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www.fairchildsemi.com

FAN7930C • Rev. 1.0.0

18

Typical Application Circuit

Application

Device

Input Voltage

Range

Rated Output

Power

Output Voltage

(Maximum

Current)

LCD TV Power Supply

FAN7930C

195W

390V (0.5A)

Features

Average efficiency of 25%, 50%, 75%, and 100% load conditions is higher than 95% at universal input.

Power factor at rated load is higher than 0.98 at universal input.

Total Harmonic Distortion (THD) at rated load is lower than 15% at universal input.

Key Design Notes

winding. The power consumption of R103 is quite high, so its power rating needs checking.

Because the input bias current of INV pin is almost zero, output voltage sensing resistors (R112~R115) should

be as high as possible. However, too-high resistance makes the node susceptible to noise. Resistor values need

to strike a balance between power consumption and noise immunity.

Quick-charge diode D106 can be eliminated. Without D106, system operation is normal due to the controller’s

highly reliable protection features.

1. Schematic

ZNR101

,10D471

230mH,

49:6

D105

600V 8A

DC OUTPUT

Q101

FCPF

20N60

D106

600V 3A

R101,1M-

J

C101,

220nF

C114

,2.2n

F

C102,

680nF

BD101,

600V,15A

R109

47

R108

4.7

D103,1N414

8

LP101,EER3124N

1

7

6

8

5

2

FAN7930C

Com

p

INV

Out

GND

ZC

D

CS

RD

Y

4

3

C115

,2.2n

F

R103,

10k,1W

D102,

UF4004

C104,

12nF

Optional

Figure 45.

Demonstration Circuit