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参数资料
| 型号： | MAX8686EVKIT+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 12/23页 |
| 文件大小： | 0K |
| 描述： | BOARD EVAL FOR MAX8686 |
| 标准包装： | 1 |
| 主要目的： | DC/DC，步降 |
| 输出及类型： | 1，非隔离 |
| 输出电压： | 0.7 V ~ 5.5 V |
| 电流 - 输出： | 25A |
| 输入电压： | 4.5 V ~ 20 V |
| 稳压器拓扑结构： | 降压 |
| 频率 - 开关： | 300kHz ~ 1MHz |
| 板类型： | 完全填充 |
| 已供物品： | 板 |
| 已用 IC / 零件： | MAX8686 |
Single/Multiphase, Step-Down,
DC-DC Converter Delivers Up to 25A Per Phase
For using an external reference on REFIN, SS needs to
be tied to REFIN either directly or indirectly through a
resistor for soft-start. For REFIN voltage lower than
1.25V, connect a resistor between SS and REFIN such
that the voltage drop across the resistor due to the soft-
start current (31μA max) coming out of SS, causing the
final SS voltage to be at least 1.25V (see Figure 1a).
The external reference should be able to sink at least
31μA. Calculate R REFIN as follows:
The right timing of the phase shedding signal from the
system is critical for the safe operation of the multiphase
converter. Only after the load current drops below a cer-
tain level, should the phase shedding signal become
high. When the open-drain or open-collector switch is
logic-low, it shuts down the slave phases connected to
the switch to reduce power loss. Before the load current
increases to a certain level, the phase shedding signal
should become logic-high to release the EN/SLOPE of
these slave devices, thus turning these phases back on
R REFIN =
1.25 ? V EXT
19 μA
again to prepare for the higher load current. A minimum
load of 2A per phase in the remaining phases is
required for the shedded phase(s) to turn on.
where V EXT is the external reference voltage.
In a multiphase converter, only REFIN of the master
device is connected to a reference voltage, and the
REFIN of all slave devices should be tied to GND.
The REFIN also allows for coincident voltage tracking of
multiple converters during power-up/power-down by
applying the same voltage on REFIN of the master
device in each converter.
Enable, Phase Shedding, and
Slope Compensation Input (EN/SLOPE)
An internal 10μA current source pulls the EN/SLOPE
input high. The device shuts down when the voltage at
the EN/SLOPE falls below 0.7V. By connecting an
open-drain or open-collector switch to the EN/SLOPE,
this pin can be used to enable/disable a single-phase
or multiphase converter system.
A separate system signal can be used to shed some
phases of the converter at light load to eliminate all the
power loss from these phases and thus improve the sys-
tem efficiency. The phase shedding signal is connected
to the EN/SLOPE pins of the slave devices to be shed.
SS
The transfer function of the power stage is different with a
different number of phases. As the number of phases
increases, the power stage gain increases. The compen-
sation network should be designed such that the convert-
er is always stable with the maximum number of phases.
The EN/SLOPE input is also used to set the slope com-
pensation ramp voltage by connecting a resistor from this
input to GND. The slope compensation is used to stabi-
lize the converters when the duty cycle is more than 40%.
High-Side Gate-Drive Supply (BST)
A flying capacitor between BST and LX generates the
gate-drive voltage for the internal high-side n-channel
MOSFET. When the low-side MOSFET is turned on, the
capacitor is charged by VL to 5.4V minus the drop
across the internal boost switch. When the low-side
MOSFET is turned off, the stored voltage of the capaci-
tor is stacked above LX to provide the necessary turn-
on voltage (V GS ) for the high-side MOSFET. An internal
switch between BST and the internal high-side MOSFET’s
gate closes to turn the MOSFET on.
Current-Sense Amplifier
The current-sense circuit amplifies the differential current-
sense voltage (V CS+ - V CS- ). This amplified current-sense
signal and the internal-slope-compensation signal are
summed (V SUM ) together and fed into the PWM com-
parator’s inverting input. The high-side MOSFET is turned
on by the clock in the device and is shut off when V SUM
MAX8686
REFIN
Figure 1a. Using an External Reference
R REFIN
V EXT
exceeds the error-amplifier output voltage (V COMP ) at
the noninverting input of the PWM comparator. The dif-
ferential current sense is also used to provide peak
inductor current limiting. The limit can be set by adjust-
ing the analog current-limit input (ILIM).
The current-sense amplifier is used to measure the cur-
rent across the inductor by connecting to the inductor
through an RC network for lossless current sensing or
connecting to a current-sense resistor for higher accu-
racy. The input common-mode voltage range of the
current-sense amplifier is from 0 to 5.5V.
12
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX8686EVKIT# | 功能描述:电源管理IC开发工具 MAX8686 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 |
| MAX8686EVKIT+ | 功能描述:电源管理IC开发工具 MAX8686 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 |
| MAX8687ETL+ | 制造商:Maxim Integrated Products 功能描述:SINGLE /MULTIPHASE, DC/DC CONVERTER - Rail/Tube |
| MAX8688AHETG+ | 功能描述:电流和电力监控器、调节器 Digital Power-Supply Controller/Monitor RoHS:否 制造商:STMicroelectronics 产品:Current Regulators 电源电压-最大:48 V 电源电压-最小:5.5 V 工作温度范围:- 40 C to + 150 C 安装风格:SMD/SMT 封装 / 箱体:HPSO-8 封装:Reel |
| MAX8688AHETG+T | 功能描述:电流和电力监控器、调节器 Digital Power-Supply Controller/Monitor RoHS:否 制造商:STMicroelectronics 产品:Current Regulators 电源电压-最大:48 V 电源电压-最小:5.5 V 工作温度范围:- 40 C to + 150 C 安装风格:SMD/SMT 封装 / 箱体:HPSO-8 封装:Reel |
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