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参数资料
| 型号： | MAX1926ETC+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 14/16页 |
| 文件大小： | 0K |
| 描述： | IC CHARGER LI+ 12-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 75 |
| 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： | 4.5 V ~ 12 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 12-WQFN 裸露焊盘 |
| 供应商设备封装： | 12-TQFN-EP（4x4） |
| 包装： | 管件 |
Switch-Mode 1-Cell Li+ Chargers
R ESR > × R SET
mode. To ensure stable transition from CCM to CVM
choose a capacitor with the following ESR:
V VHIST
V IHIST
where V VHIST is the voltage hysteresis (15mV typ) and
V IHIST is the current-sense threshold hysteresis (typi-
cally 30mV). Tantalum capacitors are recommended.
However a ceramic capacitor (typically 10μF) with a
series resistor can also be used.
MOSFET Selection
The MAX1925/MAX1926 drive an external P-channel
MOSFET ’ s gate from IN to GND. Choose a P-channel
MOSFET with a |V DS,MAX | > V IN . Since EXT drives from
rail to rail the MOSFET must also be rated for |V GS,MAX |
> V IN . At the lower operating frequencies and currents
for typical MAX1925/MAX1926 applications resistive
and diode losses dominate switching losses. For this
reason choose a MOSFET with a low R DSON . The resis-
tive losses are:
P Resistive_losses ? D ? I CHG 2 ? R DSON + I CHG 2 ?
(R SET + R L )
where D is the operating duty cycle (V OUT /V IN ) and R L
is the inductor resistance. The MOSFET ’ s power dissi-
pation must exceed D ? I CHG 2 ? R DSON .
This results in an average current of 142mV/R SET . At
input voltages near dropout (4.6V at IN for the typical
circuit), the inductor current ramp waveform becomes
somewhat flattened as inductor, MOSFET, input diode,
and battery resistance limit inductor current. When the
inductor current waveform flattens, it ’ s average value
rises with respect to the upper and lower current
thresholds. This creates a slight peak (about 5%) in
charging current at high battery voltages as seen in the
Charging Current vs. Battery Voltage plot in the Typical
Operating Characteristics . Charging current is still con-
trolled in dropout and the charger operates normally.
The dropout current peak can be minimized by reduc-
ing MOSFET and inductor resistance, as well as for-
ward voltage in the input diode.
Thermistor Interface
An external thermistor inhibits charging by setting a
fault flag when the cell is cold (<0 ° C) or hot (>+50 ° C).
The THRM time-multiplexes two sense currents to test
for both hot and cold qualification. Connect the thermis-
tor between THRM and GND. If no temperature qualifi-
cation is desired, replace the thermistor with a 10k ?
resistor connected through the battery-latch mecha-
nism. The thermistor should be 10k ? at +25 ° C and
have a negative temperature coefficient, as defined by
the expression below:
? ? ? 1
? β ? ?
R T = R 25 ° C × e ? ? ? T + 273
? ? 1 ? ? ? ?
? ? 298 ? ? ? ?
Diode Selection
In the event of a short-circuited source, the body diode
inherent in the external PFET allows the cell to dis-
?
? ? ? ? ? ?
charge. To prevent this and to protect against negative
input voltages, add a Schottky or silicon diode between
the power source and IN.
The MAX1925/MAX1926 use a diode for catching the
inductor current during the off cycle. Select a Schottky
diode with a current rating greater than V IPK /R SET and
a voltage rating greater than V IN .
Table 3 shows nominal fault detection temperatures
that result from a wide range of available thermistor
temperature curves.
For a given thermistor characteristic, it is possible to
adjust the fault-detection temperatures by adding a
resistor in series with the thermistor or a parallel resistor
from THRM to GND.
Dropout Behavior
The MAX1925/MAX1926 regulate charging current by
ramping inductor current between upper and lower
thresholds, typically 128mV and 158mV across R SET .
TRANSISTOR COUNT: 5722
PROCESS: BiCMOS
Chip Information
Table 3. Fault Temperature for Different Thermistors
THERMISTOR BETA
Resistance at +25 ° C
Resistance at +50 ° C
Resistance at 0 ° C
Nominal Hot Trip Temperature
Nominal Cold Trip Temperature
3000
10000 ?
4587.78 ?
25140.55 ?
55.14 ° C
-3.24 ° C
3250
10000 ?
4299.35 ?
27148.09 ?
52.60 ° C
-1.26 ° C
3500
10000 ?
4029.06 ?
29315.94 ?
50.46 ° C
0.46 ° C
3750
10000 ?
3775.75 ?
31656.90 ?
48.63 ° C
1.97 ° C
14
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相关代理商/技术参数 |
参数描述 |
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| MAX1926ETC+ | 功能描述:电池管理 Switch-Mode 1-Cell Li+ Charger RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| MAX1926ETC+T | 功能描述:电池管理 Switch-Mode 1-Cell Li+ Charger RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| MAX1926ETC-T | 功能描述:电池管理 Switch-Mode 1-Cell Li+ Charger RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| MAX1926EVKIT | 功能描述:电池管理 Evaluation Kit for the MAX1925 MAX1926 RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| MAX1927REUB | 功能描述:直流/直流开关转换器 800mA PWM Step-Down DC/DC Converter RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
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