参数资料
| 型号： | MAX17497AATE+T |
| 厂商： | Maxim Integrated |
| 文件页数： | 21/30页 |
| 文件大小： | 0K |
| 描述： | IC OFF-LINE CONVERTER 16TQFN |
| 产品培训模块： | Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 输出隔离： | 隔离 |
| 频率范围： | 235kHz ~ 265kHz |
| 输入电压： | 4.5 V ~ 29 V |
| 工作温度： | -40°C ~ 125°C |
| 封装/外壳： | 16-WFQFN 裸露焊盘 |
| 供应商设备封装： | 16-TQFN-EP（3x3） |
| 包装： | 带卷 (TR) |
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MAX17497A/MAX17497B
AC-DC and DC-DC Peak Current-Mode Converters
with Integrated Step-Down Regulator
? 1 + ? ? ? ? × V OUTF OUTF
? 0.1f SW
? ? ?
?
R = 450 ×
2 × L PRI SW
× f
f P =
( V OUT + V D )
? ? V INNOM OUT D ) ? ?
× K + ( V
D NOM =
diode current) should be low enough to ensure that the
junction temperature is within limits. This necessitates
the diode-current rating be in the order of 2 x I OUTF to
3x I OUTF . Select fast-recovery diodes with a recovery
time less than 50ns, or Schottky diodes with low junction
capacitance.
Error-Amplifier Compensation Design
The loop-compensation values are calculated as:
? 2 ?
× I
? f P
?
Z
I OUTF
π × V OUTF × C OUTF
+ V
The output current, down to which the flyback converter
should operate in CCM, is determined by selection of
the fraction A in the above primary inductance formula.
For example, A should be selected as 0.15 so that the
converter operates in CCM down to 15% of the maxi-
mum output-load current. Since the ripple in the primary
current waveform is a function of duty cycle, and is
maximum-at-maximum DC input voltage, the maximum
(worst-case) load current, down to which the converter
operates in CCM, occurs at maximum operating DC input
voltage. V D is the forward drop of the selected output
diode at maximum output current.
C Z =
C P =
1
π × R Z × f P
1
π × R Z × f SW
Peak and RMS Current Calculation
RMS current values in the primary and secondary are
needed by the transformer manufacturer to design the
wire diameter for the different windings. Peak-current
calculations are useful in setting the current limit. Use the
following equations to calculate the primary and second-
? I OUTF × K ? ? V INMIN × D MAX ?
1 ? D MAX ? ? 2 × L PRI SW ?
= ? ? +? ?
?
The devices’ switching frequency (f SW ) can be ob-
tained from the Electrical Characteristics section.
In a typical application, the integrated step-down
regulator is fed off the flyback converter’s output. The
step-down regulator poses negative input impedance
or constant input power behavior. Due to this behavior,
the loop bandwidth measured for the flyback converter
would be smaller than the design bandwidth.
CCM Flyback
ary peak and RMS currents:
Maximum primary peak current:
Maximum primary RMS current:
× f
I PRIPEAK 2 + ? ? ? ( I PRIPEAK PRI )
? ? I 2 ?
× ? I
? ?
Transformer Turns Ratio Calculation (K = Ns/Np)
The transformer turns ratio can be calculated using the
following equation:
I PRIRMS
=
? 3 ?
PRI
( V OUT + V D ) × (1 ? D MAX )
× D MAX
? V INMIN × D MAX ?
? I PRI = ?
? ?
( V OUTF + V D ) × (1 ? D NOM ) 2
2 × I OUTF SW × K 2
I SECPEAK = PRIPEAK
K =
V INMIN × D MAX
where D MAX is the duty cycle assumed at minimum input
(0.35 for the MAX17497A and 0.7 for the MAX17497B).
Primary Inductance Calculation
Calculate the primary inductance based on the ripple:
L PRI =
×β× f
where D NOM , the nominal duty cycle at nominal operat-
ing DC input voltage (V INNOM ), is given as:
Maxim Integrated
2
where D I PRI is the ripple current in the primary current
waveform, and is given by:
L PRI × f SW
Maximum secondary peak current:
I
K
Maximum secondary RMS current:
21
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX17497AEVKIT# | 功能描述:电源管理IC开发工具 MAX17497 Eval Kit 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 |
| MAX17497BATE+ | 功能描述:电流型 PWM 控制器 Univ AC/DC-Iso DC/DC Flyback controller 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 |
| MAX17497BATE+T | 功能描述:电流型 PWM 控制器 Univ AC/DC-Iso DC/DC Flyback controller 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 |
| MAX17498AATE+ | 功能描述:电流型 PWM 控制器 Uvrsl AC/DC & Iso DC/DC Flyback ctlr 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 |
| MAX17498AATE+T | 功能描述:电流型 PWM 控制器 Uvrsl AC/DC & Iso DC/DC Flyback ctlr 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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