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参数资料
| 型号： | LTC3812EFE-5 |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 1 A SWITCHING CONTROLLER, PDSO16 |
| 封装： | 4.40 MM, PLASTIC, TSSOP-16 |
| 文件页数： | 3/32页 |
| 文件大小： | 425K |
| 代理商： | LTC3812EFE-5 |
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LTC3812-5
11
38125fb
Main Control Loop
The LTC3812-5 is a current mode controller for DC/DC
step-down converters. In normal operation, the top
MOSFET is turned on for a xed interval determined by
a one-shot timer (OST). When the top MOSFET is turned
off, the bottom MOSFET is turned on until the current
comparator ICMP trips, restarting the one-shot timer and
initiating the next cycle. Inductor current is determined by
sensing the voltage between the PGND and SW pins using
the bottom MOSFET on-resistance. The voltage on the ITH
pin sets the comparator threshold corresponding to the
inductor valley current. The fast 25MHz error amplier EA
adjusts this voltage by comparing the feedback signal VFB
to the internal 0.8V reference voltage. If the load current
increases, it causes a drop in the feedback voltage relative
to the reference. The ITH voltage then rises until the average
inductor current again matches the load current.
The operating frequency is determined implicitly by the top
MOSFET on-time and the duty cycle required to maintain
regulation. The one-shot timer generates an on time that is
proportional to the ideal duty cycle, thus holding frequency
approximately constant with changes in VIN. The nominal
frequency can be adjusted with an external resistor RON.
Pulling the RUN/SS pin low forces the controller into its
shutdown state, turning off both M1 and M2. Forcing a
voltage above 1.5V will turn on the device.
Pulse Skip Mode
The LTC3812-5 can operate in one of two modes selectable
with the FCB pin—pulse skip mode or forced continuous
mode (see Figure 1). Pulse skip mode is selected when
increased efciency at light loads is desired (see Figure 2).
In this mode, the bottom MOSFET is turned off when
inductor current reverses to minimize efciency loss due
to reverse current ow and gate charge switching. At low
load currents, ITH will drop below the zero current level
(1.2V) shutting off both switches. Both switches will
remain off with the output capacitor supplying the load
current until the ITH voltage rises above the zero current
Figure 1. Comparison of Inductor Current Waveforms for Pulse Skip Mode
and Forced Continuous Operation
OPERATION
Figure 2. Efciency in Pulse Skip/Forced Continuous Modes
LOAD (A)
0.01
40
EFFICIENCY
(%)
50
60
70
80
0.1
1
10
38125 F02
30
20
10
0
90
100
VIN = 12V
VIN = 42V
PULSE
SKIP
FORCED
CONTINUOUS
DECREASING
LOAD
CURRENT
38125 F01
PULSE SKIP MODE
0A
FORCED CONTINUOUS
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| LTC3812IFE-5#TR | 1 A SWITCHING CONTROLLER, PDSO16 |
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3812EFE5#PBF | 制造商:Linear Technology 功能描述: |
| LTC3812EFE-5#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 16TSSOP 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 |
| LTC3812EFE-5#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 16TSSOP 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) |
| LTC3812IFE-5#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 16TSSOP 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) |
| LTC3812IFE-5#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 16TSSOP 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) |
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