6 Modes of Operation
工作模式
After initializing the 33771 enters one of three basic modes. In Normal mode the device is in full operation performing the necessary safety
functions as well as on demand conversions. When commanded to Sleep mode, the device continues monitoring safety functions with
reduced current consumption. Diagnostic mode provides a method for diagnosing the integrity of many safety functions as well as internal
or external faults which may have occurred. From Power On Reset (POR), the 33771 must be initialized with a device address before the
device is allowed to enter Normal mode. In the event the device is powered up and not initialized, the 33771 enters the low-power Idle
mode after a t(init) timeout period. Detecting bus activity transfers 33771 to the initialization state INIT where the address can be
programmed.
初始化后，33771進入三種基本模式之一。在正常模式下，設備正在運行，執行必要的安全功能以及按需轉換。診斷模式提供了診斷許多安全功能的完整性以及可能發生的內部或外部故障。從上電復位（POR）開始，33771必須在設備允許進入正常模式之前用設備地址進行初始化。在設備上電並未初始化的情況下，33771在t（init）超時時間后進入低功耗空閑模式。檢測總線活動將33771傳輸到可以編程地址的初始化狀態INIT。
6.1 Normal Mode
In Normal mode, commands sent over the bus are directly ported through the transformer or through the SPI to the 33771. On reception
of a valid message, the 33771 executes the commanded operation. Device configuration registers control the operating characteristics of
the 33771 are all programmed while the device is in Normal mode. Once programmed, the 33771 performs safety operations like
overvoltage and undervoltage in the background without further instruction from the pack controller.
在正常模式下，通過總線發送的命令直接通過變壓器或通過SPI傳輸到33771。接收到有效消息后，33771執行命令操作，設備配置寄存器控制33771的工作特性在設備處於正常模式時都被編程。一旦編程，33771執行安全操作，如后台的過電壓和欠壓無需進一步指示從控制器。
To accomplish the safety operations in Normal mode, the 33771 performs a cyclic conversion sequence at the programmed timed interval.
In the event the 33771 receives an “On Demand” conversion request from the pack controller during a cyclic conversion, the device stops
the cyclic conversion and immediately starts the “On Demand” conversion cycle. Halting the cyclic conversion and performing the “On
Demand” conversion allows all 33771 devices in the system to achieve synchronized measurements. From Normal mode, the 33771 may
be commanded to Sleep mode or DIAG mode.
6.2 Sleep Mode
Sleep mode provides a method to significantly reduce battery current and the overall quiescent current of the Battery Management
system. In Sleep mode the overvoltage, undervoltage, and overtemperature protection circuitry remains cyclically active.
Based on the CYCLIC_TIMER setting the 33771 continues to perform cyclic conversion in Sleep mode. This is the meaning of the dotted
bubble labeled as CYCLIC_WUP in the state diagram shown in the Operating Mode State Diagram. The permanence time in the
CYCLIC_WUP transient state is really short: it is basically the time needed to turn on the VCOM power supply and to acquire 20 channels.
In the event a conversion value is greater than or less than the threshold value and the particular wake-up/fault is unmasked, the 33771
performs a bus wake-up and/or activate the FAULT pin.To let the 33771 enter SLEEP mode, the user has to set, by means of a global
command, the SYS_CFG_GLOBAL[GO2SLEEP] bit to logic 1. The 33771 can enter SLEEP mode also in case the bus communication
is not active for over tSLEEP time period (transition condition based on tSLEEP
is only available starting from Si pass 3.0).
6.3 Diagnostic Mode
In Diagnostic mode, the system controller has extended control of the 33771 in order to execute performance integrity checks of the
device. It is critical to note when the 33771 is in Diagnostic mode, cyclic conversions are halted and OV/UV/OT/UT detection is not
performed automatically. In order to perform OV/UV/OT/UT or any other protection feature which requires a conversion, an “On Demand”
conversion message must be sent by the pack controller.
