ʱṩġһ˵յģҲͬѧ˵Ĺ
裺
1TTL·COMS·ʱTTL·ĸߵƽCOMS·ĺܵߵƽһΪ3.5VʱҪTTL˽裬ߵƽֵ
2OCŵ·裬ʹá
3ΪӴŵеĵƬܽҲʹ衣
4COMSоƬϣΪ˷ֹõĹܽŲգһ迹ṩйͨ·
5оƬĹܽżƽӶоƬźŵǿ
6ߵĿŸܽվͱȽĵŸš
7ߴе費ƥ䲨ţǵƥ䣬ЧƷ䲨š
ֵѡԭ:
1ӽԼļоƬĹӦ㹻С
2ȷ㹻Ӧ㹻СС
3ڸٵ·ܱرƽۺϿ
,ͨ1k10k֮ѡȡҲƵ
ѡӦϿعԺ¼·Խ趨ҪҪ¼أ
1 빦ĵƽ⡣Ϊһ˵ԽСԽǿԽӦע֮ľ⡣
2 ¼·ͬΪߵƽʱعܶϿӦʵѡܹ¼·ṩ㹻ĵ
3 ߵ͵ƽ趨ͬ·ĸߵ͵ƽżƽвͬӦʵ趨ȷܵѹֵӦȷƽż֮¡
4 ƵԡΪͿع©Դ֮ĵݺ¼·֮ݻγRCӳ٣ԽӳԽ趨Ӧǵ·ⷽ
趨ԭһġ
OCߵƽʱһ̬Ҫṩÿ˿ڲ100uA,Լ500uAѹ5Vڵĸߵ͵ƽΪ0.8V(ڴֵΪ͵ƽ)2V(ߵƽֵ)
ѡʱ
500uA x 8.4K= 4.2ѡ8.4Kʱ0.8V£ΪСֵСˡϴֵɼС֤ʱܵ0.8Vɡ
ߵƽʱԹӵ©200uA
200uA x15K=3VѹΪ3Vڿɴﵽ2VֵΪֵܴٴ2Vˡѡ10KáCOMSŵĿɲο74HCϵ
ʱӵ©ɺԣIOʵʵڲͬƽҲDzͬģԭһ仰ΪߵƽʱҪιڣ͵ƽҪιˣĵι˼ڣڵ͵ƽֵͲɿˣ
ֵ·вõŶҪӹ̶ƽͨ1kӸߵƽӵء
1. ã
• ӵΪ˷ֹ
• ⲿоƬĸ
• cmosڵı,һ10mA
•
1. ıƽĵλTTL-CMOSƥ
2. ʱȷ״̬
3.Ӹߵƽʱ
4ΪOCṩ
• ҪʲôҪߵѹĻڵѹֲҪ衣
• Ķ˿ĬֵΪߵƽҪõ͵ƽ̬ܿŵ·ܵļ缫ȥưĵΪ͵ƽ֮
• ڽӿڵ·,Ϊ˵õȷĵƽ,һַ,Ա֤ȷĵ·״̬,ⷢ,,ڵ,ű۲ֱͨ,ǶͬһƬ,óʼ״̬.ֱֹͨ!
2壺
• ǽȷźͨһǶλڸߵƽͬʱãͬ
• Ƕע
• ǿֵֻͬûʲôϸ
• ڷǼ缫©·͵·ͨŵ·͵ѹģĹҪΪ缫·͵·ͨ
3ΪʲôҪʹ裺
• һʹʱICûڽӵ裬Ϊʹάڲ״̬Ǵصԭ״̬ICⲿһ衣
• ֵ·״̬ߵƽ͵ƽ״̬ЩӦóϲϣָ״̬ͨķʽʹȶ״̬Ҫ
• һ˵I/O˿ڣеĿãеIJãеãеҪӣI/O˿ڵһܵCCͨһ͵ԴһʱõΪC裬Ҳ˵ö˿ʱΪߵƽCͨһ͵һʱõΪ裬ʹö˿ƽʱΪ͵ƽ
磺һĶ˿Ϊ״̬ʱij̬Ϊߵƽڼ͵ƽ롣
• ʱṩġһ˵յģҲͬѧ˵Ĺ
ϲ