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参数资料
| 型号： | MAX5015CSA+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 11/14页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR ISO PWM CM 8-SOIC |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 275kHz |
| 占空比： | 50% |
| 电源电压： | 18 V ~ 110 V |
| 降压： | 无 |
| 升压： | 无 |
| 回扫： | 无 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 是 |
| 工作温度： | 0°C ~ 70°C |
| 封装/外壳： | 8-SOIC（0.154"，3.90mm 宽） |
| 包装： | 带卷 (TR) |
Current-Mode PWM Controllers with Integrated
Startup Circuit for Isolated Power Supplies
V REF
V OUT
=
R 2
R 1 + R 2
all of the leakage energy to be dissipated across a
resistor.
To calculate the minimum duty cycle (D MIN ) use the
D MIN =
V IN_MAX × S - V D1
where V REF is the reference voltage of the shunt
regulator, and R 1 and R 2 are the resistors shown in
Figures 2 and 3.
3) The turns ratio of the transformer is calculated based
=
following equation:
V OUT
N
N P
= 19 . 8
on the minimum input voltage and the lower limit of
the maximum duty cycle for the MAX5015 (44%). To
enable the use of MOSFETs with drain-source
breakdown voltages of less than 200V use the
MAX5015 with the 50% maximum duty cycle.
Calculate the turns ratio according to the following
equation:
where V IN_MAX is the maximum input voltage (72V).
4) The reset winding turns ratio (N R /N P ) needs to be
low enough to guarantee that the entire energy in
the transformer is returned to V+ within the off cycle
at the maximum duty cycle. Use the following equa-
tion to determine the reset winding turns ratio:
N S
N P
≥
V OUT + ( V D1 × D MAX )
D MAX × V IN_MIN
N R ≤ N P ×
1-D MAX ′
D MAX ′
where:
N S /N P = Turns ratio (N S is the number of secondary
turns and N P is the number of primary turns).
V OUT = Output voltage (5V).
where:
N R /N P = Reset winding turns ratio.
D MAX ’ = Maximum value of Maximum Duty Cycle.
V D1 = Voltage drop across D1 (typically 0.5V for
power Schottky diodes).
D MAX = Minimum value of maximum operating duty
N R ≤ 1 4 ×
1- 0.5
0.5
= 14
cycle (44%).
V IN_MIN = Minimum Input voltage (36V).
In this example:
Round N R to the nearest smallest integer.
The turns ratio of the reset winding (N R /N P ) will
determine the peak voltage across the N-channel
MOSFET.
N S
N P
≥
5V + ( 0.5V × 0.44 )
0 . 44 × 36 V
= 0 . 330
Use the following equation to determine the maxi-
mum drain-source voltage across the N-channel
MOSFET:
V DSMAX IN_MAX × ? 1 +
≥ V
Choose N P based on core losses and DC resis-
tance. Use the turns ratio to calculate N S , rounding
up to the nearest integer. In this example N P = 14
?
?
N P ?
N R ? ?
and N S = 5.
For a forward converter choose a transformer with a
magnetizing inductance in the neighborhood of
V DSMAX = Maximum MOSFET drain-source voltage.
V IN_MAX = Maximum input voltage.
V DSMAX ≥ 7 2 V × ? 1 +
? = 144 V
200μH. Energy stored in the magnetizing inductance
of a forward converter is not delivered to the load
and must be returned back to the input; this is
accomplished with the reset winding.
?
?
14 ?
14 ?
The transformer primary to secondary leakage
inductance should be less than 1μH. Note that all
leakage energy will be dissipated across the MOS-
FET. Snubber circuits may be used to direct some or
Choose MOSFETs with appropriate avalanche
power ratings to absorb any leakage energy.
5) Choose the tertiary winding turns ratio (N T /N P ) so
that the minimum input voltage provides the mini-
mum operating voltage at V DD (13V). Use the follow-
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX5015ESA | 功能描述:电流型 PWM 控制器 w/Integrated Startup 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 |
| MAX5015ESA+ | 功能描述:电流型 PWM 控制器 w/Integrated Startup 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 |
| MAX5015ESA+T | 功能描述:电流型 PWM 控制器 w/Integrated Startup 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 |
| MAX5015ESA-G077 | 功能描述:电流型 PWM 控制器 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 |
| MAX5015ESA-T | 功能描述:电流型 PWM 控制器 w/Integrated Startup 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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