ãã®èšäºã§ã¯ãæå§ã³ã³ããŒã¿ãã«ã€ããŠ
- æå§ã³ã³ããŒã¿ãšã¯
- æå§ã³ã³ããŒã¿ã®åçã»èšç®åŒã»ã·ãã¥ã¬ãŒã·ã§ã³
- ãæå§ã³ã³ããŒã¿ããšãéå§ã³ã³ããŒã¿ãã®éã
ãªã©ãå³ãçšããŠåããããã説æããããã«å¿æããŠããŸãããåèã«ãªãã°å¹žãã§ãã
æå§ã³ã³ããŒã¿(æå§ãã§ãã)ãšã¯
æå§ã³ã³ããŒã¿ã¯åºåé»å§\(V_{OUT}\)ãå ¥åé»å§\(V_{IN}\)ãããé«ããªãåè·¯ã§ãããã³ã€ã«(ã€ã³ãã¯ã¿)\(L\)ãMOSFET\(Q\)ããã€ãªãŒã\(D\)ãåºåã³ã³ãã³ãµ\(C_{OUT}\)ã§æ§æãããŠããŸãã
åŸã»ã©åäœåçã«ã€ããŠèª¬æããŸãããMOSFET\(Q\)ã®ONæã«ã³ã€ã«\(L\)ã«ãšãã«ã®ãŒãèããMOSFET\(Q\)ã®OFFæã«ã³ã€ã«\(L\)ã«èãããããšãã«ã®ãŒãæŸåºããããšã§ãåºåé»å§\(V_{OUT}\)ãå ¥åé»å§\(V_{IN}\)ãããé«ãããããšãã§ããŸãã
MOSFET\(Q\)ã®ONæéãé·ããã³ã€ã«\(L\)ã«èããããããšãã«ã®ãŒã倧ããã»ã©ãåºåé»å§\(V_{OUT}\)ãé«ããªããMOSFET\(Q\)ã®ONæéãçãã»ã©ãåºåé»å§\(V_{OUT}\)ã¯äœããªããŸãããã®ãããMOSFET\(Q\)ã®ãªã³ãã¥ãŒãã£æ¯\(D\)(1åšæ\(T\)ã«ããããªã³æé\(T_{ON}\)ã®å²å)ãå¶åŸ¡ããããšã§ãææã®åºåé»å§\(V_{OUT}\)ãåŸãããšãã§ããŸãã
è£è¶³
- æå§ã³ã³ããŒã¿ã¯ãããŒã¹ãã³ã³ããŒã¿(Boost Converter)ãããã¹ãããã»ã¢ããã»ã³ã³ããŒã¿ãããæå§ãã§ããããšãåŒã°ããŠããŸãã
- MOSFET\(Q\)ã¯ãã€ããŒã©ãã©ã³ãžã¹ã¿ãªã©ä»ã®ã¹ã€ããã³ã°çŽ åã§ã䜿çšå¯èœã§ãã
âãã§ãã(Chopper)ã¯è±èªã§ãåãå»ããã®ããšããæå³ããããMOSFET\(Q\)ã§é»æµãé»å§ãåãå»ãã§æå§ããŠããããã«èŠããããšãããæå§ãã§ãããšåŒã°ããŠããŸãã
æå§ã³ã³ããŒã¿ã®åäœåç
ã§ã¯ãããããæå§ã³ã³ããŒã¿ã®åäœåçã«ã€ããŠèª¬æããŸããMOSFET\(Q\)ããONã®æããšãOFFã®æãã«åããŠèããŸãã
MOSFET\(Q\)ãONã®æ
MOSFET\(Q\)ãONã®æã黿µçµè·¯ã¯ãå ¥åé»å§\(V_{IN}\)âã³ã€ã«\(L\)âMOSFET\(Q\)ããšãªããŸãã
MOSFET\(Q\)ãONããŠããéãã³ã€ã«\(L\)ã«æµãã黿µ\(i_L\)ãåŸã ã«å¢å ããŸããã³ã€ã«\(L\)ã«é»æµãæµããããšã§ããšãã«ã®ãŒãèããããŸãããŸãããã®æéã§ã¯ãåºåã³ã³ãã³ãµ\(C_{OUT}\)ã«å é»ãããŠããé»è·ãè² è·æµæ\(R_{OUT}\)ã«æŸé»ãããŠããŸãã
