LED teeb pom kev zoo yog dav siv vim nws cov hauj lwm zoo, durability, thiab ntev lifespan. Ib qho nyuaj tshaj plaws ntawm kev siv LEDs yog tswj lawv qhov ci. Ntawm no, PWM dimming yog cuam tshuam. Kev tswj ntawm LEDs PWM dimming yog ib txoj hauv kev los tswj cov teeb ci LED los ntawm kev hloov cov mem tes dav ntawm cov hluav taws xob tam sim no. PWM dimming tau dhau los ua ntau thiab zoo-nyiam los ua ib txoj hauv kev zoo thiab muaj txiaj ntsig ntawm kev tswj cov teeb ci LED.
PWM dimming yog dab tsi?
PWM lub peev xwm los tswj ntau yam khoom siv hauv txhua qhov khoom siv hluav taws xob yog lub luag haujlwm loj rau nws txoj kev siv dav hauv kev lag luam hluav taws xob niaj hnub no. PWM cov teeb liab yog siv los dim LEDs, tswj lub cev muaj zog, thiab khiav cov khoom siv hluav taws xob sib txawv. Yog li ntawd, PWM txoj kev ua haujlwm yog dab tsi?
PWM yog ib txoj hauv kev los txo qhov nruab nrab lub zog xa tawm ntawm lub teeb liab hluav taws xob. Tsis tas li ntawd, cov txheej txheem ua tiav los ntawm kev sib cais cov teeb liab ua tiav rau hauv nws cov khoom siv. Nyob rau hauv cov nqe lus ntawm functionality, qhov kev hloov ntawm lub load thiab lub hauv paus tej zaum yuav sai sai tig rau thiab tawm los tswj qhov nruab nrab tam sim no thiab voltage nkag mus rau lub load.
Los ntawm qhov sib txawv ntawm lub sijhawm lub teeb liab siab (ON) lossis qis (OFF), PWM tso cai rau ntau qhov ci ntsa iab (OFF). Nyob rau hauv sib piv rau analog dimming, uas dims LEDs los ntawm altering output zog, lub PWM teeb liab tej zaum yuav ON los yog OFF nyob rau hauv ib lub sij hawm, lub ntsiab lus hais tias cov LEDs yuav tau tag nrho cov voltage los yog tsis muaj hluav taws xob (ie, muab 10V es tsis txhob ntawm 12V rau Hloov brightness).
Dab tsi yog Kev Txo Tam Sim No (CCR)?
cov tsis tu ncua tam sim no txo Cov txheej txheem muab cov dej ntws tsis tu ncua mus rau LED (CCR). Nyob rau hauv sib piv rau txoj kev PWM, nyob rau hauv uas lub xeev LED fluctuates ntawm on thiab off, lub LED yog tas li nyob rau. Txawm li cas los xij, koj tuaj yeem tswj cov LED qhov ci los ntawm kev kho lossis hloov cov qib tam sim no siv CCR.
Qhov zoo ntawm CCR Dimming Method:
- Zoo tagnrho rau tej thaj chaw deb daim ntaub ntawv uas yuav tsum tau ntev hlau ntev thiab nruj EMI specifications.
- Cov neeg tsav tsheb CCR muaj kev txwv ntau dua qhov tso zis hluav taws xob (60 V) dua li PWM tsav tsheb (24.8 V). Cov kev qhia tshwj xeeb no siv rau Chav Kawm 2 tsav tsheb uas tau ntawv pov thawj UL rau siv nyob rau hauv ob qho tib si ntub thiab qhuav.
Qhov tsis zoo ntawm CCR Dimming Method:
- LEDs 'kev tsim lub teeb tsis sib haum ntawm qhov tsis tshua muaj tam sim no ua rau CCR txoj kev tsis tsim nyog rau cov ntawv thov kom dimming qis dua 10% ntawm qhov siab tshaj plaws. Hauv kev xaus, qhov kev ua tau zoo ntawm LED tsim los ntawm cov qauv no ntawm cov qib tam sim no yog subpar.
