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参数资料
| 型号： | IRDC3853 |
| 厂商： | International Rectifier |
| 文件页数： | 14/35页 |
| 文件大小： | 0K |
| 描述： | BOARD EVAL FOR IR3853 |
| 标准包装： | 1 |
| 系列： | SupIRBuck™ |
| 主要目的： | DC/DC，步降 |
| 输出及类型： | 1，非隔离 |
| 输出电压： | 1.8V |
| 电流 - 输出： | 0 ~ 4A |
| 输入电压： | 12V |
| 稳压器拓扑结构： | 降压 |
| 频率 - 开关： | 600kHz |
| 板类型： | 完全填充 |
| 已供物品： | 板 |
| 已用 IC / 零件： | IR3853 |
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PD-97516
IR3853MPbF
I OCSet ( μ A ) =
.......... .......... .......... .....( 2 )
Operating Frequency
The switching frequency can be programmed
between 250kHz – 1500kHz by connecting an
external resistor from R t pin to Gnd. Table 1
tabulates the oscillator frequency versus R t .
Table 1. Switching Frequency and I OCSet vs.
External Resistor ( R t )
R t (k ? ) F s (kHz) I ocset ( μ A)
1400
R t (k Ω )
Table 1. shows I OCSet at different switching
frequencies. The internal current source
develops a voltage across R OCSet . When the low
side MOSFET is turned on, the inductor current
flows through the Q2 and results in a voltage at
OCSet which is given by:
V OCSet = ( I OCSet ? R OCSet ) ? ( R DS (on ) ? I L ) .......... .(3)
47.5
35.7
28.7
23.7
20.5
17.8
15.8
14.3
12.7
11.5
10.7
300
400
500
600
700
800
900
1000
1100
1200
1300
29.4
39.2
48.7
59.07
68.2
78.6
88.6
97.9
110.2
121.7
130.8
9.76
9.31
1400
1500
143.4
150.3
Fig. 7. Connection of over current sensing resistor
An over current is detected if the OCSet pin goes
R OCSet =
R DS ( on ) * I Limit
Shutdown
The IR3853 can be shutdown by pulling the
Enable pin below its 1 V threshold. This will tri-
state both, the high side driver as well as the low
side driver. Alternatively, the output can be
shutdown by pulling the soft-start pin below 0.3V.
Normal operation is resumed by cycling the
voltage at the Soft Start pin.
Over-Current Protection
The over current protection is performed by
sensing current through the R DS(on) of low side
MOSFET. This method enhances the converter’s
efficiency and reduces cost by eliminating a
current sense resistor. As shown in figure 7, an
external resistor (R OCSet ) is connected between
OCSet pin and the switch node (SW) which sets
the current limit set point.
An internal current source sources current ( I OCSet
) out of the OCSet pin. This current is a function
of Rt and hence, of the free-running switching
frequency.
Rev 4.0
below ground. Hence, at the current limit
threshold, V OCset =0. Then, for a current limit
setting I Limit , R OCSet is calculated as follows:
.......... .......... .... (4)
I OCSet
An overcurrent detection trips the OCP
comparator, latches OCP signal and cycles the
soft start function in hiccup mode.
The hiccup is performed by shorting the soft-start
capacitor to ground and counting the number of
switching cycles. The Soft Start pin is held low
until 4096 cycles have been completed. The
OCP signal resets and the converter recovers.
After every soft start cycle, the converter stays in
this mode until the overload or short circuit is
removed.
The OCP circuit starts sampling current typically
160 ns after the low gate drive rises to about 3V.
This delay functions to filter out switching noise.
14
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相关代理商/技术参数 |
参数描述 |
|---|---|
| IRDC3853 - SUPIRBUCK | 制造商:International Rectifier 功能描述:INTERNATIONAL RECIFIER - GEN 2.1 SUPIRBUCK FAMILY - Bulk |
| IRDC3853 | 制造商:International Rectifier 功能描述:; MCU Supported Families:IR3853; Feature |
| IRDC3856 | 功能描述:BOARD EVAL FOR IR3856 RoHS:否 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:SupIRBuck™ 标准包装:1 系列:- 主要目的:DC/DC，步降 输出及类型:1，非隔离 功率 - 输出:- 输出电压:3.3V 电流 - 输出:3A 输入电压:4.5 V ~ 28 V 稳压器拓扑结构:降压 频率 - 开关:250kHz 板类型:完全填充 已供物品:板 已用 IC / 零件:L7981 其它名称:497-12113STEVAL-ISA094V1-ND |
| IRDC3856 - SUPIRBUCK | 制造商:International Rectifier 功能描述:INTERNATIONAL RECIFIER - GEN 2.1 SUPIRBUCK FAMILY - Bulk |
| IRDC3856 | 制造商:International Rectifier 功能描述:; MCU Supported Families:IR3856; Feature |
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