- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄361102 > NCP5214A (ON SEMICONDUCTOR) 2−in−1 Notebook DDR Power Controller PDF資料下載
參數(shù)資料
| 型號： | NCP5214A |
| 廠商： | ON SEMICONDUCTOR |
| 英文描述： | 2−in−1 Notebook DDR Power Controller |
| 文件頁數(shù)： | 19/31頁 |
| 文件大?。?/td> | 376K |
| 代理商： | NCP5214A |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁當前第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁
NCP5214A
http://onsemi.com
19
APPLICATION INFORMATION
Input Capacitor Selection for VDDQ Buck Regulator
The input capacitor is important for proper regulation
operation of the buck regulator. It minimizes the input
voltage ripple and current ripple from the power source by
providing a local loop for switching current. The input
capacitor should be placed close to the drain of the
highside MOSFET and source of the lowside MOSFET
with short, wide traces for connection. The input capacitor
must have large enough rms ripple current rating to
withstand the large current pulses present at the input of the
bulk regulator due to the switching current. The required
input capacitor rms ripple current rating can be estimated
by the following with minimum V
IN
:
ICIN(RMS)
IOUT
VOUT
VIN
VOUT
VIN
2
(eq. 1)
Besides, the voltage rating of the input capacitor should
be at least 1.25 times of the maximum input voltage.
Capacitance of around 20 F to 50 F should be sufficient
for most DDR applications. Ceramic capacitors are the
most suitable choice of input capacitor for notebook
applications due to their low ESR, high ripple current, and
high voltage rating. POSCAP or OSCON capacitors can
also be used since they have good ESR and ripple current
rating, but they are larger in size and more expensive.
Aluminum electrolytic capacitors are also a choice for their
high voltage rating and low cost, but several aluminum
capacitors in parallel should be used for the required ripple
current. If ceramic capacitors are used, X5R and X7R types
are preferred rather than the Y5V type since the X5R and
X7R types are ceramic capacitors and have smaller
tolerance and temperature coefficient.
Output Capacitor Selection for VDDQ Buck Regulator
The output filter capacitor plays an important role in
steady state output ripple voltage, load transient
requirement, and loop compensation stability. The ESR
and the capacitance of the output capacitor are the most
important parameters needed to be considered. In general,
the output capacitor must have small enough ESR for
output ripple voltage and load transient requirement.
Besides, the capacitance of the output capacitor should be
large enough to meet the overshoot and undershoot during
load transient. Since steady state output ripple voltage,
transient load undershoot and overshoot are the largest at
maximum V
IN
, the ESR and capacitance of output
capacitor should be estimated at the maximum V
IN
condition.
For steady output ripple voltage, both ESR and
capacitance of the output capacitor are the contributing
factors, however, the capacitor ESR is the dominant factor.
The output ripple voltage is calculated as follows:
Vripple
IL(ripple)
ESR
IL(ripple)
COUT
ton
(eq. 2)
Vripple
IL(ripple)
ESR, for small tonand large COUT
(eq. 3)
where I
L(ripple)
is the inductor ripple current, t
on
is ontime,
and C
OUT
is the output capacitance.
The inductor ripple current can be calculated by the
equation:
(VINVOUT)
L
IL(ripple)
VOUT
VIN
fSW
(eq. 4)
where L is the inductance and f
SW
is the switching
frequency. The output ripple voltage can be reduced by
either using the inductor with larger inductance or the
output capacitor with smaller ESR. Thus, the ESR needed
to meet the ripple voltage requirement can be obtained by:
Vripple
(VINVOUT)
The inductor ripple current is typically 30% of the
maximum load current and the ripple voltage is typically
2% of the output voltage. Thus, the above inequality can be
simplified to:
0.02
0.3
ESR
L
fSW
VIN
VOUT
(eq. 5)
ESR
VOUT
ILOAD(max)
(eq. 6)
For the load transient, the output capacitor contributes to
both the loadrise and the loadrelease responses. The
voltage undershoot during stepup load can be calculated
by the equation:
Vundershoot
ILOAD
ESR
ILOAD
COUT
1
VOUT
fSW
VIN
(eq. 7)
where I
LOAD
is the change in output current. If the second
term is ignored, then it becomes the following inequality:
Vundershoot
ESR
ILOAD
(eq. 8)
The maximum ESR requires to meet voltage undershoot
requirement at stepup load transient can be estimated
from the above inequality.
Then, the required output capacitor capacitance can be
obtained by the following:
COUT
ILOAD
Vundershoot ILOAD
ESR
1
VOUT
fSW
VIN
(eq. 9)
The output voltage overshoot during loadrelease is
because the excessive stored energy in the inductor is
absorbed by the output capacitor. The overshoot voltage
can be calculated by the following equation:
Vovershoot
LI2STEP(peak)
COUTV2OUT
COUT
VOUT
(eq. 10)
相關PDF資料 |
PDF描述 |
|---|---|
| NCP5214AMNR2G | 2−in−1 Notebook DDR Power Controller |
| NCP5214 | 2-in-1 Notebook DDR Power Controller |
| NCP5214MNR2 | 2-in-1 Notebook DDR Power Controller |
| NCP5218 | 2−in−1 Notebook DDR Power Controller |
| NCP5218MNR2G | 2−in−1 Notebook DDR Power Controller |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| NCP5214AMNR2G | 功能描述:DC/DC 開關控制器 OSPI 2 IN 1 NTEBOOK RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風格: 封裝 / 箱體:CPAK |
| NCP5214EVB | 功能描述:電源管理IC開發(fā)工具 ANA NCP5214 EVAL BRD RoHS:否 制造商:Maxim Integrated 產品:Evaluation Kits 類型:Battery Management 工具用于評估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V |
| NCP5214MNR2 | 功能描述:DC/DC 開關控制器 2-IN-1 NOTBOOK DDR CNTLR RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風格: 封裝 / 箱體:CPAK |
| NCP5214MNR2G | 功能描述:DC/DC 開關控制器 2-IN-1 NOTBOOK DDR CNTLR RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風格: 封裝 / 箱體:CPAK |
| NCP5215 | 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:Dual Synchronous Buck Controller for Notebook Power System |
發(fā)布緊急采購，3分鐘左右您將得到回復。