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参数资料
| 型号： | ISL6421EVAL1 |
| 厂商： | Intersil |
| 文件页数： | 5/18页 |
| 文件大小： | 0K |
| 描述： | EVALUATION BOARD 1 ISL6421 |
| 标准包装： | 1 |
| 主要目的： | DC/DC，LDO 步升 |
| 输出及类型： | 1，非隔离 |
| 输出电压： | 13V，14V，18V 或 19V |
| 输入电压： | 8 ~ 14 V |
| 稳压器拓扑结构： | 升压 |
| 频率 - 开关： | 220kHz |
| 板类型： | 完全填充 |
| 已供物品： | 板 |
| 已用 IC / 零件： | ISL6421 |
Application Note 1083
Overcurrent Hiccup Mode
Figure 8 shows a typical overcurrent trip.
Output Ripple
Figure 10 shows the typical output ripple waveforms. VOUT
is set to 13V and 450mA load.
IOUT
200mA/DIV
V OUT 20mV/DI V
VOUT
10V/DIV
50μs/DIV
FIGURE 8. OVERCURRENT TRIP
FIGURE 10. OUTPUT RIPPLE
When the DCL (dynamic current limiting) bit is set LOW, the
overcurrent protection circuit works dynamically in a hiccup
mode; as soon as an overload is detected, the output is
shutdown for a time t OFF , typically 900ms. The output is
resumed for a time t ON = 20ms. At the end of t ON , if the
overload condition is still detected, the protection circuit will
cycle again through t OFF and t ON . Figure 9 shows the typical
waveforms for the overcurrent hiccup mode.
External Back-Bias Protection
Some applications may need to be able to protect the
ISL6421/ISL6425 from an inadvertent back-bias voltage
condition. For the case where a DC supply is connected to
the output of the ISL6421/ISL6425, a series connected diode
as shown in Figure 11 will protect the IC. The LLC bit can be
set high through the I 2 C bus to increase the output voltage
by 1V to compensate for the diode voltage drop.
D1
STPS2L40U
IOUT
200mA/DIV
ISL6405
(LLC = HIGH)
V D
C LOAD
X DEVICE
LNB
FIGURE 11. DC BACK-BIAS PROTECTION CIRCUIT
The DiSEqC standard recommends a maximum bus load of
VOUT 10V/DIV
500ms/DIV
0.25μF. For the circuit in Figure 11 to provide proper 22kHz
tone operation, the bus would have to have a minimum
FIGURE 9. OVERCURRENT HICCUP MODE
5
loading of 12mA.
If tone operation is required at zero load conditions, a
resistor can be placed from the cathode of the protection
diode to ground, scaled to provide the minimum 12mA. To
avoid the added dissipation of this method, a capacitor can
be placed in parallel with the back-bias protection diode as
shown in Figure 12. This capacitor should be scaled with the
capacitive load present on the DiSEqC bus line. For a load of
0.25μF, use a 10μF capacitor. Consider the maximum load
of 0.25μF and the highest output voltage of 19V and a 0.5V
drop across the Schottky diode. After the tone rise time,
Qd(rise)~0, Qload(rise) = 19V*0.25μF = 4750nC
AN1083.1
May 6, 2005
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL6422BERZ | 功能描述:直流/直流开关转换器 DL LNB SUPPLY + CONT VAGEG W/I2C RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| ISL6422BERZ-T | 功能描述:直流/直流开关转换器 DL LNB SUPPLY + CONT VAGEG W/I2C RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| ISL6422BEVEZ | 功能描述:直流/直流开关转换器 DL LNB SUPPLY + CONT VAGEG W/I2C RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| ISL6422BEVEZ-T | 功能描述:直流/直流开关转换器 DL LNB SUPPLY + CONT VAGEG W/I2C RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| ISL6422ERZ | 功能描述:电流型 PWM 控制器 DL LNB SUPPLY + CONT VAGEG W/I2C RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
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