Kev soj ntsuam thiab txo cov suab nrov ntawm cov khoom siv hluav taws xob hauv High-Frequency PCB tsim txheej txheem

Hauv high-frequency PCBs, fais fab mov suab nrov sawv tawm raws li ib qho tseem ceeb ntawm kev cuam tshuam. Tsab ntawv xov xwm no ua rau muaj kev tshuaj xyuas zoo ntawm cov yam ntxwv thiab keeb kwm ntawm lub suab nrov ntawm lub zog hluav taws xob hauv PCBs, thiab muab cov kev daws teeb meem zoo thiab siv tau raws li kev siv engineering.

A.Kev soj ntsuam ntawm Lub Hwj Chim Lub Zog

Lub hwj chim mov suab nrov yog hais txog lub suab nrov tsim los yog cuam tshuam los ntawm lub hwj chim mov nws tus kheej. Qhov kev cuam tshuam no tshwm sim hauv cov hauv qab no:

1. Distributed suab nrov tshwm sim los ntawm covlub hauv paus impedancentawm lub hwj chim mov. Nyob rau hauv high-frequency circuits, lub hwj chim mov suab nrov cuam tshuam rau high-frequency signals. Yog li ntawd, thawj qhov yuav tsum tau muaj yog lub suab qisfais fab mov. Qhov tseem ceeb sib npaug yog cov av huv si thiab cov khoom siv hluav taws xob.

Nyob rau hauv qhov zoo tshaj plaws scenario, lub hwj chim mov yuav yogtsis muaj impedance, ua rau tsis muaj suab nrov. Txawm li cas los xij, hauv kev xyaum, cov khoom siv hluav taws xob muaj qee qhov impedance, uas yog faib thoob plaws tag nrho cov khoom siv hluav taws xob, ua rau lub suab nrov nrov. Yog li ntawd, yuav tsum tau siv zog los txo cov hwj huam mov impedance. Nws yog qhov zoo dua kom muaj kev mob siab rau lub zog dav hlauthiabhauv av dav hlau. Nyob rau hauv high-frequency Circuit Court tsim, nws yog feem ntau zoo dua los tsim lub hwj chim mov nyob rau hauv cov khaubncaws sab nraud povtseg es tsis yog nyob rau hauv ib tug tsheb npav hom, xyuas kom meej tias lub voj tsis tu ncua raws li txoj kev nrog impedance tsawg tshaj plaws. Tsis tas li ntawd, lub hwj chim board muab ateeb liab vojrau tag nrho cov teeb liab tsim thiab tau txais ntawm PCB, yog li txo qis lub teeb liab voj thiab txo cov suab nrov.

2. Common Hom Field Interference: Hom kev cuam tshuam no cuam tshuam rau lub suab nrov ntawm lub zog hluav taws xob thiab hauv av. Nws tshwm sim los ntawm kev cuam tshuam los ntawm ib lub voj uas tsim los ntawm kev cuam tshuam ntawm Circuit Court thiab cov hom voltage uas tshwm sim los ntawm qhov siv dav dav. Qhov loj yog nyob ntawm qhov txheeb ze hluav taws xob thiab sib nqus teb, thiab nws qhov kev siv zog tsawg.

Hauv qhov xwm txheej no, qhov txo qis tam sim no (Ic) ua rau muaj qhov sib txawv-hom voltage hauv kooblub voj voog tam sim no, cuam tshuam rau seem txais. Yog tiasmagnetic tebpredominates, hom hom voltage generated nyob rau hauv series av voj yog muab los ntawm cov mis:

ΔB hauv formula (1) sawv cev rau kev hloov pauv hauv kev sib nqus induction, ntsuas hauv Wb / m²; S qhia thaj chaw hauv m².

