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1. Power Control Circuit
1-1. VB voltage
Fig.1-1 shows VB voltage generator circuit. Power Control IC9002 is the main power control IC and starts up when VB voltage is supplied to pin-27 [VB].
1. Driving voltage
When the unit is not connected to USB Adaptor
The voltage from the built-in battery is supplied to Pin-6[IN2] of AUTO SELECT POWER SWITCH IC9504.
When the unit is connected to USB Adaptor
5[V] from the USB Adaptor is supplied to Pin-8[IN1] of AUTO SELECT POWER SWITCH IC9504.
Note:
5[V] from the USB Adaptor is not the VBUS voltage supplied from PC. 5[V] is generated inside the USB Adaptor based on the voltage supplied from the AC power adapter.
VBUS voltage from PC is used for a Wake-up condition of the unit.
2. AUTO SELECT POWER SWITCH IC9504
AUTO SELECT POWER SWITCH IC9504 works corresponding to the truth table shown in Table.1-1. When 5[V] is supplied to the unit from the USB Adaptor, VB voltage is
changed from the battery voltage to the 5[V]. And also IC9504 outputs “L” signal from Pin-1[STAT]. This signal is used for a Wake-up condition of the unit.
1. Driving voltage
When the unit is not connected to USB Adaptor
The voltage from the built-in battery is supplied to Pin-6[IN2] of AUTO SELECT POWER SWITCH IC9504.
When the unit is connected to USB Adaptor
5[V] from the USB Adaptor is supplied to Pin-8[IN1] of AUTO SELECT POWER SWITCH IC9504.
Note:
5[V] from the USB Adaptor is not the VBUS voltage supplied from PC. 5[V] is generated inside the USB Adaptor based on the voltage supplied from the AC power adapter.
VBUS voltage from PC is used for a Wake-up condition of the unit.
2. AUTO SELECT POWER SWITCH IC9504
AUTO SELECT POWER SWITCH IC9504 works corresponding to the truth table shown in Table.1-1. When 5[V] is supplied to the unit from the USB Adaptor, VB voltage is
changed from the battery voltage to the 5[V]. And also IC9504 outputs “L” signal from Pin-1[STAT]. This signal is used for a Wake-up condition of the unit.
Table.1-1 Truth table of AUTO SELECT POWER SWITCH IC9504
Pin-2 [XEN]
V[VSES] > 0.8[V]
V[IN2] > V[IN1]
Pin-1 [STAT]
Pin-7 [OUT]
Remark
L
Yes
X
L
IN1
Not used
L
No
No
L
IN1
When the unit is in the 5[V] driving.
L
No
Yes
Hi-Z
IN2
When the unit is in the battery driving.
H
X
X
L
Hi-Z
Not used
Next, when the Built-in Battery Switch is turned “ON”, the voltage output from Pin-7 of IC9504 is supplied to Pin-27 of Power Control IC9002 as VB voltage. Then IC9002
starts up.
3. MAIN SYSTEM CONTROLLER IC1003
When MAIN SYSTEM CONTROLLER IC1003 starts up, it outputs “H” signal from Pin-147[PQ1/FFCLR]. By this “H” signal, the switch inside IC1001 is turned “ON”. Then
XCHG_PG signal is input to Pin-150 [PQ4] of MAIN SYSTEM CONTROLLER IC1003. IC1003 detects whether the driving voltage is the battery voltage or 5[V] supplied from
the USB Adaptor by using this input status shown in Table.1-2.
Table.1-2 Detecting the 5[V] supplied form the USB Adaptor
IC1003 Pin-150 [PQ4]
Description
L
5[V] is supplied from the USB Adaptor.
H
5[V] is not supplied from the USB Adaptor.
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