Transcript ECE 11 Final Project: Boom Box Design and Implementation

ECE 11 Final Project: Boom Box
Design and Implementation
By Scott Trocchia
ECE 11 Fall 2008
Professor Korman, GTA Yi Jin
Presented on 12/16/08
The Approach: Divide and Conquer
Definition: break large project (seemingly
complicated and daunting task) into its
constituents (piece by piece)
 The following slides will explain the circuit
through this concept

C1
680p

R1
R2

24k
24k

V1
.425Vac
0Vdc
-
OPAMP
OUT

0
+
U1

0
1st order
Inverting design
Establish unity
gain
Simple illustration
of phasor usage
Eliminates all noise
above 10 kHz
Stage [1] : Initial Low Pass Filter
R1
8.2k
C1
C2
U1
+
1000p
1000p
OUT
V1
-
.425Vac
0Vdc
R2
56k
0
0
Treble channel
2nd order high
pass filter
 Reason for
order?
 Unity gain
 Frequency
range of
interest: 5360
Hz to 10 kHz

OPAMP
Stage [2a]: Decision to make Treble or Bass?
Bass channel 2nd
order low pass
filter
 R  C, C  R
 Unity gain, again
 Frequency range
of interest: 150
Hz to 7360 Hz

C1
820p
R1
R2
68k
160k
U1
+
OUT
V1
-
.425Vac
0Vdc
C2
100p
0
OPAMP
0
Stage [2b]: Decision to make Treble or Bass?
Same for treble and
bass channels
 C6 and R8 together
represent passive
low pass filter
 Attenuates all
frequency <150 Hz
 C7 makes sure AC
voltage passes to
speaker

R7
U3
+
1000k
R22
10
C7
OUT
220u
-
OPAMP
C6
.047u
RLtreble
8
0
R8
5.1
0
0
-
OPAMP
Stage
[3]:
Output Stage
D3
D4
-
OUT
+
OPAMP
OUT
R23
510
+
R24
510
Concept of
voltage ladder
(+,- polarity)
 Initial resistor
 highest
voltage drop
 Personal
preference
and guess and
check
 LED resistor?

Treble’s Voltage Ladder
Concept of
voltage
ladder (+,polarity)
 Personal
preference,
again
 LED resistor
and why we
need it

Bass’s Voltage Ladder
Troubleshooting / Problems /
Resolutions
Troubleshooting
 Parts
 Time issue?
 Lessons learned and applications