- Tsawg tsav tam sim no ua rau muaj xim tsis sib xws.
PWM as A Dimming Signal
Cia peb nthuav peb txoj kev nkag siab tam sim no ntawm pulse width modulation. Tam sim no, PWM yuav tsum tau lees paub tias yog lub teeb liab.
Pulse width modulation signals muaj ib ntus ntawm square-wave-shaped pulses (PWM). Muaj cov ncov thiab hav hauv lub waveform ntawm txhua lub teeb liab. Lub sijhawm ua haujlwm yog thaum lub teeb liab lub zog siab, thaum lub sijhawm tawm yog thaum lub teeb liab lub zog qis.
Ua haujlwm ua haujlwm
Lub voj voog ua haujlwm yog thaum lub teeb liab tuaj yeem nyob siab hauv lub tswv yim dimming. Li no, lub teeb liab muaj 100% lub luag haujlwm lub voj voog yog tias nws ib txwm nyob. PWM teeb liab raws sijhawm tuaj yeem hloov kho. Thaum PWM lub voj voog ua haujlwm tau teem rau 50%, lub teeb liab khiav 50% ntawm lub sijhawm thiab 50% tawm.
Zaus
Pulse width modulation (PWM) signal zaus yog lwm qhov tseem ceeb. PWM zaus txiav txim siab sai npaum li cas rau lub sijhawm - lub sijhawm nws siv rau lub teeb liab qhib thiab tawm - ua tiav los ntawm PWM teeb liab.
PWM as LED Driver Output
Thaum lub teeb liab PWM hloov mus rau DC voltage thiab siv los ua ib qho LED tsav tsheb tso zis, mem tes dav modulation tshwm sim. Lub PWM tso zis Circuit Court txiav DC LED tam sim no ntawm lub xeev rau thiab tawm ntawm lub siab zaus. Yog li ntawd, qhov flicker uas ua rau muaj kev hloov pauv hauv cov teeb pom kev zoo ntawm LED yog qhov tsis pom ntawm tib neeg lub qhov muag.
Tib neeg feem ntau tsis meej pem ob peb yam hais txog qhov sib txawv ntawm PWM tso zis thiab dimming teeb liab. Yog li cia peb sau ob peb yam.
Lub tshuab tsim lub teeb liab PWM ua lub teeb liab digital, uas ua rau nws zoo ib yam ntawm dimmable cable. Hauv qhov sib piv, tus neeg tsav tsheb txiav txim siab cov zis tam sim no los ntawm kev kuaj xyuas PWM lub luag haujlwm voj voog.
PWM Dimming Drivers in the Market
PWM dimming tsav tsheb tau dhau los ua qhov tseem ceeb rau LED teeb pom kev zoo. Txawm li cas los xij, nws yuav tsum paub tias PWM dimming tsav tsheb yuav raug pom nyob rau hauv ob txoj kev sib txawv, thiab cia saib seb lawv yog dab tsi.
Fake PWM Dimming
Lub hom phiaj ntawm txoj kev fake dimming yog hloov PWM inputs rau hauv lub teeb liab tswj analog. Lub lim dej resistor-capacitor (RC) nyob hauv tus tsav tsheb.
RC lim hloov PWM teeb liab mus rau qhov sib npaug DC voltage raws li lub voj voog ua haujlwm. Fake PWM dimming muaj qhov zoo ntawm qhov tsis muaj suab nrov, thiab tsis muaj suab nrov ntawm cov zis vim tias cov LED tam sim no txuas ntxiv.
Txawm li cas los xij, txoj kev no yog teeb meem vim qhov tseeb tsis zoo yog tias PWM tus nqi siab tshaj yog qis dua 10V. Ntxiv mus, tus nqi resistor-capacitor (RC) txwv qhov zaus ntawm PWM teeb liab.
