- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄377709 > LT1619ES8 (LINEAR TECHNOLOGY CORP) Low Voltage Current Mode PWM Controller PDF資料下載
參數(shù)資料
| 型號(hào)： | LT1619ES8 |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | Low Voltage Current Mode PWM Controller |
| 中文描述： | 1.5 A SWITCHING CONTROLLER, 360 kHz SWITCHING FREQ-MAX, PDSO8 |
| 封裝： | 0.150 INCH, PLASTIC, SO-16 |
| 文件頁數(shù)： | 8/20頁 |
| 文件大?。?/td> | 256K |
| 代理商： | LT1619ES8 |
8
LT1619
1619fa
Power MOSFET
MOSFET power dissipation can be separated into fre-
quency independent and frequency dependent compo-
nents. The R
DS(ON)
loss in the switch is the product of the
mean square switch current and switch R
DS(ON)
and it
does not vary with the operating frequency.
The frequency-dependent switching losses consist of 1)
switch transition loss due to finite rise and fall times of the
drain source voltage and the drain current 2) gate switch-
ing loss, i.e., a packet of charge Q
g
(the total gate charge)
which is moved from the gate drive power supply to
ground in every switch cycle, and 3) the drain switching
loss, charge stored on the parasitic drain capacitance,
C
OSS
is dumped to ground as the switch is turned on. The
transistor loss can be expressed as:
P
LOSS
= I
DRMS2
R
DS(ON)
+ transition loss + Q
g
V
G
f
S
+ 1/2C
OSS
V
DS(OFF)2
f
S
where the transition loss can be estimated with:
TransitionLoss
I
C
I
G AVG
(
f
D
RSS DS OFF
S
=
(
)
)
2
Q
g
= The total gate charge
V
G
= Gate drive voltage
≈
V
DRV
I
G(AVG)
= The average MOSFET buffer output current
f
S
= Operating frequency
C
RSS
= The average C
GD
between V
DS
= 0V
and V
DS
= V
DS(OFF)
At low V
DS(OFF)
(
≤
12V) and operating frequencies below
500kHz, the ohmic losses often dominate. For high voltage
converters, the transition loss and C
OSS
charge dumping
loss can dramatically impact the converter efficiency.
MOSFETs with lower parasitic capacitances but higher
R
DS(ON)
may actually provide better efficiency in these
situations.
Capacitors
In a switch mode DC/DC converter, output ripple voltage
is the product of the equivalent series resistance (ESR) of
the output capacitor and the peak-to-peak capacitor
current. Depending on topology, current feeding the out-
put capacitor can be continuous or discontinuous. The input
current can also be continuous or discontinuous even if the
inductor current itself is continuous. In boost topology, the
inductor is in series with the input source so the input
current is continuous and the output current is discontinu-
ous. In buck-boost or flyback converters, the inductor is
not in series with the input source nor the output, so nei-
ther the input current nor output current is continuous.
Whenever a terminal current is discontinuous, the capaci-
tor at that terminal should be chosen to handle the ripple
current. Capacitor reliability will be adversely affected if
the ripple current exceeds the maximum allowable rat-
ings. This maximum rating is specified as the RMS ripple
current. Several capacitors may be mounted in parallel to
meet the size and ripple current requirements.
Besides the ripple voltage requirements, the output ca-
pacitor also needs to be sized for acceptable output
voltage variation under load transients.
Current Sensing Resistor R
SENSE
The LT1619 drives a low side N-channel MOSFET switch.
The switch current is sensed with an external resistor
R
SENSE
connected between the source of the MOSFET and
ground. The internal blanking circuit blocks the voltage
spike developed across R
SENSE
for 280ns at switch turn-
on. The switch is turned off when the instantaneous
voltage across R
SENSE
exceeds the current limit threshold,
V
SENSE
. Allowing variations in V
SENSE
yields:
R
V
I
SENSE
SENSE MIN
L MAX
(
=
(
)
)
The current limit threshold is constant and does not vary
with duty ratio.
Due to low signal level of the sense voltage, low inductance
sense resistors are required to reduce switching noise.
Low TC resistors maintain constant current limit over
temperature. Dale WSL and IRC series sense resistors
meet these criteria.
APPLICATIOU
W
U
U
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LT1619EMS8 | Low Voltage Current Mode PWM Controller |
| LT1620CS8 | Rail-to-Rail Current Sense Amplifier |
| LT1620IGN | CAP 0.1UF 200V 10% X7R SMD-1206 TR-7 PLATED-NI/SN |
| LT1621IGN | Rail-to-Rail Current Sense Amplifier |
| LT1620CGN | Rail-to-Rail Current Sense Amplifier |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LT1619ES8#PBF | 功能描述:IC REG CTRLR PWM CM 8-SOIC RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 特色產(chǎn)品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 標(biāo)準(zhǔn)包裝:1 系列:PowerWise® PWM 型:電壓模式 輸出數(shù):1 頻率 - 最大:1MHz 占空比:81% 電源電壓:4.5 V ~ 18 V 降壓:是 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-5°C ~ 125°C 封裝/外殼:32-WFQFN 裸露焊盤 包裝:Digi-Reel® 產(chǎn)品目錄頁面:1303 (CN2011-ZH PDF) 其它名稱:LM3754SQDKR |
| LT1619ES8#PBF | 制造商:Linear Technology 功能描述:DC/DC Converter IC |
| LT1619ES8#TR | 功能描述:IC REG CTRLR PWM CM 8-SOIC RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:500kHz 占空比:96% 電源電壓:4 V ~ 36 V 降壓:無 升壓:是 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:24-WQFN 裸露焊盤 包裝:帶卷 (TR) |
| LT1619ES8#TRPBF | 功能描述:IC REG CTRLR PWM CM 8-SOIC RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:500kHz 占空比:96% 電源電壓:4 V ~ 36 V 降壓:無 升壓:是 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:24-WQFN 裸露焊盤 包裝:帶卷 (TR) |
| LT1619ES8PBF | 制造商:Linear Technology 功能描述:PWM Controller Current Mode 1.5A SOIC8 |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。