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參數(shù)資料
| 型號： | LP3972 |
| 廠商： | National Semiconductor Corporation |
| 英文描述： | Power Management Unit for Advanced Application Processors |
| 中文描述： | 電源管理單元的高級應用處理器 |
| 文件頁數(shù)： | 50/59頁 |
| 文件大小： | 1072K |
| 代理商： | LP3972 |
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LP3972 Controls
(Continued)
GENERAL PURPOSE I/O FUNCTIONALITY (GPIO1 AND
GPIO2)
LP3972 has 2 general purpose I/Os for system control. I
2
C
compatible interface will be used for setting any of the pins to
input, output or hi-Z mode. Inputs value can be read via
serial interface (GPI1,2 bits). The pin 29 functionality needs
to be set to GPIO by serial interface register bit nEXTCH-
GEN. (GPIO/CHG)
Controls
Port Function
GPIO1
Input = 0
Input = 1
X
X
HiZ
Input (dig)-
>
Output = 0
Output = 1
Reg
Gpin 1
0
0
0
batmonchg
Function
Enabled
Not Enabled
GPIO
<
1
>
X
X
1
X
0
1
0
1
GPIO
<
1
>
X
X
0
X
0
0
1
1
Nextchgen_sel
1
1
1
X
0
0
0
0
bucen
0
0
X
1
X
X
X
X
Enabled
Input
0
0
GPIO
<
1
>
0
1
0
1
GPIO
<
1
>
0
0
1
1
Factory fm disabled
GPIO_tstiob
1
1
1
1
GPIO2
HiZ
Input (dig)-
>
Output = 0
Output = 1
gpin2
0
input
0
0
The LP3972 has provision for two battery connections, the
main battery Vbat and Backup Battery (See Applications
Schematic Diagrams 1 & 2 of the LP3972 Data Sheet).
The function of the battery switch is to connect power to the
RTC LDO from the appropriate battery, depending on con-
ditions described below:
If only the backup battery is applied, the switch will auto-
matically connect the RTC LDO power to this battery.
If only the main battery is applied, the switch will auto-
matically connect the RTC LDO power to this battery.
If both batteries are applied, and the main battery is
sufficiently charged (V
>
3.1V), the switch will auto-
matically connect the RTC LDO power to the main bat-
tery.
As the main battery is discharged by use, the user will be
warned by a separate circuit called nBATT_FLT. Then if
no action is taken to restore the charge on the main
battery, and discharging is continued the battery switch
will protect the RTC LDO by disconnecting from the main
battery and connecting to the backup battery.
— The main battery voltage at which the RTC LDO is
switched from main to backup battery is 2.9V typically.
— There is a hysterisis voltage in this switch operation
so, the RTC LDO will not be reconnected to main
battery until main battery voltage is greater than 3.1V
typically.
Additionally, the user may wish to disable the battery
switch, such as, in the case when only a main battery is
used. This is accomplished by setting the “no back up
battery bit” in the control register 8h’0B bit 7 NBUB. With
this bit set to “1”, the above described switching will not
occur, that is the RTC LDO will remain connected to the
main battery even as it is discharged below the 2.9 Volt
threshold.
REGULATED VOLTAGES OK
All the power domains have own register bit (X_OK) that
processor can read via serial interface to be sure that en-
abled powers are OK (regulating). Note that these read only
bits are only valid when regulators are settled (avoid reading
these bits during voltage change or power up).
L
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50
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| LP3972_08 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Power Management Unit for Advanced Application Processors |
| LP3972SQ-0514/NOPB | 功能描述:PMIC 解決方案 RoHS:否 制造商:Texas Instruments 安裝風格:SMD/SMT 封裝 / 箱體:QFN-24 封裝:Reel |
| LP3972SQ-5810/NOPB | 功能描述:監(jiān)控電路 Pwr Mgmt Unit RoHS:否 制造商:STMicroelectronics 監(jiān)測電壓數(shù): 監(jiān)測電壓: 欠電壓閾值: 過電壓閾值: 輸出類型:Active Low, Open Drain 人工復位:Resettable 監(jiān)視器:No Watchdog 電池備用開關:No Backup 上電復位延遲（典型值）:10 s 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:UDFN-6 封裝:Reel |
| LP3972SQ-A413 | 功能描述:PMIC 解決方案 RoHS:否 制造商:Texas Instruments 安裝風格:SMD/SMT 封裝 / 箱體:QFN-24 封裝:Reel |
| LP3972SQ-A413/NOPB | 功能描述:PMIC 解決方案 RoHS:否 制造商:Texas Instruments 安裝風格:SMD/SMT 封裝 / 箱體:QFN-24 封裝:Reel |
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