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参数资料
| 型号： | MAX1904EAI+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 20/33页 |
| 文件大小： | 0K |
| 描述： | IC CNTRLR PWR SPLY LN 28-SSOP |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,000 |
| 应用： | 控制器，笔记本电脑电源系统 |
| 输入电压： | 4.2 V ~ 30 V |
| 输出数： | 4 |
| 输出电压： | 2.5 V ~ 5 V |
| 工作温度： | 0°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-SSOP（0.209"，5.30mm 宽） |
| 供应商设备封装： | 28-SSOP |
| 包装： | 带卷 (TR) |
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500kHz Multi-Output, Low-Noise Power-Supply
Controllers for Notebook Computers
tor (primary) current, pulling current from the output fil-
ter capacitor and causing the flyback transformer to
operate in forward mode. The low impedance present-
ed by the transformer secondary in forward mode
dumps current into the secondary output, charging up
the secondary capacitor and bringing V DD or SECFB
back into regulation. The secondary feedback loop
does not improve secondary output accuracy in normal
flyback mode, where the main (primary) output is heavi-
ly loaded. In this condition, secondary output accuracy
is determined by the secondary rectifier drop, trans-
former turns ratio, and accuracy of the main output volt-
age. A linear post-regulator may still be needed to meet
strict output-accuracy specifications.
MAX1902 has a V DD pin that regulates at a fixed 13.5V,
set by an internal resistor-divider. The MAX1901/
MAX1904 have an adjustable secondary-output voltage
set by an external resistor-divider on SECFB (Figure 5).
Ordinarily, the secondary regulation point is set 5% to
10% below the voltage normally produced by the flyback
effect. For example, if the output voltage as determined
by turns ratio is 15V, set the feedback resistor ratio to pro-
duce 13.5V. Otherwise, the SECFB one-shot might be
triggered unintentionally, unnecessarily increasing supply
current and output noise.
12V Linear Regulator Output (MAX1902)
The MAX1902 includes a 12V linear regulator output
capable of delivering 120mA of output current.
Typically, greater current is available at the expense of
output accuracy. If an accurate output of more than
120mA is needed, an external pass transistor can be
added. The circuit in Figure 6 delivers more than
200mA. Total output current is constrained by the V+
input voltage and the transformer primary load (see
Maximum V DD Output Current vs. Input Voltage graphs
in the Typical Operating Characteristics ).
Design Procedure
The three predesigned 3V/5V standard application cir-
cuits (Figure 1 and Table 1) contain ready-to-use solu-
tions for common application needs. Also, one
standard flyback transformer circuit supports the
12OUT linear regulator in the Applications Information
section. Use the following design procedure to optimize
these basic schematics for different voltage or current
requirements. But before beginning a design, firmly
establish the following:
Maximum Input (Battery) Voltage, V IN(MAX) . This value
should include the worst-case conditions, such as no-
load operation when a battery charger or AC adapter is
SECFB
R2
12OUT
0.1 μ F
12V OUTPUT
200mA
10 μ F
1-SHOT
TRIG
2.5V REF
V+
R1
POSITIVE
SECONDARY
V DD
0.1 μ F
10 ?
2N3906
OUTPUT
DH_
MAX1902
V+
0.1 μ F
V DD OUTPUT
MAX1901
MAX1904
MAIN
OUTPUT
DH_
2.2 μ F
DL_
MAIN
OUTPUT
(
)
R1
+V TRIP = V REF 1 + –––
R2
WHERE V REF (NOMINAL) = 2.5V
DL_
Figure 5. Adjusting the Secondary Output Voltage with SECFB
Figure 6. Increased 12V Linear Regulator Output Current
20
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相关PDF资料 |
PDF描述 |
|---|---|
| MAX1902EAI+T | IC CNTRLR PWR SPLY LN 28-SSOP |
| UPM1A561MPD6 | CAP ALUM 560UF 10V 20% RADIAL |
| UPM1A561MPD | CAP ALUM 560UF 10V 20% RADIAL |
| MAX1901EAI+T | IC CNTRLR PWR SPLY LN 28-SSOP |
| UPM1A471MPD6 | CAP ALUM 470UF 10V 20% RADIAL |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1904EAI-TG074 | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX1904ETJ | 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 |
| MAX1904ETJ+ | 功能描述:DC/DC 开关控制器 500kHz Multi-Output Power-Supply Ctlr 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 |
| MAX1904ETJ+T | 功能描述:DC/DC 开关控制器 500kHz Multi-Output Power-Supply Ctlr 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 |
| MAX1904ETJ-T | 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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