Power Distribution - Nokia 1265 Description And Troubleshooting

1265 (RH-103)
Baseband Description and Troubleshooting
In active mode, this is a normal operating mode for PM.
VREG_MSMP, VREG_MSMA, VREG_RUIM, VREG_RFRX, VREG_RFTX, and
VREG_TCXO regulators are all turned on. TCXO oscillator is enabled, and TCXO
buffers are turned on. All other functions and regulators are controlled individually via
SBI.
Charging Mode
Charging mode can function in parallel with any other operating mode. A BSI resistor
inside the battery pack indicates the battery type/ size. The resistor value
corresponds to a specific battery capacity. The PM measures the battery voltage,
temperature, size, and charging current.
Charger control block inside the PM controls the charging current delivered from the
charger to the battery and mobile terminal. The maximum battery voltage is limited
by turning the PM switch off when the battery voltage reaches 4.2 V. The charging
current is monitored by measuring the voltage drop across a 0.1 ohm resistor.

Power Distribution

In normal operation, the baseband is powered by the mobile terminal's battery pack.
The battery pack consists of one lithium-ion cell with a capacity of 820 mAh and
safety and protection circuits.
The PM controls the power distribution to the whole mobile terminal, which includes
the baseband and the RF regulators, but excludes the RF power amplifier (RF PA)
RF power amplifier drains power from the battery directly. The battery provides
power directly to the following parts of the system:
PM
RF PA
Vibrator
Keyboard & LCD backlights
The heart of the power distribution is the power control block inside the PM. It
includes all the voltage regulators and feeds the power to the entire system. The PM
handles hardware power-up functions so that the regulators are not powered on and
the power up reset (PURX) is not released if the battery voltage is less than 3 V.
Page 8 © 2007 Nokia Corporation Company Confidential
VREG_MSMC,
Issue 1 04/2007