- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄383343 > MAX1980 (Maxim Integrated Products, Inc.) Quick-PWM Slave Controller with Driver Disable for Multiphase DC-DC Converter PDF資料下載
參數(shù)資料
| 型號(hào)： | MAX1980 |
| 廠商： | Maxim Integrated Products, Inc. |
| 元件分類： | DC/DC變換器 |
| 英文描述： | Quick-PWM Slave Controller with Driver Disable for Multiphase DC-DC Converter |
| 中文描述： | Quick-PWM從控制器，帶有驅(qū)動(dòng)禁止功能，用于多相DC-DC轉(zhuǎn)換器 |
| 文件頁數(shù)： | 23/33頁 |
| 文件大小： | 1153K |
| 代理商： | MAX1980 |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁當(dāng)前第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁第33頁
M
Quick-PWM Slave Controller with
Driver Disable for Multiphase DC-DC Converter
______________________________________________________________________________________
23
For in-phase operation, the maximum ESR to meet rip-
ple requirements is:
The actual capacitance value required relates to the
physical size needed to achieve low ESR, as well as to
the chemistry of the capacitor technology. Thus, the
capacitor is usually selected by ESR and voltage rating
rather than by capacitance value (this is true of tanta-
lums, OS-CONs, and other electrolytics).
When using low-capacity filter capacitors such as
ceramic or polymer types, capacitor size is usually
determined by the capacity needed to prevent V
SAG
and V
SOAR
from causing problems during load tran-
sients. Generally, once enough capacitance is added to
meet the overshoot requirement, undershoot at the ris-
ing load edge is no longer a problem (see the V
SAG
and
V
SOAR
equations in the
Transient Response
section).
Output Capacitor Stability Considerations
For Quick-PWM controllers, stability is determined by
the value of the ESR zero relative to the switching fre-
quency. The boundary of instability is given by the fol-
lowing equation:
For a standard 300kHz application, the ESR zero fre-
quency must be well below 95kHz, preferably below
50kHz. Tantalum, Sanyo POSCAP, and Panasonic SP
capacitors in wide-spread use at the time of publication
have typical ESR zero frequencies below 30kHz. In the
standard application used for inductor selection, the
ESR needed to support a 30mV
P-P
ripple is 30mV/(40A
x 0.3) = 2.5m
. Eight 270μF/2.0V Panasonic SP capac-
itors in parallel provide 1.9m
(max) ESR. Their typical
combined ESR results in a zero at 39kHz.
Do not put high-value ceramic capacitors directly
across the output without taking precautions to ensure
stability. Ceramic capacitors have a high ESR zero fre-
quency and may cause erratic, unstable operation.
However, it
’
s easy to add enough series resistance by
placing the capacitors a couple of centimeters down-
stream from the junction of the inductor and FB pin.
Unstable operation manifests itself in two related but
distinctly different ways: double-pulsing and feedback
loop instability. Double-pulsing occurs due to noise on
the output or because the ESR is so low that there isn
’
t
enough voltage ramp in the output voltage signal. This
“
fools
”
the error comparator into triggering a new cycle
immediately after the minimum off-time period has
expired. Double-pulsing is more annoying than harmful,
resulting in nothing worse than increased output ripple.
However, it can indicate the possible presence of loop
instability due to insufficient ESR. Loop instability can
result in oscillations at the output after line or load
steps. Such perturbations are usually damped, but can
cause the output voltage to rise above or fall below the
tolerance limits.
The easiest method for checking stability is to apply a
very fast zero-to-max load transient and carefully
observe the output voltage ripple envelope for over-
shoot and ringing. It can help to simultaneously monitor
the switching waveforms (V
LX
and/or I
INDUCTOR
). Don
’
t
allow more than one cycle of ringing after the initial
step-response under/overshoot.
Input Capacitor Selection
The input capacitor must meet the ripple current require-
ment (I
RMS
) imposed by the switching currents. The
MAX1980 multiphase slave controllers operate out-of-
phase (POL = V
CC
or float), staggering the turn-on times
of each phase. This minimizes the input ripple current by
dividing the load current among independent phases:
for out-of-phase operation.
When operating the MAX1980 in-phase (POL = GND),
the high-side MOSFETs turn on simultaneously, so
input capacitors must support the combined input rip-
ple currents of each phase:
for in-phase operation.
For most applications, nontantalum chemistries (ceramic,
aluminum, or OS-CON) are preferred because of their
resilience to inrush surge currents typical of systems with
a mechanical switch or connector in series with the input.
I
I
V
V
V
V
RMS
LOAD
OUT
IN
OUT
IN
=
(
)
I
I
V
V
V
V
RMS
LOAD
η
OUT
IN
OUT
IN
=
(
)
f
f
where f
R
ESR
SW
π
ESR
ESR OUT
≤
=
π
1
2
R
V
I
LIR
)
V
f
L
V
V
V
V
ESR
RIPPLE
(
LOAD MAX
RIPPLE
SW
OUT
IN
IN
OUT
≤
=
(
)
η
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| MAX1980ETP | Quick-PWM Slave Controller with Driver Disable for Multiphase DC-DC Converter |
| MAX1982 | Low-Voltage, Low-Dropout Linear Regulators with External Bias Supply |
| MAX1982-MAX1983 | EPS300 3/4 CR 48 IN 5700750CR |
| MAX1982EUT-T | Low-Voltage, Low-Dropout Linear Regulators with External Bias Supply |
| MAX1983EUT-T | Low-Voltage, Low-Dropout Linear Regulators with External Bias Supply |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX1980EGP | 功能描述:DC/DC 開關(guān)控制器 RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK |
| MAX1980EGP-T | 功能描述:DC/DC 開關(guān)控制器 RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK |
| MAX1980ETP | 功能描述:DC/DC 開關(guān)控制器 RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK |
| MAX1980ETP+ | 功能描述:DC/DC 開關(guān)控制器 PWM Slave Controller w/Driver Disable RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK |
| MAX1980ETP+T | 功能描述:DC/DC 開關(guān)控制器 PWM Slave Controller w/Driver Disable RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。