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参数资料
| 型号： | ISL62392LOEVAL1Z |
| 厂商： | Intersil |
| 文件页数： | 18/21页 |
| 文件大小： | 0K |
| 描述： | EVALUATION BOARD FOR ISL62392LO |
| 标准包装： | 1 |
| 系列： | Robust Ripple Regulator™ (R³) |
| 主要目的： | DC/DC，LDO 步降 |
| 输出及类型： | 3，非隔离 |
| 输出电压： | 3.3V，5V，3.3V |
| 电流 - 输出： | 8A，8A，100mA |
| 输入电压： | 5.5 ~ 25 V |
| 稳压器拓扑结构： | 降压 |
| 板类型： | 完全填充 |
| 已供物品： | 板 |
| 已用 IC / 零件： | ISL62392 |
ISL62391, ISL62392, ISL62391C, ISL62392C
The inductance of the capacitor can cause a brief voltage dip
if the load transient has an extremely high slew rate. Low
inductance capacitors should be considered in this scenario.
A capacitor dissipates heat as a function of RMS current and
frequency. Be sure that I P-P is shared by a sufficient quantity
of paralleled capacitors so that they operate below the
0.60
0.55
0.50
0.45
0.40
maximum rated RMS current at f SW . Take into account that
the rated value of a capacitor can fade as much as 50% as
the DC voltage across it increases.
Selection of the Input Capacitor
The important parameters for the bulk input capacitance are
the voltage rating and the RMS current rating. For reliable
0.35
0.30
0.25
0.20
0.15
0.10
0.05
x=1
x = 0.75
x = 0.50
x = 0.25
x=0
operation, select bulk capacitors with voltage and current
ratings above the maximum input voltage and capable of
supplying the RMS current required by the switching circuit.
Their voltage rating should be at least 1.25x greater than the
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
DUTY CYCLE
FIGURE 28. NORMALIZED RMS INPUT CURRENT
1.0
maximum input voltage, while a voltage rating of 1.5x is a
preferred rating. Figure 28 is a graph of the input RMS ripple
current (normalized relative to output load current) as a
function of duty cycle and is adjusted for a converter efficiency
of 80%. The ripple current calculation is written as
Equation 21:
MOSFET Selection and Considerations
Typically, a MOSFET cannot tolerate even brief excursions
beyond their maximum drain to source voltage rating. The
MOSFETs used in the power stage of the converter should
have a maximum V DS rating that exceeds the sum of the
upper voltage tolerance of the input power source and the
( D – D ) + ? D ? ------ ?
I IN_RMS , NORMALIZED =
? 12 ?
2 x
2
(EQ. 21)
voltage spike that occurs when the MOSFET switches off.
There are several power MOSFETs readily available that are
Where:
- I MAX is the maximum continuous I LOAD of the converter
- x is a multiplier (0 to 1) corresponding to the inductor
peak-to-peak ripple amplitude expressed as a
percentage of I MAX (0% to 100%)
- D is the duty cycle that is adjusted to take into account
the efficiency of the converter which is written as
Equation 22.
optimized for DC/DC converter applications. The preferred
high-side MOSFET emphasizes low gate charge so that the
device spends the least amount of time dissipating power in
the linear region. Unlike the low-side MOSFET, which has
the drain-source voltage clamped by its body diode during
turn off, the high-side MOSFET turns off with a V DS of
approximately V IN - V OUT , plus the spike across it. The
preferred low-side MOSFET emphasizes low r DS(ON) when
fully saturated to minimize conduction loss. It should be
V O
V IN ? EFF
D = --------------------------
(EQ. 22)
noted that this is an optimal configuration of MOSFET
selection for low duty cycle applications (D < 50%). For
In addition to the bulk capacitance, some low ESL ceramic
capacitance is recommended to decouple between the drain
of the high-side MOSFET and the source of the low-side
MOSFET.
higher output, low input voltage solutions, a more balanced
MOSFET selection for high- and low-side devices may be
warranted.
For the low-side (LS) MOSFET, the power loss can be
assumed to be conductive only and is written as Equation 23:
P CON_LS ≈ I LOAD ? r DS ( ON ) _LS ? ( 1 – D )
2
(EQ. 23)
For the high-side (HS) MOSFET, the conduction loss is
written as Equation 24:
P CON_HS = I LOAD
2
?
r DS ( ON ) _HS ? D
(EQ. 24)
P SW_HS = ----------------------------------------------------------------- + -------------------------------------------------------------
For the high-side MOSFET, the switching loss is written as
Equation 25:
V IN ? I VALLEY ? t ON ? f SW V IN ? I PEAK ? t OFF ? f SW
2 2
(EQ. 25)
18
FN6666.7
August 22, 2013
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL6244 | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Multi-Phase PWM Controller |
| ISL6244CR | 功能描述:IC REG CTRLR BUCK PWM 32-QFN RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,000 系列:- PWM 型:电压模式 输出数:1 频率 - 最大:1.5MHz 占空比:66.7% 电源电压:4.75 V ~ 5.25 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 85°C 封装/外壳:40-VFQFN 裸露焊盘 包装:带卷 (TR) |
| ISL6244CR-T | 功能描述:IC REG CTRLR BUCK PWM 32-QFN RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,000 系列:- PWM 型:电压模式 输出数:1 频率 - 最大:1.5MHz 占空比:66.7% 电源电压:4.75 V ~ 5.25 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 85°C 封装/外壳:40-VFQFN 裸露焊盘 包装:带卷 (TR) |
| ISL6244CRZ | 功能描述:电流型 PWM 控制器 VER OF ISL6244CR 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 |
| ISL6244CRZ-T | 功能描述:电流型 PWM 控制器 VER OF ISL6244CR-T 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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