Private Communication Systems
Mobile Phones
4.3Power Supply Concept
The S11 has two main power inputs (see Blockdiagram):
1) Battery Voltage (3.6 Volts) connected at the battery contacts
2) Charging Voltage (6.5 Volts) delivered by
a) The plug-in charger at the charging plug
b) The desktop charger using the charging contacts at the bottom of the phone
c) The car kit using the charging connection at the bottom of teh phone
Since the battery voltage is supplying the power supply asic, it is always needed to
operate the phone. You cannot switch on the handset if the battery voltage is not
present.
From the 3.6 V battery voltage, all other supply voltages of the S11 are derived,
controlled by the power supply ASIC.
The VCC_DD voltage is used to supply external accessories through the bottom
connector.
The RF module needs 6.0 V for its PA, this voltage is generated by a step-up
converter.
The logic module uses 2.8 V, generated by a simple linear regulator.
V1.1
12
PN MP ST
D. Schnoor
04/98
ON_OFF Button
S11
Power Supply
ASIC
+3.6 V
Batt+
+6.5 V
Power
VDD
Ignition
Watchdog
Charging
Control
Power Detection
(to µP)
Charging On
(from µP)
Switching
Regulator
Linear
Regulator
+6.0 V
+2.8 V
Logic Supply
RF Supply
Control
Control
Blockdiagram S11 Power Supply
SIM Supply
RESET
1A
VCC_DD
0.25 A