3
Power Supplies
3.3V
Reg
Reg
Bose Brand FET
Quasi-Regulator
VRAW
VSNUB
1.2V
Reg
U50, U51
U902, Q9031
Q10
U11
10V
Reg
U20
5V
Power Supply Block Diagram
Bass module rectifies un-regulated power VSNUB from the secondary of the line power transformer. VSNUB is,
in turn, converted to the various other potentials required by the system. Nominally 26VDC, this voltage varies
with load and line levels, but is limited to 31.5V maximum(assuming line voltage of 140V AC). This voltage is
present whenever the bass module is plugged into the wall. All the voltage level source are listed in following
table:
Node
Name
Output
Voltage
nominal
Type
Input from
Outputs to
Vsnub +26 Full
wave
rectifier
transformer
secondary
Vraw
Vraw +14
(no
load)
pre-
regulator
output
VSNUB
Power Amplifiers, +5V, VRAWSEN.
+10V
+10
linear
VSNUB
Headphone power amplifiers, control module
green LED.
+5V
+5
linear
Vraw
CODEC Analog power supply
+3.3V
+3.3
switching VSNUB
DSP I/O power supply, digital supply for USB
controller, CODEC, EEROM.
+1.2V
+1.2
switching VSNUB
DSP core power supply.
3.0
series
switch
+3.3
Switch able supply for control module touch
sensor, control module red LED
