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NOTE:
During charging, the voltage could rise as high as 9.4V and all circuitry connected to the battery must be
designed to operate up to this voltage.
A block diagram for a four cell power supply is shown in figure 2 below, note that the battery voltage is stepped-up
to power 5V SIM cards or the 5V RF power amplifier. This circuit also shows a Power-On-Reset (POR) to hold the
CPU in a reset state while the supply voltage and system clock stabilize.
Figure 2
: Power supply block diagram
600-1002
MCUK980101G8
Section 9
Issue 1
Technical Guide
9 - 5
Revision 0
POWER SUPPLIES
Battery
VBAT
Li-ION:7.2V, Ni-MH:4.8V
LV1
Charge IC
9.2V 400mA
5.5V Step-up Reg
5V Reg
D5V
SIM Power
SIM 5V
RF:1st VCO, APC circuit
D3V
Logic Digital part
A3V
Logic Analogue part
3V Reg
3V Reg
DC OUT
3.4V Step-down Reg
DC OUT
RF: RX.TX 2nd VCO Synth
RF: PA
VBAT
2.7V Det
RESET
CPU (Gemini)
External Power
EXT PWR
VDD