Page 9 - 電子學含實習

ཥɿኪўྼ୦€ɨ

ၚ፯ᇍԷ 1 ΝӉᇖ୦ 1

٤˶ۨ N ஷ༸ MOSFETdண I DSS = 12mAd ݔɓ P ஷ༸ MOSFET ʘѰ˟ཥᏀ V =
P
V = – 4Vdۆί V = –1.5V ࣛd༈ MOSFET 6Vdίཛྷ๕ཥᏀ V = 2V ࣛdI ཥݴމ
P
GS
GS
D
ʘʝኬ g މОk 4mAi຅ V = 3V ࣛdՉʝኬ g މОk
m
GS
m
༆ ٤˶ۨ MOSFET ʘʝኬ
ഈ
×
I 2 V 212 −15 .
g = V DSS 1 ( − V GS ) = | −4 | ×− −4 )
1 (
m
P
P
= 3.75(mA/V、m Ω 或 mS)。
ʔሞ P ஷ༸א N ஷ༸dFET ٙ g m ޫމ͍࠽f

ၚ፯ᇍԷ 2 ΝӉᇖ୦ 2

ݔɓ N ஷ༸ᄣ੶ۨ MOSFET ٙᑗޢཥᏀ ݔɓ P ஷ༸ᄣ੶ۨ MOSFET ٙ V = –2Vd
T
2
V = 3Vd຅ V = 5V ࣛdMOSFET ʈЪ ਞᅰ K = 0.5mA/V d߰ MOSFET ʈЪ׵
GS
T
׵֛ཥݴਜdϤࣛ I = 4mAi߰຅ V = ཱིձਜd຅ཛྷ๕฽ཥᏀ V = –5V ࣛdՉ
GS
D
GS
7V ࣛdՉᔷኬ g މОk ᔷ୅ཥኬ g މОk
m
m
༆ (1) I D = K(V GS – V T ) d ഈ
2
2
2
4 = K(5 – 3) d੻ K = 1mA/V
(2) ᔷኬ€אᔷ୅ཥኬ
g m = 2K(V GS – V T ) = 2 × 1 × (7 – 3) = 8(mA/V)
(3) ̤༆j
1 I D = K(V GS – V T ) d
2
4 = K(5 – 3) d੻ K = 1mA/V
2
2
2 ຅ V GS = 7V ࣛd
2
I D = 1 × (7 – 3) = 16(mA)
×
2
V
g = 2 KI D = × 116 = 8(mA / )
m

4