参数资料
| 型号： | SC811ULTRT |
| 厂商： | Semtech |
| 文件页数： | 16/23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 (continued)
which is the safest default mode with the lowest fast-
charge current.
Enable Input
The ENB pin is a tri-level logical input that allows selection
of the following behaviors:
Note that if a GPIO with a weak pull-up input configura-
tion is used, its pull-up current will flow from the GPIO into
the ENB pin while it is floating to mid-range. Since the
GPIO is driving a 1V equivalent voltage source through a
resistance (looking into ENB), this current is small — pos-
sibly less than 1 μ A. Nevertheless, this current is drawn
?
?
?
charging enabled with float-charging after ter-
mination (ENB = low range)
charging enabled with float-charging disabled
and battery monitoring at termination (ENB =
mid range)
charging disabled (ENB = high range).
from the GPIO peripheral power supply and, therefore,
from the battery after termination. (See the next section,
Monitor State.) For this reason, it is preferable that the
GPIO chosen to operate the ENB pin should provide a true
high impedance (CMOS) configuration or a weak pull-
down when configured as an input. When pulled below
the float voltage, the ENB pin output current is sourced
If the ENB input voltage is permitted to float to mid-range,
the charger is enabled but it will turn off its output follow-
ing charge termination and will enter the monitor state.
This state is explained in the next section. Mid-range can
be selected either by floating the input (sourcing or
sinking less than 5μA) or by being externally forced such
that V ENB falls within the midrange limits specified in the
Electrical Characteristics table.
When driven low (V ENB < Max V IL ), the charger is enabled
and will continue to float-charge the battery following
termination. If the charger is already in monitor state fol-
lowing a previous termination, it will exit the monitor state
and begin float-charging.
When ENB is driven high (V ENB > Min V IH ), the charger is
disabled and the ENB input pin enters a high impedance
state, suspending tri-level functionality. The specified
high level input current I IH is required only until a high
level is recognized by the SC811/3 internal logic. The tri-
level float circuitry is then disabled and the ENB input
becomes high impedance. Once forced high, the ENB pin
will not float to mid range. To restore tri-level operation,
the ENB pin must first be pulled down to mid or low range
(at least to V ENB < Max V IM ), then, if desired, released (by
reconfiguring the GPIO as an input) to select mid-range. If
the ENB GPIO has a weak pull-down when configured as
an input, then it is unnecessary to drive ENB low to restore
tri-level operation; simply configure the GPIO as an input.
When the ENB selection changes from high-range to mid-
or low-range, a new charge cycle begins and STATB goes
low.
from VIN, not from the battery.
Monitor State
If the ENB pin is floating, the charger output and STATB pin
will turn off and the device will enter the monitor state
when a charge cycle is complete. If the battery voltage
falls below the re-charge threshold (V CV - V ReQ ) while in the
monitor state, the charger will automatically initiate a re-
charge cycle. The battery leakage current during monitor
state is no more than 1 μ A over temperature and typically
less than 0.1 μ A at room temperature.
While in the monitor state, the ENB tri-level input pin
remains fully active, and although in midrange, is sensitive
to both high and low levels. The SC811/3 can be forced
from the monitor state (no float-charging) directly to float-
charging operation by driving ENB low. This operation will
turn on the charger output, but will not assert the STATB
output. If the ENB pin is again allowed to float to mid-
range, the charger will remain on only until the output
current becomes less than the termination current, and
charging terminates. The SC811/3 turns off its charging
output and returns to the monitor state within a millisec-
ond. This forced re-charge behavior is useful for
periodically testing the battery state-of-charge and
topping-off the battery, without float-charging and
without requiring the battery to discharge to the auto-
matic re-charge voltage. ENB should be held low for at
least 1ms to ensure a successful forced re-charge.
Forced re-charge can be requested at any time during the
charge cycle, or even with no charging source present,
with no detrimental effect on charger operation. This
allows the host processor to schedule a forced re-charge
? 2008 Semtech Corporation
16
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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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