參數(shù)資料
型號(hào)： SC804A
廠商： Semtech Corporation
英文描述： Fully Integrated 4.4V Lithium-Ion Battery Charger System with Timer
中文描述： 完全集成的4.4V鋰離子電池充電器系統(tǒng)的計(jì)時(shí)器
文件頁(yè)數(shù)： 20/21頁(yè)
文件大?。?/td> 550K
代理商： SC804A
8
2005 Semtech Corp.
www.semtech.com
SC804A
PRELIMINARY
POWER MANAGEMENT
DRAFT
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 SC804A
is obtained by use of a patented* polarity-switched
(i.e., chopped) current sense amplier to nullify current
measurement 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. RIPRGM can
be as large as 12.1k
Ω, for a nominal FCI as small as 130
mA, but must exceed PCI by at least 80mA. Note that for
a given program resistor the current into 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 SC804A
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 SC804A automatically
uses this pin voltage to set the maximum fast-charge
current according to the following equation:
This adjustment to the fast charge current is obtained
by replacing the xed V
IPRGM reference voltage with the
General Operation
The SC804A 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 SC804A 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 SC804A will output the
pre-charge current. Once the pre-charge threshold voltage
is exceeded, the SC804A 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 SC804A 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.
Applications Information
PCI =
V
ITERM_Typ
× 100
R
ITERM
FCI =
V
AFC
× 1000
R
IPRGM
*US Patent 6,836,095.
× 1000
FCI =
R
IPRGM
V
IPRGM_Typ
相關(guān)PDF資料
PDF描述
SC804EVB Fully Integrated Lithium-Ion Battery Charger System with Timer
SC804IMLTRT Fully Integrated Lithium-Ion Battery Charger System with Timer
SC804 Fully Integrated Lithium-Ion Battery Charger System with Timer
SC805EVB Miniature Integrated High Current Lithium-Ion Battery Charger
SC805IMLTRT Miniature Integrated High Current Lithium-Ion Battery Charger
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
SC804AMLTRT 功能描述:IC LI-ION BATT CHARGER 16-MLPQ RoHS:是 類別:集成電路 (IC) >> PMIC - 電池管理 系列:- 標(biāo)準(zhǔn)包裝:1 系列:- 功能:充電管理 電池化學(xué):鋰離子（Li-Ion）、鋰聚合物（Li-Pol） 電源電壓:3.75 V ~ 6 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:SC-74A，SOT-753 供應(yīng)商設(shè)備封裝:SOT-23-5 包裝:剪切帶 (CT) 產(chǎn)品目錄頁(yè)面:669 (CN2011-ZH PDF) 其它名稱:MCP73831T-2ACI/OTCT
SC804EVB 制造商:SEMTECH 制造商全稱: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 類別:集成電路 (IC) >> PMIC - 電池管理 系列:- 標(biāo)準(zhǔn)包裝:1 系列:- 功能:充電管理 電池化學(xué):鋰離子（Li-Ion）、鋰聚合物（Li-Pol） 電源電壓:3.75 V ~ 6 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:SC-74A，SOT-753 供應(yīng)商設(shè)備封裝:SOT-23-5 包裝:剪切帶 (CT) 產(chǎn)品目錄頁(yè)面:669 (CN2011-ZH PDF) 其它名稱: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
SC805 制造商:SEMTECH 制造商全稱:Semtech Corporation 功能描述:Miniature Integrated High Current Lithium-Ion Battery Charger
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