MOSFET\(Q\)ãOFFã®æ
MOSFET\(Q\)ãOFFã®æã黿µçµè·¯ã¯ãå ¥åé»å§\(V_{IN}\)âã³ã€ã«\(L\)âãã€ãªãŒã\(D\)âåºåéš(åºåã³ã³ãã³ãµ\(C_{OUT}\)ïŒè² è·æµæ\(R_{OUT}\))ããšãªããŸãã
ãã®æããå ¥åé»å§\(V_{IN}\)ããã®äŸçµŠãšãã«ã®ãŒ+ã³ã€ã«\(L\)ã«èãããããšãã«ã®ãŒããåºåéšã«äŸçµŠããããšã§ãåºåé»å§\(V_{OUT}\)ãå ¥åé»å§\(V_{IN}\)ãããé«ããªããŸãã
æå§ã³ã³ããŒã¿ã®åºåé»å§ã®åŒ
æå§ã³ã³ããŒã¿ã®åºåé»å§\(V_{OUT}\)ã¯æ¬¡åŒãšãªããŸãã
V_{OUT}=\frac{1}{1-D}V_{IN}\tag{1}
\end{eqnarray}
äžåŒã«ãããŠããªã³ãã¥ãŒãã£æ¯\(D\)ã¯MOSFET\(Q\)ã®1åšæ\(T\)ã«ããããªã³æé\(T_{ON}\)ã®å²åãªã®ã§ã次åŒã§è¡šãããŸãã
\begin{eqnarray}
D=\frac{T_{ON}}{T}=\frac{T_{ON}}{T_{ON}+T_{OFF}}=T_{ON}Ãf_{SW}\tag{2}
\end{eqnarray}
(2)åŒã«ãããŠã\(f_{SW}\)ã¯MOSFET\(Q\)ã®ã¹ã€ããã³ã°åšæ³¢æ°ã§ãããŸãã(2)åŒããåããããã«ããªã³ãã¥ãŒãã£æ¯\(D\)ã¯1ããå°ããå€ãªã®ã§ã(1)åŒããåºåé»å§\(V_{OUT}\)ã¯å ¥åé»å§\(V_{IN}\)ãããé«ããªãããšãåãããŸãã
äŸãã°ããªã³ãã¥ãŒãã£æ¯\(D\)ã0.5ã®å Žå(1åšæ\(T\)ã«ããããªã³æé\(T_{ON}\)ãååã®å Žå)ãæ¬¡åŒã«ç€ºãããã«çè«äžã¯åºåé»å§\(V_{OUT}\)ã¯å ¥åé»å§\(V_{IN}\)ã®2åãšãªããŸã(å®éã«ã¯ããã€ãªãŒã\(D\)ãMOSFET\(Q\)ãªã©ã®æå€±ããããããåºåé»å§\(V_{OUT}\)ã¯2åãããå°ãããªããŸã)ã
\begin{eqnarray}
V_{OUT}=\frac{1}{1-D}V_{IN}=\frac{1}{1-0.5}V_{IN}=2V_{IN}\tag{3}
\end{eqnarray}
ããããŠèªã¿ãã
(1)åŒã®å°åºæ¹æ³ã«ã€ããŠã¯äžèšã®èšäºã§è©³ãã説æããŠããŸãã®ã§ãæ°ã«ãªãæ¹ã¯ãåèã«ããŠãã ããã
-
ãæå§ã³ã³ããŒã¿ã®èšèšãããªã³ãã¥ãŒãã£æ¯Dãã®å°åº
ç¶ããèŠã
æå§ã³ã³ããŒã¿ã®ã·ãã¥ã¬ãŒã·ã§ã³
æå§ã³ã³ããŒã¿ãLTspiceã§ã·ãã¥ã¬ãŒã·ã§ã³ããæã®çµæãäžå³ã«ç€ºããŠããŸãã
äžå³ã®å³åŽã«ç€ºããŠããæ³¢åœ¢ã¯äžãã
- å ¥åé»å§\(V_{IN}\)
- åºåé»å§\(V_{OUT}\)
- ã¹ã€ãã\(S\)ã®é§åä¿¡å·\(v_{GS}\)
