Ma capacitor amagwira ntchito yofunikira pakupanga kothamanga kwa PCB ndipo nthawi zambiri ndi chipangizo chomwe chimagwiritsidwa ntchito kwambiri pa PCBS.Mu PCB, ma capacitors nthawi zambiri amagawidwa mu fyuluta capacitors, decoupling capacitors, capacitors yosungirako mphamvu, etc.
1.Power linanena bungwe capacitor, fyuluta capacitor
Nthawi zambiri timatchula capacitor ya zolowetsa ndi zotulutsa za module ya mphamvu monga fyuluta capacitor.Kumvetsetsa kosavuta ndikuti capacitor imatsimikizira kukhazikika kwa zolowetsa ndi zotulutsa mphamvu.Mu gawo lamagetsi, capacitor ya fyuluta iyenera kukhala yayikulu isanakwane.Monga momwe chithunzichi chikusonyezera, fyuluta capacitor imayikidwa yaikulu ndiyeno yaying'ono kumbali ya mivi.
Popanga magetsi, ziyenera kuzindikiridwa kuti mawilo ndi khungu lamkuwa ndi lalikulu mokwanira ndipo chiwerengero cha mabowo ndi chokwanira kuonetsetsa kuti mphamvu yothamanga ikukwaniritsa zofunikira.M'lifupi ndi chiwerengero cha mabowo amawunikidwa mogwirizana ndi panopa.
Mphamvu yolowetsa mphamvu
Mphamvu yolowetsa capacitor imapanga loop yapano ndi lopu yosinthira.Lupu lamakonoli limasiyanasiyana ndi matalikidwe akulu, matalikidwe a Iout.Ma frequency ndi ma frequency osinthira.Pakusintha kwa chipangizo cha DCDC, zomwe zimapangidwa ndi loop pano zikusintha, kuphatikiza di/dt mwachangu.
Munjira yofananira ya BUCK, njira yopitilira pano iyenera kudutsa pa pin ya GND ya chip, ndipo cholowera cholowera chiyenera kulumikizidwa pakati pa GND ndi Vin ya chip, kotero njirayo ikhoza kukhala yaifupi komanso yakuda.
Dera la mphete yamakonoyi ndi yaying'ono mokwanira, ndi bwino kuti ma radiation akunja a mphete yamakonoyi azikhala bwino.
2. Decoupling capacitor
Pini yamphamvu ya IC yothamanga kwambiri imafunikira ma capacitor okwanira, makamaka imodzi pini.M'mapangidwe enieni, ngati palibe malo a decoupling capacitor, akhoza kuchotsedwa ngati kuli koyenera.
The decoupling capacitance wa IC mphamvu pini nthawi zambiri yaing'ono, monga 0.1μF, 0.01μF, etc. Phukusi lolingana ndi laling'ono, monga 0402 phukusi, 0603 phukusi ndi zina zotero.Poyika ma capacitors odulira, mfundo zotsatirazi ziyenera kudziwika.
(1)Ikani pafupi ndi pini yamagetsi, apo ayi sizingakhale ndi zotsatira zochepetsera.Mwachidziwitso, capacitor ili ndi ma radius ena odulira, kotero mfundo yakuyandikira iyenera kukhazikitsidwa mosamalitsa.
(2) The decoupling capacitor ku nsonga ya pini yamagetsi iyenera kukhala yaifupi momwe ingathere, ndipo chowongoleracho chizikhala chokhuthala, nthawi zambiri m'lifupi mwake ndi 8 ~ 15mil (1mil = 0.0254mm).Cholinga cha thickening ndi kuchepetsa kutsogolera inductance ndi kuonetsetsa ntchito magetsi.
(3) Pambuyo popereka mphamvu ndi zikhomo za pansi za capacitor decoupling amatsogozedwa kuchokera pazitsulo zowotcherera, nkhonya mabowo pafupi ndikugwirizanitsa ndi magetsi ndi ndege yapansi.Mthovu uyeneranso kukhuthala, ndipo dzenjelo likhale lalikulu momwe ndingathere.Ngati bowo lokhala ndi pobowo la 10mil lingagwiritsidwe ntchito, dzenje la 8mil sayenera kugwiritsidwa ntchito.
(4)Onetsetsani kuti cholumikizira ndi chaching'ono momwe mungathere
3.Capacitor yosungirako mphamvu
Udindo wa capacitor yosungirako mphamvu ndikuonetsetsa kuti IC ikhoza kupereka mphamvu mu nthawi yochepa kwambiri pogwiritsa ntchito magetsi.Mphamvu ya capacitor yosungirako mphamvu nthawi zambiri imakhala yayikulu, ndipo phukusi lofananira limakhalanso lalikulu.Mu PCB, capacitor yosungirako mphamvu ikhoza kukhala kutali ndi chipangizocho, koma osati patali kwambiri, monga momwe chithunzichi chikusonyezera.Njira wamba yosungiramo mphamvu ya capacitor fan-hole ikuwonetsedwa pachithunzi.
Mfundo za mabowo a fan ndi zingwe ndi izi:
(1) Mtsogolere ndi waufupi komanso wandiweyani momwe ndingathere, kotero kuti pamakhala kachidutswa kakang'ono ka parasitic.
(2) Kwa ma capacitor osungira mphamvu, kapena zida zokhala ndi ma overcurrent akulu, gundani mabowo ambiri momwe mungathere.
(3) Zachidziwikire, magwiridwe antchito abwino kwambiri amagetsi pabowo la fan ndi dzenje la disc.Zowona zimafunikira kuganiziridwa mozama