Real PWM Dimming
Nyob rau hauv tiag tiag PWM dimming, LED tam sim no hloov mus rau thiab tawm ntawm lub zaus thiab lub luag hauj lwm voj voog teev. Lub xub ntiag ntawm MCU lossis microcontroller hauv tus neeg tsav tsheb ua rau PWM teeb liab txhawm rau txheeb xyuas qhov siab tshaj. Tiag tiag PWM dimming txhawb qhov dav dav ntawm PWM zaus.
Ib qho tseem ceeb ntawm PWM dimming yog nws lub peev xwm los tuav lub ntsiab lus dawb ntawm LED tso zis. Tsis tas li ntawd, qhov kev siv hluav taws xob siab siab tshaj qhov kev ua yuam kev offset raug tso cai.
Tus tsav tsheb txhim kho software xav kom cov neeg siv xaiv PWM dimming hom.
Altering the Duty Cycle (brightness) With PWM
Thaum cov khoom siv tau hloov ON thiab OFF yog li siv cov khoom siv mem tes dav dav, cov LEDs tsis flicker. Duty Cycle yog lo lus siv los piav qhia qhov ntsuas ntawm PWM ci ntsa iab.
Lub voj voog ua haujlwm yog qhov feem ntawm lub voj voog lub sijhawm ua haujlwm uas nws yog ON. Lub voj voog lub luag haujlwm yog qhia raws li feem pua, nrog 100 feem pua sawv cev rau qhov ua tau zoo tshaj plaws (tag nrho ON) thiab qis feem pua ua rau cov teeb pom kev tsis zoo ntawm LED.
Lub teeb liab PWM muaj 50% lub voj voog ua haujlwm yog tias nws nyob ntawm 50% ntawm lub sijhawm thiab tawm 50% ntawm lub sijhawm. Lub teeb liab tshwm sim raws li lub voj voog square, thiab qhov ci ntawm lub teeb yuav tsum yog qhov nruab nrab. Thaum qhov feem pua tau ntau dua 50%, lub teeb liab siv sijhawm ntau dua hauv lub xeev ON dua li hauv lub xeev OFF, thiab rov ua dua thaum lub voj voog ua haujlwm tsawg dua 50%.
Pulse Width Modulation (PWM) vs. Analog Dimming of LEDs
Nrog rau kev loj hlob ntawm cov teeb pom kev zoo ntawm LED nyob rau hauv kev ua lag luam, tau muaj kev nce siab hauv kev thov kom muaj txiaj ntsig zoo thiab raug tswj hwm cov tsav tsheb LED. Txhawm rau khaws lub zog txuag lub tswv yim thiab kev siv qhov kawg ntawm kev siv LED tsim, "ntse" txoj kev teeb, teeb nyem, thiab cov cim digital, ntawm lwm yam kev siv, yuav tsum tau tswj xyuas tam sim no thiab, ntau zaus, dimming functionality.
PWM Dimming
Nrog pulse width modulation (PWM) dimming, LED tam sim no yog ib ntus rau thiab tawm. Txhawm rau tiv thaiv qhov tshwm sim flickering, qhov zaus ntawm / tawm yuav tsum nrawm dua li qhov tib neeg lub qhov muag pom tau (feem ntau tshaj 100Hz). PWM dimming tuaj yeem siv los ntawm ntau txoj hauv kev:
- Siv lub teeb liab PWM hloov hluav taws xob ncaj qha.
- Los ntawm txoj kev ntawm qhib collector transistor
- Los ntawm microcontroller.
Qhov nruab nrab tam sim no ntawm LED yog sib npaug rau cov lej ntawm nws tag nrho cov nominal tam sim no thiab nws lub voj voog dimming. Tus tsim qauv kuj tseem yuav tsum tau coj mus rau hauv tus account qhov kev ncua sij hawm ntawm lub converter tso zis kaw thiab pib, uas ua rau muaj kev txwv rau PWM dimming zaus thiab lub luag haujlwm lub voj voog ntau.
