ye-phototransistor iqiniswa, i-voltage ye-pin 2 ye-PWM yomlawuli wamandla we-SG6841 chip iya kuhla ngexesha elifanayo. Ekubeni lo mbane wongezwa kwigalelo lokuguqula i-amplifier yempazamo yangaphakathi ye-SG6841, umjikelo womsebenzi we-pulse ye-SG6841 ulawulwa ukunciphisa umbane wokuphuma. Ngale ndlela, i-overvoltage output feedback loop yenziwa ukufezekisa umsebenzi wokuzinzisa imveliso, kwaye i-voltage ephumayo inokuzinziswa malunga ne-12V kunye ne-5V yemveliso.
icebiso:
I-optocoupler isebenzisa ukukhanya njengendlela yokuhambisa imiqondiso yombane. Inefuthe elihle lokuzihlukanisa kwiimpawu zombane zegalelo kunye nemveliso, ngoko isetyenziswa ngokubanzi kwiisekethe ezahlukeneyo. Okwangoku, iye yaba yenye yezona zinto zihlukeneyo kwaye zisetyenziswa ngokubanzi izixhobo ze-optoelectronic. I-optocoupler ngokubanzi inamacandelo amathathu: ukukhutshwa kokukhanya, ukwamkela ukukhanya, kunye nokwandisa umqondiso. Igalelo lombane lombane liqhuba i-diode ekhupha ukukhanya (i-LED) ukuba ikhuphe ukukhanya kwe-wavelength ethile, efunyenwe yi-photodetector ukuvelisa i-photocurrent, eyongezelelekileyo kunye nemveliso. Oku kugqiba ukuguqulwa kombane-optical-electrical, ngaloo ndlela kudlala indima yegalelo, imveliso, kunye nokwahlula. Ekubeni igalelo kunye nemveliso ye-optocoupler ihlukanisiwe komnye nomnye, kwaye ukuhanjiswa kombane wombane kuneempawu ze-unidirectionality, inamandla okufakelwa kombane kunye nekhono lokuchasana nokuphazamiseka. Kwaye ngenxa yokuba isiphelo segalelo se-optocoupler yinto ephantsi-impedance esebenza kwimodi yangoku, inamandla okulahla imo yesiqhelo. Ke ngoko, inokuphucula kakhulu umlinganiso we-signal-to-noise njengento yokwahlula i-terminal ekuhanjisweni kwexesha elide lolwazi. Njengesixhobo sojongano lokwahlula umqondiso kunxibelelwano lwedijithali lwekhompyuter kunye nolawulo lwexesha lokwenyani, linokunyusa kakhulu ukuthembeka komsebenzi wekhompyuter.
7. isiphaluka sokukhusela i-overvoltage
Umsebenzi wesiphaluka sokukhusela i-overvoltage kukubona i-voltage ye-output ye-output circuit. Xa i-voltage ephumayo ye-transformer iphakama ngokungaqhelekanga, i-pulse output ivaliwe ngumlawuli we-PWM ukufezekisa injongo yokukhusela isiphaluka.
Isekethe yokukhusela i-overvoltage ikakhulu iqulunqwe ngumlawuli we-PWM, i-optocoupler, kunye ne-voltage regulator tube. Njengoko kubonisiwe kulo mzobo ungasentla, ityhubhu yokulawula i-voltage ZD902 okanye i-ZD903 kumzobo wesicwangciso sesekethe isetyenziselwa ukufumanisa i-voltage ephumayo.
Xa i-voltage yesibini yokuphuma kwe-transformer yokutshintsha inyuka ngokungaqhelekanga, i-voltage regulator ityhubhu i-ZD902 okanye i-ZD903 iya kwaphulwa, nto leyo eya kubangela ukuba ukukhanya kwetyhubhu ekhupha ukukhanya ngaphakathi kwe-optocoupler inyuke ngokungaqhelekanga, ibangele iphini yesibini yesilawuli se-PWM. ukudlula kwi-optocoupler. I-phototransistor ngaphakathi kwesixhobo isekelwe, umlawuli we-PWM unqumla ngokukhawuleza ukukhutshwa kwe-pulse ye-pin 8, kunye ne-tube yokutshintsha kunye nokutshintsha i-transformer ukuyeka ukusebenza ngokukhawuleza ukufezekisa injongo yokukhusela isiphaluka.
Ixesha lokuposa: Oct-07-2023