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參數(shù)資料
| 型號(hào)： | IRU3046 |
| 廠商： | International Rectifier |
| 元件分類： | 基準(zhǔn)電壓源/電流源 |
| 英文描述： | DUAL SYNCHRONOUS PWM CONTROLLER WITH CURRENT SHARING CIRCUITRY AND LDO CONTROLLER |
| 中文描述： | 雙同步PWM控制器，帶有均流電路和LDO控制器 |
| 文件頁數(shù)： | 8/20頁 |
| 文件大?。?/td> | 163K |
| 代理商： | IRU3046 |
8
Rev. 1.9
09/27/02
IRU3046
www.irf.com
The R
DS(ON)
temperature dependency should be consid-
ered for the worst case operation. This is typically given
in the MOSFET data sheet. Ensure that the conduction
losses and switching losses do not exceed the package
ratings or violate the overall thermal budget.
Choose IRF7460 for control MOSFET and IRF7457 for
synchronous MOSFET. These devices provide low on-
resistance in a compact SOIC 8-Pin package.
The MOSFETs have the following data:
IRF7460
V
DSS
= 20V
I
D
= 10A @ 75
8
C
R
DS(ON)
= 10m
@
V
GS
=10V
= 1.8 for 150
8
C
(Junction Temperature)
The total conduction losses for the master channel is:
The total conduction losses for the slave channel is:
The control MOSFET contributes to the majority of the
switching losses in synchronous Buck converter. The
synchronous MOSFET turns on under zero-voltage con-
dition, therefore the turn on losses for synchronous
MOSFET can be neglected. With a linear approxima-
tion, the total switching loss can be expressed as:
t
r
+
t
f
T
Figure 4 - Switching time waveforms.
From IRF7460 data sheet we obtain:
IRF7460
t
r
= 6.9ns
t
f
= 4.3ns
These values are taken under a certain condition test.
For more detail please refer to the IRF7460 and IRF7457
data sheets.
By using equation (7), we can calculate the switching
losses.
P
SW(MASTER)
= 44.8mW
P
SW(SLAVE)
= 107.5mW
Feedback Compensation
The control scheme for master and slave channels is
based on voltage mode control, but the compensation of
these two feedback loops is slightly different.
The Master channel sets the output voltage and its feed-
back loop should take care of double pole introduced by
the output filter as a regular voltage mode control loop.
The goal is to provide a close loop transfer function with
the highest 0dB crossing frequency and adequate phase
margin. The slave feedback loop acts slightly different
and its goal is using the current information for current
sharing.
The master feedback loop sees the output filter. The out-
put LC filter introduces a double pole, -40dB/decade gain
slope above its corner resonant frequency, and a total
phase lag of 180
8
(see Figure 5). The resonant frequency
of the LC filter expressed as follows:
Figure 5 shows gain and phase of the LC filter. Since we
already have 180
8
phase shift just from the output filter,
the system risks being unstable.
Figure 5 - Gain and phase of LC filter.
P
CON(MASTER)
= 0.85W
P
CON(SLAVE)
= 0.77W
IRF7457
V
DSS
= 20V
I
D
= 12A @ 70
8
C
R
DS(ON)
= 7.5m
@
V
GS
=10V
= 1.5 for 150
8
C
(Junction Temperature)
Where:
V
DS(OFF)
= Drain to Source Voltage at off time
t
r
= Rise Time
t
f
= Fall Time
T = Switching Period
I
LOAD
= Load Current
P
SW
= V
×
×
I
LOAD
---(7)
2
DS(OFF)
F
LC(MASTER)
= 1
2
π
Lo
×
Co
V
DS
90%
V
GS
10%
t
d
(ON)
t
d
(OFF)
t
r
t
f
Gain
F
LC
0dB
Phase
0
8
F
LC
-180
8
Frequency
Frequency
-40dB/decade
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相關(guān)代理商/技術(shù)參數(shù) |
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|---|---|
| IRU3046CF | 制造商:IRF 制造商全稱:International Rectifier 功能描述:DUAL SYNCHRONOUS PWM CONTROLLER WITH CURRENT SHARING CIRCUITRY AND LDO CONTROLLER |
| IRU3046CFTR | 功能描述:IC REG CTRLR BUCK PWM VM 24TSSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:75 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:1MHz 占空比:81% 電源電壓:4.3 V ~ 13.5 V 降壓:是 升壓:是 回掃:是 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:0°C ~ 70°C 封裝/外殼:8-SOIC（0.154"，3.90mm 寬） 包裝:管件 產(chǎn)品目錄頁面:1051 (CN2011-ZH PDF) 其它名稱:296-2543-5 |
| IRU3046CFTRPBF | 制造商:International Rectifier 功能描述:DUAL SYNCHRONOUS PWM CONTROLLER WITH CURRENT SHARING CIRCUITRY AND LDO CONTROLLER |
| IRU3047 | 制造商:IRF 制造商全稱:International Rectifier 功能描述:DUAL SYNCHRONOUS PWM CONTROLLER WITH CURRENT SHARING CIRCUITRY AND LDO CONTROLLER |
| IRU3047CW | 制造商:IRF 制造商全稱:International Rectifier 功能描述:DUAL SYNCHRONOUS PWM CONTROLLER WITH CURRENT SHARING CIRCUITRY AND LDO CONTROLLER |
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