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參數(shù)資料
| 型號： | ADP3522 |
| 廠商： | Analog Devices, Inc. |
| 元件分類： | 基準電壓源/電流源 |
| 英文描述： | GSM Power Management System |
| 中文描述： | 手機電源管理系統(tǒng) |
| 文件頁數(shù)： | 15/20頁 |
| 文件大?。?/td> | 467K |
| 代理商： | ADP3522 |
REV. 0
ADP3522
–15–
Applying an external charger can also turn the handset on. This
will turn on all the LDOs, except the SIM LDO, again starting
up the baseband processor. Note that if the battery voltage is
below the undervoltage lockout threshold, applying the adapter
will not start up the LDOs.
Deep Discharge Lockout (DDLO)
The DDLO block in the ADP3522 shuts down the handset in
the event that the software fails to turn off the phone when the
battery voltage drops below 2.9 V to 3.0 V. The DDLO will
shut down the handset when the battery falls below 2.4 V to
prevent further discharge and damage to the battery.
The DDLO will also shut down the RTC LDO when the main
battery is removed. This will prevent reverse current from dis-
charging the backup coin cell.
Undervoltage Lockout (UVLO)
The UVLO function in the ADP3522 prevents startup when the
initial voltage of the battery is below the 3.2 V threshold. If the
battery voltage is this low with no load, there is insufficient
capacity left to run the handset. When the battery is greater
than 3.2 V, such as inserting a fresh battery, the UVLO com-
parator trips, and the threshold is reduced to 3.0 V. This allows
the handset to start normally until the battery decays to below 3.0 V.
Once the system is started and the core and memory LDOs are
up and running, the UVLO function is entirely disabled. The
ADP3522 is then allowed to run until the battery voltage
reaches the DDLO threshold, typically 2.4 V. Normally, the
battery voltage is monitored by the baseband processor, which
usually shuts the phone off at a battery voltage of around 3.0 V.
If the handset is off and the battery voltage drops below 3.0 V,
the UVLO circuit disables startup and puts the ADP3522 into
UVLO shutdown mode. In this mode, the ADP3522 draws very
low quiescent current, typically 30
μ
A. In DDLO mode, the
ADP3522 draws 15
μ
A of quiescent current. NiMH batteries can
reverse polarity if the 3-cell battery voltage drops below 3.0 V,
which will degrade the batteries’ performance. Lithium ion bat-
teries will lose their capacity if overdischarged repeatedly, so
minimizing the quiescent currents helps prevent battery damage.
RESET
The ADP3522 contains a reset circuit that is active both at
power-up and power-down. The
RESET
pin is held low at
initial power-up. An internal power good signal is generated by
the core LDO when its output is up, starting the reset delay
timer. The delay is set by an external capacitor on RESCAP:
t
ms
nF
C
RESET
RESCAP
=
×
1 2
(1)
At power-off,
RESET
will be kept low to prevent any baseband
processor starts.
Overtemperature Protection
The maximum die temperature for the ADP3522 is 125
°
C. If
the die temperature exceeds 160
°
C, the ADP3522 will disable
all the LDOs except the RTC LDO. The LDOs will not be
re-enabled before the die temperature is below 125
°
C, regard-
less of the state of
PWRONKEY
, PWRONIN, and CHRDET.
This ensures that the handset will always power off before the
ADP3522 exceeds its absolute maximum thermal ratings.
Battery Charging
The ADP3522 battery charger can be used with lithium ion
(Li+) and nickel metal hydride (NiMH) batteries. The charger
initialization, trickle charging, and Li+ charging are imple-
mented in hardware. Battery type determination and NiMH
charging must be implemented in software.
The charger block works in three different modes:
1. Low current (trickle) charging
2. Lithium ion charging
3. Nickel metal hydride charging
See Figure 5 for the charger flow chart.
Charge Detection
The ADP3522 charger block has a detection circuit that deter-
mines if an adapter has been applied to the CHRIN pin. If the
adapter voltage exceeds the battery voltage by 100 mV, the
CHRDET output will go high. If the adapter is then removed
and the voltage at the CHRIN pin drops to only 50 mV above
the BATSNS pin, CHRDET goes low. The CHRDET signal is
not asserted if the battery voltage is below the UVLO threshold.
Trickle Charging
When the battery voltage is below the UVLO threshold, the
charge current is set to the low current limit, or about 10% of
the full charge current. The low current limit is determined by
the voltage developed across the current sense resistor. There-
fore, the trickle charge current can be calculated by
I
mV
R
CHR TRICKLE
(
SENSE
)
=
20
(2)
Trickle charging is performed for deeply discharged batteries to
prevent undue stress on either the battery or the charger.
Trickle charging will continue until the battery voltage exceeds
the UVLO threshold.
Once the UVLO threshold has been exceeded, the charger will
switch to the default charge mode, the LDOs will start up, and
the baseband processor will start to run. The processor must
then poll the battery to determine which chemistry is present
and set the charger to the proper mode. Control of the charge
mode, Li+ or NiMH, is determined by the
CHGEN
input.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| ADP3522ACP-1.8 | GSM Power Management System |
| ADP3522ACP-3 | GSM Power Management System |
| ADP3604 | |
| ADP3604AR | Secondary Over-Voltage Protection for 2-4 cell in series Li-Ion/Poly (4.45V) 8-SM8 -40 to 110 |
| ADP3604* | Dual/Quad Rail-to-Rail Output, Picoamp Input Precision Op Amps; Package: SO; No of Pins: 8; Temperature Range: -40°C to +85°C |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| ADP3522ACP-1.8 | 制造商:AD 制造商全稱:Analog Devices 功能描述:GSM Power Management System |
| ADP3522ACP-1.8-RL | 制造商:Analog Devices 功能描述:GSM Power Management System 32-Pin LFCSP EP T/R |
| ADP3522ACP-1.8-RL7 | 制造商:Analog Devices 功能描述:GSM Power Management System 32-Pin LFCSP EP T/R |
| ADP3522ACP-3 | 制造商:AD 制造商全稱:Analog Devices 功能描述:GSM Power Management System |
| ADP3522ACP-3-REEL | 制造商:Analog Devices 功能描述:GSM Power Management System 32-Pin LFCSP EP T/R |
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