- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄44991 > LTC3554EPD#TRPB (LINEAR TECHNOLOGY CORP) 0.5 A BATTERY CHARGE CONTROLLER, 1295 kHz SWITCHING FREQ-MAX, PQCC20 PDF資料下載
參數(shù)資料
| 型號： | LTC3554EPD#TRPB |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | 0.5 A BATTERY CHARGE CONTROLLER, 1295 kHz SWITCHING FREQ-MAX, PQCC20 |
| 封裝： | 3 X 3 MM, 0.55 MM HEIGHT, LEAD FREE, PLASTIC, UTQFN-20 |
| 文件頁數(shù)： | 14/36頁 |
| 文件大?。?/td> | 418K |
| 代理商： | LTC3554EPD#TRPB |
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頁當(dāng)前第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頁第29頁第30頁第31頁第32頁第33頁第34頁第35頁第36頁
LTC3554
21
3554p
PGOOD Operation
The PGOOD pin is an open-drain output which indicates
that all enabled step-down switching regulators have
reached their nal regulation voltage. It goes high-imped-
ance 230ms after all enabled switching regulators reach
92% of their regulation value. The delay allows ample time
for an external processor to reset itself. PGOOD may be
used as a power-on reset to a microprocessor powered
by the step-down switching regulators. Since PGOOD is
an open-drain output, a pull-up resistor to an appropriate
power source is needed. A suggested approach is to con-
nect the pull-up resistor to one of the step-down switching
regulator output voltages so that power is not dissipated
while the regulators are disabled.
Normal Operating Mode (STBY Pin Low)
In normal mode (STBY pin low), the regulators perform
as traditional constant-frequency current mode switch-
ing regulators. Switching frequency is determined by an
internal oscillator whose frequency is selectable via the
FSEL pin. An internal latch is set at the start of every
oscillator cycle, turning on the main P-channel MOSFET
switch. During each cycle, a current comparator compares
the inductor current to the output of an error amplier.
The output of the current comparator resets the internal
latch, which causes the main P-channel MOSFET switch
to turn off and the N-channel MOSFET synchronous
rectier to turn on. The N-channel MOSFET synchronous
rectier turns off at the end of the clock cycle, or when
the current through the N-channel MOSFET synchronous
rectier drops to zero, whichever happens rst. Via this
mechanism, the error amplier adjusts the peak inductor
current to deliver the required output power. All neces-
sary compensation is internal to the step-down switching
regulator requiring only a single ceramic output capacitor
for stability.
At light load and no-load conditions, the buck automatically
switches to a power-saving hysteretic control algorithm
that operates the switches intermittently to minimize
switching losses. Known as Burst Mode operation, the
buck cycles the power switches enough times to charge
the output capacitor to a voltage slightly higher than
the regulation point. The buck then goes into a reduced
quiescent current sleep mode. In this state, power loss
is minimized while the load current is supplied by the
output capacitor. Whenever the output voltage drops
below a predetermined value, the buck wakes from sleep
and cycles the switches again until the output capacitor
voltage is once again slightly above the regulation point.
Sleep time thus depends on load current, since the load
current determines the discharge rate of the output capaci-
tor. Should load current increase above roughly 50mA, the
buck resumes constant-frequency operation.
Standby Mode (STBY Pin High)
There are situations where even the low quiescent current
of Burst Mode operation is not low enough. For instance,
in a static memory keep alive situation, load current may
fall well below 1μA. In this case, the 25μA typical BVIN
quiescent current per active regulator in Burst Mode
operation becomes the main factor determining battery
run time.
Standby mode cuts BVIN quiescent current down to just
1.5μA per active regulator, greatly extending battery run
time in this essentially no-load region of operation. The
application circuit commands the LTC3554 into and out
of standby mode via the STBY pin logic input. Bringing
the STBY pin high places both regulators into standby
mode, while bringing it low returns them to Burst Mode
operation. In standby mode, load capability drops to 5mA
per regulator.