In order to prevent the 33771 from remaining in Diagnostic mode without automatic OV/UV/OT/UT, a protection DIAG_TIMEOUT timer
has been implemented. In the event of the timeout, the 33771 reverts to Normal mode.
To enter Diagnostic mode, the user must set the SYS_CFG1[GO2DIAG] bit to logic 1. To exit Diagnostic mode, the user must clear the
GO2DIAG bit
6.4 IDLE Mode
The 33771 enters IDLE mode from POR when the communication bus is not active for the tIDLE time period. While the 33771 is in IDLE
Mode, no messages are recognized, only a valid wake-up sequence lets the device transition from IDLE mode to INIT mode. When the
33771 is configured as a SPI interface and enters IDLE mode, the device transitions from IDLE mode to INIT mode when a rising edge
of CSB is received and remains at logic 1 for CSBWU_FLT filter time period.
The CSB wake-up capability imply some system considerations when SPI communication is used. Assumed the CSB line is pulled up to
the same power supply used by the MCU: when the MCU commands the 33771 to go sleeping and then the MCU itself goes to sleep,
then both devices will sleep until the time the MCU wakes up; but when that happens, then also the 33771 will wake up, because the CSB
line will transition from low state to high state. If this behavior is not wished, the MCU has to take care to force the CSB line to the high
state during the whole sleep time
6.5 Operation with Fault Conditions
6.6 Internal Temperature Fault
In addition to the digital temperature measurement register, the 33771 is equipped with a silicon overtemperature thermal shutdown
(TSD). In the event the silicon thermal shutdown is activated in Normal mode, the 33771 halts all monitoring operations and enters a low-
power state with the FAULT pin activated. When the temperature of the die returns to normal level, the 33771 resumes operation in Normal
mode.
In the event of an internal TSD:
1. Conversion sequence is aborted and the 33771 stops converting.
2. The FAULT Pin is activated and the FAULT2_STATUS[IC_TSD_FLT] bit is set.
3. VCOM and VANA are in shutdown.
4. All Cell Balance Switches are disabled and CB_DRVEN cleared.
When the die temperature returns to normal level the 33771 resumes Normal mode operation with cell balancing disabled.
Overtemperature TSD events are also detected while the 33771 is in Sleep mode during cyclic measurements. TSD events detected
during the sleep mode cyclic measurement force the 33771 to set the IC_TSD_FLT bit and activate the FAULT pin while remaining in
Sleep mode. When the 33771 returns to normal operating temperature it transfers to Normal mode and initiates a wake-up sequence on
the bus.
6.6.1 FAULT Pin Daisy Chain Operation
The FAULT pin may be programmed to provide the Battery Management System with a safety pulse heart beat. Implementing the safety
heart beat provides a higher integrity level on the FAULT activation system. The pulse heart beat configuration can be activated in Normal
mode, Sleep mode, and Diagnostic mode. The pulse heart beat is implemented by programming register
SYS_CFG1[FAULT_WAVE,WAVE_DC_BITx] control bits of the battery pack highest potential cluster to produce the heart beat. This
heart beat signal is made into a current source and daisy chained to the next lower 33771 GPIO0 port. Subsequent 33771 devices are
programmed to pass the heart beat through to the next device in the system. In this configuration, any fault detected by each 33771 in
the system activates the FAULT pin high.
To configure the 33771 for Daisy Chain Fault output set the GPIO0 port as an input.
1. Set GPIO0 as an input GPIO0_CFG = 10.
2. Disable wake-up on GPIO0 with GPIO0_WU = 0.
3. Set GPIO0 to propagate signal to FAULT pin with GPIO0_FLT_ACT = 1.
To configure the 33771 to heart beat, the signal set the SYS_CFG1[FAULT_WAVE,WAVE_DC_BITx] to enable the heart beat and set
the desired off time.
