- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄369850 > LTC1957-2EMS AMP POWER CONTROLLER PDF資料下載
參數(shù)資料
| 型號： | LTC1957-2EMS |
| 英文描述： | AMP POWER CONTROLLER |
| 中文描述： | 安培電源控制器 |
| 文件頁數(shù)： | 10/28頁 |
| 文件大?。?/td> | 389K |
| 代理商： | LTC1957-2EMS |
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頁當前第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頁第23頁第24頁第25頁第26頁第27頁第28頁
LTC1929/LTC1929-PG
OPERATIOU
Main Control Loop
The LTC1929 uses a constant frequency, current mode
step-down architecture with inherent current sharing.
During normal operation, the top MOSFET is turned on
each cycle when the oscillator sets the RS latch, and
turned off when the main current comparator, I
1
, resets
the RS latch. The peak inductor current at which I
1
resets
the RS latch is controlled by the voltage on the I
TH
pin,
which is the output of the error amplifier EA. The differen-
tial amplifier, A1, produces a signal equal to the differential
voltage sensed across the output capacitor but re-refer-
ences it to the internal signal ground (SGND) reference.
The EAIN pin receives a portion of this voltage feedback
signal at the DIFFOUT pin which is compared to the
internal reference voltage by the EA. When the load current
increases, it causes a slight decrease in the EAIN pin
voltage
relative to the 0.8V reference, which in turn causes
the I
TH
voltage to increase until the average inductor
current matches the new load current. After the top
MOSFET has turned off, the bottom MOSFET is turned on
for the rest of the period.
The top MOSFET drivers are biased from floating boot-
strap capacitor C
B
, which normally is recharged during
each off cycle through an external Schottky diode. When
V
IN
decreases to a voltage close to V
OUT
, however, the loop
may enter dropout and attempt to turn on the top MOSFET
continuously. A dropout detector detects this condition
and forces the top MOSFET to turn off for about 400ns
every 10th cycle to recharge the bootstrap capacitor.
The main control loop is shut down by pulling Pin 1 (RUN/
SS) low. Releasing RUN/SS allows an internal 1.2
μ
A
current source to charge soft-start capacitor C
SS
. When
C
SS
reaches 1.5V, the main control loop is enabled with the
I
TH
voltage clamped at approximately 30% of its maximum
value. As C
SS
continues to charge, I
TH
is gradually re-
leased allowing normal operation to resume. When the
RUN/SS pin is low, all LTC1929 functions are shut down.
If V
OUT
has not reached 70% of its nominal value when C
SS
has charged to 4.1V, an overcurrent latchoff can be
invoked as described in the Applications Information
section.
(Refer to Functional Diagram)
Low Current Operation
The LTC1929 operates in a continuous, PWM control
mode. The resulting operation at low output currents
optimizes transient response at the expense of substantial
negative inductor current during the latter part of the
period. The level of ripple current is determined by the
inductor value, input voltage, output voltage, and fre-
quency of operation.
Frequency Synchronization
The phase-locked loop allows the internal oscillator to be
synchronized to an external source via the PLLIN pin. The
output of the phase detector at the PLLFLTR pin is also the
DC frequency control input of the oscillator that operates
over a 140kHz to 310kHz range corresponding to a DC
voltage input from 0V to 2.4V. When locked, the PLL aligns
the turn on of the top MOSFET to the rising edge of the
synchronizing signal. When PLLIN is left open, the PLLFLTR
pin goes low, forcing the oscillator to minimum frequency.
Input capacitance ESR requirements and efficiency losses
are substantially reduced because the peak current drawn
from the input capacitor is effectively divided by two and
power loss is proportional to the RMS current squared. A
two stage, single output voltage implementation can re-
duce input path power loss by 75% and radically reduce
the required RMS current rating of the input capacitor(s).
INTV
CC
/EXTV
CC
Power
Power for the top and bottom MOSFET drivers and most
of the IC circuitry is derived from INTV
CC
. When the
EXTV
CC
pin is left open, an internal 5V low dropout
regulator supplies INTV
CC
power. If the EXTV
CC
pin is
taken above 4.7V, the 5V regulator is turned off and an
internal switch is turned on connecting EXTV
CC
to INTV
CC
.
This allows the INTV
CC
power to be derived from a high
efficiency external source such as the output of the regu-
lator itself or a secondary winding, as described in the
Applications Information section. An external Schottky
diode can be used to minimize the voltage drop from
EXTV
CC
to INTV
CC
in applications requiring greater than
the specified INTV
CC
current.
Voltages up to 7V can be
applied to EXTV
CC
for additional gate drive capability.
Powered by ICminer.com Electronic-Library Service CopyRight 2003
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LTC25501PAK | Optoelectronic |
| LTC25601PAK | Optoelectronic |
| LTC3405AES6 | Analog IC |
| LTC5502A1P12 | Optoelectronic |
| LTC5612ELM | Optoelectronic |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LTC1957-2EMS#PBF | 功能描述:IC RF PWR CONTROLLR DUAL 10-MSOP RoHS:是 類別:RF/IF 和 RFID >> RF 電源控制器 IC 系列:- 標準包裝:3,000 系列:- RF 型:GSM 頻率:450MHz ~ 2GHz 特點:四頻帶 封裝/外殼:8-VFBGA 供應(yīng)商設(shè)備封裝:8-MicroSMD（1.51x1.51） 包裝:帶卷 (TR) 其它名稱:LMV243BLX |
| LTC1957-2EMS#TR | 功能描述:IC RF PWR CONTROLLR DUAL 10-MSOP RoHS:否 類別:RF/IF 和 RFID >> RF 電源控制器 IC 系列:- 標準包裝:3,000 系列:- RF 型:GSM 頻率:450MHz ~ 2GHz 特點:四頻帶 封裝/外殼:8-VFBGA 供應(yīng)商設(shè)備封裝:8-MicroSMD（1.51x1.51） 包裝:帶卷 (TR) 其它名稱:LMV243BLX |
| LTC1957-2EMS#TRPBF | 功能描述:IC RF PWR CONTROLLR DUAL 10-MSOP RoHS:是 類別:RF/IF 和 RFID >> RF 電源控制器 IC 系列:- 標準包裝:3,000 系列:- RF 型:GSM 頻率:450MHz ~ 2GHz 特點:四頻帶 封裝/外殼:8-VFBGA 供應(yīng)商設(shè)備封裝:8-MicroSMD（1.51x1.51） 包裝:帶卷 (TR) 其它名稱:LMV243BLX |
| LTC1960CG | 功能描述:IC BATT CHRGR/SELECTR DUAL36SSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 電池管理 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:2,500 系列:- 功能:電池監(jiān)控器 電池化學(xué):堿性，鋰離子，鎳鎘，鎳金屬氫化物 電源電壓:1 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:SOT-23-6 供應(yīng)商設(shè)備封裝:SOT-6 包裝:帶卷 (TR) |
| LTC1960CG#PBF | 功能描述:IC BATT CHRGR/SELECTR DUAL36SSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 電池管理 系列:- 其它有關(guān)文件:STC3100 View All Specifications 特色產(chǎn)品:STC3100 - Battery Monitor IC 標準包裝:4,000 系列:- 功能:燃料，電量檢測計/監(jiān)控器 電池化學(xué):鋰離子（Li-Ion） 電源電壓:2.7 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:8-TSSOP，8-MSOP（0.118"，3.00mm 寬） 供應(yīng)商設(shè)備封裝:8-MiniSO 包裝:帶卷 (TR) 其它名稱:497-10526-2 |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。