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参数资料
| 型号： | IRDC3837 |
| 厂商： | International Rectifier |
| 文件页数： | 15/36页 |
| 文件大小： | 0K |
| 描述： | KIT EVAL REG 14A SUPIRBUCK DC/DC |
| 标准包装： | 1 |
| 系列： | SupIRBuck™ |
| 主要目的： | DC/DC，LDO 步降 |
| 输出及类型： | 1，非隔离 |
| 输出电压： | 1.8V |
| 电流 - 输出： | 14A |
| 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： | IR3837 |
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IR3837MPbF
Soft-Start
The IR3837 has a digital internal soft-start to
Table 1. Switching Frequency and I OCSet vs.
External Resistor ( R t )
control the output voltage rise and to limit the
current surge at the start-up. To ensure correct
start-up, the soft-start sequence initiates when
the Enable and Vcc rise above their UVLO
thresholds and generate the Power On Ready
(POR) signal. The internal SS signal linearly
rises with the rate of 0.2mV / μs from 0V to 2V.
Figure 6 shows the waveforms during soft start
(also refer to figure 11). The normal start up time
is fixed, and is equal to:
R t (k ? )
47.5
35.7
28.7
23.7
20.5
17.8
15.8
F s (kHz)
300
400
500
600
700
800
900
I ocset ( μ A)
14.7
19.6
24.35
29.54
34.1
39.3
44.3
T start ?
? 1.3V - 0.7V ? ? 3ms
0.2mV/ ? s
- - - - - - - - - - - - - - (1)
14.3
12.7
1000
1100
48.95
55.1
During the soft start the OCP is enabled to
protect the device for any short circuit and over
current condition.
11.5
10.7
9.76
9.31
1200
1300
1400
1500
60.85
65.4
71.7
75.15
Over-Current Protection
The over current protection is performed by
sensing current through the R DS(on) of the sync
FET. 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
( IOCSet ) out of the OCSet pin. This current is a
function of Rt and hence, of the free-running
switching frequency.
I OCSet ( μ A) ?
700
R t (k ? )
.......... .......... .......... .....(2)
Fig. 6. Theoretical operation waveforms
during soft-start (non tracking / non sequencing)
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 .
Shutdown
The IR3837 can be shutdown by pulling the
Enable pin below its 0.85 V threshold. This will
tri-state both, the high side driver as well as the
low side driver.
Rev 1.31
Table 1. shows IOCSet at different switching
frequencies. The internal current source
develops a voltage across R OCSet . When the sync
FET is turned on, the inductor current flows
through Q2 and results in a voltage at OCSet
which is given by:
V OCSet ? ( I OCSet ? R OCSet ) ? ( R DS (on ) ? I L ) .......... .(3)
An over current is detected if the OCSet pin goes
below ground. However, to avoid false tripping ,
due to the noise generated when the sync FET is
turned on, the OCP comparator is enabled about
200ns after sync-FET is turned on .
15
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相关代理商/技术参数 |
参数描述 |
|---|---|
| IRDC3837 | 制造商:International Rectifier 功能描述:; MCU Supported Families:IR3837; Feature |
| IRDC3838 | 功能描述:电源管理IC开发工具 User Guide IR3838 Eval Brd RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| IRDC3838 | 制造商:International Rectifier 功能描述:; MCU Supported Families:IR3838; Feature |
| IRDC3839 | 功能描述:电源管理IC开发工具 User Guide IR3839 Eval Brd RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| IRDC3840 | 功能描述:电源管理IC开发工具 IR3840 SYNC CONV 600kHz EVAL BRD RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
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