Analog Dimming
Kho qhov LED tam sim no theem yog hu ua analog dimming. Siv ib qho DC sab nraud tswj qhov hluav taws xob lossis tiv thaiv dimming tuaj yeem ua tiav qhov no. Txawm hais tias qhov tseeb tias analog dimming tam sim no tso cai rau kev hloov kho, xim kub tuaj yeem hloov pauv. Analog dimming tsis pom zoo rau cov ntawv thov uas qhov xim ntawm LED yog qhov tseem ceeb.
Cia peb saib ntawm qhov sib txawv ntawm PWM & analog dimming
| PWM Dimming | Analog Dimming |
| Brightness yog hloov kho los ntawm kev hloov kho qhov siab tshaj plaws tam sim no hauv tus neeg tsav tsheb | Brightness kho los ntawm kev hloov DC mus rau LED |
| Tsis Muaj Xim Hloov | Muaj peev xwm hloov xim raws li LED tam sim no hloov |
| Muaj peev xwm tam sim no inrush teeb meem | Tsis muaj inrush tam sim no rau ntaus ntawv |
| Cov kev txwv ntau zaus & kev txhawj xeeb ntau zaus | Tsis muaj kev txhawj xeeb ntau zaus |
| Heev linear hloov nyob rau hauv brightness | Brightness linearity tsis zoo li |
| Lower Optical rau hluav taws xob efficiency | Kev kho qhov muag siab dua rau kev siv hluav taws xob (> lumens ib watt noj) |
Hardware Considerations for PWM
PWM dimming yuav tsum tau xav txog qee yam thaum tsim lub kaw lus (lossis PC board).
Tus neeg tsav tsheb feem ntau tsim nyog nrog backlight-hom LEDs vim yog qib tam sim no. Cov zis digital, zoo li ib qho los ntawm microcontroller, tsis tuaj yeem siv los tsav nws ncaj qha.
Ib qho yooj yim logic theem FET (Field-Effect Transistor) hom transistor feem ntau yog siv los ua tus tsav tsheb hauv ntau daim ntawv thov. Lub resistor ntawm lub rooj vag yuav tsum tau siv los hloov FET los tswj lub rooj vag tam sim no, thiab ib qho kev tiv thaiv yog tsim nyog yog tias qhov kev txwv tam sim no xav tau. Xyuas kom tseeb tias koj saib qhov zoo backlight tsav voltages thiab tam sim no ntawm LCD datasheet.
Ib tug hloov-hom LED tsav tsheb yuav tsav lub LED backlight ntawm lub siab dua tam sim no thiab ntau npaum. Cov tsav tsheb no nyuaj dua, thiab tus kws tshaj lij IC feem ntau ua haujlwm rau kev hloov pauv. PWM cov tswv yim ntawm ob peb ICs yog tsim los qhia meej rau kev siv dimming.
Yog tias siv microcontroller, yuav tsum tau saib xyuas kom txuas mus rau tus pin tso zis uas txhawb nqa PWM (timer / counter) tso zis yog PWM siv los ua haujlwm kho vajtse.
PWM – Firmware/Software Considerations
PWM dimming xav tau tshwj xeeb tsim kev txiav txim siab (lossis PC board).
Vim hais tias mus rau lub siab tam sim no, backlight-hom LEDs feem ntau xav tau tus tsav tsheb. Cov txiaj ntsig digital, xws li cov los ntawm microcontrollers, tsis tuaj yeem siv los tsav nws ncaj qha.
Feem ntau, qhov yooj yim logic theem FET (Field-Effect Transistor) hom transistor yog siv los ua tus tsav tsheb hauv ntau yam kev siv. Hloov lub FET los tswj lub rooj vag tam sim no yuav tsum muaj tus resistor ntawm lub rooj vag, thiab yuav tsum muaj qhov resistor yog tias xav tau kev txwv tam sim no. Txheeb xyuas cov ntaub ntawv LCD rau qhov tseeb backlight tsav voltages thiab tam sim no.
