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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(yīng)用處理器 |
| 文件頁數(shù)： | 52/59頁 |
| 文件大?。?/td> | 1072K |
| 代理商： | LP3972 |
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Application Note - LP3972 Reset Sequence
INITIAL COLD START POWER ON SEQUENCE
1.
The Back up battery is connected to the PMU, power is
applied to the back-up battery pin, the RTC_LDO turns
on and supplies a stable output voltage to the
V
_BATT pin of the Applications processor (initiating
the power-on reset event) with nRSTO asserted from the
LP3972 to the processor.
2.
nRSTO de-asserts after a minimum of 50 mS.
3.
The Applications processor waits for the de-assertion of
nBATT_FLT to indicate system power (V
IN
) is available.
4.
After system power (V
) is applied, the LP3972 de-
asserts nBATT_FLT. Note that BOTH nRSTO and
nBATT_FLT need to be de-asserted before SYS_EN is
enabled. The sequence of the two signals is indepen-
dent of each other.
5.
The Applications processor asserts SYS_EN, the
LP3972 enables the system high-voltage power sup-
plies. The Applications processor starts its countdown
timer set to 125 mS.
The LP3972 enables the high-voltage power supplies.
— LDO1 power for V
_MVT (Power for internal logic
and I/O Blocks), BG (Bandgap reference voltage),
OSC13M (13 MHz oscillator voltage) and PLL en-
abled first, followed by others if delay is on.
Countdown timer expires; the Applications processor
asserts PWR_EN to enable the low-voltage power sup-
plies. The processor starts the countdown timer set to
125 mS period.
TheApplications processor asserts PWR_EN (ext. pin or
I
2
C), the LP3972 enables the low-voltage regulators.
Countdown timer expires; If enabled power domains are
OK (I
2
C read) the power up sequence continues by
enabling the processors 13 MHz oscillator and PLL’s.
10. The Applications processor begins the execution of
code.
6.
7.
8.
9.
20207622
* Note that BOTH nRSTO and nBATT_FLT need to be de-asserted before SYS_EN is enabled. The sequence of the two signals is independent of each other and
can occur is either order.
L
www.national.com
52
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相關(guān)代理商/技術(shù)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(fēng)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(fù)位:Resettable 監(jiān)視器:No Watchdog 電池備用開關(guān):No Backup 上電復(fù)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(fēng)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(fēng)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(fēng)格:SMD/SMT 封裝 / 箱體:QFN-24 封裝:Reel |
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