參數(shù)資料
型號: MAX5038EAI18
廠商: MAXIM INTEGRATED PRODUCTS INC
元件分類: 穩(wěn)壓器
英文描述: Dual-Phase, Parallelable, Average Current-Mode Controllers
中文描述: SWITCHING CONTROLLER, 525 kHz SWITCHING FREQ-MAX, PDSO28
封裝: 5.30 MM, MO150, SSOP-28
文件頁數(shù): 17/26頁
文件大?。?/td> 406K
代理商: MAX5038EAI18
M
Dual-Phase, Parallelable, Average Current-Mode
Controllers
______________________________________________________________________________________
17
Set the voltage-positioning window (
V
OUT
) using the
resistive feedback of the VEA. Use the following equa-
tions to calculate the voltage-positioning window for the
MAX5038:
Use the following equation to calculate the voltage-posi-
tioning window for the MAX5041:
where R
IN
and R
F
are the input and feedback resistors of
the VEA, G
C
is the current-loop gain and R
S
is the cur-
rent-sense resistor or, if using lossless inductor current
sensing, the DC resistance of the inductor.
Phase-Loc ked Loop: Operation and
Compensation
The PLL synchronizes the internal oscillator to the
external frequency source when driving CLKIN.
Connecting CLKIN to V
CC
or SGND forces the PWM
frequency to default to the internal oscillator frequency
of 500kHz or 250kHz, respectively. The PLL uses a
conventional architecture consisting of a phase detec-
tor and a charge pump capable of providing 20μA of
output current. Connect an external series combination
capacitor (C25) and resistor (R4) and a parallel capaci-
tor (C26) from PLLCMP to SGND to provide frequency
compensation for the PLL (Figure 1). The pole-zero pair
compensation provides a zero at f
Z
= 1 / [R4 x (C25 +
C26)] and a pole at f
P
= 1 / (R4 x C26). Use the follow-
ing typical values for compensating the PLL:
R4 = 7.5k
, C25 = 4.7nF, C26 = 470pF. If changing the
PLL frequency, expect a finite locking time of approxi-
mately 200μs.
The MAX5038/MAX5041 require compensation on
PLLCMP even when operating from the internal oscilla-
tor. The device requires an active PLL in order to gen-
erate the proper internal PWM clocks.
MOS FET Gate Drivers (DH_, DL_)
The high-side (DH_) and low-side (DL_) drivers drive
the gates of external N-channel MOSFETs (Figures 1
and 2). The drivers’ high-peak sink and source current
capability provides ample drive for the fast rise and fall
times of the switching MOSFETs. Faster rise and fall
times result in reduced cross-conduction losses. For
modern CPU voltage-regulating module applications
where the duty cycle is less than 50%, choose high-
side MOSFETs (Q1 and Q3) with a moderate R
DS(ON)
and a very low gate charge. C hoose low-side
MOSFETs (Q2 and Q4) with very low R
DS(ON)
and
moderate gate charge.
The driver block also includes a logic circuit that pro-
vides an adaptive non-overlap time to prevent shoot-
through currents during transition. The typical
non-overlap time is 60ns between the high-side and
low-side MOSFETs.
BS T _
V
DD
powers the low- and high-side MOSFET drivers.
Connect a 0.47μF low-ESR ceramic capacitor between
BST_ and LX_. Bypass V
CC
to PGND with 4.7μF and
0.1μF low-ESR ceramic capacitors. Reduce the PC
board area formed by these capacitors, the rectifier
diodes between V
CC
and the boost capacitor, the
MAX5038/MAX5041, and the switching MOSFETs.
G
R
C
S
=
0 05
.
V
I
R
×
G
R
R
R
R
OUT
OUT
×
IN
C
F
H
L
L
=
×
(
)
×
+
2
G
R
C
S
=
0 05
.
V
I
R
×
G
R
OUT
OUT
×
2
IN
C
F
=
×
LOAD (A)
V
CNTR
NOLOAD
1/2 LOAD
FULL LOAD
V
V
CNTR
+
V
OUT
/2
V
CNTR
-
V
OUT
/2
Figure 5. Defining the Voltage-Positioning Window
(8)
(9)
(10)
(11)
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相關代理商/技術參數(shù)
參數(shù)描述
MAX5038EAI18+ 制造商:Maxim Integrated Products 功能描述:- Rail/Tube
MAX5038EAI18-T 功能描述:電流型 PWM 控制器 RoHS:否 制造商:Texas Instruments 開關頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風格:SMD/SMT 封裝 / 箱體:TSSOP-14
MAX5038EAI25 功能描述:電流型 PWM 控制器 RoHS:否 制造商:Texas Instruments 開關頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風格:SMD/SMT 封裝 / 箱體:TSSOP-14
MAX5038EAI25+ 制造商:Maxim Integrated Products 功能描述:- Rail/Tube
MAX5038EAI25-T 功能描述:電流型 PWM 控制器 RoHS:否 制造商:Texas Instruments 開關頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風格:SMD/SMT 封裝 / 箱體:TSSOP-14