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参数资料
| 型号： | LM5046SQ |
| 厂商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分类： | 稳压器 |
| 英文描述： | SWITCHING CONTROLLER, 540 kHz SWITCHING FREQ-MAX, QCC28 |
| 封装： | 5 X 5 MM, LLP-28 |
| 文件页数： | 11/32页 |
| 文件大小： | 888K |
| 代理商： | LM5046SQ |
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Table 1: Soft-Stop in Fault
Conditions
Fault Condition
SSSR
UVLO
(UVLO<1.25V)
Soft-Stop
3x the charging rate
OVP
(OVP>1.25V)
Hard-Stop
Hiccup
(CS>0.75 and RES>1V)
Soft-Stop
6x the charging rate
VCC/VREF UV
Hard-Stop
Internal Thermal Limit
Hard-Stop
Note: All the above conditions are valid with SSOFF pin tied
to GND. If SSOFF=5V, the LM5046 hard-stops in all the con-
ditions. The SS pin remains high in all the conditions until the
SSSR pin reaches 1V.
Thermal Protection
Internal thermal shutdown circuitry is provided to protect the
integrated circuit in the event the maximum rated junction
temperature is exceeded. When activated, typically at 160°C,
the controller is forced into a shutdown state with the output
drivers, the bias regulators (VCC and REF) disabled. This
helps to prevent catastrophic failures from accidental device
overheating. During thermal shutdown, the SS and SSSR ca-
pacitors are fully discharged and the controller follows a nor-
mal start-up sequence after the junction temperature falls to
the operating level (140 °C).
Applications Information
30147862
FIGURE 9. Operating States of the PSFB Topology
PHASE-SHIFTED FULL-BRIDGE OPERATION
The phase shifted full-bridge topology is a derivative of the
conventional full-bridge topology. When tuned appropriately
the PSFB topology achieves zero voltage switching (ZVS) of
the primary FETs while maintaining constant switching fre-
quency. The ZVS feature is highly desirable as it reduces both
the switching losses and the EMI emissions. The realization
of the PSFB topology using the LM5046 is explained as fol-
lows:
Operating State 1 (Power Transfer/Active Mode)
The power transfer mode of the PSFB topology is similar to
the hard switching full-bridge i.e. When the FETs in the diag-
onal of the bridge are turned-on (HO1 & LO2 or HO2 & LO1),
a power transfer cycle from the primary to the secondary is
initiated. Figure 9 depicts the case where the diagonal switch-
es HO1 and LO2 are activated. In this state, full VIN is applied
to the primary of the power transformer, which is typically
stepped down on the secondary winding.
Operating State 2 (Active to Passive Transition)
At the end of the power transfer cycle, PWM turns off switch
LO2. In the primary side, the reflected load current plus the
magnetizing current propels the SW2 node towards VIN. The
active to passive transition is finished when either the body
diode of HO2 is forward-biased or HO2 is turned-on, whichev-
er happens earlier. A delay can be introduced by setting RD2
to an appropriate value, such that HO2 is turned-on only after
the body-diode is forward biased. In this mode, the I
mag
+I
Lpeak act as a current source charging the parasitic capacitor
located at the node SW2. At light load conditions, it takes a
longer time to propel SW node towards VIN.
The active to passive transition time can be approximated by
using the following formula:
19
www.national.com
LM5046
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LM5046SQ/NOPB | 功能描述:电流型 PWM 控制器 Phase-Shifted Full- Bridge PWM Cntrlr RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| LM5046SQX | 制造商:TI 制造商全称:Texas Instruments 功能描述:LM5046 Phase-Shifted Full-Bridge PWM Controller with Integrated MOSFET Drivers |
| LM5046SQX/NOPB | 功能描述:IC PWM CTRLR FULL BRIDG 28LLP RoHS:是 类别:集成电路 (IC) >> PMIC - AC-DC 转换器，离线开关 系列:PowerWise® 标准包装:1 系列:FPS™ 输出隔离:隔离 频率范围:61kHz ~ 73kHz 输入电压:8 V ~ 26 V 输出电压:650V 功率（瓦特）:12W 工作温度:-40°C ~ 115°C 封装/外壳:8-DIP（0.300"，7.62mm） 供应商设备封装:8-MDIP 包装:Digi-Reel® 其它名称:FSL206MRBNFSDKR |
| LM505 | 制造商:LM TECHNOLOGIES 功能描述:ADAPTER BLUETOOTH NANO EDR 40M USB 制造商:LM TECHNOLOGIES 功能描述:BLUETOOTH ADAPTER, USB, BCM2045, EDR 制造商:LM TECHNOLOGIES 功能描述:BLUETOOTH ADAPTER, USB, BCM2045, 40M, EDR; Data Rate:2.166Mbps; Operating Temperature Min:-20C; Operating Temperature Max:75C; Operating Frequency Range:2.402GHz to 2.48GHz; Operating Temperature Range:-20C to +75C ;RoHS Compliant: Yes |
| LM5050-1 | 制造商:TI 制造商全称:Texas Instruments 功能描述:High Side OR-ing FET Controller |
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