In standby mode, each regulator operates hysteretically.
When the FB pin voltage falls below the internal 0.8V
reference, a current source from BVIN to SW turns on,
delivering current through the inductor to the switching
regulator output capacitor and load. When the FB pin
voltage rises above the reference plus a small hysteresis
voltage, that current is shut off. In this way, output regula-
tion is maintained.
OPERATION
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LTC3560IS6#TRPBF | 2.1 A SWITCHING REGULATOR, 2700 kHz SWITCHING FREQ-MAX, PDSO6 |
| LTC3563EDC | 1.75 A SWITCHING REGULATOR, 2700 kHz SWITCHING FREQ-MAX, PDSO6 |
| LTC3568EDD#TR | 4 A SWITCHING REGULATOR, 4000 kHz SWITCHING FREQ-MAX, PDSO10 |
| LTC3568IDD | 4 A SWITCHING REGULATOR, 4000 kHz SWITCHING FREQ-MAX, PDSO10 |
| LTC3568IDD#TR | 4 A SWITCHING REGULATOR, 4000 kHz SWITCHING FREQ-MAX, PDSO10 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LTC3554EPDTRPBF | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Micropower USB Power Manager with Li-Ion Charger and Two Step-Down Regulators |
| LTC3554EUD#PBF | 功能描述:IC USB POWER MANAGER 20UTQFN RoHS:是 類別:集成電路 (IC) >> PMIC - 電源管理 - 專用 系列:PowerPath™ 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:50 系列:- 應(yīng)用:熱電冷卻器 電流 - 電源:- 電源電壓:3 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:28-SOIC（0.173"，4.40mm 寬）裸露焊盤 供應(yīng)商設(shè)備封裝:28-TSSOP 裸露焊盤 包裝:管件 產(chǎn)品目錄頁面:1410 (CN2011-ZH PDF) |
| LTC3554EUD#TRPBF | 功能描述:IC USB POWER MANAGER 20UTQFN RoHS:是 類別:集成電路 (IC) >> PMIC - 電源管理 - 專用 系列:PowerPath™ 標(biāo)準(zhǔn)包裝:1 系列:- 應(yīng)用:手持/移動設(shè)備 電流 - 電源:- 電源電壓:3 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:14-WFDFN 裸露焊盤 供應(yīng)商設(shè)備封裝:14-LLP-EP（4x4） 包裝:Digi-Reel® 配用:LP3905SD-30EV-ND - BOARD EVALUATION LP3905SD-30 其它名稱:LP3905SD-30DKR |
| LTC3554EUD-1#PBF | 功能描述:IC USB POWER MANAGER 20QFN RoHS:是 類別:集成電路 (IC) >> PMIC - 電源管理 - 專用 系列:PowerPath™ 標(biāo)準(zhǔn)包裝:1 系列:- 應(yīng)用:手持/移動設(shè)備 電流 - 電源:- 電源電壓:3 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:14-WFDFN 裸露焊盤 供應(yīng)商設(shè)備封裝:14-LLP-EP（4x4） 包裝:Digi-Reel® 配用:LP3905SD-30EV-ND - BOARD EVALUATION LP3905SD-30 其它名稱:LP3905SD-30DKR |
| LTC3554EUD-1#TRPBF | 功能描述:IC USB POWER MANAGER 20QFN RoHS:是 類別:集成電路 (IC) >> PMIC - 電源管理 - 專用 系列:PowerPath™ 標(biāo)準(zhǔn)包裝:1 系列:- 應(yīng)用:手持/移動設(shè)備 電流 - 電源:- 電源電壓:3 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:14-WFDFN 裸露焊盤 供應(yīng)商設(shè)備封裝:14-LLP-EP（4x4） 包裝:Digi-Reel® 配用:LP3905SD-30EV-ND - BOARD EVALUATION LP3905SD-30 其它名稱:LP3905SD-30DKR |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。