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参数资料
| 型号： | LT3782AIUFD |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | SWITCHING CONTROLLER, PQCC28 |
| 封装： | 4 X 5 MM, PLASTIC, MO-220, QFN-28 |
| 文件页数： | 19/20页 |
| 文件大小： | 233K |
| 代理商： | LT3782AIUFD |
LT3782A
8
3782af
Operation
The LT3782A is a two phase constant frequency current
mode boost controller. Switching frequency can be pro-
grammed up to 500kHz. During normal switching cycles,
the two channels are controlled by internal ip-ops and
are 180 degrees out-of-phase.
Referring to the Block Diagram, the LT3782A’s basic func-
tions include a transconductance amplier (gm) to regulate
the output voltage and to control the current mode PWM
current loop. It also includes the necessary logic and ip-
op to control the PWM switching cycles, two high speed
gate drivers to drive high power N-channel MOSFETs, and
2-phase control signals to drive external gate drivers for
optional synchronous operation.
In normal operation, each switching cycle starts with a
switch turn-on. The inductor current of each channel is
sampled through the current sense resistor and amplied
then compared to the error amplier output VC to turn
the switch off. The phase delay of the second channel is
controlled by the divide-by-two D ip-op and is exactly
180 degrees out-of-phase of the rst channel. With a re-
sistor divider connected to the FB pin, the output voltage
is programmed to the desired value. The 10V gate drivers
are sufcient to drive most high power N-channel MOSFET
in many industrial applications.
Additional important features include shutdown, cur-
rent limit, soft-start, synchronization and programmable
maximum duty cycle. Additional slope compensation can
be added also.
Output Voltage Programming
With a 2.44V feedback reference voltage VREF, the output
VOUT is programmed by a resistor divider as shown in
the Block Diagram.
VOUT = 2.44 1+
RF1
RF2
Soft-Start and Shutdown
During soft-start, the voltage on the SS pin (VSS) controls
the output voltage. The output voltage thus ramps up fol-
lowing VSS. The effective range of VSS is from 0V to 2.44V.
The typical time for the output to reach the programmed
level is
t =
C 2.44V
10μA
C is the capacitor connected from the SS pin to GND.
Undervoltage Lockout and Shutdown
Only when VRUN is higher than 2.45V VGBIAS will be active
and the switching enabled. The LT3782A goes into low
current shutdown when VRUN is below 0.3V. A resistor
divider can be used on RUN pin to set the desired VCC
undervoltage lockout voltage. 80mV of hysteresis is built
in on RUN pin thresholds.
Oscillation Frequency Setting and Synchronization
The switching frequency of LT3782A can be set up to
500kHz by a resistor RFREQ from pin RSET to ground.
For fSET = 250kHz, RFREQ = 80k
Once the switching frequency fSET is chosen, RFREQ can be
found from the Switching Frequency vs RFREQ graph found
under the Typical Performance Characteristics section.
Note that because of the 2-phase operation, the internal
oscillator is running at twice the switching frequency. To
synchronize the LT3782A to the system frequency fSYSTEM,
the synchronizing frequency fSYNC should be two times
fSYSTEM, and the LT3782A switching frequency fSET should
be set below 80% of fSYSTEM.
fSYNC = 2fSYSTEM and fSET < (fSYSTEM 0.8)
For example, to synchronize the LT3782A to 200kHz sys-
tem frequency fSYSTEM, fSYNC needs to be set at 400kHz
and fSET needs to be set at 160kHz. From the Switching
Frequency vs RFREQ graph found under the Typical Per-
formance Characteristics section, RFREQ = 130k.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LT3782AIUFD#PBF | 功能描述:IC REG CTRLR BST PWM CM 28-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 |
| LT3782AIUFD#TRPBF | 功能描述:IC REG CTRLR BST PWM CM 28-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 |
| LT3782AIUFD-PB | 制造商:LINER 制造商全称:Linear Technology 功能描述:2-Phase Step-Up DC/DC Controller |
| LT3782AIUFD-TR | 制造商:LINER 制造商全称:Linear Technology 功能描述:2-Phase Step-Up DC/DC Controller |
| LT3782EFE | 制造商:Linear Technology 功能描述:DC DC Cntrlr Single-OUT Synchronous Step Up Controller 6V to 40V Input 28-Pin TSSOP EP |
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