LED PWM inodzima
PWM dimming ndiyo yakajairika dimming tekinoroji inoshandiswa muLED dimming magetsi zvigadzirwa. Mudunhu reiyo analogi chiratidzo, kupenya kwekutonga luminaire kunoburitswa nedigital. Iyi dimming nzira ine akawanda mabhenefiti kana ichienzaniswa neyechinyakare analog chiratidzo dimming. Zvechokwadi, pane zvimwe zvinokanganisa mune zvimwe zvinhu. Ndezvipi zvakanakira uye zvakaipira?
Ngatitangei kutarisa musimboti wekutanga we pwm dimming. Muchokwadi, mukushandiswa kunoshanda kwechigadzirwa, zvinogona kunzwisiswa kuti MOS switch chubhu yakabatana mumutoro we LED. Iyo anode yetambo inofambiswa neinogara iripo ikozvino sosi. Chiratidzo chePWM chinobva chaiswa kugedhi reMOS transistor kukurumidza kushandura tambo ye LED kuti iderere.
Zvakanakira zve pwm dimming:
Kutanga, pwm dimming ndiyo chaiyo dimming.
Dimming kunyatsoita chinhu chinoshamisa chedhijitari siginecha dimming yakajairika, nekuti pwm dimming inoshandisa pulse waveform masiginecha ane yakanyanya kurongeka.
Chechipiri, pwm dimming, hapana musiyano wemavara.
Mukati mese dimming range, sezvo LED yemazuva ano iri pamutengo wepamusoro kana kuti yakadzimwa, chiyero chemazuva ano che LED chinoshandurwa nekugadzirisa chiyero chepulse duty, saka chirongwa chinogona kudzivisa kusiyana kwemavara panguva yekuchinja ikozvino.
Chechitatu, pwm dimming, inogadziriswa renji.
Iyo PWM dimming frequency inowanzo 200 Hz (yakaderera frequency dimming) kusvika 20 kHz kana kupfuura (yakakwira frequency dimming).
Chechina, pwm dimming, hapana strobe.
Chero bedzi iyo PWM dimming frequency yakakwira kupfuura 100 Hz, hapana kupenya kwe LED kunoonekwa. Iyo haishandure mamiriro ekushanda eiyo inogara iripo sosi (boost ratio kana nhanho-pasi reshiyo), uye hazvibviri kupisa. Nekudaro, PWM pulse wide dimming inewo matambudziko ekuziva. Yekutanga isarudzo ye pulse frequency: nekuti iyo LED iri mukukurumidza kushandura mamiriro, kana iyo yekushanda frequency yakaderera kwazvo, ziso remunhu rinonzwa kupenya. Kuti ushandise zvizere zvinoonekwa zvakasara zveziso remunhu, mafambiro ayo ekushanda anofanira kunge ari pamusoro pe100 Hz, zvichida 200 Hz.
Ndezvipi zvakaipira pwm dimming?
Mutsindo unokonzerwa nekudzima ndeimwe. Kunyange zvazvo isingaonekwe neziso remunhu pamusoro pe200 Hz, irworwo rwekunzwa kwevanhu kusvika pa20 kHz. Panguva ino, zvinokwanisika kunzwa kurira kwesilika. Pane nzira mbiri dzekugadzirisa dambudziko iri. Imwe ndeyekuwedzera switching frequency kusvika pamusoro pe20 kHz uye kusvetuka kubva kunzeve yemunhu. Nekudaro, yakawandisa frequency inogona kukonzera mamwe matambudziko, nekuti pesvedzero yeakasiyana parasitic paramita inokonzeresa pulse waveform (kumberi nekumashure kumucheto) kukanganisa. Izvi zvinoderedza kurongeka kwe dimming. Imwe nzira ndeyekutsvaga mudziyo wekurira uye woibata. Muchokwadi, iyo huru yekuridza dhizaini ndeye ceramic capacitor pakubuda, nekuti ceramic capacitors inowanzo gadzirwa neakakwirira dielectric anogara ari ceramics, ane piezoelectric zvimiro. Mechanical vibration inoitika pasi pekuita kwe200 Hz pulse. Mhinduro ndeyokushandisa tantalum capacitor panzvimbo. Zvisinei, high-voltage tantalum capacitors yakaoma kuwana, uye mutengo unodhura zvikuru, izvo zvichawedzera mamwe mari.
Kupfupisa, zvakanakira pwm dimming ndezvi: nyore kushandisa, kushanda kwepamusoro, kunyatsojeka, uye yakanaka dimming maitiro. Izvo zvakashata ndezvekuti sezvo mutyairi we LED akavakirwa pamusimboti wekuchinja magetsi, kana iyo PWM dimming frequency iri pakati pe200 ne20 kHz, iyo inductance uye inobuda capacitance yakatenderedza iyo LED dimming magetsi inowanzoitika kune ruzha runonzwika nzeve yomunhu. Uye zvakare, kana uchiita PWM dimming, iyo iri padhuze iyo frequency yechiratidzo chekugadzirisa ndeye frequency ye LED driver chip kune gedhi rekudzora chiratidzo, zvakanyanya kuipa mutsara mhedzisiro.