MOTOROLA CONFIDENTIAL - PROPRIETARY
14
November 20, 2000
6881036B20
Circuit Description
Product Family 38C
• AOC_DRIVE (
U390
Pin 8
) controls the output power of the transmitter. Under
normal conditions, the control loop will adjust the voltage on EXC so that the
power level presented to the RF detector results in equal voltages present at
INT and AOC. The input level is between 0 and 2.5V.
• ACT (
U390
Pin 9
). With no RF present, this pin stays high. Once the RF level
increases enough to cause the detector output to rise a few millivolts, this out-
put goes low. ACT is connected to the AOC input through a resister which
causes the transmitter to ramp-up the power until the detector goes active.
Controller
Power-Up sequence
The three power sources available for the PF38C Personal Communicator are:
• Internal battery
• External power via mid-rate charger (Battery must be present to power up)
• External power via fast charger (Battery must be present to power up)
Battery Power Source
The Personal Communicator uses a 3.6V Lithium Ion battery. Power from the
battery is taken from BATT + (battery contacts
J604
) and routed through battery
FET
Q901
. Once B+ is available, the unit carries out the following checks.
• Battery temperature is measured to establish whether rapid charge is
required. Table 2 shows voltages appearing at BATT_THERM_AD (
J604 Pin 3
and
GCAP II Pin B3
) for various battery temperatures.
• Presence and type of charger is sensed MANTEST_AD (
J600 Pin 5
and
GCAP
II Pin A1
). This is achieved by using different sense resistors within each type
of charger.
• Battery voltage is sensed (
GCAP II Pin F7
BATTERY).
• Input B+ level is sensed (
GCAP II Pin E10
B+).
Charger Power Source
When the charger is connected to accessory plug
J600
, EXT B+ is available at
Pin 14
and sensed at MOBPORTB (GCAP II
U900 Pin D10
). Once sensed, the
power is passed through protection diode
CR903
and output to EXT B+ FET
Q905
.
The output is controlled by MIDRATE_1 and power is made available at B+.
Because the charger supports both the Personal Communicator and its internal
battery, the battery is charged at the same time B+ is supplied to operate the unit.
Table 2. Battery Temp vs. BATT_THERM_AD
-40° C
2.75V
25° C
1.39V
40° C
0.96V
Table 3. Charger Type vs. MANTEST_AD
Fast Charger
2.13V
Mid-Rate Charger
1.38V
Summary of Contents for 38C V100
Page 1: ...Level 3 Service Manual Model V100 GSM Technology Product Family 38C Personal Communicator ...
Page 2: ......
Page 73: ...V100 BOARD LAYOUT PAGE 1 2 ...
Page 74: ...V100 BOARD LAYOUT PAGE 2 2 ...
Page 77: ...V100 CONNECTOR SCHEMATICS ...
Page 78: ...V100 DISPLAY SCHEMATICS ...
Page 79: ...V100 FM SCHEMATICS ...
Page 81: ......
Page 83: ......