參數(shù)資料
型號: LM5026SD
廠商: NATIONAL SEMICONDUCTOR CORP
元件分類: 穩(wěn)壓器
英文描述: Active Clamp Current Mode PWM Controller
中文描述: 3 A SWITCHING CONTROLLER, 660 kHz SWITCHING FREQ-MAX, DSO16
封裝: 5 X 5 MM, EXPOSED PAD, LLP-16
文件頁數(shù): 15/23頁
文件大?。?/td> 936K
代理商: LM5026SD
Overload Protection Timer
(Continued)
3.
Delayed Hiccup:
The most common configuration as
previously described, is a programmed interval of cycle-
by-cycle limiting before initiating a hiccup mode restart.
The advantage of this configuration is short term over-
load conditions will not cause a hiccup mode restart,
however during extended overload conditions the aver-
age dissipation of the power converter will be very low.
4.
Externally Controlled Hiccup:
The RES pin can also
be used as an input. By externally driving the pin to a
level greater than the 2.5V hiccup threshold, the control-
ler will be forced into the delayed restart sequence. If the
RES pin is used as an input, the driving source should
be current limited to less than 5 mA. For example, the
external trigger for a delayed restart sequence could
come an over-temperature protection circuit.
Oscillator and Sync Capability
The LM5026 oscillator frequency is set by the external resis-
tance connected between the RT pin and ground (AGND).
To set a desired oscillator frequency (F) the necessary value
of total R
T
resistance can be calculated from:
The R
T
resistor(s) should be located very close to the device
and connected directly to the pins of the IC (RT and AGND).
The SYNC pin can be used to synchronize the internal
oscillator to an external clock. An open drain output is the
recommended interface between the external clock to the
LM5026 SYNC pin as illustrated in
Figure 8
. The clock pulse
width must be greater than 15 ns. The external clock fre-
quency must be a higher than the free running frequency set
by the R
T
resistance.
20147918
FIGURE 7. Hiccup Over-Load Restart Timing
20147919
FIGURE 8. Sync from External Clock
L
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LM5026SD/NOPB 功能描述:電流型 PWM 控制器 RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時間: 下降時間: 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 安裝風格:SMD/SMT 封裝 / 箱體:TSSOP-14
LM5026SDX 功能描述:電流型 PWM 控制器 RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時間: 下降時間: 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 安裝風格:SMD/SMT 封裝 / 箱體:TSSOP-14
LM5026SDX/NOPB 功能描述:電流型 PWM 控制器 RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時間: 下降時間: 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 安裝風格:SMD/SMT 封裝 / 箱體:TSSOP-14
LM5027 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Voltage Mode Active Clamp Controller
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