参数资料
型号: MAX8686EVKIT#
厂商: Maxim Integrated Products
文件页数: 21/23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:
已用 IC / 零件: MAX8686
Single/Multiphase, Step-Down,
DC-DC Converter Delivers Up to 25A Per Phase
f pMOD C ≤ SW
<< f
G EA ( fc ) = g mEA C × zMOD
× R
be  less  than  or  equal  to  1/5  the  switching  frequency.
Select a value for f C in the range:
f
5
The error-amplifier gain at f C is:
R C is calculated as:
f
f C
R C = ×
The feedback voltage-divider gain (V REF /V OUT ) should
be included for an output voltage higher than 3.3V,
where V REFIN is equal to 3.3V.
At the crossover frequency, the total loop gain must
V OUT
V FB
f C
g mEA × G MOD ( fc ) × f zMOD
equal 1, and is expressed as:
where g mEA = 1.7mS.
G EA ( fc ) × G MOD ( fc ) × = 1
V REFIN
V OUT
For the case where f zMOD is greater than f C :
G EA ( fc ) = g mEA × R C
C C is calculated from:
C C =
C F is calculated from:
1
2 π × f pMOD × R C
G MOD ( fc ) = G MOD ( dc ) ×
f pMOD
f C
C F =
1
2 π × R C × f zMOD
Then R C can be calculated as:
The current-mode control model on which the above
R C =
g mEA × V REFIN × G MOD ( fc )
V OUT
design procedure is based requires an additional high-
frequency term, G S (s), to account for the effect of sam-
pling the peak inductor current. The term G S (s) produces
additional phase lag at crossover and should be modeled
where g mEA = 1.7mS.
The error-amplifier compensation zero formed by R C
and C C should be set at the modulator pole f PMOD .
Calculate the value of C C as follows:
to estimate the phase margin obtainable by the selected
compensation components. As a final step, it is useful to
plot the dB gain and phase of the following loop-gain
transfer function and check the obtained phase margin. A
phase margin of at least 45° is recommended:
? 1 +
× ?? ( Ks × ( 1 ? D ) ) ? 0 . 5 ?? ?
C C =
1
2 π × f pMOD × R C
G LOOP ( s ) =
?
?
L × f SW ?
R LOAD × g MC
R LOAD ?
×
( 1 + s / 2 π × f zMOD )
( 1 + s / 2 π × f pMOD )
×
× mEA
If f PMOD is less than 5 x f C , add a second capacitor C F
from COMP to GND. The value of C F is:
( 1 + s / 2 π × f zEA )
( 1 + s / 2 π × f pEA ) × ( 1 + s / 2 π × f pdEA )
g
× Ro × V REFIN
V OUT
G S (
C F =
? 1 +
?
?
( π × f SW ) ?
1
2 π × R C × f zMOD
As the load current decreases, the modulator pole also
decreases; however, the modulator gain increases
G S ( s ) =
?
?
?
1
s
π × Q c × f SW
+
s 2
2 ?
accordingly and the crossover frequency remains the
where the sampling effect quality factor is:
same.
For the case where f zMOD is less than f C :
The power modulator gain at f C is:
f pMOD
G MOD ( fc ) = G MOD ( dc ) ×
f zMOD
Q C =
1
[ π × ( K S × ( 1 ? D ) ? 0 . 5 ) ]
______________________________________________________________________________________
21
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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
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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