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WM8321GEFL/RV 参数 Datasheet PDF下载

WM8321GEFL/RV图片预览
型号: WM8321GEFL/RV
PDF下载: 下载PDF文件 查看货源
内容描述: 处理器电源管理子系统 [Processor Power Management Subsystem]
分类和应用:
文件页数/大小: 253 页 / 1578 K
品牌: WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
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Production Data  
WM8321  
11 DEVICE DESCRIPTION  
11.1 GENERAL DESCRIPTION  
The WM8321 is a multi-purpose Power Management device with a comprehensive range of features.  
The WM8321 provides 4 DC-DC synchronous buck converters and 11 LDO regulators which are all  
programmable to application-specific requirements. The on-board oscillator and two additional LDOs  
support the clocking and control functions for the DC-DC converters and other core functions.  
The WM8321 provides a 32.768kHz crystal oscillator and secure Real Time Clock (SRTC). An  
auxiliary ADC is included, for measurement of external voltages. Other features include flexible GPIO  
capability, and LED outputs for system status indications.  
Under typical operating conditions, the device is powered up and shut down under the control of the  
O¯¯N pin. The device executes a programmable sequence of enabling or disabling the DC-DC  
converters, LDOs and other functions when commanded to power up or shut down respectively. An  
alternate device state (SLEEP power state) is provided, in which selected functions may be  
separately configured for a low-power or other operating condition. The configuration of the normal  
operating state may be programmed into an integrated OTP non-volatile memory. If desired, the OTP  
memory can be programmed during device manufacture in accordance with the user’s specification.  
See Section 14 for details of the OTP and associated bootstrap configuration functions.  
In the absence of a main power supply, the WM8321 automatically reverts to a backup state, under  
which a minimal functionality is maintained to enable a smooth return to normal operation when the  
supply is restored. With a backup battery present, the RTC is updated in the backup state, allowing  
the main battery to be depleted or changed without loss of RTC function. Without a backup battery, a  
small capacitor is sufficient to maintain the RTC (unclocked) for up to 5 minutes.  
11.2 POWER STATES  
The WM8321 has 6 main power states, which are described below. Different levels of functionality are  
associated with each of the power states. Some of the state transitions are made autonomously by  
the WM8321 (eg. transitions to/from BACKUP are scheduled according to the available power supply  
conditions). Other transitions are initiated as a result of instructions issued over the Control Interface  
or as a result of software functions (eg. Watchdog timer) or hardware functions such as the O¯¯N pin.  
The valid transitions and the associated conditions are detailed below.  
NO POWER - This is the device state when no power is available. All functions are disabled and all  
register data is lost.  
OFF - This is the device state when power is available but the device is switched off. The RTC is  
enabled and the register map contents are maintained. The R¯¯E¯S¯E¯T¯ pin is pulled low in this state.  
LDO11 may optionally be enabled in this state; all other DC-DCs and LDOs are disabled (apart from  
LDO12, which supports internal functions).  
ON - This is the normal operating state when the device is switched on. All device functions are  
available in this state.  
SLEEP - This is a user-configurable operating state which is intended for a low-power operating  
condition. Selected functions may be enabled, disabled or re-configured according to the user’s  
requirements. A programmable configuration sequence for the DC-DCs and LDOs is executed on  
transition to/from SLEEP mode.  
BACKUP - This is the operating state when the PVDD power supply is below the reset threshold of  
the device. Typically, this means that the PVDD supply has been removed. All DC-DC converters and  
LDO regulators are disabled in this state. The RTC and oscillator and a ‘software scratch’ memory  
area can be maintained from the backup supply (if available) in this state. All other functions and  
registers are reset in BACKUP. (Note that, for power saving, an ‘unclocked’ mode, in which the RTC  
is held constant, may be selected if required.)  
PROGRAM - This is a special operating state which is used for programming the integrated OTP  
memory with the device configuration data. The settings stored in the OTP define the device  
configuration in the ON state, and also the time/sequencing data associated with ON/OFF power  
state transitions. See Section 14 for details of the OTP features.  
PD, February 2012, Rev 4.0  
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