參數(shù)資料
型號(hào)： LM5026
廠商： National Semiconductor Corporation
英文描述： Active Clamp Current Mode PWM Controller
中文描述： 有源鉗位電流模式PWM控制器
文件頁(yè)數(shù)： 16/23頁(yè)
文件大?。?/td> 936K
代理商： LM5026
Oscillator and Sync Capability
(Continued)
Multiple LM5026 devices can be synchronized together sim-
ply by connecting the devices SYNC pins together as shown
in
Figure 9
. Care should be taken to ensure the ground
potential differences between devices are minimized. In this
configuration all of the devices will be synchronized to the
highest frequency device. The internal block diagram of the
oscillator and synchronization circuit is shown in
Figure 10
.
The SYNC I/O pin is a CMOS buffer with pull-up current
limited to 200 μA. If an external device forces the SYNC pin
low before the internal oscillator ramp completes its charging
cycle, the ramp will be reset and another cycle begins. If the
SYNC pins of multiple LM5026 devices are connected to-
gether, the first SYNC pin that pulls low will reset the oscil-
lator RAMP of all other devices. All controllers will operate in
phase when synchronized using the SYNC I/O feature. Up to
five LM5026 devices can be synchronized using this tech-
nique.
Thermal Protection
Internal Thermal Shutdown circuitry is provided to protect the
integrated circuit in the event the maximum junction tem-
perature is exceeded. When activated, typically at 165C,
the controller is forced into a low power standby state with
the output drivers and the bias regulator disabled. The de-
vice will restart after the thermal hysteresis (typically 25C).
During thermal shutdown, the soft-start capacitor is fully
discharged and the controller follows a normal start-up se-
quence after the junction temperature falls to the operating
level.
Applications Information
LINE INPUT (VIN)
The LM5026 contains an internal high voltage start-up regu-
lator that allows the input pin (VIN) to be connected directly
to a nominal 48V line voltage. The voltage applied to the VIN
pin can vary in the range of 13 to 100V with transient
capability to 105V. When power is applied and the UVLO pin
potential is greater than 0.4V, the VCC regulator is enabled
and sources current into an external capacitor connected to
the VCC pin. When the voltage on the VCC pin reaches the
regulation point of 7.7V, the internal voltage reference (REF)
is enabled. The reference regulation set point is 5V. The
controller outputs are enabled when the UVLO pin potential
is greater than 1.25V. In typical applications, an auxiliary
transformer winding is connected through a diode to the
VCC pin. This winding must raise the VCC voltage above 8V
to shut off the internal start-up regulator. It is recommended
a filtering circuit shown in
Figure 11
be used to suppress
transients, which may occur at the input supply, in particular
when VIN is operated close to the maximum operating rat-
ing.
FOR APPLICATION
>
100V
For applications where the system input voltage exceed
100V or IC power dissipation is a concern, the LM5026 can
be powered from an external start-up regulator as shown in
Figure 12
. In this configuration, the VIN and the VCC pins
should be connected together, which allows the LM5026 to
be operated below 13V. The voltage at the VCC pin must be
greater than 8V yet not exceed 15V.An auxiliary winding can
be used to reduce the dissipation in the external regulator
once the power converter is active.
20147920
FIGURE 9. Sync from Multiple Devices
20147921
FIGURE 10. Oscillator Sync I/O Block Diagram
20147922
FIGURE 11. Input Transient Protection
L
www.national.com
16
相關(guān)PDF資料
PDF描述
LM5026MT Active Clamp Current Mode PWM Controller
LM5026MTX Active Clamp Current Mode PWM Controller
LM5026SD Active Clamp Current Mode PWM Controller
LM5026SDX Active Clamp Current Mode PWM Controller
LM5030 100V Push-Pull Current Mode PWM Controller
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LM5026_09 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Active Clamp Current Mode PWM Controller
LM5026EVAL 功能描述:BOARD EVALUATION LM5026 RoHS:否 類別:編程器，開(kāi)發(fā)系統(tǒng) >> 評(píng)估板 - DC/DC 與 AC/DC（離線）SMPS 系列:PowerWise® 產(chǎn)品培訓(xùn)模塊:Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:1 系列:True Shutdown™ 主要目的:DC/DC，步升 輸出及類型:1，非隔離 功率 - 輸出:- 輸出電壓:- 電流 - 輸出:1A 輸入電壓:2.5 V ~ 5.5 V 穩(wěn)壓器拓?fù)浣Y(jié)構(gòu):升壓 頻率 - 開(kāi)關(guān):3MHz 板類型:完全填充 已供物品:板 已用 IC / 零件:MAX8969
LM5026EVAL/NOPB 功能描述:電源管理IC開(kāi)發(fā)工具 LM5026 EVAL BOARD RoHS:否 制造商:Maxim Integrated 產(chǎn)品:Evaluation Kits 類型:Battery Management 工具用于評(píng)估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V
LM5026MT 功能描述:電流型 PWM 控制器 RoHS:否 制造商:Texas Instruments 開(kāi)關(guān)頻率:27 KHz 上升時(shí)間: 下降時(shí)間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14
LM5026MT/NOPB 功能描述:電流型 PWM 控制器 Current Mode Active Reset RoHS:否 制造商:Texas Instruments 開(kāi)關(guān)頻率:27 KHz 上升時(shí)間: 下降時(shí)間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。

采購(gòu)需求

(若只采購(gòu)一條型號(hào)，填寫一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

*型號(hào) *數(shù)量 廠商 批號(hào) 封裝
添加更多采購(gòu)

我的聯(lián)系方式

*
*
*