Motorola Internal Use
13
A008 / A6188+ – Circuit Description
mechanical SIM presence detect switch and to prevent the SIM card being removed
whilst connected to Aux Power.
NB With no SIM card, Antenna Off can be selected and the unit can be used
directly as an organiser without the use of the transceiver.
Logic: Charger Circuit
1)
The charging operation is as follows:
2)
After a charger has been detected
MAN_TEST_AD
, the
Whitecap U700
will
communicate with the device via
DSC_EN
.
3)
EXT B+
is fed in from
Accessory Connector J600
Pin 14
to the source of
Q901
,
controlled by
U9819
,(these components are placed purely for high voltage
protection), this voltage will then be passed back to the source of
Q932
, where the
line
MOBPORTB
detects the presence of
EXT B+.
The current is sensed through
R932
Current Sense Resistor
, the voltage drop over it is sent to
GCAP II
Pin D9
I_SENSE
, this is used to evaluate the charging current.
4)
The charging current is then passed through
CR932
to charge
BATT +
. The charge
current is restricted by the signal
CHRGC
–
GCAP II
Pin E8
, this opens the gate of
Q635
.
CHRGC
is programmed during charger phasing.
5)
CHRG_EN
Whitecap
Pin 1
, biases
Q634
On or Off
Logic: Deep Sleep Mode
1)
Deep sleep mode is there to provide a facility to save battery life by intermittently
shutting off part of the PCB. This is achieved in the following way. The signal
STDBY
is generated from Whitecap
Pin F1
, and from here the signal is then passed
onto
Q960
and
Q921.
This has the effect respectively of:
2)
Grounding
VREF
which makes MAGIC inoperable
3)
Grounding
V2
This switches off MAGIC, and inhibits the Transmit path through
RF_V2
4)
Also the signal is passed through a standby delay using the logic gate
U9820
and
diode
CR701
these provide a short delay between the de-activation of
V2
and
VREF
and the activation of
LS_V1
. Which will support the Down-link lines during sleep
mode.
5)
The shutdown is only for a fraction of a second and during that time the GCAP Clock
supports the logic side of the unit. The GCAP clock is generated by
Y900
, which
generates a 32.768MHz clock. This clock is output from Whitecap
Pin C7
and fed
directly to Whitecap
Pin P4
. The clock is always monitored by Whitecap and should
it fail, the unit will no longer go into deep sleep mode.
