参数资料
| 型号： | NCP5389MNR2G |
| 厂商： | ON Semiconductor |
| 文件页数： | 22/28页 |
| 文件大小： | 0K |
| 描述： | IC CTLR BUCK 2/3PHASE 32-QFN |
| 产品变化通告： | Product Discontinuation 01/Oct/2008 |
| 标准包装： | 3,000 |
| 应用： | 控制器，Intel Pentium? IV |
| 输入电压： | 10.8 V ~ 13.2 V |
| 输出数： | 3 |
| 工作温度： | 0°C ~ 70°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 32-VFQFN 裸露焊盘 |
| 供应商设备封装： | 32-QFN（5x5） |
| 包装： | 带卷 (TR) |
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NCP5389
Programming the Current Limit and the Oscillator
Frequency
The demo board is set for an operating frequency of
approximately 300 kHz. The OSC pin provides a 2.0 V
This equation is valid for the individual phase frequency in
both three and four phase mode.
32.36 k W ^ 10.14 109 * 1440
ROSC + 10.14 109 * 1440
ROSC + 9.711 109 * 1111
reference voltage which is divided down with a resistor
divider and fed into the current limit pin ILIM. Calculate
the total series resistance to set the frequency and then
calculate the individual values for current limit divider.
The series resistors RLIM1 and RLIM2 sink current to
ground. This current is internally mirrored into a capacitor
to create an oscillator. The period is proportional to the
resistance and frequency is inversely proportional to the
resistance. The resistance may be estimated by equation 2.
100
90
80
100
90
80
300 · k
2 Phase Mode
Frequency
3 Phase Mode
Frequency
(eq. 2)
(eq. 3)
70
60
50
40
30
20
10
F OSC (2, Measured)
F OSC (2, Calculated)
70
60
50
40
30
20
10
F OSC (3, Calculated)
F OSC (3, Measured)
0
0
200
400 600
800
1000
0
0
200
400
600
800
1000
F OSC (kHz)
Figure 14. ROSC vs. Phase Frequency
The current limit function is based on the total sensed
current of all phases multiplied by a gain of 5.94. DCR
F OSC (kHz)
Figure 15. R OSC vs. 3 ? Phase Mode
current limit based on the expected average maximum
temperature of the inductor windings.
sensed inductor current is function of the winding
temperature. The best approach is to set the maximum
Calculate the current limit voltage:
DCRTmax + DCR25C ·
(1 ) 0.00393 · C ? 1 (TTmax ? 25 · C))
(eq. 4)
· Vin ? Vout * (N ? 1) · Vout
VILIMIT ^ 5.94 · IMIN_OCP · DCRTmax )
DCR50C · Vout
2 · Vin · Fs
L L
* 0.02
(eq. 5)
Solve for the individual resistors:
RLIM2 +
VILIMIT · ROSC
2·V
RLIM1 + ROSC ? RLIM2
(eq. 6)
Final Equation for the Current Limit Threshold
) 0.02
· Vin ? Vout * (N ? 1) · Vout
ILIMIT(Tinductor) ^
2 · V · RLIM2
RLIM1 ) RLIM2
5.94 · (DCR25C · (1 ) 0.00393 · C ? 1(TInductor ? 25 · C)))
*
Vout
2 · Vin · Fs
L L
(eq. 7)
The inductors on the demo board have a DCR at 25 ° C of
0.75 m W . Selecting the closest available values of 16.9 k W
for RLIM1 and 15.8 k W for RLIM2 yield a nominal
operating frequency of 305 kHz and an approximate
current limit of 180 A at 100 ° C. The total sensed current
can be observed as a scaled voltage at the VDRP pin added
to a positive, no ? load offset of approximately 1.3 V.
Inductor Selection
When using inductor current sensing it is recommended
that the inductor does not saturate by more than 10% at
maximum load. The inductor also must not go into hard
saturation before current limit trips. The demo board includes
a four phase output filter using the T50 ? 8 core from
Micrometals with 4turns and a DCR target of 0.75 m W @
25 ° C. Smaller DCR values can be used, however, current
sharing accuracy and droop accuracy decrease as DCR
http://onsemi.com
22
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相关代理商/技术参数 |
参数描述 |
|---|---|
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| NCP5392 | 制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:2/3/4-Phase Controller for CPU Applications |
| NCP5392EMNR2G | 功能描述:DC/DC 开关控制器 2/3/4 PHASE CONTROLLER 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 |
| NCP5392HMNR2G | 功能描述:DC/DC 开关控制器 2/3/4 PHASE CTRL 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 |
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