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| 型号： | MAX17480EVKIT+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 39/48页 |
| 文件大小： | 0K |
| 描述： | EVALUATION KIT FOR MAX17480 |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 1 |
| 主要目的： | DC/DC，步降 |
| 输出及类型： | 3，非隔离 |
| 输入电压： | 4 ~ 26 V |
| 稳压器拓扑结构： | 降压 |
| 板类型： | 完全填充 |
| 已供物品： | 板 |
| 已用 IC / 零件： | MAX17480 |
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AMD 2-/3-Output Mobile Serial
VID Controller
? V
? ? ? V ?
L = ??
? ? OUT ?
? f SW LOAD ( MAX ) LIR ? ? V IN ?
( R ESR + R PCB ) ≤
( V ? V )
? I INDUCTOR = OUT IN OUT
V IN SW L
Core SMPS Design Procedure
Core Inductor Selection
By design, the AMD mobile serial VID application
should regard each of the MAX17480 SMPSs as inde-
pendent, single-phase SMPSs. The switching frequen-
cy and operating point (% ripple current or LIR)
determine the inductor value as follows:
V IN OUT
I ?
where I LOAD(MAX) is the maximum current per phase,
and f SW is the switching frequency per phase.
Find a low-loss inductor with the lowest possible DC
resistance that fits in the allotted dimensions. If using a
swinging inductor (where the inductance decreases lin-
early with increasing current), evaluate the LIR with
properly scaled inductance values. For the selected
inductance value, the actual peak-to-peak inductor
ripple current ( ? I INDUCTOR ) is defined by:
V
f
Ferrite cores are often the best choice, although pow-
dered iron is inexpensive and can work well at 200kHz.
The core must be large enough not to saturate at the
peak inductor current (I PEAK ):
where R SENSE is the resistance value of the current-
sense element (inductors’ DCR or current-sense resis-
tor), and I LIMIT(PK) is the desired peak current limit (per
phase). The peak current-limit threshold voltage adjust-
ment range is from 10mV to 50mV.
Core Output Capacitor Selection
The output filter capacitor must have low enough ESR to
meet output ripple and load-transient requirements. In
CPU V CORE converters and other applications where the
output is subject to large load transients, the output
capacitor’s size typically depends on how much ESR is
needed to prevent the output from dipping too low under a
load transient. Ignoring the sag due to finite capacitance:
V STEP
? I LOAD ( MAX )
In non-CPU applications, the output capacitor’s size
often depends on how much ESR is needed to maintain
an acceptable level of output ripple voltage. The output
ripple voltage of a step-down controller equals the total
inductor ripple current multiplied by the output capaci-
tor’s ESR. When operating multiphase systems out-of-
phase, the peak inductor currents of each phase are
staggered, resulting in lower output ripple voltage
(V RIPPLE ) by reducing the total inductor ripple current.
For nonoverlapping, multiphase operation (V IN ≥ V OUT ),
the maximum ESR to meet the output-ripple-voltage
? I LOAD ( MAX ) ? ? ? I
I PEAK = ? ?+ ?
INDUCTOR ?
?
?
? ?
V IN SW L
R ESR ≤ ?
? V RIPPLE
? η PH ? ?
2
requirement is:
f
? ?
? ( V IN ? V OUT ) V OUT ?
Core Peak Inductor Current Limit (ILIM12)
The MAX17480 overcurrent protection employs a peak
current-sensing algorithm that uses either current-
sense resistors or the inductor’s DCR as the current-
sense element (see the Current Sense section). Since
the controller limits the peak inductor current, the maxi-
mum average load current is less than the peak cur-
rent-limit threshold by an amount equal to half the
inductor ripple current. Therefore, the maximum load
capability is a function of the current-sense resistance,
inductor value, switching frequency, and input-to-out-
put voltage difference. When combined with the output
undervoltage-protection circuit, the system is effectively
protected against excessive overload conditions.
The peak current-limit threshold is set by the voltage
difference between ILIM and REF using an external
resistor-divider:
where f SW is the switching frequency per phase. The
actual capacitance value required relates to the physi-
cal size needed to achieve low ESR, as well as to the
chemistry of the capacitor technology. Thus, the capac-
itor selection is usually limited by ESR and voltage rat-
ing rather than by capacitance value (this is true of
polymer types).
The capacitance value required is determined primarily
by the output transient-response requirements. Low
inductor values allow the inductor current to slew faster,
replenishing charge removed from or added to the out-
put filter capacitors by a sudden load step. Therefore,
the amount of output soar when the load is removed is
a function of the output voltage and inductor value. The
minimum output capacitance required to prevent over-
shoot (V SOAR ) due to stored inductor energy can be
calculated as:
( ? I LOAD ( MAX ) )
2 V OUT SOAR
V CS(PK) = V CSP _ - V CSN _ = 0.052 x (V REF - V ILIM12 )
I LIMIT(PK) = V CS(PK) /R SENSE
C OUT ≥
V
2
L
______________________________________________________________________________________
39
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX17480EVKIT+ | 功能描述:电源管理IC开发工具 MAX17480 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 |
| MAX17480GTL+ | 功能描述:显示驱动器和控制器 2-/3-Output Mobile erial VID Ctlr RoHS:否 制造商:Panasonic Electronic Components 工作电源电压:2.7 V to 5.5 V 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:QFN-44 封装:Reel |
| MAX17480GTL+T | 功能描述:显示驱动器和控制器 2-/3-Output Mobile erial VID Ctlr RoHS:否 制造商:Panasonic Electronic Components 工作电源电压:2.7 V to 5.5 V 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:QFN-44 封装:Reel |
| MAX17482GTL+ | 功能描述:电压模式 PWM 控制器 NDA IC RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| MAX17482GTL+T | 功能描述:电压模式 PWM 控制器 NDA IC RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
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