参数资料
| 型号： | LT3782EUFD#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 8/20页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BST PWM CM 28-QFN |
| 标准包装： | 73 |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 533kHz |
| 占空比： | 94% |
| 电源电压： | 6 V ~ 40 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： | 28-WFQFN 裸露焊盘 |
| 包装： | 管件 |
| 产品目录页面： | 1332 (CN2011-ZH PDF) |
LT3782
APPLICATIONS INFORMATION
Operation
The LT3782 is a two phase constant frequency current mode
boost controller. Switching frequency can be programmed
up to 500kHz. During normal switching cycles, the two
channels are controlled by internal ?ip-?ops and are 180
degrees out-of-phase.
Soft-Start and Shutdown
During soft-start, the voltage on the SS pin (V SS ) controls
the output voltage. The output voltage thus ramps up fol-
lowing V SS . The effective range of V SS is from 0V to 2.44V.
The typical time for the output to reach the programmed
level is
Referring to the Block Diagram, the LT3782’s basic func-
tions include a transconductance amplifer (g m ) to regulate
the output voltage and to control the current mode PWM
t =
C ? 2.44V
10 μ A
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 ampli?ed
then compared to the error ampli?er output V C 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 suf?cient 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 V REF , the output
V OUT is programmed by a resistor divider as shown in
the Block Diagram.
C is the capacitor connected from the SS pin to Gnd.
Undervoltage Lockout and Shutdown
Only when V RUN is higher than 2.45V V GBIAS will be ac-
tive and the switching enabled. The LT3782 goes into low
current shutdown when V RUN is below 0.3V. A resistor
divider can be used on RUN pin to set the desired V CC
undervoltage lockout voltage. 80mV of hysteresis is built
in on RUN pin thresholds.
Oscillation Frequency Setting and Synchronization
The switching frequency of LT3782 can be set up to 500kHz
by a resistor R FREQ from pin R SET to ground.
For f SET = 250kHz, R FREQ = 80k
Once the switching frequency f SET is chosen, R FREQ can be
found from the Switching Frequency vs R FREQ 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 LT3782 to the system frequency f SYSTEM ,
the synchronizing frequency f SYNC should be two times
f SYSTEM , and the LT3782 switching frequency f SET should
be set below 80% of f SYSTEM .
f SYNC = 2f SYSTEM and f SET < (f SYSTEM ? 0.8)
V OUT = 2.44 1 +
R F1
R F2
For example, to synchronize the LT3782 to 200kHz system
frequency f SYSTEM , f SYNC needs to be set at 400kHz and f SET
needs to be set at 160kHz. From the Switching Frequency
vs R FREQ graph found under the Typical Performance
Characteristics section, R FREQ = 130k.
3782fg
8
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相关代理商/技术参数 |
参数描述 |
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| LT3782EUFD-TR | 制造商:LINER 制造商全称:Linear Technology 功能描述:2-Phase Step-UP DC/DC Controller |
| LT3782EUFD-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:2-Phase Step-UP DC/DC Controller |
| LT3782IFE | 制造商:LINER 制造商全称:Linear Technology 功能描述:2-Phase Step-UP DC/DC Controller |
| LT3782IFE#PBF | 功能描述:IC REG CTRLR BST PWM CM 28-SSOP 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 |
| LT3782IFE#TRPBF | 功能描述:IC REG CTRLR BST PWM CM 28-SSOP 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 |
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