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P7389i – Circuit Description
For DHFA Charger - 2.75V
• Senses battery voltage
• Senses input B+ level
3) Charger Power Source: The L7389, 9 used the mid rate charger.
available to the P7389I, if used the unit will power down!
When the charger is connected into the accessory plug J600,
available at Pin 14. This will be sensed at
Once sensed the power will then be passed through the
made available as
NB. The charger supports the phone in conjunction with the batteries, therefore the
batteries are charged as
4) The
GCAP II
is programmed to Boost mode (5.6V) by
G8 both being tied to Ground. Once
appropriate voltages to supply the circuit are provided. These are:
•
V1
– Programmed to 5.0V.
to 5.0V through the switch mode power supply
for basic operation.
MAGIC DM.
V1
The basic circuit operation for the Boost circuit is as follows the
Pin B10) allows a path for
capacitor then discharges through the inductor (switch off), setting up an electric
field. The field then collapses setting up a back EMF to charge the capacitor, and so
on and so on. The back EMF created by the inductor is greater than
half of the cycle passing through the diode to charge a capacitor from where the
V_BOOST
voltage is taken. The frequency of the switching signal
duty cycle of the output wave and therefore the resultant voltage.
back into the GCAP.
•
V2
– Programmed to 2.775V, available whenever the radio is on and supplies most of
the logic side of the board.
measured on either
Logic memory circuitry differs from that of the standard Leap by using 2 x 4Mbit
SRAM instead of 1 x 2Mbit SRAM band also using Whitecap SPS ROM 6. This
change is incorporated to allow the extra memory capacity for GPRS operation.
Motorola Internal Use
For Fast Charger – 2.13V
(GCAP II
Pin F7 – BATTERY)
GCAP II
Pin E10 – B+)
B+.
B+
is supplied.
B+
V1
is at 2.775V at immediate power on, but is 'boosted'
V1
supplies the DSC bus drivers, negative voltage regulators and
is created from GCAP II Pin A6 and can be measured on C906.
B+ FREAK
LX
Fig 6.1
B+
to charge the capacitor, when the switch is on, the
V2
is supplied out of GCAP II Pin J2 and can be
C939
or C941.
EXT B+
GCAP II U900
Pin D10 MOBPORTB.
protection diode CR903
PGB0
is applied to GCAP II Pin K5, all the
L901 / CR902
Output
9
This will not be
will be
and
Pin G7 and
PGM1
Pin
and C913. See Fig 6.1
LX
signal (GCAP II
B+
with the +ve
LX
decides the
V_BOOST
is fed
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