MC33771_datasheet翻译
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进入三种基本模式之一。在正常模式下，设备正在运行，执行必要的安全功能以及按需转换。诊断模式提供了诊断许多安全功能的完整性以及可能发生的内部或外部故障。从上电复位（POR）开始，33771必须在设备允许进入正常模式之前用设备地址进行初始化。在设备上电并未初始化的情况下，33771在t（init）超时时间后进入低功耗空闲模式。检测总线活动将33771传输到可以编程地址的初始化状态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，通过总线发送的命令直接通过变压器或通过SPI传输到33771。接收到有效消息后，33771执行命令操作，设备配置寄存器控制33771的工作特性在设备处于正常模式时都被编程。一旦编程，33771执行安全操作，如后台的过电压和欠压无需进一步指示从控制器。
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
典型应用
7.1 Introduction
简介
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.
飞思卡尔开发出支持集中分布式电池管理架构的IC芯片。集中式电池监控系统包含一个控制器模块，可以通过线束检测各个差分电池电压。分布式系统通过靠近锂离子电池的监控设备，和主MCU通信。将数据传送到主控MCU。
7.1.1 Centralized Battery Management System
集中式电池管理系统
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.
集中式系统包括单个传输驱动和在每个电池的隔离传输。通信系统是半双通菊花链主从网络。MC33664传输物理层（通过基于从MCU的SPI传出的位模式的相位编码-理解为SPI通信呗）。初始化每个33771时分配了指定的地址。通过系统初始化，消息从MCU发送给33771的菊花链。只有33771有正确的地址消息才会响应。由33771生成的相位编码响应由MC33664收发器接收并转换为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可以通过全局命令通信到所有从设备。当链中的每个从设备接收到全局命令时，不会产生响应。
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.
分离式电池管理系统。
分布式电池管理解决方案与集中式系统相同，在包装控制器中带有附加的变压器。菊花链设计用于支持最多15个远程节点，总线长度为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.
使用变压器进行隔离和通信具有重要的优势。脉冲变压器最明显的优点是高度的电压隔离。本文件中规定的变压器符合汽车级认证，额定值为3750 Vrms。
使用脉冲变压器，飞思卡尔电池管理系统可实现2.0 Mbps的通信速率，并具有非常低的辐射发射功率。变压器凭借磁耦合，强制二次信号成为真正的差分减少辐射发射同时提供隔离。变压器菊花链网络的另一个好处是能够将网络环回到控制器。此功能允许用户验证与菊花链中每个节点的通信。
