参数资料
型号: MAX15004AAUE+T
厂商: Maxim Integrated Products
文件页数: 15/27页
文件大小: 0K
描述: IC REG CTRLR PWM CM 16-TSSOP
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: 1MHz
占空比: 50%
电源电压: 4.5 V ~ 40 V
降压:
升压:
回扫:
反相:
倍增器:
除法器:
Cuk:
隔离:
工作温度: -40°C ~ 125°C
封装/外壳: 16-TSSOP(0.173",4.40mm)裸露焊盘
包装: 带卷 (TR)
MAX15004A/B/MAX15005A/B
4.5V to 40V Input Automotive
Flyback/Boost/SEPIC Power-Supply Controllers
When the voltage produced by this current (through the
current-sense resistor) exceeds the current-limit com-
parator threshold, the MOSFET driver (OUT) quickly ter-
minates the on-cycle. In most cases, a short-time
constant RC filter is required to filter out the leading-
edge spike on the sense waveform. The amplitude and
width of the leading edge depends on the gate capaci-
tance, drain capacitance (including interwinding capac-
itance), and switching speed (MOSFET turn-on time).
Set the RC time constant just long enough to suppress
the leading edge. For a given design, measure the lead-
ing spike at the highest input and rated output load to
determine the value of the RC filter.
The low 305mV current-limit threshold reduces the
power dissipation in the current-sense resistor. The cur-
rent-limit threshold can be further reduced by adding
an offset to the CS input from REG5 voltage. Do not
reduce the current-limit threshold below 150mV as it
may cause noise issues. See Figure 4. For a new value
of the current-limit threshold (V CS-LOW ), calculate the
value of R1 using the following equation.
Applications Information
Boost Converter
The MAX15004A/B/MAX15005A/B can be configured
for step-up conversion. The boost converter output can
be fed back to V CC (see Figure 5) so that the controller
can function even during cold-crank input voltage
( ≤ 2.5V). Use a Schottky diode (D VIN ) in the V IN path to
avoid backfeeding the input source. A current-limiting
resistor (R VCC ) is also needed from the boost converter
output to V CC depending upon the boost converter out-
put voltage. The total current sink into V CC must be lim-
ited to 30mA. Use the equations in the following
sections to calculate R VCC , inductor (L MIN ), input
capacitor (C IN ), and output capacitor (C OUT ) when
using the converter in boost operation.
Inductor Selection in Boost Configuration
Using the following equation, calculate the minimum
inductor value so that the converter remains in continu-
ous mode operation at minimum output current (I OMIN ).
R 1 =
4 . 75 × R CS
0 . 290 ? V CS ? Low
L MIN =
V IN 2 × D × η
2 × f OUT × V OUT × I OMIN
where:
V IN
and
D =
V OUT + V D ? V IN
V OUT + V D ? V DS
MAX15004A/B
REG5
I OMIN = (0.1 × I O ) to (0.25 × I O )
MAX15005A/B
0.3V
CURRENT-LIMIT
COMPARATOR
R1
C CS
R CS
N
R S
The higher value of I OMIN reduces the required induc-
tance; however, it increases the peak and RMS currents
in the switching MOSFET and inductor. Use I OMIN from
10% to 25% of the full load current. The V D is the for-
ward voltage drop of the external Schottky diode, D is
the duty cycle, and V DS is the voltage drop across the
external switch. Select the inductor with low DC resis-
tance and with a saturation current (I SAT ) rating higher
than the peak switch current limit of the converter.
Figure 4. Reducing Current-Sense Threshold
Maxim Integrated
15
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MAX15004BAUE/V+T 功能描述:电流型 PWM 控制器 Flyback/Boost/SEPIC Power-Supply 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
MAX15004BAUE+ 功能描述:电流型 PWM 控制器 Flyback/Boost/SEPIC Power-Supply 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
MAX15004BAUE+T 功能描述:电流型 PWM 控制器 Flyback/Boost/SEPIC Power-Supply 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
MAX15005AAUE/V+ 功能描述:电流型 PWM 控制器 Flyback/Boost/SEPIC Power-Supply 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