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参数资料
| 型号： | SC804 |
| 厂商： | Semtech Corporation |
| 英文描述： | Fully Integrated Lithium-Ion Battery Charger System with Timer |
| 中文描述： | 完全集成的锂离子电池充电器系统的计时器 |
| 文件页数： | 20/21页 |
| 文件大小： | 548K |
| 代理商： | SC804 |
8
2007 Semtech Corp.
www.semtech.com
SC804
PRELIMINARY
POWER MANAGEMENT
Fast-Charge Mode (CC)
The fast-charge CC (Constant Current) mode is active when
the battery voltage is above VT
PreQ and less than VCV. The
fast-charge current can be set to a maximum of 1.5A and
is selected by the program resistor on the IPRGM pin. The
voltage on this pin will represent the current through the
battery, enabling a microprocessor via an analog-to-digital
converter (ADC) to monitor battery current by sensing the
voltage on the IPRGM pin. The equation to set the fast-
charge current is given by:
The superior fast-charge current accuracy of the SC804
is obtained by use of a patented* polarity-switched (i.e.,
chopped) current sense amplier to nullify current mea-
surement offset errors.
Compliance with the absolute maximum output current
I
VOUTMAX, allowing for current regulation tolerance, requires
that R
IPRGM be no smaller than 1.05kΩ nominal.
R
IPRGM
can be as large as 11.5k
Ω, for a nominal FCI as small
as 130mA, but must exceed PCI by at least 80mA. Note
that for a given program resistor the current through
the battery in CV mode can be determined by replacing
V
IPRGM_Typ with the actual voltage on the IPRGM pin in the
above equation. The CC current can also be modied by
applying an analog voltage to the AFC pin as described
below.
Analog Fast Charge (AFC Pin)
Many applications require more than one current setting
for fast-charge. This behavior is obtained in the SC804
using the AFC function. When the AFC pin is connected
to VCC the device behaves as described in the previous
section. When the AFC pin is driven by an analog voltage
between 0V and (V
VCC-1.0)V, the SC804 automatically uses
this pin voltage to set the maximum fast-charge current
according to the following equation:
General Operation
The SC804 can be congured independently with respect
to fast-charge and termination current, output voltage,
and timing, depending on the application. A typical
charging cycle is described below. Details on alternative
applications and output programmability are covered in
the individual sections.
The charging cycle begins when the power adapter is
connected to the device. The SC804 performs glitch
ltering on the VCC input and initiates a charge cycle when
V
VCC is greater than the under-voltage lockout (UVLO) rising
threshold voltage. If the battery voltage is less than the
pre-charge threshold level, the SC804 will output the pre-
charge current. Once the pre-charge threshold voltage
is exceeded, the SC804 enters fast-charge constant
current (CC) mode. When the battery voltage reaches its
nal value, the charger enters the constant voltage (CV)
mode. In this mode the output current decreases as the
battery continues to charge until the termination current
level is reached. The CHRGB output turns off when IOUT
drops below the termination current. If the charge timer
is active, the SC804 continues to hold the battery in CV
charge mode until the timer expires. When the timer
expires the charger enters the monitor mode where the
output remains off until the voltage at VOUT drops by
VT
ReQ. At this point a new charge cycle is initiated.
Pre-Charge Mode
Pre-charge mode is automatically enabled whenever
the battery voltage is below the pre-charge threshold
voltage, VT
PreQ. It is used to limit the power dissipation and
precondition the battery for fast charging. The pre-charge
current value is determined by the resistor on the ITERM
pin. The pre-charge current is programmable from 50mA
to 350mA. The equation to select the pre-charge current
is given by:
Where V
ITERM_Typ designates the typical value of VITERM. When
the timer is enabled there is also a maximum allowed pre-
charge duration. If the pre-charge time exceeds 25% of
the total charge cycle the charger will turn off due to a
pre-charge fault. This fault is cleared when VCC is toggled
or the output voltage rises above VT
PreQ.
PCI =
V
ITERM_Typ
× 100
R
ITERM
V
IPRGM_Typ
× 1000
FCI =
R
IPRGM
FCI =
V
AFC
× 1000
R
IPRGM
Applications Information
*US Patent 6,836,095.
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相关代理商/技术参数 |
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| SC804A | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:Fully Integrated 4.4V Lithium-Ion Battery Charger System with Timer |
| SC804AMLTRT | 功能描述:IC LI-ION BATT CHARGER 16-MLPQ RoHS:是 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 标准包装:1 系列:- 功能:充电管理 电池化学:锂离子（Li-Ion）、锂聚合物（Li-Pol） 电源电压:3.75 V ~ 6 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SC-74A，SOT-753 供应商设备封装:SOT-23-5 包装:剪切带 (CT) 产品目录页面:669 (CN2011-ZH PDF) 其它名称:MCP73831T-2ACI/OTCT |
| SC804EVB | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:Fully Integrated 4.4V Lithium-Ion Battery Charger System with Timer |
| SC804IML.TRT | 功能描述:IC LI-ION BATTERY CHRGR 16MLPQ RoHS:是 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 标准包装:1 系列:- 功能:充电管理 电池化学:锂离子（Li-Ion）、锂聚合物（Li-Pol） 电源电压:3.75 V ~ 6 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SC-74A，SOT-753 供应商设备封装:SOT-23-5 包装:剪切带 (CT) 产品目录页面:669 (CN2011-ZH PDF) 其它名称:MCP73831T-2ACI/OTCT |
| SC804IMLTRT | 制造商:Semtech Corporation 功能描述:Battery Charger Li-Ion 1500mA 4.2V 16-Pin MLPQ EP T/R |
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