- ã³ã€ã«\(L\)ã«æµãã黿µ\(i_L\)
- ã¹ã€ãã\(S\)ã«æµãã黿µ\(i_S\)
- ãã€ãªãŒã\(D\)ã«æµãã黿µ\(i_D\)
ãšãªã£ãŠããŸãã
ã·ãã¥ã¬ãŒã·ã§ã³çµæãèŠããšãå ¥åé»å§\(V_{IN}\)ã¯5Vããªã³ãã¥ãŒãã£æ¯\(D\)ã¯0.5ãªã®ã§ãåºåé»å§\(V_{OUT}\)ã10Vã«ãªã£ãŠããããšã確èªã§ããŸãããªããã·ãã¥ã¬ãŒã·ã§ã³åè·¯ã§ã¯MOSFET\(Q\)ã¯çæ³ã¹ã€ããããã€ãªãŒã\(D\)ã¯çæ³ãã€ãªãŒããçšããŠããŸãã
ããããŠèªã¿ãã
LTspiceã§çæ³ã¹ã€ãããšçæ³ãã€ãªãŒããäœãæ¹æ³ã«ã€ããŠã¯ãäžèšã®èšäºã§èª¬æããŠãŸãã®ã§ããåèã«ãªãã°å¹žãã§ãã
-
ãLTspiceãçæ³ã¹ã€ããã§ãããé»å§å¶åŸ¡ã¹ã€ãããã®äœ¿ãæ¹
ç¶ããèŠã
-
ãLTspiceããçæ³ãã€ãªãŒããã®äœææ¹æ³
ç¶ããèŠã
ãæå§ã³ã³ããŒã¿ããšãéå§ã³ã³ããŒã¿ãã®éã
éå§ã³ã³ããŒã¿ãæå§ã³ã³ããŒã¿ãšåæ§ã«ãã³ã€ã«\(L\)ãMOSFET\(Q\)ããã€ãªãŒã\(D\)ãåºåã³ã³ãã³ãµ\(C_{OUT}\)ã§æ§æãããŠããŸãããäžå³ã«ç€ºãããã«ãåéšåã®æ¥ç¶ç®æãç°ãªããŸãã
æå§ã³ã³ããŒã¿ãéå§ã³ã³ããŒã¿ãMOSFET\(Q\)ããªã³ã®æã«ã³ã€ã«\(L\)ã«ãšãã«ã®ãŒãèããã®ã¯åãã§ãã
æå§ã³ã³ããŒã¿ã¯MOSFET\(Q\)ãOFFã®æã«ãå ¥åé»å§\(V_{IN}\)ããã®äŸçµŠãšãã«ã®ãŒ+ã³ã€ã«\(L\)ã«èãããããšãã«ã®ãŒããåºåéšã«äŸçµŠããŠããŸãããéå§ã³ã³ããŒã¿ã¯MOSFET\(Q\)ãOFFã®æã«ãã³ã€ã«\(L\)ã«èãããããšãã«ã®ãŒãã®ã¿åºåéšã«äŸçµŠããŠããŸãã
ããããŠèªã¿ãã
éå§ã³ã³ããŒã¿ã®åçãç¹åŸŽã«ã€ããŠã¯ãäžèšã®èšäºã§èª¬æããŠããŸããèå³ã®ããæ¹ã¯äžèšã®ãªã³ã¯ãããã²ãã§ãã¯ãããŠã¿ãŠãã ããã
-
éå§ã³ã³ããŒã¿(éå§ãã§ãã)ãšã¯ïŒåçãªã©ã解説ïŒ
ç¶ããèŠã
ãŸãšã
ãã®èšäºã§ã¯ãæå§ã³ã³ããŒã¿ãã«ã€ããŠã以äžã®å 容ã説æããŸããã
- æå§ã³ã³ããŒã¿ãšã¯
- æå§ã³ã³ããŒã¿ã®åçã»èšç®åŒã»ã·ãã¥ã¬ãŒã·ã§ã³
- ãæå§ã³ã³ããŒã¿ããšãéå§ã³ã³ããŒã¿ãã®éã
ãèªã¿é ãããããšãããããŸããã
åœãµã€ãã§ã¯é»æ°ã«é¢ããæ§ã ãªæ å ±ãèšèŒããŠããŸããåœãµã€ãã®å šèšäºäžèЧã¯ä»¥äžã®ãã¿ã³ããç§»åããããšãã§ããŸãã
ãŸããäžèšã«åœãµã€ãã®äººæ°èšäºãèšèŒããŠããŸãããåèã«ãªãã°å¹žãã§ãã