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| 型号： | MAX1874ETE+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 12/17页 |
| 文件大小： | 0K |
| 描述： | IC LI+ CHARGER DUAL-IN 16-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 60 |
| 功能： | 充电管理 |
| 电池化学： | 锂离子（Li-Ion） |
| 电源电压： | 4.35 V ~ 6.5 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-WQFN 裸露焊盘 |
| 供应商设备封装： | 16-TQFN-EP（5x5） |
| 包装： | 托盘 |
| 产品目录页面： | 1410 (CN2011-ZH PDF) |
Dual-Input, USB/AC Adapter, 1-Cell
Li+ Charger with OVP and Thermal Regulation
The MAX1874 ’ s thin QFN package includes a bottom
metal plate that reduces thermal resistance between the
die and the PCB. The external pad should be soldered to
a large ground plane. This helps dissipate power and
keeps the die temperature below the thermal limit. The
REF
MAX1874 thermal resistance from the die to the package
thermal pad is typically 5 ° C/W. The thermal resistance of
1in 2 of 1oz copper on typical FR4 PC board material in
0.1 μ F
10k ?
THRM
100mV
TO REGULATOR
free air is +42 ° C/W (typ). Consequently, the PC board
pad area dominates the MAX1874 ’ s ability to dissipate
heat. The MAX1874 ’ s thermal regulator is set for a
+105 ° C die temperature. With the example thermal resis-
tance of +47 ° C/W, the MAX1874 charge-current thermal
limiting can be expected to occur when dissipating
approximately 1.7W at +25 ° C ambient, and when dissi-
pating approximately 0.75W at +70 ° C ambient.
The power dissipated in the charger is P DISS = [V IN
(either V USB or V DCLV ) - V BATT ] ? I CHARGE . Power dis-
sipation drops as the battery voltage rises, so thermal-
charge current limiting, if it occurs, typically releases
soon after charging begins and has little impact on
charge time.
External Thermistor Monitor (THRM)
The MAX1874 features an internal window comparator to
monitor battery pack temperature or ambient tempera-
ture with an external negative temperature coefficient
thermistor. In typical systems, temperature is monitored
to prevent charging at ambient temperature extremes
(below 0 ° C or above +50 ° C). When the temperature
moves outside these limits, charging is stopped. If the
V THERM returns to within its normal window, charging
resumes. Connect THRM to GND when not using this
feature. The THRM block diagram is detailed in Figure 1.
Note that the temperature monitor at THRM is entirely
separate from the on-chip temperature limiting dis-
cussed in the Package Thermal Limiting section.
The input thresholds for the THRM input are 0.74 ?
V REF for the COLD trip point and 0.29 ? V REF for the
HOT trip point.
Applications Information
Input Overvoltage Protection Switch
The DCLV input from an AC adapter or other source
can be protected against overvoltage of up to 18V by
connecting an external P-channel MOSFET (Q2 in
Figures 3, 4, and 5) between DC and DCLV. When V DC
exceeds 6.2V, the DCOK output turns the P-channel
MOSFET off. On power-up, DCOK remains high until it
has been verified that V DC is in range. If protection
above 6.5V is not needed, then the MOSFET from the
DC to DCLV can be omitted (Figure 2).
T COLD
THERMISTOR
10K ? AT +25 ° C
T HOT
Figure 1. Thermistor Sensing Block Diagram
Battery-Load Switch
When input power is connected to the charger, some
systems prefer that the battery is disconnected from the
load and that system load current is taken directly from
the DC input or USB source. This is an alternative to the
basic case where the system load is permanently con-
nected to the battery. The later setup is lower cost but
has the disadvantage that if the battery is completely
discharged, the system might not be ready to operate
immediately, or might have limited functionality immedi-
ately upon plugging in the charger. If the battery has a
load-disconnect switch, the system is more complex,
but operation does not depend on the state of the bat-
tery. When system power is taken from the DC or USB
input source, use D1, D2, Q1, and Q2 (Figure 4).
A partial approach to battery-load switching can con-
nect the AC power adapter (DC) directly to the load, but
not USB power (Figure 5). This can be useful when USB
power is insufficient to fully power the system and
charge the battery. When DC is powered, D2 provides a
direct connection to the system and Q3 disconnects the
battery. The battery does not power the load while it is
charging. When only USB is connected, there is no
bypass path from USB to the system. The battery is
charged from the BATT output, and any system power is
drawn from the battery through D5. If the system load
exceeds the current supplied by the charger from USB
(500mA or 100mA), then the battery can still discharge.
In addition, if the system load does not allow the BATT
current to fall below the USB battery full current thresh-
old listed in Table 2, then CHG does not go high to indi-
cate a full battery.
12
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1874ETE+ | 功能描述:电池管理 Dual-Input USB/AC Adapter 1-Cell Li+ 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 |
| MAX1874ETE+T | 功能描述:电池管理 Dual-Input USB/AC Adapter 1-Cell Li+ 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 |
| MAX1874ETE-T | 功能描述:电池管理 Dual-Input USB/AC Adapter 1-Cell Li+ 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 |
| MAX1874EVKIT | 功能描述:电池管理 Evaluation Kit for the MAX1874 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 |
| MAX1875AEEG | 功能描述:DC/DC 开关控制器 RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
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