參數(shù)資料
型號(hào): DS14285
廠商: MAXIM INTEGRATED PRODUCTS INC
元件分類: Timer or RTC
英文描述: 1 TIMER(S), REAL TIME CLOCK, PDIP24
封裝: 0.600 INCH, DIP-24
文件頁數(shù): 16/16頁
文件大?。?/td> 312K
代理商: DS14285
Detailed Description
The MAX774/MAX775/MAX776 are negative-output,
inverting power controllers that can be configured to drive
an external P-channel MOSFET. The output voltages are
preset to -5V (MAX774), -12V (MAX775), or -15V
(MAX776). Additionally, all three parts can be set to any
desired output voltage using an external resistor divider.
The MAX774/MAX775/MAX776 have a unique control
scheme (Figure 1) that combines the advantage of
pulse-skipping, pulse-frequency-modulation (PFM)
converters (ultra-low supply current) with the advan-
tage of pulse-width modulation (PWM) converters (high
efficiency with heavy loads). This control scheme
allows the devices to achieve 85% efficiency with loads
from 5mA to 1A.
As with traditional PFM converters, the external
P-channel MOSFET power transistor is turned on when
the voltage comparator senses that the output is below
the reference voltage. However, unlike traditional PFM
converters, switching is controlled by the combination
of a switch current limit (210mV/RSENSE) and
on-time/off-time limits set by one-shots. Once turned
on, the MOSFET stays on until the 16s maximum on-
time limit is reached or the switch current reaches its
limit (as set by the current-sense resistor).
Once off, the switch is typically held off for a minimum of
2.3s. It will stay off until the output drops below the level
determined by VREF and the feedback divider network.
With light loads, the MOSFET switches on for one or
more cycles and then switches off, much like in tradi-
tional PFM converters. To increase light-load efficiency,
MAX774/MAX775/MAX776
-5V/-12V/-15V or Adjustable, High-Efficiency,
Low IQ Inverting DC-to-DC Controllers
_______________________________________________________________________________________
9
N
1.5V
REFERENCE
Q
TRIG
ONE-SHOT
Q
TRIG
ONE-SHOT
CURRENT-
CONTROL CIRCUITS
MODE
COMPARATOR
ERROR
COMPARATOR
CURRENT
COMPARATOR
FROM V+
FROM OUT
0.2V
(FULL CURRENT)
0.1V
(HALF CURRENT)
FROM
V+
MAX774
MAX775
MAX776
REF
V+
SHDN
FB
OUT
CS
EXT
GND
S
R
Q
50mV
Figure 1. Functional Diagram
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
DS14285_05 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:Real-Time Clock with NV RAM
DS14285+ 功能描述:實(shí)時(shí)時(shí)鐘 RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時(shí)間格式:HH:MM:SS RTC 存儲(chǔ)容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube
DS14285-DS14287 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:Real Time Clock with NV RAM Control
DS14285N 功能描述:實(shí)時(shí)時(shí)鐘 RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時(shí)間格式:HH:MM:SS RTC 存儲(chǔ)容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube
DS14285N+ 功能描述:實(shí)時(shí)時(shí)鐘 RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時(shí)間格式:HH:MM:SS RTC 存儲(chǔ)容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube