参数资料
| 型号： | NCP5314FTR2G |
| 厂商： | ON Semiconductor |
| 文件页数： | 19/29页 |
| 文件大小： | 0K |
| 描述： | IC CTLR CPU 2/3/4 PHASE 32-LQFP |
| 产品变化通告： | Product Discontinuation 01/Oct/2008 |
| 标准包装： | 2,000 |
| 应用： | 控制器，CPU |
| 输入电压： | 9.5 V ~ 13.2 V |
| 输出数： | 4 |
| 工作温度： | 0°C ~ 70°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 32-LQFP |
| 供应商设备封装： | 32-LQFP（7x7） |
| 包装： | 带卷 (TR) |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页当前第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页
NCP5314
3. Output Inductor Selection
For decreasing current:
The output inductor may be the most critical component
in the converter because it will directly effect the choice of
D tDEC + Lo @ D IO (VOUT)
(3.2)
other components and dictate both the steady?state and
transient performance of the converter. When selecting an
inductor, the designer must consider factors such as DC
current, peak current, output voltage ripple, core material,
magnetic saturation, temperature, physical size and cost
(usually the primary concern).
In general, the output inductance value should be
electrically and physically as small as possible to provide the
best transient response at minimum cost. If a large
inductance value is used, the converter will not respond
For typical processor applications with output voltages
less than half the input voltage, the current will be increased
much more quickly than it can be decreased. Thus, it may be
more difficult for the converter to stay within the regulation
limits when the load is removed than when it is applied and
excessive overshoot may result.
The output voltage ripple can be calculated using the
output inductor value derived in this Section (Lo MIN ), the
number of output capacitors (N OUT,MIN ) and the per
capacitor ESR determined in the previous Section:
quickly to rapid changes in the load current. On the other
hand, too low an inductance value will result in very large
ripple currents in the power components (MOSFETs,
VOUT,P?P + (ESR per cap NOUT,MIN) @
(VIN * #Phases @ VOUT) @ D (LoMIN @ fSW)
(4)
capacitors, etc.) resulting in increased dissipation and lower
converter efficiency. Increased ripple currents force the
designer to use higher rated MOSFETs, oversize the thermal
solution, and use more, higher rated input and output
capacitors, adversely affecting converter cost.
One method of calculating an output inductor value is to
size the inductor to produce a specified maximum ripple
current in the inductor. Lower ripple currents will result in
less core and MOSFET losses and higher converter
efficiency. Equation 3 may be used to calculate the
minimum inductor value to produce a given maximum
ripple current ( α ) per phase. The inductor value calculated
by this equation is a minimum because values less than this
will produce more ripple current than desired. Conversely,
higher inductor values will result in less than the selected
maximum ripple current.
This formula assumes steady?state conditions with no
more than one phase on at any time. The second term in
Equation 4 is the total ripple current seen by the output
capacitors. The total output ripple current is the “time
summation” of the four individual phase currents that are 90
degrees out?of?phase. As the inductor current in one phase
ramps upward, current in the other phase ramps downward
and provides a canceling of currents during part of the
switching cycle. Therefore, the total output ripple current
and voltage are reduced in a multi?phase converter.
4. Input Capacitor Selection
The choice and number of input capacitors is primarily
determined by their voltage and ripple current ratings. The
designer must choose capacitors that will support the worst
case input voltage with adequate margin. To calculate the
LoMIN +
(VIN * VOUT) @ VOUT
( a @ IO,MAX @ VIN @ fSW)
(3)
number of input capacitors, one must first determine the
total RMS input ripple current. To this end, begin by
calculating the average input current to the converter:
α is the ripple current as a percentage of the maximum
output current per phase ( α = 0.15 for ± 15%, α = 0.25 for
± 25%, etc.). If the minimum inductor value is used, the
inductor current will swing ± α % about its value at the
center. Therefore, for a four?phase converter, the inductor
IIN,AVG + IO,MAX @ D h
where:
D is the duty cycle of the converter, D = V OUT /V IN ;
η is the specified minimum efficiency;
(5)
must be designed or selected such that it will not saturate
with a peak current of (1 + α ) ? I O,MAX /4.
The maximum inductor value is limited by the transient
response of the converter. If the converter is to have a fast
transient response, the inductor should be made as small as
possible. If the inductor is too large its current will change
I O,MAX is the maximum converter output current.
The input capacitors will discharge when the control FET
is ON and charge when the control FET is OFF as shown in
Figure 24.
The following equations will determine the maximum and
minimum currents delivered by the input capacitors:
too slowly, the output voltage will droop excessively, more
bulk capacitors will be required and the converter cost will
be increased. For a given inductor value, it is useful to
determine the times required to increase or decrease the
current.
For increasing current:
IC,MAX + ILo,MAX h * IIN,AVG
IC,MIN + ILo,MIN h * IIN,AVG
I Lo,MAX is the maximum output inductor current:
ILo,MAX + IO,MAX f ) D ILo 2
(6)
(7)
(8)
D tINC + Lo @ D IO (VIN * VOUT)
(3.1)
where φ is the number of phases in operation.
I Lo,MIN is the minimum output inductor current:
ILo,MIN + IO,MAX f * D ILo 2
(9)
http://onsemi.com
19
相关PDF资料 |
PDF描述 |
|---|---|
| NCP5318FTR2G | IC CTLR CPU 2/3/4 PHASE 32-LQFP |
| NCP5322ADW | IC CTLR BUCK 2PH DRVR/DAC 28SOIC |
| NCP5331FTR2G | IC CTLR PWM 2PH W/DRVRS 32-LQFP |
| NCP5332ADW | IC CTLR BUCK 2PH DRVR/DAC 28SOIC |
| NCP5378MNR2G | IC CTLR 1PH SYNC BUCK 32QFN |
相关代理商/技术参数 |
参数描述 |
|---|---|
| NCP5314MNR2 | 功能描述:IC CTRLR BUCK CPU 2/3/4PH 32QFN RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - 专用型 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,000 系列:- 应用:电源，ICERA E400，E450 输入电压:4.1 V ~ 5.5 V 输出数:10 输出电压:可编程 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:42-WFBGA，WLCSP 供应商设备封装:42-WLP 包装:带卷 (TR) |
| NCP5316 | 制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:Four/Five/Six−Phase Buck CPU Controller |
| NCP5316/D | 制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:Four/Five/Six-Phase Buck CPU Controller |
| NCP5316_06 | 制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:Four/Five/Six−Phase Buck CPU Controller |
| NCP5316FTR2 | 功能描述:IC CTRLR BUCK CPU 4/5/6PH 48LQFP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - 专用型 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,000 系列:- 应用:电源，ICERA E400，E450 输入电压:4.1 V ~ 5.5 V 输出数:10 输出电压:可编程 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:42-WFBGA，WLCSP 供应商设备封装:42-WLP 包装:带卷 (TR) |
发布紧急采购，3分钟左右您将得到回复。