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| 型号： | MAX1909ETI+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 18/30页 |
| 文件大小： | 0K |
| 描述： | IC CHARGER BATTERY 28-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 功能： | 充电管理 |
| 电池化学： | 多化学 |
| 电源电压： | 8 V ~ 28 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-WFQFN 裸露焊盘 |
| 供应商设备封装： | 28-TQFN-EP（5x5） |
| 包装： | 带卷 (TR) |
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Multichemistry Battery Chargers with Automatic
System Power Selector
The input range for ICTL is 0 to 3.6V on the MAX1909,
and 0 to 3.2V on the MAX8725. The charger shuts down
if ICTL is forced below 0.75V for the MAX1909 and 0.06V
for the MAX8725. When choosing current-sense resistor
RS2, note that it must have a sufficient power rating to
handle the full-load current. The sense resistor’s I 2 R
power loss reduces charger efficiency. Adjusting ICTL to
drop the voltage across the current-sense resistor
improves efficiency, but may degrade accuracy due to
the current-sense amplifier ’s input offset error. The
charge-current error amplifier (GMI) is compensated at
the CCI pin. See the Compensation section.
Conditioning Charge
The MAX1909 includes a battery voltage comparator
that allows a conditioning charge of overdischarged Li+
battery packs. If the battery-pack voltage is less than
3.1V x the number of cells programmed by MODE, the
MAX1909 charges the battery with 300mA current when
using sense resistor RS2 = 0.015 Ω . After the battery
voltage exceeds the conditioning charge threshold, the
MAX1909 resumes full-charge mode, charging to the
programmed voltage and current limits. The MAX8725
does not provide automatic support for providing a
conditioning charge. To configure the MAX8725 to pro-
vide a conditioning charge current, ICTL should be
directly driven.
Setting the Input Current Limit
The total input current, from a wall cube or other DC
source, is the sum of the system supply current and the
current required by the charger. The MAX1909/MAX8725
reduce the source current by decreasing the charge cur-
rent when the input current exceeds the set input current
limit. This technique does not truly limit the input current.
As the system supply current rises, the available charge
current drops proportionally to zero. Thereafter, the total
input current can increase without limit.
An internal amplifier compares the differential voltage
between CSSP and CSSN to a scaled voltage set with
the CLS input. V CLS can be driven directly or set with a
resistive voltage-divider between REF and GND.
Connect CLS to REF to set the input current-limit sense
voltage to the maximum value of 75mV. Calculate the
input current as follows:
Duty cycle affects the accuracy of the input current
limit. AC load current also affects accuracy (see the
Typical Operating Characteristics ). Refer to the
MAX1909/MAX8725 EV kit data sheet for more details
on reducing the effects of switching noise.
When choosing the current-sense resistor RS1, carefully
calculate its power rating. Take into account variations
in the system’s load current and the overall accuracy of
the sense amplifier. Note that the voltage drop across
RS1 contributes additional power loss, which reduces
efficiency.
System currents normally fluctuate as portions of the
system are powered up or put to sleep. Without input
current regulation, the input source must be able to
deliver the maximum system current and the maximum
charger input current. By using the input current-limit
circuit, the output current capability of the AC wall
adapter can be lowered, reducing system cost.
Current Measurement
The MAX1909/MAX8725 include an input current monitor
IINP. The current delivered at the IINP output is a scaled-
down replica of the system load current plus the input-
referred charge current that is sensed across CSSP and
CSSN inputs. The output voltage range is 0 to 3V.
The voltage of IINP is proportional to the input current
according to the following equation:
V IINP = I SOURCE ? R S1 ? G IINP ? R 9
where I SOURCE is the DC current supplied by the AC
adapter power, G IINP is the transconductance of IINP
(3mA/V typ), and R9 is the resistor connected between
IINP and ground.
Leave the IINP pin unconnected if not used.
LDO Regulator
LDO provides a 5.4V supply derived from DCIN and
can deliver up to 10mA of extra load current. The low-
side MOSFET driver is powered by DLOV, which must
be connected to LDO as shown in Figure 1. LDO also
supplies the 4.2235V reference (REF) and most of the
control circuitry. Bypass LDO with a 1μF capacitor.
Shutdown and Charge Inhibit ( PKPRES )
When the AC adapter is removed, the MAX1909/
× CLS
I IN =
0 . 075
RS 1
V
V REF
MAX8725 shut down to a low-power state that does not
significantly load the battery. Under these conditions, a
maximum of 6μA is drawn from the battery through the
V CLS determines the reference voltage of the GMS
error amplifier. Sense resistor RS1 sets the maximum
allowable source current. Once the input current limit is
reached, the charge current is decreased linearly until
the input current is below the desired threshold.
combined load of the SRC, CSSP, CSSN, CSIP, CSIN,
and BATT inputs. The charger enters this low-power state
when DCIN falls below the undervoltage-lockout (UVLO)
threshold of 7V. The PDS switch turns off, the PDL switch
turns on, and the system runs from the battery.
18
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1909EVKIT | 功能描述:电池管理 Evaluation Kit for the MAX1909 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 |
| MAX190ACNG | 功能描述:模数转换器 - ADC RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32 |
| MAX190ACNG+ | 功能描述:模数转换器 - ADC 12Bit 75ksps 5V Precision ADC RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32 |
| MAX190ACWG | 功能描述:模数转换器 - ADC RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32 |
| MAX190ACWG+ | 功能描述:模数转换器 - ADC 12Bit 75ksps 5V Precision ADC RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32 |
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