6.7 User Safety Feature Summary
Freescale Semiconductor has implemented a comprehensive list of safety features in the 33771 can be used to facilitate the required
system Automotive Safety Integrity Level (ASIL).
Table 29. User Safety Feature Summary
7 Typical Applications
典型應用
7.1 Introduction
簡介
Freescale Semiconductor has developed a battery cell controller IC supporting both centralized and distributed battery management
architectures. Centralized battery monitoring systems contain a controller module sensing individual differential cell voltages through a
wiring harness. Distributed systems locate monitoring devices close to the lithium ion batteries and use a communication interface to
transfer data to the main controller MCU.
飛思卡爾開發出支持集中分布式電池管理架構的IC芯片。集中式電池監控系統包含一個控制器模塊，可以通過線束檢測各個差分電池電壓。分布式系統通過靠近鋰離子電池的監控設備，和主MCU通信。將數據傳送到主控MCU。
7.1.1 Centralized Battery Management System
集中式電池管理系統
A centralized system is comprised of a single transformer driver and isolation transformers between each battery cell controller IC.
The communication system is a half duplex 2.0 MHz daisy chain master/slave network. The MC33664 transformer physical layer creates
a phase encoded signal based on the bit pattern it receives from the MCU SPI transmit port. During initialization each 33771 device is
assigned a specific address. With the system initialized, messages sent from the MCU are received by each 33771 in the daisy chain.
Only the 33771 with the correct address acts upon and responds to the message. The phase encoded response generated by the 33771
are received by the MC33664 transceiver and converted to a SPI message for the MCU.
集中式系統包括單個傳輸驅動和在每個電池的隔離傳輸。通信系統是半雙通菊花鏈主從網絡。MC33664傳輸物理層（通過基於從MCU的SPI傳出的位模式的相位編碼-理解為SPI通信唄）。初始化每個33771時分配了指定的地址。通過系統初始化，消息從MCU發送給33771的菊花鏈。只有33771有正確的地址消息才會響應。由33771生成的相位編碼響應由MC33664收發器接收並轉換為MCU的SPI消息。
After initialization, the MCU may communicate globally to all slave devices by using global command. No response is generated when a
global command is received by each slave device in the chain.
初始化后，MCU可以通過全局命令通信到所有從設備。當鏈中的每個從設備接收到全局命令時，不會產生響應。
7.1.2 Distributed Battery Management System
The Distributed Battery Management solution is identical to the centralized system with an additional transformer in the pack controller.
The transformer daisy chain is designed to support up to 15 remote nodes with a total bus wire length of five meters.
分離式電池管理系統。
分布式電池管理解決方案與集中式系統相同，在包裝控制器中帶有附加的變壓器。菊花鏈設計用於支持最多15個遠程節點，總線長度為5米。
There are significant advantages to using transformers for isolation and communication. The most obvious benefit to the pulse
transformers is the high degree of voltage isolation. Transformers specified in this document are automotive qualified and rated at
3750 Vrms. Using pulse transformers allow the Freescale battery management system to achieve communication rates of 2.0 Mbps with
very low radiated emissions. Transformers by virtue of magnetic coupling, force the secondary signals to be true differential reducing
radiated emissions while providing isolation.
An added benefit to the transformer daisy chain network is ability to loop the network back to the Pack Controller. This feature allows the
user to verify communication to each node in the daisy chain.
使用變壓器進行隔離和通信具有重要的優勢。脈沖變壓器最明顯的優點是高度的電壓隔離。本文件中規定的變壓器符合汽車級認證，額定值為3750 Vrms。
使用脈沖變壓器，飛思卡爾電池管理系統可實現2.0 Mbps的通信速率，並具有非常低的輻射發射功率。變壓器憑借磁耦合，強制二次信號成為真正的差分減少輻射發射同時提供隔離。變壓器菊花鏈網絡的另一個好處是能夠將網絡環回到控制器。此功能允許用戶驗證與菊花鏈中每個節點的通信。