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參數(shù)資料
| 型號： | NCP1411DMR2 |
| 廠商： | ON SEMICONDUCTOR |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | Sync-Rect PFM Step-Up DC-DC Converter with Low-Battery Detector and Ring-Killer |
| 中文描述： | 1 A SWITCHING REGULATOR, 600 kHz SWITCHING FREQ-MAX, PDSO8 |
| 封裝： | PLASTIC, MICROPACK-8 |
| 文件頁數(shù)： | 12/14頁 |
| 文件大?。?/td> | 133K |
| 代理商： | NCP1411DMR2 |
NCP1411
http://onsemi.com
12
GENERAL DESIGN PROCEDURES
Switching mode converter design is considered as black
magic to most engineers, some complicate empirical
formulae are available for reference usage. Those formulae
are derived from the assumption that the key components,
i.e. power inductor and capacitors are available with no
tolerance. Practically, its not true, the result is not a matter
of how accurate the equations you are using to calculate the
component values, the outcome is still somehow away from
the optimum point. In below a simple method base on the
most basic first order equations to estimate the inductor and
capacitor values for NCP1411 operate in Continuous
Conduction Mode is introduced. The component value set
can be used as a starting point to fine tune the circuit
operation. By all means, detail bench testing is needed to get
the best performance out of the circuit.
Design Parameters:
V
IN
V
OUT
I
OUT
V
LB
V
OUTRIPPLE
= 40 mV
PP
at I
OUT
= 250 mA
= 1.8 V to 3.0 V, Typical 2.4 V
= 3.3 V
= 200 mA (250 mA max)
= 2.0 V
Calculate the feedback network:
Select R
FB2
= 200 K
RFB1
RFB2
VOUT
VREF
1
RFB1
200 K
3.3 V
1.19 V
1
355 K
With the feedback resistor divider, additional small
capacitor, C
FB1
in parallel with R
FB1
is required to ensure
stability. The value can be in between 68 pF to 220 pF, the
rule is to select the lowest capacitance to ensure stability.
Also a small capacitor, C
FB2
in parallel with R
FB2
may also
be needed to lower the feedback ripple hence improve
output regulation. The use of C
FB2
is a compromise between
output ripple level and regulation, so careful selection of the
value according to end application requirement is needed. In
this example, values for C
FB1
and C
FB2
are 150 pF and
220 pF respectively.
Calculate the Low Battery Detect divider:
V
LB
= 2.0 V
Select R
LB2
= 330 K
RLB1
RLB2
VLB
VREF
1
RLB1
330 K
2.0 V
1.19 V
1
225 K
CEN
28 msec
225 K
120 nF
Determine the Steady State Duty Ratio, D for typical V
IN
,
operation will be optimized around this point:
VOUT
VIN
1
1
D
D
1
VIN
VOUT
1
2.4 V
3.3 V
0.273
Determine the average inductor current, I
LAVG
at maximum
I
OUT
:
IOUT
1
D
1
ILAVG
250 mA
0.273
344 mA
Determine the peak inductor ripple current, I
RIPPLEP
and
calculate the inductor value:
Assume I
RIPPLEP
is 20% of I
LAVG
, the inductance of the
power inductor can be calculated as in below:
I
RIPPLEP
= 0.20 x 344 mA = 68.8 mA
VIN
tON
2IRIPPLEP
2(68.8 mA)
Standard value of 22 H is selected for initial trial.
L
2.4 V
1.4 S
24.4 H
Determine the output voltage ripple, V
OUTRIPPLE
and
calculate the output capacitor value:
V
OUTRIPPLE
= 40 mV
PP
at I
OUT
= 250 mA
IOUT
VOUT
RIPPLE
where t
ON
= 1.4 S and ESR
COUT
= 0.1 ,
250 mA
40 mV
250 mA
From above calculation, we need at least 23.33 F in order
to achieve the specified ripple level at conditions stated.
Practically, a one level larger capacitor will be used to
accommodate factors not take into account in the
calculation. So a capacitor value of 33 F is selected.
COUT
tON
IOUT
ESRCOUT
COUT
1.4 S
0.1
23.33 F
相關PDF資料 |
PDF描述 |
|---|---|
| NCP1411D | Sync-Rect PFM Step-Up DC-DC Converter with Low-Battery Detector and Ring-Killer |
| NCP1411DMR2G | Sync-Rect PFM Step-Up DC-DC Converter with Low-Battery Detector and Ring-Killer |
| NCP1411 | Sync-Rect PFM Step-Up DC-DC Converter(帶有同步整流器的PFM升壓DC-DC轉換器) |
| NCP1417DMR2(中文) | 200 mA DC-DC Step-up Converter with Dual Low Battery Protection(帶雙路低電池保護的200mA步升DC-DC轉換器) |
| NCP1417 | 200 mA DC-DC Step-up Converter with Dual Low Battery Protection |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| NCP1411DMR2G | 功能描述:直流/直流開關轉換器 250mA Monolithic High Frequency Boost RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風格:SMD/SMT |
| NCP1417DMR2 | 功能描述:直流/直流開關轉換器 200mA DC/DC Boost RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風格:SMD/SMT |
| NCP1417-SKT | 制造商:ON Semiconductor 功能描述:Sample Kit, Including 2 NCP1417DM2 and 1 Development Resource CD-ROM 制造商:P&S 功能描述:Sample Kit, Including 2 NCP1417DM2 and 1 Development Resource CD-ROM |
| NCP1421DMR2 | 功能描述:直流/直流開關轉換器 600mA PFM Boost RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風格:SMD/SMT |
| NCP1421DMR2G | 功能描述:DC/DC 開關控制器 600mA PFM Boost w/Ring Killer 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 |
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