Rau ibelectromagnetic teb, thaum hluav taws xob teb Tus nqi yog paub, qhov induced voltage yog muab los ntawm Equation (2), uas yog feem ntau siv tau thaum L = 150 / F los yog tsawg dua, nrog F sawv cev rauelectromagnetic yoj zaushauv MHz. Yog tias qhov kev txwv no dhau lawm, kev suav ntawm qhov siab tshaj plaws induced voltage tuaj yeem ua kom yooj yim raws li hauv qab no:

3. Differential Mode Field Interference: Qhov no yog hais txog kev cuam tshuam ntawm lub hwj chim mov thiab lubinput thiab output fais fab kabs. Hauv kev tsim PCB tiag tiag, tus sau tau pom tias nws qhov kev txhawb nqa rau lub zog hluav taws xob muaj suab nrov tsawg, thiab yog li tuaj yeem tshem tawm ntawm no.
4. Interline cuam tshuam: Hom kev cuam tshuam no cuam tshuam txog kev cuam tshuam ntawm cov kab hluav taws xob. Thaum muaj kev sib nrig sib capacitance (C) thiab kev sib nrig sib inductance (M1-2) ntawm ob lub voj voog sib txawv, qhov cuam tshuam yuav tshwm sim hauv kev cuam tshuam Circuit Court yog tias muaj qhov hluav taws xob (VC) thiab tam sim no (IC) hauv qhov cuam tshuam los ntawm Circuit Court:
   1. Qhov voltage txuas los ntawm lub capacitive impedance yog muab los ntawm Equation (4), qhov twg RV sawv cev rau tus nqi sib npaug ntawmnyob ze-kawg kujthiab covdeb kawg tsis kamntawminterfered circuit.
   2. Series kuj los ntawm inductive coupling: Yog hais tias muaj ntau hom suab nrov nyob rau hauv qhov kev cuam tshuam, qhov cuam tshuam interline feem ntau tshwm nyob rau hauv ob qho tib si hom thiab txawv hom.
5. Fais fab Kab Coupling: Qhov tshwm sim no tshwm sim thaum cov kab hluav taws xob xa tawm cuam tshuam rau lwm yam khoom siv tom qab raugelectromagnetic cuam tshuamlos ntawm AC lossis DC lub zogQhov no sawv cev rau ib daim ntawv indirect ntawm lub hwj chim mov suab nrov cuam tshuam rau high-frequency Circuit Courts. Nws yog ib qho tseem ceeb uas yuav tsum nco ntsoov tias lub suab nrov ntawm lub zog hluav taws xob yuav tsis tas yuav yog tus kheej tsim, tab sis kuj tuaj yeem tshwm sim los ntawm kev cuam tshuam sab nraud, ua rau lub superimposition (radiated los yog ua) ntawm lub suab nrov tsim los ntawm nws tus kheej, yog li cuam tshuam nrog lwm cov circuits lossis cov khoom siv.

• Countermeasures kom tshem tawm Power Supply Noise Interference

Xav txog ntau yam kev tshwm sim thiab ua rau lub zog ntawm lub suab nrov cuam tshuam tau txheeb xyuas saum toj no, cov xwm txheej ua rau lub zog hluav taws xob muaj suab nrov tuaj yeem cuam tshuam tshwj xeeb, ua kom muaj kev cuam tshuam zoo. Cov kev daws teeb meem hauv qab no raug pom zoo:

