參數(shù)資料
型號: MAX1745EUB+T
廠商: MAXIM INTEGRATED PRODUCTS INC
元件分類: 穩(wěn)壓器
英文描述: High-Voltage, Step-Down DC-DC Controller in µMAX
中文描述: SWITCHING CONTROLLER, 330 kHz SWITCHING FREQ-MAX, PDSO10
封裝: MICRO MAX PACKAGE-10
文件頁數(shù): 14/14頁
文件大小: 256K
代理商: MAX1745EUB+T
MAX1744/MAX1745
High-Voltage, Step-Down DC-DC
Controller in MAX
_______________________________________________________________________________________
9
At light output loads, the inductor current is discontinu-
ous, causing the MAX1744/MAX1745 to operate at
lower frequencies, reducing the MOSFET gate drive
and switching losses. In discontinuous mode, under
most circumstances, the on-time will be the fixed mini-
mum on-time of 1s. If the inductor value is small, or
the current-sense resistor large, the current limit will be
tripped before the minimum on-time, terminating the
on-time and thus setting the fixed on-time.
If the inductance is too large, or the output capacitance
high and equivalent series resistance (ESR) low, then
the MOSFET remains on longer than the minimum on-
time, until the output capacitor charges beyond the
error comparator’s (VOUT / 1.25V) 8mV hysteresis,
causing the part to operate in hysteretic mode.
Operating in hysteretic mode results in lower frequency
operation. The transition to hysteretic mode occurs at
the critical output capacitor ESR:
ESRCRITICAL = (VOUT / 1.25V) 8mV / IRIPPLE
where IRIPPLE is the inductor ripple current, and can be
determined by:
IRIPPLE = (VIN - VOUT) tON(MIN) / L
where tON(MIN) is the minimum on-time (1s) for mini-
mum on-time-control, or:
IRIPPLE = (VOUT) tOFF(MIN) / L
where tOFF(MIN) is the minimum off-time (2s) for mini-
mum off-time-control.
REF
MINIMUM
OFF-TIME
ONE SHOT
Q
TRIG
VL
LINEAR
REGULATOR
VH
LINEAR
REGULATOR
1.25
REFERENCE
(FB)
ERROR
COMPARATOR
OUT
3/5
SHDN
CS
100mV
+
-
Q
R
S
VL
SHDN
VH
EXT
IN
MINIMUM
ON-TIME
ONE SHOT
Q
TRIG
( ) MAX1745 ONLY
- - - MAX1744 ONLY
Figure 2. Simplified Functional Diagram
相關(guān)PDF資料
PDF描述
MAX1744AUB+ High-Voltage, Step-Down DC-DC Controller in µMAX
MAX1744EUB+ High-Voltage, Step-Down DC-DC Controller in µMAX
MAX1745AUB+ High-Voltage, Step-Down DC-DC Controller in µMAX
MAX1745EUB/V+ High-Voltage, Step-Down DC-DC Controller in µMAX
MAX1745EUB+ High-Voltage, Step-Down DC-DC Controller in µMAX
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MAX1745EUB-TG069 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述:
MAX1745EVKIT 功能描述:DC/DC 開關(guān)控制器 NULL 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
MAX1747EUP 功能描述:電荷泵 RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 輸出電壓:- 1.5 V to - 5.5 V, 3 V to 11 V 輸出電流:100 mA 電源電流:1 mA 最大工作溫度:+ 70 C 封裝 / 箱體:SOIC-8 Narrow 封裝:Tube
MAX1747EUP+ 功能描述:電荷泵 Triple Charge-Pump TFT LCD DC/DC Conv RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 輸出電壓:- 1.5 V to - 5.5 V, 3 V to 11 V 輸出電流:100 mA 電源電流:1 mA 最大工作溫度:+ 70 C 封裝 / 箱體:SOIC-8 Narrow 封裝:Tube
MAX1747EUP+T 功能描述:電荷泵 Triple Charge-Pump TFT LCD DC/DC Conv RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 輸出電壓:- 1.5 V to - 5.5 V, 3 V to 11 V 輸出電流:100 mA 電源電流:1 mA 最大工作溫度:+ 70 C 封裝 / 箱體:SOIC-8 Narrow 封裝:Tube