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参数资料
| 型号： | MAX8723ETE+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 11/18页 |
| 文件大小： | 0K |
| 描述： | IC REG FOR LCD DISPLAY 16-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 应用： | 转换器，LCD |
| 输入电压： | 6 V ~ 13.2 V |
| 输出数： | 1 |
| 输出电压： | 3.3V，2 V ~ 3.6 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（4x4） |
| 包装： | 带卷 (TR) |
Low-Cost, Internal-Switch, Step-Down
Regulator for LCD Displays
The output voltage is regulated by changing the duty
cycle of the high-side MOSFET. A bootstrap circuit that
uses a 0.1μF flying capacitor between LX and BST pro-
vides the supply voltage for the high-side gate driver.
Although the MAX8723 also includes a low-side MOS-
FET (20 ? , typ), this switch is only used to charge the
bootstrap capacitor during startup and maintain fixed-
frequency operation at no load, or to sink a small
amount load current. This MOSFET cannot be used as
a synchronous rectifier; an external Schottky diode or
MOSFET is required (Figure 1). If an external low-side
MOSFET switch (driven by EXT) is used as a synchro-
nous rectifier (Figure 3), the Schottky diode can be
omitted or replaced by a smaller device for even
greater efficiency.
PWM Controller Block
The heart of the PWM control block is a multi-input,
open-loop comparator that sums three signals: the out-
put voltage-feedback signal with respect to the refer-
ence voltage, the current-sense signal, and the slope
compensation. The PWM controller is a direct-summing
type, lacking a traditional error amplifier and the phase
shift associated with it. This direct-summing configura-
tion approaches ideal cycle-by-cycle control over the
output voltage.
The PWM controller operates in a fixed-frequency
mode. Each pulse from the oscillator sets the main
PWM latch that turns on the high-side switch until the
PWM comparator changes state. As the high-side
switch turns off, the low-side switch turns on. The low-
side switch stays on until the beginning of the next
clock cycle.
Inductor DCR Current Sensing and Current Limiting
The MAX8723 employs a type of current-mode control.
An internal sense network is built for this control
method. The sense network derives a current-sense
signal from the voltage across the inductor’s DC resis-
tance. This sensing method does not require additional
external components, thus, is cost, space, and power
efficient. The internal current-sense signal is AC-cou-
pled into the PWM comparator, eliminating most DC
output voltage variation under different load current.
The current-limit circuit turns off the high-side MOSFET
switch whenever the voltage across the high-side MOS-
FET exceeds an internal voltage threshold that corre-
sponds to an actual current of 2.75A (typ). This feature
guarantees the safe operation of MAX8723 under vari-
ous load conditions.
Soft-Start
To limit the inrush current during startup, the step-down
regulator includes a 7-bit DAC that steps its internal ref-
erence voltage from 0 to 2V in 128 steps. The soft-start
BST
LX
0.1 μ F
L
OUT
time is 1.7ms (typ) and FB fault detection is disabled
during soft-start. See Waveforms in the Typical
Operating Characteristics section.
Low-Frequency Operation
The step-down regulator of the MAX8723 enters low-
MAX8723
EXT
PGND
FDN339AN
(OPTIONAL)
C OUT
frequency operating mode if the voltage on OUT is
below 1.3V. In the low-frequency mode, the step-down
regulator switching frequency drops to 1/6 of the oscil-
lator frequency. This feature prevents potentially uncon-
OUT
trolled inductor current if OUT is overloaded or shorted
to ground.
Figure 3. Optional Synchronous Rectifier External MOSFET
______________________________________________________________________________________
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相关代理商/技术参数 |
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| MAX8723EVKIT | 功能描述:电源管理IC开发工具 MAX8723 Eval Kit RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| MAX8724AETI+ | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX8724ETI | 功能描述:电池管理 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 |
| MAX8724ETI+ | 功能描述:电池管理 Multichemistry Battery 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 |
| MAX8724ETI+T | 功能描述:电池管理 Multichemistry Battery 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 |
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