Siemens C55 Repair Documentation

V1.20 Page 29 of 48 ICM MP CCQ GRM
A55/C55_Hitachi Company Confidential © Copyright Siemens AG 04/03
Mode
Pin
Requirements
Description
Trickle charge
mode to be able
to support
charging of the
battery
VDD_CHARGE
EXT_PWR
In case of a rising edge at VDD_CHARGE
(PinC3) the ASIC goes from power down to
interim mode. In this mode, the oscillator and
the reference are started. The fuses are read
in. If the voltage is high enough (after a delay
time of 1 ms to filter a ringing), the internal
signal EXT_PWR is going to H and the power
up continues. The ASIC shuts off if the voltage
is below threshold. In Trickle Charge Mode,
first the charge unit starts and charges the
battery in case of under voltage. After reaching
this threshold voltage or if the battery has
enough voltage from the beginning, a start up
similar to the regular startup mode is initiated.
In case of voltage drop under battery threshold,
the first trickle charging can be started again
until the Active Mode is entered. In this case,
the internal VDDREF regulator, the reference
generator and oscillator are started and the
ASIC is supplied by VDDREF. If any failure is
detected, the ASIC is switched off.
6.1.3 Power Supply Functions:
Functions
Pin
Requirements
Sequence
Switching on the
mobile phone
ON_OFF,
ON_OFF2,
VDD_CHARGE
There are 3 different possibilities to switch on
the phone by external pins:
- VDD_CHARGE (PinC3) with rising edge
after POR or high level at end of POR
signal
- ON/OFF (PinH2) with falling edge
- ON/OFF2 (PinJ3) with rising edge
In order to guarantee a defined start-up
behavior of the external components, a
sequential power up is used and the
correct start up of these blocks is
supervised. In active mode, a continuous
signal at watchdog is needed to keep the
system running. If the signals fails, the
ASIC will switch to power down mode. It
must be guaranteed that each start-up
condition does not interfere and block the
other possible startup signals. In case of
failure during start-up, the device will go
back to power down mode. To guarantee
that VDDCHARGE (PinC3) is always
sensed we must be able to detect whether
the VDDCHARGE (PinC3) will have a
rising edge during POR (this can happen in
case of an empty battery). Therefore this
signal is sensed as level sensitive at the
end of POR and edge sensitive after POR
signal.

Siemens C55 Specifications

General

Brand	Siemens
Model	C55
Category	Cell Phone
Language	English