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参数资料
| 型号： | IR3628MPBF |
| 厂商： | International Rectifier |
| 文件页数： | 10/22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
Over-Current Protection
28uA
The over current protection is performed by
sensing current through the R DS(on) of low side
MOSFET. This method enhances the converter’s
20uA
OCP
efficiency and reduce cost by eliminating a
current sense resistor. As shown in figure 7, an
external resistor (R SET ) is connected between
OCSet pin and the drain of low side MOSFET
(Q2) which sets the current limit set point.
SS1 / SD
20
3uA
The internal current source develops a voltage
across R SET . When the low side MOSFET is
turned on, the inductor current flows through the
Q2 and results a voltage which is given by:
Fig. 8: 3uA current source for discharging
soft-start capacitor during hiccup
The OCP circuit starts sampling current when the
V OCSet = (I OCSet ? R OCSet ) ? (R DS(on) ? I L )
--( 2 )
low gate drive is about 3V. The OCSet pin is
internally clamped (~1.5V) during on time of high
side MOSFET including deadtime to prevent
false trigging, figure 9 shows the OCSet pin
IR3628
IR3624
I OCSET
OCSet R SET
Q1
L1
V OUT
during one switching cycle. As it is shown there
is about 150ns delay to mask the deadtime, since
this node contains switching noises, this delay
also functions as a filter.
Hiccup
Control
Q2
Fig. 7: Connection of over current sensing resistor
The critical inductor current can be calculated by
setting:
Deadtime
V OCSet = (I OCSet ? R OCSet ) ? (R DS(on) ? I L ) = 0
R OCSet ? I OCSet
I SET = I L ( critical ) =
--( 3 )
R DS ( on )
I OCSet *R OCSet
Blanking time
Clamp voltage
An over current is detected if the OCSet pin goes
below ground. This trips the OCP comparator
and cycles the soft start function in hiccup mode.
The hiccup is performed by charging and
discharging the soft-start capacitor in certain
slope rate. As shown in figure 8 a 3uA current
source is used to discharge the soft-start
capacitor.
The OCP comparator resets after every soft start
cycles, the converter stays in this mode until the
overload or short circuit is removed. The
converter will automatically recover.
08/10/2007
Fig. 9: OCset pin during normal condition
Ch1: Inductor point, Ch2:Ldrv, Ch3:OCSet
The value of R SET should be checked in an actual
circuit to ensure that the over current protection
circuit activates as expected. The IR3628 current
limit is designed primarily as disaster preventing,
and doesn't operate as a precision current
regulator.
10
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相关代理商/技术参数 |
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|---|---|
| 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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