Baseband Unit; Power-On Management Circuits - Huawei Ascend Maintenance Manual

Y210 Mobile Phone
Maintenance Manual
Subsystem Module

9.2 Baseband Unit

9.2.1 Power-on Management Circuits

On the Y210U, most power supplies are provided by the power management chip PM8029.
The PM8029 provides two types (switched-mode power supply and LDO regulators) of
programmable voltage regulators with a total of 24 output channels. Table 9-2 lists the voltage
regulator parameters.
Issue 1.0 (2012-11-28)
Unit
RTC
HKADC
TCXO driver
UVLO
Overheat protection
Internal driver circuit
Interrupt management
USB driver
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
9 Principles and Failure Analysis
Function
power-saving analysis, the board
software manages the power supplies
to the units on the board to reduce
power consumption.
The built-in RTC circuit uses a sleep
clock of 32.768 kHz to provide
precise time.
Contains 8 multipurpose pin (MPP)
interfaces. Analog-to-digital
conversion can be implemented inside
the PM8029.
The PM8029 has a built-in TCXO
driver providing two analog signal
output channels and two digital signal
output channels.
Provides the Undervoltage-Lockout
(UVLO) function. When the input
voltage is lower than the threshold for
a specific period of time, the phone
powers off.
When the on-chip junction
temperature exceeds 150° C, the
phone powers off.
Provides one vibration motor driver
and one speaker driver.
The built-in interrupt manager
handles related interrupt signals.
Supports USB 2.0; does not support
USB On-The-Go (USB OTG).
26