Ua rau thiab tiv thaiv MOSFET Failure

Ob lub ntsiab ua rauof MOSFET ua tsis tiav:

Voltage tsis ua hauj lwm: uas yog, lub BVdss voltage ntawm qhov ntws thiab qhov chaw tshaj qhov ntsuas voltage ntawm lubMOSFET thiab ncav cuag ib lub peev xwm, ua rau MOSFET ua tsis tiav.

Gate Voltage Failure: Lub rooj vag muaj qhov txawv txav tsis zoo, ua rau lub rooj vag oxygen txheej tsis ua haujlwm.

Collapse txhaum (voltage tsis ua hauj lwm)

Dab tsi yog qhov kev puas tsuaj avalanche? Cias muab,ib MOSFET yog hom tsis ua haujlwm tsim los ntawm superposition ntawm cov tsheb npav voltages, transformer reflection voltages, to spike voltages, etc. thiab MOSFET. Nyob rau hauv luv luv, nws yog ib qho kev tsis ua hauj lwm uas tshwm sim thaum qhov hluav taws xob ntawm qhov ntws-qhov ncej ntawm MOSFET tshaj nws cov nqi hluav taws xob uas tau teev tseg thiab ncav cuag qee lub zog txwv.

Kev ntsuas los tiv thaiv kev puas tsuaj avalanche:

- Txo cov tshuaj kom tsim nyog. Hauv kev lag luam no, nws feem ntau yog txo los ntawm 80-95%. Xaiv raws li lub tuam txhab cov lus cog lus thiab kab ua ntej.

- Reflective voltage yog tsim nyog.

-RCD, TVS nqus Circuit Court tsim yog tsim nyog.

-High tam sim no thaiv yuav tsum loj npaum li sai tau kom txo tau tus kab mob parasitic inductance.

-Xaiv lub rooj vag tsim nyog resistor Rg.

-Ntxiv RC damping lossis Zener diode nqus rau cov khoom siv hluav taws xob siab raws li xav tau.

Ua rau thiab tiv thaiv MOSFET Failure (1)

Rooj vag Voltage Failure

Muaj peb lub ntsiab ua rau muaj qhov txawv txav ntawm cov kab hluav taws xob siab: hluav taws xob zoo li qub thaum tsim khoom, kev thauj mus los thiab kev sib dhos; high voltage resonance generated los ntawm parasitic parameters ntawm cov khoom thiab circuits thaum lub hwj chim system ua hauj lwm; thiab xa cov hluav taws xob siab dhau los ntawm Ggd mus rau kab sib chaws thaum lub sij hawm muaj hluav taws xob poob siab (ib qho txhaum uas muaj ntau dua thaum lub sij hawm ntsuas hluav taws xob).

Kev ntsuas los tiv thaiv lub rooj vag voltage faults:

Kev tiv thaiv overvoltage ntawm lub rooj vag thiab qhov chaw: Thaum lub impedance ntawm lub rooj vag thiab qhov chaw siab dhau lawm, qhov kev hloov tam sim ntawd ntawm qhov hluav taws xob ntawm lub rooj vag thiab qhov chaw yog txuas mus rau lub rooj vag los ntawm qhov muaj peev xwm ntawm cov electrodes, uas ua rau muaj qhov siab UGS voltage dhau kev cai, ua rau over-regulation ntawm lub rooj vag. Kev puas tsuaj oxidative tas mus li. Yog tias UGS nyob ntawm qhov zoo ntawm qhov hluav taws xob hloov pauv, lub cuab yeej kuj yuav ua rau yuam kev. Rau lub hauv paus no, lub impedance ntawm lub rooj vag tsav Circuit Court yuav tsum tau txo kom tsim nyog thiab ib tug damping resistor los yog 20V stabilizing voltage yuav tsum tau kev cob cog rua ntawm lub rooj vag thiab qhov chaw. Kev saib xyuas tshwj xeeb yuav tsum tau ua kom tsis txhob qhib qhov rooj.

Kev tiv thaiv overvoltage ntawm cov raj xa tawm: Yog tias muaj qhov inductor hauv Circuit Court, kev hloov pauv tam sim no hauv cov hluav taws xob xau (di / dt) thaum lub tsev raug kaw yuav ua rau cov hluav taws xob hluav taws xob overshoots zoo tshaj qhov khoom siv hluav taws xob, ua rau lub tsev puas tsuaj. Kev tiv thaiv yuav tsum suav nrog Zener clamp, RC clamp, lossis RC kev tiv thaiv Circuit Court.