参数资料
| 型号： | FSQ211L |
| 厂商： | Fairchild Semiconductor |
| 文件页数： | 8/13页 |
| 文件大小： | 0K |
| 描述： | IC SWIT PWM GREEN UVLO HV 8SOP |
| 标准包装： | 4,500 |
| 输出隔离： | 隔离 |
| 频率范围： | 61 ~ 73kHz |
| 输入电压： | 8 V ~ 20 V |
| 输出电压： | 650V |
| 功率（瓦特）： | 1.4W |
| 工作温度： | 25°C ~ 145°C |
| 封装/外壳： | 8-SOP，8-LSOP |
| 供应商设备封装： | 8-LSOP |
| 包装： | 管件 |
Functional Description
1. Start-up: At start-up, the internal high-voltage current
source supplies the internal bias and charges the
external V CC capacitor, as shown in Figure 14. In the
case of the FSQ211, when V CC reaches 9V, the device
starts switching and the internal high-voltage current
source stops charging the capacitor. The device is in
normal operation provided V CC does not drop below 7V.
After start-up, the bias is supplied from the auxiliary
transformer winding.
V IN ,dc
I STR
2. Feedback Control: The FSQ211 is a voltage-mode
controlled device, as shown in Figure 16. Usually, an
opto-coupler and shunt regulator, like KA431, are used
to implement the feedback network. The feedback
voltage is compared with an internally generated
sawtooth waveform. This directly controls the duty cycle.
When the shunt regulator reference pin voltage exceeds
the internal reference voltage of 2.5V, the opto-coupler
LED current increases, the feedback voltage V FB is
pulled down, and it reduces the duty cycle. This
happens when the input voltage increases or the output
load decreases.
Vstr
V cc
V ref
OSC
V cc
L
V o
V fb
4
5μA
0.40mA
Gate
driver
H
C fb
+
R
V FB
9V/7V
Figure 14. Internal Start-up Circuit
KA43 1
-
V SD
OLP
Calculating the V CC capacitor is an important step in a
design with the FSQ211. At initial start-up, the maximum
value of start operating current I STR is about 100μA,
which supplies current to UVLO and V REF blocks. The
charging current I VCC of the V CC capacitor is equal to I STR
– 100μA. After V CC reaches the UVLO start voltage, only
the bias winding supplies V CC current to the device.
When the bias winding voltage is not sufficient, the V CC
level decreases to the UVLO stop voltage and the
internal current source is activated again to charge the
V CC capacitor. To prevent this V CC fluctuation
(charging/discharging), the V CC capacitor should be
chosen with a value between 10μF and 47μF.
Figure 16. PWM and Feedback Circuit
3. Leading Edge Blanking (LEB): The instant the
internal SenseFET is turned on, the primary-side
capacitance and secondary-side rectifier diode reverse
recovery typically cause a high-current spike through the
SenseFET. Excessive voltage across the R SENSE resistor
leads to incorrect pulse-by-pulse current limit protection.
To avoid this, a leading edge blanking (LEB) circuit
disables the pulse-by-pulse current limit protection block
for a fixed time (t LEB ) after the SenseFET turns on.
4. Protection Circuit: The FSQ211 has several
protective functions, such as overload protection (OLP),
V CC
V IN , dc
I Vcc = I STR -I START
I Vcc = I STR -I START
V CC
I STR
I START
UVLO
V REF
Vstr
J-FET
under-voltage lockout (UVLO), and thermal shutdown
(TSD). Because these protection circuits are fully
integrated inside the IC without external components,
reliability is improved without increasing costs. Once a
fault condition occurs, switching is terminated and the
SenseFET remains off. This causes V CC to fall. When
V CC reaches the UVLO stop voltage V STOP (7V), the
protection is reset and the internal high-voltage current
source charges the V CC capacitor via the Vstr pin. When
V CC reaches the UVLO start voltage V START (9V), the
device resumes normal operation. In this manner, the
auto-restart can alternately enable and disable the
switching of the power SenseFET until the fault
condition is eliminated.
V START
UVLO
V CC must not drop
below V STOP
OSC
V STOP
Bias winding
voltage
V fb
4
5μA
400μA
+
-
S
R
Q
GATE
DR IVER
R
t
C fb
OLP
S
Q
Figure 15. Charging V CC Capacitor Through Vstr
RESE T
4.5V
TSD
A/R
R
OLP , TSD
Protection Block
Figure 17. Protection Block
? 2007 Fairchild Semiconductor Corporation
FSQ211 Rev. 1.0.0
8
www.fairchildsemi.com
相关PDF资料 |
PDF描述 |
|---|---|
| FSQ311L | IC SWITCH FPS LOW EMI HE 8-LSOP |
| FSQ321LX | IC SWIT PWM GREEN OVP UVLO 8LSOP |
| FSQ500L | IC SWIT PWM GREEN UVLO SOT223 |
| FSQ500N | IC PWM/SENSEFET 130KHZ 8-MDIP |
| FSQ510H | IC SWITCH FPS 0.5A 700V 8-DIP |
相关代理商/技术参数 |
参数描述 |
|---|---|
| FSQ2W | 制造商:RFE 制造商全称:RFE international 功能描述:FUSIBLE RESISTORS FM, FKN, & FSQ Series: Fusible |
| FSQ311 | 功能描述:电流型 PWM 控制器 SMPS 1A 650V Power Switch 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 |
| FSQ311L | 功能描述:电源开关 IC - 配电 SMPS Power Switch RoHS:否 制造商:Exar 输出端数量:1 开启电阻（最大值）:85 mOhms 开启时间（最大值）:400 us 关闭时间（最大值）:20 us 工作电源电压:3.2 V to 6.5 V 电源电流（最大值）: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:SOT-23-5 |
| FSQ3120RJ | 功能描述:线绕电阻器 - 透孔 FSQ3 120R 5% RoHS:否 制造商:Bourns 电阻:10 Ohms 容差:5 % 功率额定值:7 W 温度系数:200 PPM / C 系列:FW 端接类型:Axial 工作温度范围:- 55 C to + 155 C 尺寸:9.5 mm Dia. x 26 mm L 封装:Ammo 产品:Power Resistors Wirewound High Energy |
| FSQ321 | 功能描述:开关变换器、稳压器与控制器 SMPS Power Switch RoHS:否 制造商:Texas Instruments 输出电压:1.2 V to 10 V 输出电流:300 mA 输出功率: 输入电压:3 V to 17 V 开关频率:1 MHz 工作温度范围: 安装风格:SMD/SMT 封装 / 箱体:WSON-8 封装:Reel |
发布紧急采购，3分钟左右您将得到回复。