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参数资料
| 型号： | IR3628MPBF |
| 厂商： | International Rectifier |
| 文件页数： | 13/22页 |
| 文件大小： | 0K |
| 描述： | IC CTLR PWM BUCK SYNC 12-MLPD |
| 标准包装： | 122 |
| 应用： | 控制器，DDR |
| 输入电压： | 4.5 V ~ 14 V |
| 输出数： | 1 |
| 输出电压： | 0.6 V ~ 9.94 V |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 12-VFDFN 裸露焊盘 |
| 供应商设备封装： | 12-MLPD |
| 包装： | 管件 |
IR3628MP b F
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.
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:
V ds ( off ) t r + t f
The MOSFET must have a maximum operating
voltage (V DSS ) exceeding the maximum input
voltage (V in ).
Where:
P sw =
*
2 T
* I load - - - (10)
P cond = (upper switch) = I load ? R ds(on) ? D ? ?
P cond = (lower switch) = I load ? R ds(on) ? (1 ? D) ? ?
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:
2
2
? = R ds(on) temperatur e dependency
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.
V DS
90%
The R DS(on) temperature dependency should be
considered for the worst case operation. This is
typically given in the MOSFET data sheet.
10%
V GS
t d (ON)
t r
t d (OFF)
t f
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:
Fig. 18: switching time waveforms
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.
ControlFET (IRF7823) :
V ds = 30 V,Q g = 14 nC
R ds(on) = 8 . 7 m ? @ V gs = 10 V
SyncFET (IRF7832Z) :
V ds = 30 V,Q g = 45 nC
R ds(on) = 3 . 8 m ? @ V gs = 10 V
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
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
08/10/2007
losses. This is equivalent to extra current
requires to remove the minority charges from
synchronous FET. The reverse recovery loss can
be expressed as:
P Qrr = Q rr * t rr * F s
Q rr : Re verse Recovery Charge
t rr : Reverse Recovery Time
F s : Switching Frequency
13
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相关代理商/技术参数 |
参数描述 |
|---|---|
| IR3628MTRPBF | 功能描述:电压模式 PWM 控制器 HI FREQ SYNC PWM 600kHz 5 or 12V 0.6 RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| IR3629 | 制造商:IRF 制造商全称:International Rectifier 功能描述:HIGH FREQUENCY SYNCHRONOUS PWM BUCK CONTROLLER WITH POWER GOOD OUTPUT |
| IR3629A | 制造商:IRF 制造商全称:International Rectifier 功能描述:HIGH FREQUENCY SYNCHRONOUS PWM BUCK CONTROLLER WITH POWER GOOD OUTPUT |
| IR3629AMPBF | 制造商:IRF 制造商全称:International Rectifier 功能描述:HIGH FREQUENCY SYNCHRONOUS PWM BUCK CONTROLLER WITH POWER GOOD OUTPUT |
| IR3629AMTRPBF | 功能描述:电压模式 PWM 控制器 HI FREQ SYNC PWM 600kHz 5 or 12V 0.6 RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
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