參數(shù)資料
型號(hào)： LT3958IUHE#PBF
廠商： LINEAR TECHNOLOGY CORP
元件分類： 穩(wěn)壓器
英文描述： SWITCHING REGULATOR, PQCC36
封裝： 5 X 6 MM, LEAD FREE, PLASTIC, QFN-36
文件頁(yè)數(shù)： 6/28頁(yè)
文件大小： 320K
代理商： LT3958IUHE#PBF
LT3958
14
3958f
APPLICATIONS INFORMATION
APPLICATION CIRCUITS
The LT3958 can be congured as different topologies. The
rst topology to be analyzed will be the boost converter,
followed by the yback, SEPIC and inverting converters.
Boost Converter: Switch Duty Cycle and Frequency
The LT3958 can be congured as a boost converter for
the applications where the converter output voltage is
higher than the input voltage. Remember that boost con-
verters are not short-circuit protected. Under a shorted
output condition, the inductor current is limited only by
the input supply capability. For applications requiring a
step-up converter that is short-circuit protected, please
refer to the Applications Information section covering
SEPIC converters.
The conversion ratio as a function of duty cycle is
VOUT
VIN
= 1
1D
in continuous conduction mode (CCM).
For a boost converter operating in CCM, the duty cycle
of the main switch can be calculated based on the output
voltage (VOUT) and the input voltage (VIN). The maximum
duty cycle (DMAX) occurs when the converter has the
minimum input voltage:
DMAX =
VOUT VIN(MIN)
VOUT
Discontinuous conduction mode (DCM) provides higher
conversion ratios at a given frequency at the cost of reduced
efciencies and higher switching currents.
Boost Converter: Maximum Output Current Capability
and Inductor Selection
For the boost topology, the maximum average inductor
current is:
IL(MAX)= IO(MAX)
1
1DMAX
Due to the current limit of its internal power switch, the
LT3958 should be used in a boost converter whose maxi-
mum output current (IO(MAX)) is less than the maximum
output current capability by a sufcient margin (10% or
higher is recommended):
IO(MAX)≤
VIN(MIN)
VOUT
3.3A 0.5 ΔISW
(
)
The inductor ripple current
ΔISW has a direct effect on the
choice of the inductor value and the converter’s maximum
output current capability. Choosing smaller values of
ΔISW increases output current capability, but requires
large inductances and reduces the current loop gain (the
converter will approach voltage mode). Accepting larger
values of
ΔISW provides fast transient response and
allows the use of low inductances, but results in higher
input current ripple and greater core losses, and reduces
output current capability. It is recommended to choose a
ΔISW lower than 0.6A.
Given an operating input voltage range, and having chosen
the operating frequency and ripple current in the inductor,
the inductor value of the boost converter can be determined
using the following equation:
L =
VIN(MIN)
ΔISW
DMAX
The peak inductor current is the switch current limit (typical
4A), and the RMS inductor current is approximately equal
to IL(MAX). The user should choose the inductors having
sufcient saturation and RMS current ratings.
Boost Converter: Output Diode Selection
To maximize efciency, a fast switching diode with low
forward drop and low reverse leakage is desirable. The
peak reverse voltage that the diode must withstand is
equal to the regulator output voltage plus any additional
ringing across its anode-to-cathode during the on-time.
The average forward current in normal operation is equal
to the output current.
It is recommended that the peak repetitive reverse voltage
rating VRRM is higher than VOUT by a safety margin (a 10V
safety margin is usually sufcient).
相關(guān)PDF資料
PDF描述
LT3958EUHE#PBF SWITCHING REGULATOR, PQCC36
LT3958EUHE#TRPBF SWITCHING REGULATOR, PQCC36
LT4180MPGN#PBF POWER SUPPLY SUPPORT CKT, PDSO24
LT4180IGN#PBF POWER SUPPLY SUPPORT CKT, PDSO24
LT4180EGN#TRPBF POWER SUPPLY SUPPORT CKT, PDSO24
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LT3958IUHETRPBF 制造商:LINER 制造商全稱:Linear Technology 功能描述:High Input Voltage, Boost, Flyback, SEPIC and Inverting Converter
LT3959 制造商:LINER 制造商全稱:Linear Technology 功能描述:Wide Input Voltage Range Boost/SEPIC/Inverting Converter with 6A, 40V Switch
LT3959EFE#PBF 制造商:Linear Technology 功能描述:IC REG MULTI CONFIG ADJ 38TSSOP
LT3959EFE#PBF 制造商:Linear Technology 功能描述:DC-DC CONV BOOST/INVERTING TSSOP-38 制造商:Linear Technology 功能描述:DC-DC CONV, BOOST/INVERTING, TSSOP-38
LT3959EFE#TRPBF 制造商:Linear Technology 功能描述:IC REG MULTI CONFIG ADJ 38TSSOP
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。

采購(gòu)需求

(若只采購(gòu)一條型號(hào)，填寫(xiě)一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

*型號(hào) *數(shù)量 廠商 批號(hào) 封裝
添加更多采購(gòu)

我的聯(lián)系方式

*
*
*