参数资料
型号: FAN5235MTC
英文描述: Analog IC
中文描述: 模拟IC
文件页数: 10/20页
文件大小: 123K
代理商: FAN5235MTC
FAN5201
10
P
If one AC adapter is connected when the battery is not
present, the overcurrent limit does not disable the converter
because Q1 acts as an inrush current limit.
If the battery voltage exceeds certain levels, internal protection
in the battery may open. To prevent this, the FAN5201
latches off Q1, Q3 and Q4 if the output voltage exceeds
approximately 110% of the setpoint.
The power converter is a synchronous buck for efficiency.
This topology is actually two-quadrant, and could potentially
draw current from the battery, boosting it high enough to
override the AC adapter. To prevent this backfeed, the
FAN5201 turns off the synchronous rectifier if the current into
the battery drops below 200mA (with an 18m
sense resis-
tor), utilizing instead the paralleled schottky.
If the internal overvoltage switch in the battery were to open
due to a high charge current producing a high voltage (due to
battery ESR), the voltage loop would take over. With the
voltage loop in control, the battery switch would close, and
the current could surge high until the current control loop
comes out of saturation. The FAN5201 prevents this type of
oscillation by means of a special loop controlling the error
amplifier of the current loop.
Battery Conditioning
With switch B1 off (see Figure 5), the notebook load can be
applied to the batteries even in the presence of the DC adapter.
This permits deep discharge of the batteries as part of the
battery conditioning process.
Battery Present
The presence of the battery can be detected by the host
microcontroller.
Logic Section
The FAN5201 uses serial data to control its operation. The
serial interface is compliant with the SMBus specification
(see “System Management Bus Specification”, Rev. 1.08).
Charger functionality is compatible with an extended subset
of the Intel/Duracell Smart Charger Specification for a level 2
charger. The FAN5201 uses the SMBus Read-Word, Write-
Word, and Block-Read protocols to communicate with the
host system that monitors the battery. The FAN5201 never ini-
tiates communication on the bus; it only receives commands
and responds to queries for status information. Figure 9
shows examples of the SMBus Write-Word and Read-Word
protocols. Each communication with the FAN5201 begins
with a start condition that is defined as a falling edge on SDA
with SCL high. The device address follows the start condi-
tion. The FAN5201 device address is 0001001b (b indicates
a binary number). Note that the address is only seven bits, and
the binary representation uses R/W as its least significant bit.
Programming a μP Interface for the FAN5201
The μP programmer must bear in mind that the FAN5201
operates as a slave device to the host μP; all communications
to the battery are
via
the host. Thus, in particular, the Charg-
ingCurrent(), ChargingVoltage(), and AlarmWarning() com-
mands (and thermistor signals for Ni based batteries) must
all be passed to the μP. There is no way to send them directly
to the charger.
Another important aspect for the programmer to be aware of
is that at power-up, all of the internal registers of the
FAN5201 are zeroed. Thus, in order to have the FAN5201
turn on, it is necessary to write to all of the DACs. It is also
recommended to write to the Control Signals Word before
writing to the DACs.
With these suggestions in mind, a possible flowchart for the
μP interface to the FAN5201 would be as shown in Figure 3.
In the first step, the battery charge requests are read; after
this the FAN5201 can be programmed. First, the FAN5201 is
left in Power Down until the programming has been success-
ful. Next, Charging Power, Current, and Voltage are set; the
FAN5201 will not operate until all three have been written.
The μP next checks that all of the data has been correctly
written; if not, the programming sequence is retried. Finally,
the Power Down signal is turned off.
Application Schematics and BOMs
Figure 4 shows the FAN5201 in a single battery pack system.
Figure 5 shows the FAN5201 in a two battery pack system.
In a two battery system, the host microcontroller must poll to
determine the state of each battery; and then a selector must
control the switches. Figure 4 shows a typical Smart Battery
system: for Ni based chemistries the temperature informa-
tion is handled directly by the μC. The μC continuously
monitors the SMBus; in case of communications breakdown
the μC detects this and takes appropriate action. For a NiMH
battery, a hardware overtemperature protection can be imple-
mented using a comparator on the thermistor line, and turn-
ing the softstart pin off.
Notice that Q1 through Q4 are drawn with the associated
intrinsic diode in Figure 4 and Figure 5.
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FAN5235MTC_Q 功能描述:DC/DC 开关控制器 Regulator System Electronics RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK
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FAN5235QSC 功能描述:DC/DC 开关控制器 Regulator System Electronics RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK
FAN5235QSC_Q 功能描述:DC/DC 开关控制器 Regulator System Electronics RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK
FAN5235QSCX 功能描述:DC/DC 开关控制器 Regulator System Electronics RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK