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參數(shù)資料
| 型號： | MAX1873 |
| 廠商： | Maxim Integrated Products, Inc. |
| 英文描述： | Simple Current-Limited Switch-Mode Li Charger Controller |
| 中文描述： | 簡單的限流型開關(guān)模式Li+充電控制器 |
| 文件頁數(shù)： | 10/14頁 |
| 文件大小： | 206K |
| 代理商： | MAX1873 |
M
Charging-Current Regulator
The charging-current regulator limits the battery charg-
ing current. Current is sensed by the current-sense
resistor (R
CSB
in Figure 1) connected between BATT
and CSB. The voltage on ICHG/EN can also adjust the
charging current. Full-scale charging current (I
CHG
=
0.2V / RCSB) is achieved by connecting ICHG/EN to
REF. See
Setting the Charging-Current Limit
section for
more details.
The charging-current error amplifier is compensated at
CCI (Figure 1). A 47nF capacitor from CCI to GND pro-
vides suitable performance for most applications.
Input-Current Regulator
The input-current regulator limits the source current by
reducing charging current when the input current
reaches the set input-current limit. In a typical portable
design, system load current will normally fluctuate as
portions of the system are powered up or put to sleep.
Without the benefit of input-current regulation, the input
source would have to be able to supply the maximum
system current plus the maximum charger-input cur-
rent. The MAX1873 input-current loop ensures that the
system always gets adequate power by reducing
charging current as needed. By using the input-current
limiter, the size and cost of the AC adapter can be
reduced. See
Setting the Input-Current Limit
section for
design details.
Input current is measured through an external sense
resistor, R
CSS
, between CSSP and CSSN. The input-
current limit feature may be bypassed by connecting
CSSP to CSSN.
The input-current error amplifier is compensated at
CCS. A 47nF capacitor from CCS to GND provides suit-
able performance for most applications.
PWM Controller
The pulse-width modulation (PWM) controller drives the
external MOSFET at a constant 300kHz to regulate the
charging current and voltage while maintaining low
noise. The controller accepts inputs from the CCI, CCV,
and CCS error amplifiers. The lowest signal of these
three drives the PWM controller. An internal clamp limits
the noncontrolling signals to within 200mV of the con-
trolling signal to prevent delay when switching between
the battery-voltage control, charging-current control,
and input-current regulation loops.
Shutdown
The MAX1873 stops charging when ICHG/EN is pulled
low (below 0.5V) and shuts down when the voltage at
DCIN falls below the voltage at BATT. In shutdown, the
internal resistive voltage-divider is disconnected from
BATT to reduce the battery drain. When AC-adapter
power is removed, or when the part is shut down, the
MAX1873 typically draws 1.5μA from the battery.
Source Undervoltage Shutdown (Dropout)
The DCIN voltage is compared to the voltage at BATT.
When the voltage at DCIN drops below BATT + 50mV,
the charger turns off, preventing drain on the battery
when the input source is not present or is below the
battery voltage.
A diode is typically connected between the input
source and the charger input. This diode prevents the
battery from discharging through the body diode of the
high-side MOSFET should the input be shorted to GND.
It also protects the charger, battery, and systems from
reversed polarity adapters and negative input voltages.
Simple Current-Limited Switch-Mode
Li+ Charger Controller
10
______________________________________________________________________________________
VL
CSSN
CSSP
CCS
CCV
CCI
IOUT
VADJ
ICHG
/EN
DCIN
EXT
VH
GND
CSB
BATT
REF
5.4
REGULATOR
UNDERVOLTAGE
COMPARATOR
BATT
SHUTDOWN
FOR ALL
BLOCKS
VH
DRIVER
CONTROL
LOGIC
4.2V
REFERENCE
GND
VOLTAGE
ERROR AMP
CURRENT
ERROR AMP
R
R
9R
A = 1
Figure 2. Functional Block Diagram
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| MAX1873SEEE | Simple Current-Limited Switch-Mode Li Charger Controller |
| MAX1873REEE | Simple Current-Limited Switch-Mode Li Charger Controller |
| MAX1873TEEE | Simple Current-Limited Switch-Mode Li Charger Controller |
| MAX1874 | MAX1874 Evaluation Kit |
| MAX1874ETE | Dual-Input, USB/AC Adapter, 1-Cell Li+ Charger with OVP and Thermal Regulation |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX1873EVKIT | 功能描述:電池管理 Evaluation Kit for the MAX1873 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 |
| MAX1873REEE | 功能描述:電池管理 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 |
| MAX1873REEE+ | 功能描述:電池管理 Switch-Mode 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 |
| MAX1873REEE+T | 功能描述:電池管理 Switch-Mode 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 |
| MAX1873REEE-T | 功能描述:電池管理 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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