Fairchild Semiconductor FAN7527B Datasheet
FAN7527B
Po wer Factor Correction Controller
www.fairchildsemi.com
Features
• Internal Start-up Timer
• Internal R/C Filter Eliminates the Need for an External
R/C Filter
• Very Precise Adjustable Output Over Voltage Protection
• Zero Current Detector
• One Quadrant Multiplier
• Trimmed 1.5% Internal Band Gap Refe rence
• Under Voltage Lockout with 3V of Hysteresis
• Totem Pole Output With High State Clamp
• Low Start-up and Operating Current
• 8-Pin DIP or 8-Pin SOP
Applications
• Electronic Ballast
•SMPS
Description
The FAN7527B provides simple and high performance
active power factor correction. The FAN7527B is optimized
for electronic ba llasts an d low powe r and high density power
supplies which require minimum board size, reduced
external components and low power dissipation. Because the
R/C filter is included in the current sense block, the external
R/C filter is not necessary. Special circuitry has also been
added to prevent no load runaway conditions. Regardless of
the supply voltage, the output drive clamping circuit limits
the overshoot of the power MOSFET gate drive. It greatly
enhances the system reliability.
8-DIP
1
8-SOP
1
©2002 Fairchild Semiconductor Corporation
Rev 1.0.1
FAN7527B
Internal Block Diagram
Idet
CS
MULT
0.25V
++++
2.5V Ref
Internal
Bias
Timer R
S
R
Veao(L)=2.25V
Vm2
Vref~Vref+2.5V
OVP
Current
Detector
2
EA_OUT
Q
Isovp=30uA
Idovp=40uA
Static OVP
++++
−−−−
++++
−−−−
Error Amp
Vcc
Drive
Output
Vea(-)
2.25V
Vref
7
OUT
INV
1
8Vcc
++++
UVLO
−−−−
8.5V
11.5V
5
7.2V
2V 1.5V
40k
4
8pF
1.8V
3
Vm1
0 ~ 3.8V
++++
−−−−
Zero Current
++++
−−−−
Vmo
Multiplier
K
====
Detector
Current Sense
Comparator
Vmo
−−−−⋅⋅⋅⋅
Vref
−−−−
)( Vref2Vm1Vm
6
GND
2
PIN Description
FAN7527B
INV
EA_OUT
MULT
CS
1
2
3
4
8
7
6
5
Vcc
OUT
GND
ldet
(Top View)
Pin Number Pin Name Pin Function Description
1INV
2 EA_OUT
3MULT
4CS
5 ldet Zero current detection input.
6 GND The ground potential of all the pins.
7OUT
8 Vcc Supply voltage of driver and control circuits.
Inverting input of the error amplifier. The output of the boost converter
should be resistively divided to 2.5V and connected to this pin.
The output of the error amplifier. A feedback compensation network is
placed between this pin and the INV pin.
Input to the multiplier stage. The full-wave rectified AC voltage is
divided to less than 2V and is connected to this pin.
Input of the PWM comparator. The MOSFET current is sensed by a
resistor and the resulting voltage is applied to this pin. An internal R/C
filter is included to reject any high frequency noise.
Gate driver output. The push pull output stage is able to drive the
Power MOSFET with peak current of 500mA.
3
FAN7527B
Absolute Maximum Ratings (Ta=25°°°°C)
Characteristics Symbol Value Unit
Supply Voltage V
Peak Drive Output Current I
Driver Output Clamping Diodes Vo > Vcc or Vo < -0.3V lclamp ±10 mA
Detector Clamping Diodes ldet ±10 mA
Error Amp, Multiplier and Comparator Input Voltages Vin -0.3 to 6 V
Operating Junction Temperature Tj 150 °C
Operating Temperature Range Topr -25 to 125 °C
Storage Temperature Range Tstg -65 to 150 °C
Power Dissipation Pd 0.8 W
CC
OH,IOL
30 V
±500 mA
Temperature Characteristics (-25°°°°C ≤
Characteristics Symbol Min. Typ. Max. Unit
Temperature Stability for Reference Voltage (V
Temperature Stability for Multiplier Gain (K) ∆K/∆T--0.2-%/°C
≤ Ta ≤
≤ 125°°°°C)
≤ ≤
≤ ≤
) ∆Vref - 20 - mV
ref
4
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