Private Communication Systems
Mobile Phones
The C1x 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 car kit through the charging connection at the Molex connector
c) The desktop charger through the contacts at the outer ends of the Molex
connector.
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 C1x are derived,
controlled by the power supply ASIC.
The VCC_DD voltage is used to supply external accessories through the Molex
connector at the top of the telephone.
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.
Service Manual C1x V 1.0 PN MP ST
R. Fleuren
Sm_C1x_lvl2_v10_w97.doc Page 15 of 23 09/98
