参数资料
| 型号： | NCP5322ADW |
| 厂商： | ON Semiconductor |
| 文件页数： | 27/31页 |
| 文件大小： | 0K |
| 描述： | IC CTLR BUCK 2PH DRVR/DAC 28SOIC |
| 产品变化通告： | Product Obsolescence 11/Feb/2009 |
| 标准包装： | 26 |
| 应用： | 控制器，高性能处理器 |
| 输入电压： | 4.5 V ~ 14 V |
| 输出数： | 2 |
| 输出电压： | 3.3V |
| 工作温度： | 0°C ~ 70°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-SOIC（0.295"，7.50mm 宽） |
| 供应商设备封装： | 28-SOIC |
| 包装： | 管件 |
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NCP5322A
3. Input Capacitor Selection
Use Equation 5 to determine the average input current to
the converter at full?load;
the input and output capacitors, and a maximum duty cycle
(D = (1.850 V + 30 mV AVP )/12.0 V IN = 0.157).
IIN,AVG + IO,MAX @ D h
(5)
+ 45 A @ (1.565 V 12 V) 0.81 + 5.87 A
Next, use Equations 6 to 10 with the full?load inductance
value of 770 nH:
D ILo + (VIN * VOUT) @ D (Lo @ fSW)
+ (12 V * 1.565 V) @
+ 8.03 App
(1.565 V 12 V)
(770 nH @ 220 kHz)
(10)
ILo,MAX + IO,MAX 2 ) D ILo 2
+ 45 A 2 ) 8.03 App 2 + 26.5 A
(8)
ILo,MIN + IO,MAX 2 * D ILo 2
+ 45 A 2 * 8.03 App 2 + 18.5 A
IC,MAX + ILo,MAX h * IIN,AVG
+ 26.5 A 0.81 * 5.87 A + 20.63 A
IC,MIN + ILo,MIN h * IIN,AVG
+ 18.5 A 0.81 * 5.87 A + 12.63 A
(9)
(6)
(7)
Figure 27. Actual DC/DC Converter Circuitry With the
Calculated Input Inductor and Minimum Filtering
Components. The Measured Slew?Rate (dI IN /dt) of
the Input Current (0.064 A/ m s) Is Much Lower Than
Expected (0.1 A/ m s) Because of Input Voltage Drop,
Parasitic Inductance, and Lower Real ESRs Than
Specified in the Capacitors’ Data Sheets.
First, use Equation 15 to calculate the voltage across the
output inductor due to the 45 A load current being shared
equally between the two phases:
For the two?phase converter, the input capacitor(s) RMS
current at full?load is then (Note: D = 1.565 V/12 V = 0.13):
D VLo + VIN * VOUT,NO?LOAD
) (IO,MAX 2) @ ESROUT NOUT
(15)
ICIN,RMS + [2D @ (IC,MIN2 ) IC,MIN @ D IC,IN
(11)
+ 12 V * 1.85 V ) 45 A 2 @ 13 m W 7
) D IC,IN2 3) ) IIN,AVG2 @ (1 * 2D)]1 2
+ [0.26 @ (12.632 ) 12.63 @ 8.00 ) 8.002 3)
) 5.872 @ (1 * 0.26)]1 2
+ 10.19 V
Second, use Equation 16 to determine the rate of current
increase in the output inductor when the load is first applied
(i.e. Lo has not changed much due to the DC current):
+ 9.69 ARMS
At this point, the designer must decide between saving
dILo dt + D VLo Lo
+ 10.19 V 1.1 m H + 9.26 V m s
(16)
board space by using higher?rated/more costly capacitors or
saving cost by using more lower?rated/less costly
Finally, use Equations 17 and 18 to calculate the minimum
input inductance value:
capacitors. To save board space, we choose the SP (Oscon)
series capacitors by Sanyo. Part number 16SP270: 270 m F,
16 V, 4.4 A RMS , 18 m W , 10 × 10.5 mm. This design will
require 9.69 A/4.4 A = 2.2 or N IN = 3 capacitors on the input
D VCi + ESRIN NIN @ dILo dt @ D fSW
+ 18 m W 3 @ 9.26 V m s @ 0.157 220 kHz
+ 39.7 mV
(17)
for a conservative design.
LiMIN + D VCi
dIIN dtMAX
(18)
4. Input Inductor Selection
The input inductor must limit the input current slew rate
to less than 0.5 A/ m s during a load transient from 0 to 45 A.
A conservative value will be calculated assuming the
minimum number of output capacitors (N OUT = 7), three
+ 39.7 mV 0.50 A m s + 80 nH
Next, choose the small, cost effective T30?26 core from
Micrometals (33.5 nH/N 2 ) with #16 AWG. The design
requires only 1.54 turns to achieve the minimum inductance
input capacitors (N IN = 3), worst case ESR values for both
http://onsemi.com
27
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相关代理商/技术参数 |
参数描述 |
|---|---|
| NCP5322ADWG | 制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:Two−Phase Buck Controller with Integrated Gate Drivers and 5−Bit DAC |
| NCP5322ADWR2 | 功能描述:DC/DC 开关控制器 2 Phase Buck w/Gate 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 |
| NCP5322ADWR2G | 制造商:Rochester Electronics LLC 功能描述: 制造商:ON Semiconductor 功能描述: |
| NCP5331 | 制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:Two-Phase PWM Controller with Integrated Gate Drivers |
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