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参数资料
| 型号： | MAX8686EVKIT# |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 20/23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
K S = 1 + OUT
resistor, and compensation capacitors determine the
loop stability. The inductor and output capacitor are
chosen based on performance, size, and cost.
Additionally, the compensation resistor and capacitors
are selected to optimize control-loop stability. The compo-
nent values, shown in Figures 2, 3, and 4, yield stable
operation over the given range of input-to-output voltages.
The regulator uses a current-mode control scheme that
regulates the output voltage by forcing the required
compensation factor calculated from the following
equation:
V ? 0.182 x V IN _ MIN
f SW x L x ( V IN ? V OUT )
Find the pole and zero frequencies created by the
power modulator as follows:
? 2 π × L × f SW × C OUT
× [ K S × ( 1 ? D ) ? 0 . 5 ] ?
current through the external inductor. The voltage drop
across the DC resistance of the inductor or the alter-
nate series current-sense resistor is used to measure
f pMOD =
N
2 π × R LOAD × C OUT
? N
+ ?
?
?
the inductor current. Current-mode control eliminates
the double pole in the feedback loop caused by the
inductor and output capacitor resulting in a smaller
phase shift and requiring a less elaborate error-amplifi-
f zMOD =
1
2 π × C OUT × ESR
er compensation than voltage-mode control. A simple
series R C and C C is all that is needed to have a stable,
high-bandwidth loop in applications where ceramic
capacitors are used for output filtering. For other types
of capacitors, due to the higher capacitance and ESR,
the frequency of the zero created by the capacitance
and ESR is lower than the desired closed-loop crossover
frequency. To stabilize a nonceramic output-capacitor
loop, add another compensation capacitor from COMP
to GND to cancel this ESR zero. See Figure 6.
The basic regulator loop is modeled as a power modula-
tor, an output feedback divider, and an error amplifier.
The power modulator has DC gain set by g mc x R LOAD ,
with a pole and zero pair set by R LOAD , the output capac-
itor (C OUT ), and its equivalent series resistance (ESR).
Below are equations that define the power modulator:
when C OUT comprises “n” identical capacitors in paral-
lel, the resulting C OUT = n x C OUT(EACH) , and ESR =
ESR (EACH) /n. Note that the capacitor zero for a parallel
combination of like capacitors is the same as for an
individual capacitor.
The transconductance error amplifier has a DC gain,
G EA(DC) = g mEA x R O , where g mEA is the error-amplifi-
er transconductance, which is equal to 1.7mS, and R O
is the output resistance of the error amplifier, which is
30M Ω . A dominant pole (f pdEA ) is set by the compen-
sation capacitor (C C ), the amplifier output resistance
(R O ), and the compensation resistor (R C ); a zero (f zEA )
is set by the compensation resistor (R C ) and the com-
pensation capacitor (C C ). There is an optional pole
(f pEA ) set by C F and R C to cancel the output capacitor
ESR zero if it occurs near the crossover frequency (f C ).
Thus:
? 1 +
× ?? ( K S × ( ) ) ? 0..5 ?? ?
1 ? D
f pdEA =
f zEA =
G MOD ( DC ) = g mc ×
?
?
R LOAD
L × f SW
R LOAD
?
?
1
2 π × C C × ( R O + R C )
1
2 π × C C × R C
f pEA =
where R LOAD = V OUT /[I OUT(MAX) /N], f SW is the switch-
ing frequency, L is the output inductance, g mc =
1/(A VCS x R DC ), where A VCS is the gain of the current-
sense amplifier (30.5 typ), R DC is the DC resistance of
the inductor, the duty cycle D = V OUT /V IN . K S is a slope
1
2 π × C F × R C
The crossover frequency, f C , should be much higher
than the power-modulator pole f PMOD . Also, f C should
20
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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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