参数资料
型号: MAX1904EAI+T
厂商: Maxim Integrated Products
文件页数: 26/33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)
500kHz Multi-Output, Low-Noise Power-Supply
Controllers for Notebook Computers
Lossless-Inductor Current-Sensing
The DC resistance (DCR) of the inductor can be used
to sense inductor current to improve the efficiency and
to reduce the cost by eliminating the sense resistor.
Figure 7 shows the sense circuit, where L is the induc-
tance, R L is the inductor DCR, R S , and C S form an RC
low-pass sense network. If the time constant of the
inductor is equal to that of the sense network, i.e.:
Reduced Output Capacitance Application
In applications where higher output ripple is accept-
able, lower output capacitance or higher ESR output
capacitors can be used. In such cases, cycle-by-cycle
stability is maintained by adding feedforward compen-
sation to offset for the increased output ESR. Figure 8
shows the addition of the feedforward compensation
circuit. C FB provides noise filtering, R FF is the feedfor-
L
R L
= R S C S
ward resistor and C LX provides DC blocking. Use
100pF for C FB and C LX . Select R FF according to the
equation below:
then the voltage across C S becomes
V S = R L × I L
R FF ≤
4 × R3 × L × f
ESR
where I L is the inductor current.
Determine the required sense-resistor value using the
equation given in the Current-Sense Resistor Value
section. Choose an inductor with DCR equal or greater
than the sense resistor value. If the DCR is greater than
the sense-resistor value, use a divider to scale down
the voltage. Use the maximum inductance and mini-
mum DCR to get the maximum possible inductor time
constant. Select R S and C S so that the maximum sense
network time constant is equal or greater than the maxi-
mum inductor time constant.
V IN
Set the value for R FF close to the calculation. Do not
make R FF too small as that will introduce too much
feedforward, possibly causing an overvoltage to be
seen at the feedback pin, and changing the mode of
operation to a voltage mode.
PC Board Layout Considerations
Good PC board layout is required in order to achieve
specified noise, efficiency, and stability performance.
The PC board layout artist must be given explicit
instructions, preferably a pencil sketch showing the
placement of power-switching components and high-
current routing. A ground plane is essential for optimum
DH_
C IN
V IN
INDUCTOR
DH_
C IN
MAX1901
MAX1902
MAX1904
LX_
CSH_
CSL_
R S
L
R L
C S
V OUT
C OUT
CSL_
CSH_
LX_
MAX1901
MAX1902
MAX1904 FB_
C LX
L
R FF
R SENSE
C FB
V OUT
R3
C OUT
DL_
DL_
R4
Figure 7. Lossless Inductor Current Sensing
Figure 8. Adding Feedforward Compensation
26
______________________________________________________________________________________
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