參數(shù)資料
型號(hào)： IR3628MPBF
廠商： International Rectifier
英文描述： HIGH FREQUENCY SYNCHRONOUS PWM BUCK CONTROLLER
中文描述： 高頻同步PWM降壓控制器
文件頁(yè)數(shù)： 5/22頁(yè)
文件大小： 581K
代理商： IR3628MPBF
IR3628MPbF
08/10/2007
Power MOSFET Selection
The IR3628 uses two N-Channel MOSFETs per
channel. The selection criteria to meet power
transfer requirements are based on maximum
drain-source voltage (V
DSS), gate-source drive
voltage (V
gs),
maximum output current, On-
resistance R
DS(on), and thermal management.
The MOSFET must have a maximum operating
voltage (V
DSS) exceeding the maximum input
voltage (V
in).
The gate drive requirement is almost the same
for both MOSFETs. Logic-level transistor can be
used and caution should be taken with devices at
very low gate threshold voltage (V
gs) to prevent
undesired
turn-on
of
the
complementary
MOSFET, which results a shoot-through current.
The total power dissipation for MOSFETs
includes conduction and switching losses. For
the Buck converter the average inductor current
is equal to the DC load current. The conduction
loss is defined as:
The R
DS(on) temperature dependency should be
considered 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.
For this design, IRF7823 is selected for control
FET and IRF7832Z is selected for synchronous
FET. These devices provide low on resistance in
a cost effective SO8 package.
The MOSFETs have the following data:
The conduction losses will be:
P
con=0.45W. The
switching loss is more difficult to calculate, even
though
the
switching
transition
is
well
understood. The reason is the effect of the
parasitic components and switching times during
the switching procedures such as turn-on / turn-
off delays and rise and fall times. The control
MOSFET contributes to the majority of the
dependency
e
temperatur
R
D)
(1
R
I
switch)
(lower
P
D
R
I
switch)
(upper
P
ds(on)
2
load
cond
ds(on)
2
load
cond
=
=
=
V
m
R
nC
V,Q
V
gs
ds(on)
g
ds
10
7
8
14
30
=
@
.
:
(IRF7823)
ControlFET
switching losses in synchronous Buck converter.
The synchronous MOSFET turns on under zero
voltage conditions, therefore, the turn on losses
for synchronous MOSFET can be neglected.
With a linear approximation, the total switching
loss can be expressed as:
Where:
V
ds(off) = Drain to source voltage at the off time
t
r = Rise time
t
f = Fall time
T = Switching period
I
load = Load current
The switching time waveforms is shown in
figure18.
From IRF7832Z data sheet:
tr = 13ns
tf = 14ns
These values are taken under a certain condition
test. For more details please refer to the
IRF7832Z data sheet.
By using equation (10), we can calculate the
switching losses.
P
sw=0.74W
The reverse recovery loss is also another
contributing factor in control FET switching
losses. This is equivalent to extra current
requires to remove the minority charges from
synchronous FET. The reverse recovery loss can
be expressed as:
(10)
-
*
)
(
load
f
r
off
ds
sw
I
T
t
V
P
+
=
2
VDS
VGS
10%
90%
td(ON)
td(OFF)
tr
tf
Fig. 18: switching time waveforms
V
m
R
nC
V,Q
V
gs
ds(on)
g
ds
10
@
8
.
3
45
30
:
(IRF7832Z)
SyncFET
=
Frequency
Switching
F
Time
Recovery
Reverse
t
Charge
Recovery
verse
Q
F
t
Q
P
s
rr
s
rr
Qrr
:
Re
:
*
=
13
相關(guān)PDF資料
PDF描述
IR3628MTRPBF HIGH FREQUENCY SYNCHRONOUS PWM BUCK CONTROLLER
IR3629AMPBF HIGH FREQUENCY SYNCHRONOUS PWM BUCK CONTROLLER WITH POWER GOOD OUTPUT
IR3629AMTRPBF HIGH FREQUENCY SYNCHRONOUS PWM BUCK CONTROLLER WITH POWER GOOD OUTPUT
IR3629A HIGH FREQUENCY SYNCHRONOUS PWM BUCK CONTROLLER WITH POWER GOOD OUTPUT
IR3629 HIGH FREQUENCY SYNCHRONOUS PWM BUCK CONTROLLER WITH POWER GOOD OUTPUT
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
IR3628MTRPBF 功能描述:電壓模式 PWM 控制器 HI FREQ SYNC PWM 600kHz 5 or 12V 0.6 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
IR3629 制造商:IRF 制造商全稱:International Rectifier 功能描述:HIGH FREQUENCY SYNCHRONOUS PWM BUCK CONTROLLER WITH POWER GOOD OUTPUT
IR3629A 制造商:IRF 制造商全稱:International Rectifier 功能描述:HIGH FREQUENCY SYNCHRONOUS PWM BUCK CONTROLLER WITH POWER GOOD OUTPUT
IR3629AMPBF 制造商:IRF 制造商全稱:International Rectifier 功能描述:HIGH FREQUENCY SYNCHRONOUS PWM BUCK CONTROLLER WITH POWER GOOD OUTPUT
IR3629AMTRPBF 功能描述:電壓模式 PWM 控制器 HI FREQ SYNC PWM 600kHz 5 or 12V 0.6 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
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