12V -> 5V ?

[Jirka]

APa napsal(a):
> Zdravim, potrebuji ziskat z 12V z auta -> 5V/2A, jak to jednoduse vyresit?
> Asi by to nemelo moc topit, aby to nevybijelo acu. 

Nejlevneji MC34063 + externi transistor (zapojeni viz datasheet), je 
pravda, ze pro vetsi vykony/proudy se diky burst rezimu moc nehodi, ale 
tohle by snad jeste slo. Jinak monoliticka reseni od National 
Semiconductor nebo Thomson (LMxxxx, Lxxxx apod.), je to pomerne snadno 
dostupne, i kdyz drazsi. 
http://www.national.com/VCatalog/view.cgi/?command=toggleSort&attr1=InputMax+Voltage%2F%2Fdescending&attr2=0&a2=InputMax+Voltage%2F%2Fv%3A8&a3=Efficiency%2F%2Fv%3A8&a4=Switching+Frequency%2F%2Fv%3A8&s0=PNumber%2F%2F1&a1=SubCategory%2F%2Fv%3A8&a0=Category%2F%2Fv%3A8&m1=SubCategory&t=0&m2=Bpn&m0=Category&as=0&render=1&domains=PNumber&q=25&i=PNumber&c1=e%3A0%2F%2FSubCategory%2F%2F%3Aeq%2F%2FSwitchingRegulators&c0=e%3A0%2F%2FCategory%2F%2F%3Aeq%2F%2FAnalog+-+Regulators&tId=104 
a http://www.st.com/stonline/bin/sftab?db=apptree&type=&table=a_210_355

> Druha vec je, jak to ochranit proti napetovym spickam, pokud to vubec lze.

Tlumivka, kondiky (elyty + svitky + keramika paralelne), transil na 
vstupu i vystupu (ten na vystupu pro pripad "odchodu" spinaciho prvku) + 
samozrejme na vstupu pojistka (treba polyswitch).

-- 
Jirka