Lecture 11: Op Amplifier (II)

1
Lecture 11 Op Amplifier (II)

• Jeong Wan Lee
• ?????? ? ??

2
Active Filter

• Filter ???? Power Source? ??, ??? ???? ??? ??.
  (c.f. Passive Filter)
• Op Amp? ??? Active Fiter? ???

ZF
ZS
-

VS
-
VOUT
3
Low Pass Filter
CF
RS
RF
-

VS
-
VOUT
4
Cont

• Overall Transfer Function
• w ? 0 ? -RF/RS, w ? ? ? 0
• breaking point, w0 1/RFCF

amp
low pass filter
w
5
High Pass Filter
RF
RS
CS
-

VS
-
VOUT
6
Cont

• Overall Transfer Function
• w ? 0 ? 0, w ? ? ? -RF/RS
• breaking point, w0 1/RFCF

amp
high pass filter
w
7
Integrator
CF
RS
IIN
V-
IS
IF
-

V
VS
-
VOUT
-

• At Node V-
• ??? ?? ?? ??

8
Cont...

• Transfer Function
• Low pass Filter? ??? C? feedback ??? ?? - ??? ??

9
Differentiator
RF
CS
IIN
IS
V-
IF

-
V
VS
-
VOUT
-

• At Node V-
• ??? ?? ?? ??

10
Cont...

• Transfer Function
• High pass Filter? ??? C? source ??? ?? - ??? ??

11
Analog Computer

• ?? ???, ??? ????, ????
• ?? Less Flexible, ??? ??? ???? ???.
• ?? ?? Amp, Summer, ???,???
• ?)

xM
M
B
K
xR
12
Cont.

• If xe X sin (wt)
• then,
• Text p. 571 ??? ????? simulation ? ?
• scale? ? xm1m? ?? xm5V?? mag. scale ??
  30?? ??? msec?? time scale
• scale? ??? ??? error ??? ??

13
Limitation of Op Amp
1) ??? ??? ??. VOUT ? ??? ?? -Vcc
ltVOUT ltVcc??. 2) AV(OL) ? ???? ??. 3) DC
OFFSET? ???? ??. (????? ??) 4) ?? ???
????.(??? ????? ?? ??)
VCC
-
-
VOS

-VCC
VCC
IB-
-
IB
-VCC
14
Cont...
5) ??? ???? ?? ???? ???? ???. 6) IoutltIsc
??.
VCC
-
ISC
-VCC