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參數(shù)資料
| 型號： | NCP1578MNR2G |
| 廠商： | ON Semiconductor |
| 文件頁數(shù)： | 17/22頁 |
| 文件大小： | 1861K |
| 描述： | IC REG DL BCK/LINEAR SYNC 20-QFN |
| 產(chǎn)品變化通告： | Product Obsolescence 19/Dec/2008 |
| 標(biāo)準(zhǔn)包裝： | 4,000 |
| 拓?fù)洌?/td> | 降壓（降壓）同步（1），線性（LDO）（1） |
| 功能： | 任何功能 |
| 輸出數(shù)： | 2 |
| 頻率 - 開關(guān)： | 300kHz |
| 電壓/電流 - 輸出 1： | 控制器 |
| 電壓/電流 - 輸出 2： | 5V，50mA |
| 帶 LED 驅(qū)動(dòng)器： | 無 |
| 帶監(jiān)控器： | 無 |
| 帶序列發(fā)生器： | 是 |
| 電源電壓： | 4.5 V ~ 24 V |
| 工作溫度： | -40°C ~ 85°C |
| 安裝類型： | 表面貼裝 |
| 封裝/外殼： | 20-VFQFN 裸露焊盤 |
| 供應(yīng)商設(shè)備封裝： | 20-QFN（4x4） |
| 包裝： | 帶卷 (TR) |
NCP1578
http://onsemi.com
17
GENERAL APPLICATION INFORMATION
Introduction
Figure 35 depicts the general control blocks of voltage
mode control loop for a synchronous-rectified buck
converter. The voltage output V
out
is regulated to a reference
level which is basically governed by the following formula
V
out
+
1)
R1
R2
V
FB
(eq. 1)
In order to provide proper regulation, the error amplifier is
compared with the internal reference voltage and the output
of the error amplifier is used to provide pulse-width
modulated (PWM) wave.
Loop Compensation
Since NCP1578 is a voltage mode PWM controller with
LC output filter, type III compensation network is
recommended to provide the good closed loop bandwidth
and phase boot with stability under any circumstances. The
purpose of compensation is to obtain a stable close loop
system with the highest possible bandwidth. In another
word, we need to obtain a fast and stable system.
TG
SWN
BG
VOUT
PGND
COMP
FB
PWM Logic
Gate Driver &
Ramp Generator
Vref
A
Error
Amp
Q1
Q2
VIN
CIN
L
DCR
ESR
COUT
R1
R2
R4
C3
C1
C2
R3
NCP1578
Output
Filter
Compensation
Network
Modulator
Figure 35. Buck Converter with Modulator, Output Filter and Compensation Network
Equations Involved in Compensation Network
The following equations are provided as general
guidelines for defining the positions of poles and zeros of the
compensation network.
Output Filter Break Frequency
F
LC
+
1
2p L C
out
(LCDoublePole)
(eq. 2)
F
ESR
+
1
2p ESR C
out
(ESRZero)
(eq. 3)
Compensation Network Break Frequency
F
Z1
+
1
2p R3 C2
(1stZero)
(eq. 4)
F
P1
+
1
2p R3
C1 C2
C1)C2
(1stPole)
(eq. 5)
F
Z2
+
1
2p (R1)R4) C3
(2ndZero) (eq. 6)
F
P2
+
1
2p R4 C3
(2ndPole)
(eq. 7)
Guidelines for selecting compensation component
1.Select a value of R1 between 2 kW and 5 kW
2.Target for close loop bandwidth should be less
than 50% of switching frequency
3.Place 1
st
zero at 50% of filter double pole.
4.Place 1
st
pole at ESR zero
5.Place 2
nd
zero at filter double pole
6.Place 2
nd
pole at half the switching frequency.
Figure 36 shows an asymptotic plot of the converter gain
against frequency. It gives the general trend of how system
and its individual components behave. Actually, the
Modulator and Filter Gain has a high peak due to the high Q
factor of the output filter. The Open Loop Error Amplifier
Gain bounds the Compensation Gain. The Converter Gain
is constructed on the graph by summing up the Modulator
and Filter Gain (in dB) and the Compensation Gain (in dB).
The Compensation Gain uses the external impedance
network (R1, R4, C3, C1, C2, R3 at Figure 35) to provide a
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| NCP1579DR2G | 功能描述:電壓模式 PWM 控制器 BUCK CONTROLLER RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓?fù)浣Y(jié)構(gòu):Buck 輸出電壓:34 V 輸出電流: 開關(guān)頻率: 工作電源電壓:4.5 V to 5.5 V 電源電流:600 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:WSON-8 封裝:Reel |
| NCP1580DR2 | 功能描述:電壓模式 PWM 控制器 Low Voltage RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓?fù)浣Y(jié)構(gòu):Buck 輸出電壓:34 V 輸出電流: 開關(guān)頻率: 工作電源電壓:4.5 V to 5.5 V 電源電流:600 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:WSON-8 封裝:Reel |
| NCP1580DR2G | 功能描述:電壓模式 PWM 控制器 Low Voltage Synchronous Buck RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓?fù)浣Y(jié)構(gòu):Buck 輸出電壓:34 V 輸出電流: 開關(guān)頻率: 工作電源電壓:4.5 V to 5.5 V 電源電流:600 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:WSON-8 封裝:Reel |
| NCP1581DR2G | 功能描述:電壓模式 PWM 控制器 SYNCHRONOUS PWM BUCK CONV RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓?fù)浣Y(jié)構(gòu):Buck 輸出電壓:34 V 輸出電流: 開關(guān)頻率: 工作電源電壓:4.5 V to 5.5 V 電源電流:600 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:WSON-8 封裝:Reel |
| NCP1581SBCKRGEVB | 功能描述:BOARD EVAL NCP1581 RoHS:是 類別:編程器，開發(fā)系統(tǒng) >> 評估板 - DC/DC 與 AC/DC（離線）SMPS 系列:* 產(chǎn)品培訓(xùn)模塊:Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:1 系列:True Shutdown™ 主要目的:DC/DC，步升 輸出及類型:1，非隔離 功率 - 輸出:- 輸出電壓:- 電流 - 輸出:1A 輸入電壓:2.5 V ~ 5.5 V 穩(wěn)壓器拓?fù)浣Y(jié)構(gòu):升壓 頻率 - 開關(guān):3MHz 板類型:完全填充 已供物品:板 已用 IC / 零件:MAX8969 |
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