UC3843

AN 80 Khz. SWITCHING POWER SUPPLY

4R7 OR 5R6 5 W

M/W

I PREFER 1N4005 DIODES BUT YOU CAN USE A 1 AMP BRIDGE RECTIFIER IF WANTED

165 VDC.

117 VAC.

-L 250uF 250V

R4    R3

4K7    20K

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FERRITE ^MPQ^M CORE. "AL" VALUE WITH .002" GAP = 9166, uH PER 100 TURNS T1 PRIMARY = 33 TURNS, WITH A GAP OF .0025", THE INDUCTANCE = 1000uH IF 33 TURNS = 165 VOLTS, THAN 12 VOLTS = 2.4 TURNS, EACH SIDE OF OUTPUT. IF 33 TURNS = 165 VOLTS, THAN 30 VOLTS = 6 TURNS FOR FEEDBACK SUPPLY.

T1

56K

2W

.0022 uF 600 VOLT

PRIMARY 33 T

#26 A WG or

28AWG

DX

■Ol—I

2.5T

2.5T

VC IS SELF LIMITING IF SUPPLY CURRENT IS LESS THAN 30 mA.

= 4^30mA.

■KF

150K

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100 pF

.01

VC

VFA

COMP.

5V@50mA

V-REF

10K

RT

CT

.0022

2 '	r
1
UC3843
8	6
	3
4 i	5
	GND.

100uF

1N4937

0.22uF

1N4937

■KI—W\A-6

"IX"

68R -L '.5W

47uF

(100R?)

2W

IRF740

OUTPUT

22R

\w

1N5819

PROTECTS AGAINST A NEGATIVE VOLTAGE. ON PIN 6

'NOTĘ"

DIODES ^MDX^M MUST BE "HIGH SPEED" TYPES.

RATED AT THE APPROPRIATE VOLTAGES AND CURRENTS YOU HAVE CHOSEN.

ON

HEATSINK Q

dp 680pF 600 Volt

T1 = A "PQ" TYPE CORE = MAGNETICS PART NUMBER "42625"

on LU7 nPFRAT ON

—    T1 BOBBIN = MAGNETICS PART NUMBER "PCB2625-12

OTHER CORES GOULD BE USED, BUT YOU WILL NEED TO RE-CALCULATE ALL THE WINDING DATA AND ^MAL^M VALUE.