Voltage Regulators - Panasonic EB-G450 Technical Manual

external power
8.0V, 1.5A
On RF PCB
Figure 2: Power supply block diagram
9.4.2 Power On Circuit
There are two mechanisms for powering on the Hand-held, Power Key or External power. The Hand-held is kept
powered on by the CPU, stay alive, or external power. This means that the phone remains powered up all the time
that external power is present. To minimise drain on external power, for example while the phone is connected to a
car kit with ignition off the phone is put into sleep-mode to give an average power use of less than 2mA. For a
20AHr car battery this would give approximately 416 days before the battery would run flat, if left connected and the
phone powered off – assuming no battery self discharge.

9.4.3 Voltage Regulators

Using 4 cells with 3.0V logic gives no problems with high regulator voltage dropout, However the high voltage drop
means that thermal characteristics must be carefully considered.
To reduce the cost the minimum number of regulators are used.
Regulator No 1 – Baseband power supply
Voltage
Current
This regulator provides all the power requirements for the base-band except the SIM and LCD.
Regulator No 2 – RF power supply
Voltage
Current
This regulator provides the main power for the RF
Regulator No 3 – VCO power supply (located on the RF PCB)
Voltage
Current
This regulator provides a very stable power supply for the VCOs
MCUK971001G8
Technical Guide
http://cxema.ru
3.6V det
SIM
step-up
5.0V
+ reg.
10mA
VCXO
RF PCB
3.0 ± 2.5%
200mA max.
3.6 ± 2.5%
200mA max.
3.6 ± 2.5%
30mA max.
Section 9
9 - 5
CPU
3.6V
3mA
POWER SUPPLIES
power-up
logic
POR
3.0V
200mA
logic
3.5V
LCD
20mA
3.6V
200mA
RF
3.6V
30mA
VCO
450-0902
Issue 1
Revision 0