参数资料
| 型号： | SC811ULTRT |
| 厂商： | Semtech |
| 文件页数： | 12/23页 |
| 文件大小： | 0K |
| 描述： | IC BATTERY MANAGEMENT |
| 标准包装： | 1 |
| 系列： | * |
| 其它名称： | SC811ULDKR |
SC811 / SC813
Applications Information
Charger Operation
The SC811/3 is a single input tri-mode stand-alone Li-ion
battery charger. (The SC811 differs from the SC813 only in
the input voltage Over Voltage Protection threshold.) It
provides selections of adapter mode and USB high and
low power mode charging. The device is independently
programmed for battery capacity dependent currents
(adapter fast-charge current and termination current)
using the IPRGM pin. Charging currents from the USB
Vbus supply, which has a maximum load specification, are
programmed using the IPUSB pin when either of the USB
modes is selected.
When an input supply is first detected, a charge cycle is
initiated and the STATB open-drain output goes low. If the
battery voltage is less than the pre-charge threshold
voltage, the pre-charge current is supplied. Pre-charge
current is 20% of the IPRGM (adapter or USB high power
modes) or IPUSB (USB low power mode) programmed
output. If the output is turned off upon termination, the
device enters the monitor state. In this state, the output
remains off until the BAT pin voltage decreases by the re-
charge threshold (VT ReQ ). A re-charge cycle then begins
automatically and the process repeats. A forced re-
charge cycle can also be periodically commanded by the
processor to keep the battery topped-off without float-
charging. See the Monitor State section for details.
Re-charge cycles are not indicated by the STATB pin.
Charging Input Pin Mode Dependencies
The UVLO rising and falling thresholds are adjusted with
the charging mode selected. In adapter mode, if the
charging current loads the adapter beyond its current
limit, the input voltage will be pulled down to just above
the battery voltage. The adapter mode UVLO falling
threshold is set close to the battery voltage pre-charge
threshold to permit low-dissipation charging from a
current limited adapter.
fast-charge current.
The USB modes provide a higher UVLO falling threshold
When the battery voltage exceeds the pre-charge thresh-
old, typically within seconds for a standard battery with a
starting cell voltage greater than 2V, the fast-charge
Constant Current (CC) mode begins. The charge current
soft-starts in three steps (20%, 60%, and 100% of pro-
grammed fast-charge current) to reduce adapter load
transients. CC current is programmed by the IPRGM resis-
tance to ground when adapter mode is selected and by
the IPUSB resistance to ground when either USB mode is
selected. In USB low power mode, the CC current is held
at 20% of the IPUSB programmed fast-charge current.
The charger begins Constant Voltage (CV) regulation
when the battery voltage rises to the fully-charged single-
cell Li-ion regulation voltage (V CV ), nominally 4.2V. In CV
regulation, the output voltage is regulated, and as the
battery charges, the charge current gradually decreases.
The STATB output goes high when I BAT drops below the
termination threshold current, which is 10% of the IPRGM
pin programmed fast-charge current regardless of the
mode selected. This is known as charge termination.
Optional Float-charging or Monitoring
Depending on the state of the ENB input, upon termina-
tion the SC811/3 either operates indefinitely as a voltage
regulator (known as float-charging) or it turns off its
applicable to the USB specification. The USB modes also
provide Under-Voltage Load Regulation (UVLR), in which
the charging current is reduced if needed to prevent
overloading of the USB Vbus supply. UVLR can serve as a
low-cost alternative to directly programming the USB
low power charge current. This can be beneficial for
charging small batteries, for which the USB high power
fast-charge current must be programmed to less than
500mA. The fixed 20% USB low power mode fast-charge
current would be less than 100mA and, therefore, is
unsuitable for minimum charge-time applications. UVLR
can also be used where there is no signal available to
indicate whether USB low or high power mode should be
selected.
All modes use the same input Over-Voltage Protection
(OVP) threshold as defined in the Electrical Characteristics
section for the device being used.
Constant Current Mode Fast-charge Current
Programming
Constant Current (CC) regulation is active when the
battery voltage is above VT PreQ and less than V CV . When
adapter mode is selected, the programmed CC regula-
tion fast-charge (FQ) current is inversely proportional to
? 2008 Semtech Corporation
12
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SC813 | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:Adapter/USB Tri-Mode Single-cell Li-ion Charger |
| SC813EVB | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:Adapter/USB Tri-Mode Single-cell Li-ion Charger |
| SC813M-PE-FOAM-BUTTON | 制造商:SUPER MICRO COMPUTER, INC. 功能描述:CSE-813MT-300CB FOAM SET BUTTON - Bulk |
| SC813M-PE-FOAM-TOP | 制造商:Supermicro Computer Inc 功能描述:CSE-813MT-300CB FOAM SET TOP - Bulk |
| SC813MT-300C | 制造商:Supermicro Computer Inc 功能描述:1U CHASSIS |
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