- 您现在的位置：买卖IC网 > PDF目录20858 > LTC3783IFE#PBF (Linear Technology)IC LED DRVR PWM CONTROL 16-TSSOP PDF资料下载
参数资料
| 型号： | LTC3783IFE#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 14/24页 |
| 文件大小： | 0K |
| 描述： | IC LED DRVR PWM CONTROL 16-TSSOP |
| 标准包装： | 95 |
| 恒定电流： | 是 |
| 恒定电压： | 是 |
| 拓扑： | 回扫，PWM，SEPIC，降压（降压），升压（升压） |
| 输出数： | 1 |
| 内部驱动器： | 无 |
| 类型 - 主要： | 车载，通用 |
| 频率： | 20kHz ~ 1MHz |
| 电源电压： | 3 V ~ 36 V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-TSSOP（0.173"，4.40mm）裸露焊盘 |
| 供应商设备封装： | 16-TSSOP-EP |
| 包装： | 管件 |
| 工作温度： | -40°C ~ 125°C |
LTC3783
OPERATION
I IN(MAX) =
I IN(PEAK) = ? 1 + ? ?
Figure6illustratesthesevariousquantitiesinrelationto
one another.
Typically, in order to avoid visible flicker, f PWM should be
greater than 120Hz. Assuming inductor and capacitor
sizing which is close to discontinuous operation, 2 f OSC
cycles are sufficient for proper PWM operation. Thus,
within the 1MHz rated maximum f OSC , a dimming ratio
of 1/D PWM = 3000 is possible.
1/f PWM
D PWM /f PWM
the output current needs to be reflected back to the input
in order to dimension the power MOSFET properly. Based
on the fact that, ideally, the output power is equal to the
input power, the maximum average input current is:
I OUT(MAX)
1–D MAX
The peak input current is:
? c ? I OUT(MAX)
? 2 ? 1–D MAX
PWMIN
GATE
#=N
The maximum duty cycle, D MAX , should be calculated at
minimum V IN .
1/f OSC
3783 F06
Boost Converter: Ripple Current ? I L and the ‘ c ’ Factor
V + V D – V IN
V OUT(MAX) =
V IN(MIN)
1–D MAX
Figure6.PWMDimmingParameters
Boost Converter: Duty Cycle Considerations
For a boost converter operating in a continuous conduction
mode (CCM), the duty cycle of the main switch is:
D = OUT
V OUT + V D
where V D is the forward voltage of the boost diode. For
converters where the input voltage is close to the output
voltage, the duty cycle is low, and for converters that
develop a high output voltage from a low input voltage,
the duty cycle is high. The maximum output voltage for a
boost converter operating in CCM is:
– V D
The maximum duty cycle capability of the LTC3783 is
typically 90%. This allows the user to obtain high output
voltages from low input supply voltages.
Boost Converter: The Peak and Average Input Currents
The control circuit in the LTC3783 is measuring the input
current (either by using the R DS(ON) of the power MOSFET
or by using a sense resistor in the MOSFET source), so
The constant ‘ c ’ in the equation above represents the
percentage peak-to-peak ripple current in the inductor,
relative to its maximum value. For example, if 30% ripple
current is chosen, then c = 0.3, and the peak current is
15% greater than the average.
For a current mode boost regulator operating in CCM,
slope compensation must be added for duty cycles above
50% in order to avoid subharmonic oscillation. For the
LTC3783, this ramp compensation is internal. Having an
internally fixed ramp compensation waveform, however,
does place some constraints on the value of the inductor
and the operating frequency. If too large an inductor is
used, the resulting current ramp ( ? I L ) will be small relative
to the internal ramp compensation (at duty cycles above
50%), and the converter operation will approach voltage
mode (ramp compensation reduces the gain of the current
loop). If too small an inductor is used, but the converter is
still operating in CCM (near critical conduction mode), the
internal ramp compensation may be inadequate to prevent
subharmonic oscillation. To ensure good current mode
gain and to avoid subharmonic oscillation, it is recom-
mended that the ripple current in the inductor fall in the
range of 20% to 40% of the maximum average current.
For example, if the maximum average input current is 1A,
choose a ? I L between 0.2A and 0.4A, and correspondingly
a value ‘ c ’ between 0.2 and 0.4.
3783fb
14
相关PDF资料 |
PDF描述 |
|---|---|
| P51-300-G-S-I36-20MA-000-000 | SENSOR 300PSI 1/4-18NPT 4-20MA |
| P51-3000-S-F-I12-4.5V-000-000 | SENSOR 3000PSI 1/4-18NPT .5-4.5V |
| BAS16W-7 | DIODE SWITCH 75V 200MW SC70-3 |
| REC7.5-4815DRW/H2/A/M | CONV DC/DC 7.5W 36-72VIN +/-15V |
| P51-2000-S-S-MD-4.5V-000-000 | SENSOR 2000PSI 1/4-18NPT 4.5V |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3785EUF#PBF | 功能描述:IC REG CTRLR BST PWM VM 24-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 特色产品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 标准包装:1 系列:PowerWise® PWM 型:电压模式 输出数:1 频率 - 最大:1MHz 占空比:81% 电源电压:4.5 V ~ 18 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-5°C ~ 125°C 封装/外壳:32-WFQFN 裸露焊盘 包装:Digi-Reel® 产品目录页面:1303 (CN2011-ZH PDF) 其它名称:LM3754SQDKR |
| LTC3785EUF#TRPBF | 功能描述:IC REG CTRLR BST PWM VM 24-QFN 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) |
| LTC3785EUF-1#PBF | 功能描述:IC REG CTRLR BST PWM VM 24-QFN 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) |
| LTC3785EUF-1#TRPBF | 功能描述:IC REG CTRLR BST PWM VM 24-QFN 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:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 V 降压:是 升压:无 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:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX |
| LTC3785EUFPBF | 制造商:Linear Technology 功能描述:10V Synch Buck-Boost Controller LTC3785 |
发布紧急采购，3分钟左右您将得到回复。