Tài liệu Circuits & Electronics P23 pptx

6.002 Fall 2000 Lecture
1
23
6.002
CIRCUITS
AND
ELECTRONICS
Energy, CMOS
6.002 Fall 2000 Lecture
2
23

Reading: Section 11.5 of A & L.
S
V
+
–
1
R
C
2
R
1
S
2
S
f
TTT
1
21
=+=

fCVP
S
2
=
T
1
: closed
T
2
: open
open
closed
ONL
S
RR
V
P
+
=
2
O
v
S
V
ON
R
L
R
I
v


Review
6.002 Fall 2000 Lecture
3
23
Inverter —
O
v
I
v
C
S
V
L
R
ON
R
fCV
R
V
P
S
L
S
2
2
2
+=
related to switching
capacitor.

independent of f.
MOSFET ON half
the time.
STATIC
P
DYNAMIC
P
constant time
"RC"
2
T
RR
ONL
>>
>>
Square wave input
f
T
1
=
Demo
Review
In standby mode, half
the gates in a chip can
be assumed to be on.
So per gate is
still .
STATIC
P
L

2
S
R2
V
In standby mode,
f Æ 0
,
so dynamic power is 0
6.002 Fall 2000 Lecture
4
23
fCV
R
V
P
S
L
S
2
2
2
+=
Chip with 10
6
gates clocking at 100 MHz
V5V,10100f,K10RF,f1C
S
6
L
=×=Ω==

problem !
1.25KWatts
2.5Watts
not bad
+
• independent of
f
•
also standby power
(assume ½ MOSFETs
ON if
f
Æ 0)
•
must get rid of this!
•
α
f
• αV
S
2
reduce
V
S
5V
Æ
1V
2.5V
Æ
150mW

[ ]
watts5.2milliwatts25.110
6
μ
+=
⎥
⎦
⎤
⎢
⎣
⎡
×××+
××
=
−
6215
3
2
6
10100510
10102
5
10P
gates
Review
6.002 Fall 2000 Lecture
5
23
How to get rid of static power
Intuition:

O
v
S
V
ON
R
L
R
I
v
high
low
i
idea !
O
v
S
V
I
v
high
low
S
V
L
R
O
v
I
v

low
off
MOSFET
high