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参数资料
| 型号： | MAX15046EVKIT+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 14/24页 |
| 文件大小： | 0K |
| 描述： | EVAL KIT FOR MAX15046 |
| 标准包装： | 1 |
| 主要目的： | DC/DC，步降 |
| 输出及类型： | 1，非隔离 |
| 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： | MAX15046 |
MAX15046
40V, High-Performance, Synchronous
Buck Controller
17.3 × 10 9
f SW + (1x10 ) x (f SW 2 )
R RT =
V ITH DS(ON,MAX) LOAD(MAX) × ? ?
? LIR ?
V OUT (V IN - V OUT )
Setting the Switching Frequency
An external resistor connecting RT to GND sets the
switching frequency (f SW ). The relationship between f SW
and R RT is:
-7
where f SW is in Hz and R RT is in I . For example, a
300kHz switching frequency is set with R RT = 49.9k I .
Higher frequencies allow designs with lower inductor
values and less output capacitance. Peak currents and
I 2 R losses are lower at higher switching frequencies, but
core losses, gate-charge currents, and switching losses
increase.
Inductor Selection
Three key inductor parameters must be specified for
operation with the MAX15046: inductance value (L),
inductor saturation current (I SAT ), and DC resistance
(R DC ). To determine the inductance, select the ratio of
inductor peak-to-peak AC current to DC average cur-
rent (LIR) first. For LIR values that are too high, the RMS
currents are high, and therefore I 2 R losses are high.
Use high-valued inductors to achieve low LIR values.
Typically, inductor resistance is proportional to induc-
tance for a given package type, which again makes I 2 R
losses high for very low LIR values. A good compromise
between size and loss is a 30% peak-to-peak ripple cur-
rent to average-current ratio (LIR = 0.3). The switching
frequency, input voltage, output voltage, and selected
LIR determine the inductor value as follows:
L =
V IN × f SW × I OUT × LIR
where V IN , V OUT , and I OUT are typical values. The
switching frequency is set by R T (see Setting the
Switching Frequency section). The exact inductor value
is not critical and can be adjusted to make trade-offs
among size, cost, and efficiency. Lower inductor val-
ues minimize size and cost, but also improve transient
response and reduce efficiency due to higher peak cur-
rents. On the other hand, higher inductance increases
efficiency by reducing the RMS current.
Find a low-loss inductor with the lowest possible DC
resistance that fits in the allotted dimensions. The
14
saturation current rating (I SAT ) must be high enough to
ensure that saturation cannot occur below the maximum
current-limit value (I CL(MAX) ), given the tolerance of the
on-resistance of the low-side MOSFET and of the LIM
reference current (I LIM ). Combining these conditions,
select an inductor with a saturation current (I SAT ) of:
I SAT ≥ 1.35 × I CL(TYP)
where I CL(TYP) is the typical current-limit set point. The
factor 1.35 includes R DS(ON) variation of 25% and 10%
for the LIM reference current error. A variety of inductors
from different manufacturers are available to meet this
requirement (for example, Vishay IHLP-4040DZ-1-5 and
other inductors from the same series).
Setting the Valley Current Limit
The minimum current-limit threshold must be high enough
to support the maximum expected load current with the
worst-case low-side MOSFET on-resistance value as the
R DS(ON) of the low-side MOSFET is used as the current-
sense element. The inductor’s valley current occurs at
I LOAD(MAX) minus one half of the ripple current. The
minimum value of the current-limit threshold voltage
(V ITH ) must be higher than the voltage on the low-side
MOSFET during the ripple-current valley,
> R × I 1 ?
? 2 ?
where R DS(ON,MAX) in I is the maximum on-resistance
of the low-side MOSFET at maximum load current
I LOAD(MAX) and is calculated from the following equation:
=
R DS(ON,MAX) R DS(ON) × [1 + TC MOSFET × (T MAX - T AMB )]
where R DS(ON) (in I is the on-resistance of the low-
side MOSFET at ambient temperature T AMB (in degrees
Celsius), TC MOSFET is the temperature coefficient of
the low-side MOSFET in ppm/ N C, and T MAX (in degrees
Celsius) is the temperature at maximum load current
I LOAD(MAX). Obtain the R DS(ON) and TC MOSFET from the
MOSFET data sheet.
Maxim Integrated
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| MAX15046EVKIT+ | 功能描述:电源管理IC开发工具 MAX15046 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 |
| MAX15047EWE+ | 制造商:Maxim Integrated Products 功能描述:- Rail/Tube |
| MAX15048ETJ+ | 功能描述:DC/DC 开关控制器 1.2MHz Triple Buck w/Tracking RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
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| MAX15048ETJ+ | 制造商:Maxim Integrated Products 功能描述:IC PWM STEP-DOWN DC/DC CONVER |
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