- 您现在的位置：买卖IC网 > Sheet目录326 > FL7732M_F116 (Fairchild Semiconductor)IC LED DRIVER PFC PRIMARY 8-SOIC
Functional Description
techniques regulate
applications. TRUECURRENT
technique, constant-current output
TRUECURRENT
FL7732 is AC-DC PWM controller for LED lighting
?
accurate LED current independent or input voltage,
output voltage, and magnetizing inductance variations.
The linear frequency control in the oscillator reduces
conduction loss and maintains DCM operation in the
wide range of output voltage, which implements high
power factor correction in a single-stage flyback
topology. A variety of protections, such as short/open-
LED protection, over-temperature protection, and cycle-
by-cycle current limitation stabilize system operation
and protect external components.
Startup
Powering at startup is slow due to the low feedback loop
bandwidth in PFC converter. To boost powering during
startup, an internal oscillator counts 12 ms to define
Startup Mode. During Startup Mode, turn-on time is
determined by Current-Mode control with a 0.2 V CS
voltage limit and transconductance becomes 14 times
larger, as shown in Figure 15. After startup, turn-on time
is controlled by Voltage Mode using COMI voltage and
error amplifier transconductance is reduced to 85 μ mho.
?
can be precisely controlled.
PFC and THD
In a conventional boost converter, Boundary Conduction
Mode (BCM) is generally used to keep input current in-
phase with input voltage for PF and THD. In
flyback/buck boost topology, constant turn-on time and
constant frequency in Discontinuous Conduction Mode
(DCM) can implement high PF and low THD, as shown
in Figure 16. Constant turn-on time is maintained by
the internal error amplifier and a large external
capacitor (typically over 1 μF) at the COMI pin.
Constant frequency and DCM operation are managed
by linear frequency control.
Figure 16.
Input Current and Switching
Linear Frequency Control
As mentioned above, DCM should be guaranteed for
high power factor in flyback topology. To maintain DCM
across the wide range of output voltage, frequency is
linearly adjusted by output voltage in linear frequency
control. Output voltage is detected by the auxiliary
winding and the resistive divider connected to the VS
pin, as shown in Figure 17.
Figure 15.
Startup Sequence
calculation block estimates output
TRUECURRENT
Constant-Current Regulation
The output current can be estimated using the peak
drain current and inductor current discharge time since
output current is same as the average of the diode
current in steady state. The peak value of the drain
current is determined by the CS pin and the inductor
discharge time (t DIS ) is sensed by t DIS detector. By using
three points of information (peak drain current, inductor
discharging time, and operating switching period);
?
current. The output of the calculation is compared with
an internal precise reference to generate an error
voltage (V COMI ), which determines turn-on time in
Voltage-Mode control. With Fairchild’s innovative
Figure 17.
Linear Frequency Control
? 2011 Fairchild Semiconductor Corporation
FL7732 ? Rev. 1.0.6
9
www.fairchildsemi.com
发布紧急采购，3分钟左右您将得到回复。
相关PDF资料
FLASHPRO LITE
KIT PROGRAMMER FLASHPRO LITE
FLS2100XS
IC CTLR FPS HALF BRIDG LCC 9-SIP
FMD15.24G
1500W 24V DC-INPUT 48V RECTIFIER
FMP25.48G
2500W 48V AC-INPUT RECTIFIER
FND850-12DRG
FRONT END DC/DC 850W 12V
FND850-12RG
FRONT END DC/DC 850W 12V
FNR-5-12G
19" RACK FOR 5X 12V FRONT END
FPB
ADAPTER WALL FOLDING CLIP BR
相关代理商/技术参数
FL7732MF116
制造商:FAIRCHILD 制造商全称:Fairchild Semiconductor 功能描述:Single-Stage PFC Primary-Side-Regulation Offline LED Driver
FL7930
制造商:FAIRCHILD 制造商全称:Fairchild Semiconductor 功能描述:Single-Stage Flyback and Boundary-Mode PFC
FL7930BM
功能描述:功率因数校正 IC PFC Controller for Lighting; 2nd OVP RoHS:否 制造商:Fairchild Semiconductor 开关频率:300 KHz 最大功率耗散: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Reel
FL7930BMX
功能描述:功率因数校正 IC PFC Controller for Lighting; 2nd OVP
RoHS:否 制造商:Fairchild Semiconductor 开关频率:300 KHz 最大功率耗散: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Reel
FL7930BMX_G
制造商:Fairchild Semiconductor Corporation 功能描述: 制造商:Fairchild Semiconductor Corporation 功能描述:IC PFC CTLR FLYBACK/BOUND 8SOIC
FL7930CM
功能描述:功率因数校正 IC PFC Controller for Lighting; PFC Ready RoHS:否 制造商:Fairchild Semiconductor 开关频率:300 KHz 最大功率耗散: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Reel
FL7930CMX
功能描述:功率因数校正 IC Single Stage Flyback PFC Controller RoHS:否 制造商:Fairchild Semiconductor 开关频率:300 KHz 最大功率耗散: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Reel
FL7930CMX_G
制造商:Fairchild Semiconductor Corporation 功能描述:IC PFC CTLR FLYBACK/BOUND 8SOIC