Iiyama Vision Master Pro 451, Service Manual

Page: 35 / 74

4-12. USB circuit
This circuit detects connecting condition of the upstream port (CN701 UP) from PC and the downstream port
(CN702 and CN703) from peripherals and communicate with PC by IC701 (USB-CONT-IC). USB cable (series A/B)
is composed of 5V, GND, +D and -D signals. The condition of connection is judged from by detecting data transfer
rate of peripherals connected by +D and -D combination at IC701. (The condition of connection is detected whether
+D and -D signals are pulled up or not.)
IC701
(USB-CONT-IC)
PC
Upstream × 1
Downstream × 4
(0.5A/1port)
Peripherals
- 30 -
4-11. AUDIO circuit
The audio signal from CN602 (AUDIO-IN) is amplified by IC601 (AUDIO-AMP) and output to Speaker and Headphone
jack.
The VR voltage (0-1.2V) from pin 9 of IC601 switch output of pins 6, 10, 11 and 12 of IC104 to HIGH and LOW to
control the volume.
IC601 stops when Q601 is turned on under the power management mode.
Pin 6
LOW
HIGH
LOW
HIGH
LOW
HIGH
LOW
HIGH
LOW
HIGH
LOW
HIGH
LOW
HIGH
LOW
HIGH
Pin 10
LOW
LOW
HIGH
HIGH
LOW
LOW
HIGH
HIGH
LOW
LOW
HIGH
HIGH
LOW
LOW
HIGH
HIGH
Pin 11
LOW
LOW
LOW
LOW
HIGH
HIGH
HIGH
HIGH
LOW
LOW
LOW
LOW
HIGH
HIGH
HIGH
HIGH
Pin 12
LOW
LOW
LOW
LOW
LOW
LOW
LOW
LOW
HIGH
HIGH
HIGH
HIGH
HIGH
HIGH
HIGH
HIGH
IC104 output pin
Input Voltage
IC601 pin 9
0.020
0.046
0.073
0.104
0.135
0.172
0.211
0.256
0.292
0.346
0.404
0.473
0.546
0.636
0.736
0.861
Level
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15