Ib tug hloov-hom LED tsav tsheb yuav tsav lub LED backlight zoo dua thiab nyob rau hauv ntau dua tam sim no. Cov tsav tsheb no yog qhov nyuaj dua, thiab kev hloov pauv tau nquag ua haujlwm los ntawm IC tshwj xeeb. Ob peb ICs 'PWM inputs yog tsim tshwj xeeb rau kev siv dimming.
Yog tias PWM siv los ua cov khoom siv kho vajtse, yuav tsum tau ua tib zoo txuas rau tus pin tso zis uas txhawb nqa PWM (timer / counter) tso tawm ntawm lub microcontroller.
PWM Function & Applications
Thaum lub sij hawm qhib thiab tawm ntawm qhov hloov pauv hloov mus rau ib leeg, tus nqi hluav taws xob xa mus rau qhov hnyav nce. Raws li xav tau, hom kev tswj no muaj ntau yam zoo.
PWM ua ke nrog qhov siab tshaj plaws lub zog taw tes taug qab, lossis MPPT, yog ib qho tseem ceeb ntawm kev txo cov hnub ci vaj huam sib luag tso tawm kom yooj yim rau lub roj teeb siv nws.
PWM, ntawm qhov tod tes, yog qhov zoo tagnrho rau cov khoom siv hluav taws xob inertial, xws li lub cev muaj zog, vim tias qhov kev hloov pauv tshwj xeeb no tsis tshua muaj txiaj ntsig rau lawv. Vim qhov kev sib txuas ntawm cov LEDs ua haujlwm thiab cov khoom siv hluav taws xob, qhov no kuj siv tau rau LEDs.
Tsis tas li ntawd, PWM hloov zaus yuav tsum tsis muaj kev cuam tshuam rau lub load, thiab cov txiaj ntsig waveform yuav tsum du txaus rau lub load kom paub.
Nyob ntawm cov cuab yeej thiab nws txoj haujlwm, qhov hloov pauv ntawm cov khoom siv hluav taws xob feem ntau yuav txawv txav. Cov khoom siv hluav taws xob, khoom siv hluav taws xob hauv computer, thiab lub suab amplifiers txhua tus xav tau kev hloov ceev hauv kaum lossis ntau pua kilohertz ntau.
Lwm qhov txiaj ntsig tseem ceeb ntawm kev siv PWM yog qhov tsis tshua muaj hluav taws xob poob hauv kev hloov khoom siv. Thaum lub tshuab hluav taws xob raug kaw, tsis muaj qhov tam sim no ntws los ntawm nws. Tsis tas li ntawd, thaum lub tshuab hluav taws xob qhib thiab xa hluav taws xob mus rau nws qhov load, muaj qhov tsis txaus ntseeg qhov hluav taws xob poob thoob plaws nws.
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FAQ
Ntsiab lus
PWM dimming yog ib txoj hauv kev yooj yim thiab pheej yig ntawm kev kho qhov ci ntawm LED teeb. PWM dimming muaj ntau yam zoo dua analog dimming, nrog rau kev lag luam muaj zog dua, kev tswj kom meej dua, thiab lub neej ntev dua. Nws ua, txawm li cas los xij, nthuav tawm ntau yam teeb meem, xws li EMI ua tau thiab xav tau kev hloov pauv ntau zaus. Txawm li cas los xij, PWM dimming yog cov txheej txheem tseem ceeb rau kev tswj cov teeb ci LED, thiab nws lub neej yav tom ntej zoo li pheej hmoo.
LEDYi tsim cov khoom zoo LED strips thiab LED neon flex. Tag nrho peb cov khoom dhau los ntawm cov chaw soj nstuam high-tech los xyuas kom meej qhov zoo tshaj plaws. Dhau li ntawd, peb muab cov kev xaiv customizable ntawm peb LED strips thiab neon flex. Yog li, rau hwm LED sawb thiab LED neon flex, hu rau LEDYi ASAP!
