参数资料
型号: LT3757IDD#PBF
厂商: Linear Technology
文件页数: 22/36页
文件大小: 0K
描述: IC REG CTRLR BST FLYBK INV 10DFN
产品培训模块: LT3757 and LT3758 - Boost, Flyback, SEPIC and Inverting Controllers
标准包装: 121
PWM 型: 电流模式
输出数: 1
频率 - 最大: 1MHz
电源电压: 2.9 V ~ 40 V
降压:
升压:
回扫:
反相:
倍增器:
除法器:
Cuk:
隔离:
工作温度: -40°C ~ 125°C
封装/外壳: 10-WFDFN 裸露焊盘
包装: 管件
LT3757/LT3757A
APPLICATIONS INFORMATION
I SW(MAX) = I L1(MAX) + I L2(MAX) = I O(MAX) ?
SEPICConverter:SwitchDutyCycleandFrequency
For a SEPIC converter operating in CCM, the duty cycle
of the main switch can be calculated based on the output
voltage (V OUT ), the input voltage (V IN ) and the diode
forward voltage (V D ).
The maximum duty cycle (D MAX ) occurs when the converter
has the minimum input voltage:
In a SEPIC converter, the switch current is equal to I L1 +
I L2 when the power switch is on, therefore, the maximum
average switch current is defined as:
1
1 ? D MAX
and the peak switch current is:
I SW(PEAK) = ? 1 + ? ? I O(MAX) ?
D MAX =
V OUT + V D
V IN(MIN) + V OUT + V D
? 2 ?
? c ?
1
1 ? D MAX
I L1(MAX) = I IN(MAX) = I O(MAX) ?
SEPICConverter:InductorandSenseResistorSelection
As shown in Figure 1, the SEPIC converter contains two
inductors: L1 and L2. L1 and L2 can be independent, but can
also be wound on the same core, since identical voltages
are applied to L1 and L2 throughout the switching cycle.
For the SEPIC topology, the current through L1 is the
converter input current. Based on the fact that, ideally, the
output power is equal to the input power, the maximum
average inductor currents of L1 and L2 are:
D MAX
1 ? D MAX
I L2(MAX) = I O(MAX)
The constant c in the preceding equations represents the
percentage peak-to-peak ripple current in the switch, rela-
tive to I SW(MAX) , as shown in Figure 9. Then, the switch
ripple current ?I SW can be calculated by:
?I SW = c ? I SW(MAX)
The inductor ripple currents ?I L1 and ?I L2 are identical:
?I L1 = ?I L2 = 0.5 ? ? I SW
The inductor ripple current has a direct effect on the
choice of the inductor value. Choosing smaller values of
?I L requires large inductances and reduces the current
loop gain (the converter will approach voltage mode).
Accepting larger values of ?I L allows the use of low in-
ductances, but results in higher input current ripple and
greater core losses. It is recommended that c falls in the
range of 0.2 to 0.4.
I SW
I SW(MAX)
? I SW = χ ? I SW(MAX)
DT S
t
T S
3757 F08
Figure 9. The Switch Current Waveform of the SEPIC Converter
3757afd
22
相关PDF资料
PDF描述
MIC2182-5.0YM IC REG CTRLR BUCK PWM CM 16-SOIC
LTC1622IS8#PBF IC REG CTRLR BUCK PWM CM 8-SOIC
MIC2182-5.0YSM IC REG CTRLR BUCK PWM CM 16-SSOP
SPD62-352M INDUCTOR PWR SHIELDED 3.50UH SMD
SPD62-242M INDUCTOR PWR SHIELDED 2.40UH SMD
相关代理商/技术参数
参数描述
LT3757IDD-TRPBF 制造商:LINER 制造商全称:Linear Technology 功能描述:Boost, Flyback, SEPIC and Inverting Controller
LT3757IMSE 制造商:Linear Technology 功能描述:DC DC Cntrlr Single-OUT Flyback Controller 2.9V to 40V Input 10-Pin MSOP EP 制造商:Linear Technology 功能描述:CONTROLLER
LT3757IMSE#PBF 功能描述:IC REG CTRLR PWM CM 10-MSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR)
LT3757IMSE#TRPBF 功能描述:IC REG CTRLR PWM CM 10-MSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR)
LT3757IMSEPBF 制造商:Linear Technology 功能描述:Boost Flyback SEPIC Controller MSOP10EP