• Nco ntsoovBoard Los Ntawm Qhovs: Los ntawm qhov tsim nyogetching qhibs pe covfais fab mov txheejkom haum lawv txoj kev. Yog hais tias lub hwj chim txheej qhib loj heev, nws tuaj yeem cuam tshuam rau lub teeb liab voj, yuam kom lub teeb liab hla thiab ua rau lub voj voog thiab lub suab nrov. Yog hais tias qee cov kab teeb liab yog concentrated nyob ze ntawm qhov qhib thiab sib koom lub voj no, cov impedance feem ntau tuaj yeem ua rau crosstalk.
• Kev Tsim Nyog Cov Hlau Hlau rau Cables: Txhua lub teeb liab yuav tsum muaj nws tus kheej lub teeb liab lub voj voog, nrog rau lub teeb liab thiab lub voj voog cheeb tsam khaws cia me me raws li qhov ua tau, ua kom muaj kev sib luag.
• Kev Tso Hluav Taws Xob Hluav Taws Xob Noise Filter: Lub lim dej no ua haujlwm zoo tiv thaiv lub zog sab hauv lub suab nrov, txhim kho qhov system.tiv thaiv kev cuam tshuamthiab kev nyab xeeb. Nws ua haujlwm raws li ob txoj kevRF lim, lim tawm suab nrov cuam tshuam qhia los ntawm cov kab hluav taws xob (tiv thaiv kev cuam tshuam los ntawm lwm yam khoom siv) thiab lub suab nrov tsim los ntawm nws tus kheej (kom tsis txhob cuam tshuam nrog lwm yam khoom siv), nrog rau kev cuam tshuam ntawm hom sib txawv.
• Kev rho tawm fais fabHloov pauv: Qhov no cais cov hom-hom hauv av voj ntawm lubfais fab mov loopor teeb liab cable, zoo sib cais hom-hom voj tam sim no generated ntawm high frequencies.
• Kev Tswjhwm Lub Hwj Chim: Kev rov ua kom lub zog huv huv tuaj yeem txo cov suab nrov ntawm lub zog hluav taws xob.
• Kev xaim hluav taws xob: Cov khoom siv hluav taws xob thiab cov khoom siv hluav taws xob yuav tsum tau khaws cia kom deb ntawm ntug ntawm lub rooj tsav xwm dielectric kom tsis txhob tsim hluav taws xob thiab cuam tshuam nrog lwm cov circuits lossis khoom siv.
• Sib cais Analog thiab Cov Khoom Siv Hluav Taws Xob: Cov khoom siv hluav taws xob ntau yog feem ntau rhiab heev rau cov suab nrov digital, yog li ob leeg yuav tsum tau muab cais tawm thiab txuas ua ke ntawm lub zog nkag. Yog tias lub teeb liab yuav tsum hla ob qho tib si analog thiab digital domains, lub voj tuaj yeem muab tso rau thoob plaws lub teeb liab kom txo tau qhov chaw voj.
• Tsis txhob sib tshooj sib cais ntawm cov khoom siv hluav taws xob sib txawv ntawm cov txheej txheem sib txawv: sim ua kom lawv tsis txhob muaj suab nrov ntawm lub zog hluav taws xob los ntawm kev sib txuas yooj yim los ntawm cov kab mob parasitic capacitance.
• Isolate Sensitive Cheebtsam: Cov khoom siv xws li lub sijhawm kaw lub voj voog (PLLs) yog qhov nkag siab zoo rau lub suab nrov ntawm lub zog hluav taws xob thiab yuav tsum tau khaws cia kom deb li deb tau ntawm lub zog hluav taws xob.
• Kev Tso Hluav Taws Xob: Muab cov kab hluav taws xob tso rau ntawm kab teeb liab, tuaj yeem txo cov teeb liab voj voog thiab ua kom lub suab nrov txo.
• Bypass Path Grounding: Txhawm rau tiv thaiv cov suab nrov los ntawm cov khoom siv hluav taws xob cuam tshuam ntawm Circuit Court board thiab cov khoom siv hluav taws xob sab nraud cuam tshuam, txoj kev bypass tuaj yeem ua rau hauv txoj kev cuam tshuam (tsis suav cov hluav taws xob), tso cai rau lub suab nrov hla mus rau hauv av thiab tsis txhob cuam tshuam nrog lwm yam khoom siv thiab khoom siv.

Hauv kev xaus:Lub hwj chim mov suab nrov, txawm yog generated ncaj qha los yog indirectly los ntawm lub hwj chim mov, cuam tshuam rau lub Circuit Court. Thaum txo nws txoj kev cuam tshuam rau hauv Circuit Court, yuav tsum ua raws li lub hauv paus ntsiab lus: txo qis qhov cuam tshuam ntawm lub zog hluav taws xob suab nrov ntawm lub Circuit Court thaum tseem txo qis kev cuam tshuam ntawm lwm yam los yog Circuit Court ntawm lub zog hluav taws xob tiv thaiv kom tsis txhob degradation ntawm lub hwj chim mov suab nrov.