參數(shù)資料
型號: LTC1159IS-3.3
廠商: LINEAR TECHNOLOGY CORP
元件分類: 穩(wěn)壓器
英文描述: RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS
中文描述: 0.05 A SWITCHING CONTROLLER, 250 kHz SWITCHING FREQ-MAX, PDSO16
封裝: 0.150 INCH, PLASTIC, SO-16
文件頁數(shù): 7/20頁
文件大小: 288K
代理商: LTC1159IS-3.3
7
LTC1159
LTC1159-3.3/LTC1159-5
increases, the output voltage decreases slightly. This causes
the output of the gain stage to increase the current com-
parator threshold, thus tracking the load current.
The sequence of events for Burst Mode operation is very
similar to continuous operation with the cycle interrupted
by the voltage comparator. When the output voltage is at or
above the desired regulated value, the P-channel MOSFET
is held off by comparator V and the timing capacitor con-
tinues to discharge below V
TH1
. When the timing capacitor
discharges past V
TH2
, voltage comparator S trips, causing
the internal SLEEP line to go low and the N-channel MOSFET
to turn off.
The circuit now enters sleep mode with both power
MOSFETs turned off. In sleep mode, much of the circuitry
(Refer to Functional Diagram)
OPERATIOU
is turned off, dropping the supply current from several
milliamps (with the MOSFETs switching) to 300
μ
A. When
the output capacitor has discharged by the amount of
hysteresis in comparator V, the P-channel MOSFET is
again turned on and this process repeats. To avoid the
operation of the current loop interfering with Burst Mode
operation, a built-in offset is incorporated in the gain stage.
To prevent both the external MOSFETs from being turned
on at the same time, feedback is incorporated to sense the
state of the driver output pins. Before the N-gate output can
go high, the P-drive output must also be high. Likewise, the
P-drive output is prevented from going low when the
N-gate output is high.
APPLICATIOU
The LTC1159 Compared to the LTC1148/LTC1149
Families
The LTC1159 family is closest in operation to the LTC1149
and shares much of the applications information. In addi-
tion to reduced quiescent and shutdown currents, the
LTC1159 adds an internal switch which allows the driver
and control sections to be powered from an external
source for higher efficiency. This change affects Power
MOSFET Selection, EXTV
CC
Pin Connection, Important
Information About LTC1159 Adjustable Applications, and
Efficiency Considerations found in this section.
The basic LTC1159 application circuit shown in Figure 1
is limited to a maximum input voltage of 30V due to
MOSFET breakdown. If the application does not require
greater than 18V operation, then the LTC1148 or
LTC1148HV should be used. For higher input voltages
where quiescent and shutdown current are not critical, the
LTC1149 may be a better choice since it is set up to drive
standard threshold MOSFETs.
W
U
U
R
SENSE
Selection for Output Current
R
SENSE
is chosen based on the required output current. The
LTC1159 current comparator has a threshold range that
extends from a minimum of 0.025V/R
SENSE
to a maximum
of 0.15V/R
SENSE
. The current comparator threshold sets
the peak of the inductor ripple current, yielding a maximum
output current I
MAX
equal to the peak value less half the
peak-to-peak ripple current. For proper Burst Mode opera-
tion,
RIPPLE(P-P)
must be ess han or equal o he minimum
current comparator threshold.
Since efficiency generally increases with ripple current,
the maximum allowable ripple current is assumed, i.e.,
I
RIPPLE(P-P)
= 0.025V/R
SENSE
(see C
T
and L Selection for
Operating Frequency). Solving for R
SENSE
and allowing
a margin for variations in the LTC1159 and external
component values yields:
R
SENSE
=
m
100
I
MAX
A graph for selecting R
SENSE
versus maximum output
current is given in Figure 2. The LTC1159 series works well
with values of R
SENSE
from 0.02
to 0.2
.
The load current below which Burst Mode operation com-
mences, I
BURST
, and the peak short-circuit current, I
SC(PK)
,
both track I
MAX
. Once R
SENSE
has been chosen, I
BURST
and
I
SC(PK)
can be predicted from the following equations:
相關(guān)PDF資料
PDF描述
LTC1159IS-5 RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS
LTC1174 High Efficiency Step-Down and Inverting DC/DC Converter(高效率,反相DC/DC變換器)
LTC1174-3.3 High Efficiency Step-Down and Inverting DC/DC Converter(高效率,步降DC/DC變換器)
LTC1174-5 High Efficiency Step-Down and Inverting DC/DC Converter(高效率,步降DC/DC變換器)
LTC1177-12 Isolated High Side MOSFET Drivers(隔離型高邊MOS場效應(yīng)管驅(qū)動器(輸入電流2.5mA))
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LTC1159IS-5 功能描述:IC REG CTRLR BUCK PWM CM 16-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:4,500 系列:PowerWise® PWM 型:控制器 輸出數(shù):1 頻率 - 最大:1MHz 占空比:95% 電源電壓:2.8 V ~ 5.5 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:-40°C ~ 125°C 封裝/外殼:6-WDFN 裸露焊盤 包裝:帶卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名稱:LM1771SSDX
LTC1159IS-5#PBF 功能描述:IC REG CTRLR BUCK PWM CM 16-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:4,500 系列:PowerWise® PWM 型:控制器 輸出數(shù):1 頻率 - 最大:1MHz 占空比:95% 電源電壓:2.8 V ~ 5.5 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:-40°C ~ 125°C 封裝/外殼:6-WDFN 裸露焊盤 包裝:帶卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名稱:LM1771SSDX
LTC1159IS-5#TR 功能描述:IC REG CTRLR BUCK PWM CM 16-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:4,500 系列:PowerWise® PWM 型:控制器 輸出數(shù):1 頻率 - 最大:1MHz 占空比:95% 電源電壓:2.8 V ~ 5.5 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:-40°C ~ 125°C 封裝/外殼:6-WDFN 裸露焊盤 包裝:帶卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名稱:LM1771SSDX
LTC1159IS-5#TRPBF 功能描述:IC REG CTRLR BUCK PWM CM 16-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:4,500 系列:PowerWise® PWM 型:控制器 輸出數(shù):1 頻率 - 最大:1MHz 占空比:95% 電源電壓:2.8 V ~ 5.5 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:-40°C ~ 125°C 封裝/外殼:6-WDFN 裸露焊盤 包裝:帶卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名稱:LM1771SSDX
LTC1160CN 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Interface IC