Yuav ua li cas yog vim li cas rau intermittent oscillation ntawm switching fais fab mov
1. Hom ntau dhau
Hom kev txhaum no muaj ntau dua ntawm plaub qhov txhaum, thiab qhov nyuaj ntawm kev saib xyuas yog ob lub hnub qub. Nws feem ntau yog tshwm sim los ntawm kev puas tsuaj ntawm lub rectifier diode nyob rau sab thib ob ntawm kev hloov pauv hloov pauv, cov dej ntws tawm ntawm lub lim capacitor, lossis kev puas tsuaj ntawm IC ntaus ntawv ntawm cov khoom siv hluav taws xob thiab cov kiv cua txias. Thaum cov ceg thauj khoom raug muab tshem tawm, lossis cov khoom tsis raug ntawm cov khoom siv hluav taws xob nws tus kheej raug tshem tawm, cov khoom siv hluav taws xob yuav tig los ntawm kev sib cuam tshuam oscillation mus rau lub xeev cov zis.
① Yog hais tias nws yog ib tug voltage sampling, xws li ib tug ntxiv 5V load ceg los yog ib tug txhaum tshwm sim los ntawm lub hwj chim mov nws tus kheej (xws li leakage ntawm lub lim capacitor), ntsuas qhov siab tshaj plaws tus nqi ntawm cov zis voltage overshoot ntawm lwm ceg, uas tej zaum yuav me ntsis tshaj qhov ntsuas voltage. Piv txwv li, qhov ntxiv 15V tso zis yuav yog Overshoot rau ntxiv rau 17V;
② Yog hais tias nws yog ib qho txhaum los ntawm lub hwj chim mov los yog lub chaw thau khoom lwm yam tsis yog voltage stabilization sampling, lub siab tshaj plaws tus nqi ntawm cov zis voltage overshoot feem ntau yuav me dua tus nqi ntsuas. Piv txwv li, lub overshoot ntawm ntxiv 15V tso zis yog 8V.
Txawm hais tias nws yog qhov sib cuam tshuam oscillation, cov zis voltage muaj qee qhov amplitude.
2. Hom undervoltage
Feem ntau vim yog lub zog tsis zoo ntawm cov khoom siv hluav taws xob ntawm 3844 tus pin 7, los yog cov khoom xau hauv qhov rov qab nqus tam sim no ntawm lub raj hloov txuas txuas nrog rau lub hauv paus winding ntawm lub hloov pauv hloov, qhov nyuaj ntawm kev saib xyuas yog peb lossis plaub hnub qub.
①Vim tias 7- tus pin fais fab mov ceg ntawm 3844 yog qhov tsis zoo, xws li kev ua haujlwm qis ntawm lub rectifier diode (kev ntsuas rau pem hauv ntej thiab thim rov qab thiab conduction voltage poob, ob qho tib si zoo), thiab lim capacitor tsis ua haujlwm, xws li raws li kev hloov ntawm 100u rau 10u. Yog tias lub zog ua haujlwm xav tau los ntawm cov nti oscillating (lub zog excitation ntawm lub raj hloov) tsis tuaj yeem muab tau ib txwm, tus nees yuav tsis tuaj yeem rub lub tsheb yog tias nws tsis tuaj yeem noj txaus.
Rau qhov tsis ua haujlwm zoo li no, yog tias nws tau lees paub tias qhov txuas hluav taws xob ruaj khov yog qhov qub, tom qab muab DC18V lub zog ntxiv rau pins 7 thiab 5 ntawm 3844, lub zog hluav taws xob yuav hloov pauv ntawm qhov txawv txav mus rau qhov qub. Yog tias tsis muaj teeb meem nrog lub lim capacitor nyob rau lub sijhawm no, tsis txhob yig los hloov lub rectifier diode!
② Lub rov qab tam sim no absorbing Circuit Court ntawm lub switching tube txuas nyob rau hauv parallel nrog thawj winding ntawm lub switching transformer muaj ib tug to, uas zoo heev txo qhov induced voltage ntawm tus kheej-powered winding, thiab tsis txaus los muab lub zog ua hauj lwm yuav tsum tau los ntawm lub oscillating nti thiab lub raj hloov. Tom qab kuaj xyuas tias tsis muaj qhov txawv txav hauv 7-pin fais fab mov ceg ntawm 3844, lub hom phiaj ntawm kev tshuaj xyuas yuav tsum raug xa mus rau lub voj voog no. Qhov feem ntau ntawm qhov tsis ua hauj lwm yog qhov xau ntawm high-speed high-reverse voltage diodes los yog voltage regulators, tab sis qhov nyuaj yog tias nws pom zoo los ntsuas diodes lossis voltage regulators. Kev nqus hluav taws xob tuaj yeem raug txiav ib ntus, lossis cov khoom siv tuaj yeem hloov pauv rau kev sim, thiab qhov teeb meem feem ntau tuaj yeem daws tau sai.
Rau undervoltage faults, lub voltages tso zis los ntawm lub thib ob winding ntawm lub switching transformer yog tag nrho cov tsawg. Yog hais tias nws fluctuates nyob rau hauv ob peb feem kaum ntawm ib tug volt mus rau ob peb volts, nws xav tias lub hwj chim mov tsis muaj hwj chim tawm. Ha ha.
3. Tsis muaj-load hom
Qhov no yog qhov ua tsis tiav profile. Tsuas yog ntsib thaum overhauling switching power supply/driver boards ib tus zuj zus. Qhov nyuaj ntawm kev saib xyuas yog ob peb lub hnub qub, yog li kuv yuav tsis hais nws. Raws li pom nyob rau hauv lub hwj chim mov nyob rau hauv daim duab hauv qab no, ① cov zis sab ntawm lub tswv yim optocoupler yog txuas ncaj qha mus rau 12 tus pin ntawm 3844; ② qhov thib ob winding ntawm kev hloov pauv hloov pauv, tshwj xeeb tshaj yog cov lim capacitor ntawm cov qauv voltage winding, muaj peev xwm loj ntawm 1, 000 microamps. Thaum lub load ceg unloaded, vim qhov tsawg kawg nkaus ruaj khov load tam sim no tsis tuaj yeem tsim, lub zog mov tog poob lub hom phiaj thiab poob. Txawm hais tias kev faib ntau dhau los yog kev faib tsawg dua, thiab kev sib cuam tshuam oscillation yog tsim.
