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參數(shù)資料
| 型號(hào)： | MAX1925 |
| 廠商： | Maxim Integrated Products, Inc. |
| 元件分類： | 數(shù)字信號(hào)處理 |
| 英文描述： | Fixed-Point Digital Signal Processor 548-FCBGA |
| 中文描述： | 開關(guān)模式單節(jié)Li+電池充電器 |
| 文件頁數(shù)： | 12/16頁 |
| 文件大?。?/td> | 443K |
| 代理商： | MAX1925 |
M
and a new battery is connected during either fast-charge
or full topoff modes, the charger begins with full charge
current without prequalification unless the part is reset.
Detect battery insertion by connecting THRM to a ther-
mistor on the battery, if a thermistor is used, or to a 10k
resistor linked to a battery door mechanism.
Constant-Current Mode (CCM)
When the battery voltage is below 4.2V, the
MAX1925/MAX1926 regulate the charging current by
controlling the peak and valley inductor currents. When
the inductor current exceeds the 158mV/R
SET
, the
MAX1925/MAX1926 turn the external PFET off. When
the inductor current falls below 128mV/R
SET
, the
MAX1925/MAX1926 turns the external PFET on, but
only if the battery voltage is below regulation. The maxi-
mum cell charging current is programmed by selecting
the external R
SET
(see Figure 1) resistor connected
between BATT and CS. Select the external resistor
value using R
SET
= 142mV/I
FASTCHG
.
The accuracy of the charge current is a function of
input voltage, battery voltage, inductance, and com-
parator delay (300ns typ). Determine the charge-cur-
rent error according to the following equation:
where
I
CHG
is the charge-current error, and t
IDelay
is
the current-sense comparator delay.
For this reason choose L for an on-time and off-time greater
than 2
t
IDelay
to minimize error in the charging current.
Constant-Voltage Mode (CVM)
In constant-voltage mode (CVM), the controller regu-
lates the peak and valley of the output ripple. The maxi-
mum cell voltage is regulated to 4.2V. If, for any reason,
the cell voltage exceeds 4.35V, a fault alarm is set, the
CHG
output blinks, and the PFET power switch is held
off. The charger can then be restarted only by cycling
input power or the EN input.
Indication of Charge Completion (
CHG
)
The
CHG
output is a 10mA current-sink output that indi-
cates the cell
’
s charging status. Connect an LED from
IN to
CHG
for a visible indicator. Alternatively, a pullup
resistor (typically 200k
) from a logic supply to
CHG
provides a logic-level output. Table 1 relates the status
of the LED to the condition of the charger and battery.
ACON
Output
The
ACON
open-drain output indicates when usable
power is applied to IN. In the MAX1926 when V
IN
exceeds
ACON
threshold (nominally 4.25V with IN ris-
ing
—
see the
Electrical Characteristics
table),
ACON
goes low. In the MAX1925,
ACON
goes low when the
input voltage is between 4.5V and 6.1V (see Table 2).
Re-Initiating a Charging Cycle
The MAX1925/MAX1926 feature automatic restart that
resumes charging when the cell voltage drops to 4V and
t
FULL_CHG
is completed. By automatically resuming charg-
=
×
2
(
)
×
×
I
V
V
t
L
CHG
IN
BATT
2
IDelay
Switch-Mode 1-Cell Li+ Chargers
12
______________________________________________________________________________________
STATE
OFF
PREQUAL1
PREQUAL2
FAST CHARGE
FULL CHARGE
FAULT PREQUAL1
FAULT PREQUAL2
CONDITION
CHG
EN low or no battery or
input power
Charge current = 4mA until BATT reaches 2V.
Charge current = C/10 until BATT reaches 3V.
Charge current = C = 142mV/R
SET
.
Charge current has fallen to C/8.
BATT does not reach 2V before PREQUAL1 timeout.
BATT does not reach 3V before PREQUAL2 timeout.
High impedance (LED off)
Low (LED on)
Low (LED on)
Low (LED on)
High impedance (LED off)
FAULT FULL
Charge current does not drop to C/8 before FULL CHARGE
timeout.
Blinking. LED on 50% f
BLINK
(0.5Hz). Can
only be cleared by cycling input power,
THRM, or EN.
FAULT BATT
VOLTAGE
Battery voltage has exceeded 4.35V.
Blinking. LED on 50% f
BLINK
(0.5Hz).
MAX1925
—
High impedance (LED off)
MAX1926
—
Blinking (LED on 50% 0.5Hz)
FAULT TEMP
Temperature has risen above +50
°
C or fallen below 0
°
C.
Temp fault clears by itself.
NONE
Initial power-up or enable with battery not present.
Blinking at rapid rate as charger cycles
through RESET, PREQUAL1, and DONE.
Table 1.
CHG
Output States
相關(guān)PDF資料 |
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| MAX1926 | Switch-Mode 1-Cell Li+ Chargers |
| MAX1926ETC | Switch-Mode 1-Cell Li+ Chargers |
| MAX1925ETC | Switch-Mode 1-Cell Li+ Chargers |
| MAX192AMJP | Low-Power, 8-Channel, Serial 10-Bit ADC |
| MAX192AEAP | Low-Power, 8-Channel, Serial 10-Bit ADC |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX1925ETC | 功能描述:電池管理 Switch-Mode 1-Cell Li+ Charger RoHS:否 制造商:Texas Instruments 電池類型:Li-Ion 輸出電壓:5 V 輸出電流:4.5 A 工作電源電壓:3.9 V to 17 V 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:VQFN-24 封裝:Reel |
| MAX1925ETC+ | 功能描述:電池管理 Switch-Mode 1-Cell Li+ Charger RoHS:否 制造商:Texas Instruments 電池類型:Li-Ion 輸出電壓:5 V 輸出電流:4.5 A 工作電源電壓:3.9 V to 17 V 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:VQFN-24 封裝:Reel |
| MAX1925ETC+T | 功能描述:電池管理 Switch-Mode 1-Cell Li+ Charger RoHS:否 制造商:Texas Instruments 電池類型:Li-Ion 輸出電壓:5 V 輸出電流:4.5 A 工作電源電壓:3.9 V to 17 V 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:VQFN-24 封裝:Reel |
| MAX1925ETC-T | 功能描述:電池管理 Switch-Mode 1-Cell Li+ Charger RoHS:否 制造商:Texas Instruments 電池類型:Li-Ion 輸出電壓:5 V 輸出電流:4.5 A 工作電源電壓:3.9 V to 17 V 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:VQFN-24 封裝:Reel |
| MAX1926ETC | 功能描述:電池管理 Switch-Mode 1-Cell Li+ Charger RoHS:否 制造商:Texas Instruments 電池類型:Li-Ion 輸出電壓:5 V 輸出電流:4.5 A 工作電源電壓:3.9 V to 17 V 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:VQFN-24 封裝:Reel |
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