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參數(shù)資料
| 型號(hào)： | MAX1674 |
| 廠商： | Maxim Integrated Products, Inc. |
| 元件分類： | DC/DC變換器 |
| 英文描述： | High-Efficiency, Low-Supply-Current, Compact, Step-Up DC-DC Converters |
| 中文描述： | 高效率、低電源電流、緊湊的、升壓型DC-DC轉(zhuǎn)換器 |
| 文件頁數(shù)： | 7/12頁 |
| 文件大?。?/td> | 160K |
| 代理商： | MAX1674 |
Detailed Desc ription
The MAX1674/MAX1675/MAX1676 compact, step-up
DC-DC converters start up with voltages as low as 0.9V
and operate with an input voltage down to 0.7V.
Consuming only 16μA of quiescent current, these
devices offer a built-in synchronous rectifier that
reduces cost by eliminating the need for an external
diode and improves overall efficiency by minimizing
losses in the circuit (see Synchronous Rectificationsec-
tion for details). The internal MOSFET resistance is typi-
cally 0.3
, which minimizes losses. The current limit of
the MAX1674 and MAX1675 are 1A and 0.5A, respec-
tively. The MAX1675’s lower current limit allows the use
of a physically smaller inductor in space-sensitive
applications. The MAX1676 features a circuit that elimi-
nates noise due to inductor ringing. In addition, the
MAX1676 offers a selectable current limit (0.5A or 1A)
for design flexibility.
PFM Control S c heme
A unique minimum-off-time, current-limited, pulse-fre-
quency-modulation (PFM) control scheme is a key fea-
ture of the MAX1674/MAX1675/MAX1676. This scheme
combines the high output power and efficiency of a
pulse-width-modulation (PWM) device with the ultra-low
quiescent current of a traditional PFM (Figure 1). There
is no oscillator; a constant-peak-current limit in the
switch allows the inductor current to vary between this
peak limit and some lesser value. At light loads, the
switching frequency is governed by a pair of one-shots
that set a typical minimum off-time (1μs) and a typical
maximum on-time (4μs). The switching frequency
depends upon the load and the input voltage, and can
range up to 500kHz. The peak current of the internal N-
channel MOSFET power switch is fixed at 1A
(MAX1674), at 0.5A (MAX1675), or is selectable
(MAX1676). Unlike conventional pulse-skipping DC-DC
converters (where ripple amplitude varies with input
voltage), ripple in these devices does not exceed the
product of the switch current limit and the filter-capaci-
tor equivalent series resistance (ESR).
S ync hronous Rec tific ation
The internal synchronous rectifier eliminates the need
for an external Schottky diode, thus reducing cost and
board space. During the cycle off-time, the P-channel
MOSFET turns on and shunts the MOSFET body diode.
M
High-Effic ienc y, Low-S upply-Current,
Compac t, S tep-Up DC-DC Converters
_______________________________________________________________________________________
7
MAX1674
MAX1675
MAX1676
ONE-SHOT
TRIG
Q
F/F
R
S
Q
ONE-SHOT
TRIG
Q
CURRENT-LIMIT
AMPLIFIER
ERROR
AMPLIFIER
LOW-BATTERY
COMPARATOR
REFERENCE
REF
FB
V
IN
47
μ
F
47
μ
F
R1
200
R5
R6
DAMPING
SWITCH
22
μ
H
BATT
(MAX1676)
GND
LX
OUT
0.1
μ
F
0.1
μ
F
V
OUT
R4
LBI
LBO
R2
100k
R3
V
IN
V
OUT
CLSEL
(MAX1676)
SHDN
MINIMUM
OFF-TIME
ONE-SHOT
ZERO
CROSSING
AMPLIFIER
EN
MAXIMUM
ON-TIME
ONE-SHOT
P
N
Figure 1. Simplified Functional Diagram
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| MAX1674-MAX1676 | High-Efficiency, Low-Supply-Current, Compact, Step-Up DC-DC Converters |
| MAX1676EUB | High-Efficiency, Low-Supply-Current, Compact, Step-Up DC-DC Converters |
| MAX1674EUA | High-Efficiency, Low-Supply-Current, Compact, Step-Up DC-DC Converters |
| MAX1675EUA | High-Efficiency, Low-Supply-Current, Compact, Step-Up DC-DC Converters |
| MAX1677 | Compact, High-Efficiency, Dual-Output Step-Up and LCD Bias DC-DC Converter |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX1674EUA | 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 Compact Step-Up DC/DC Converter RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
| MAX1674EUA+ | 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 Compact Step-Up DC/DC Converter RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
| MAX1674EUA+T | 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 Compact Step-Up DC/DC Converter RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
| MAX1674EUA-T | 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 Compact Step-Up DC/DC Converter RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
| MAX1674EUA-TG069 | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
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