Filename L925TX1.1.Sch, Waterbeach Cambridge CB5 9PB

NOTE.

TRANSFORMER IS TO BE USED ON SECONDARY SIDE OF MAINS

ISOLATION BARRIER (I.E. THIS TRANSFORMER IS NOT REQUIRED

TO PROVIDE MAINS ISOLATION BARRIER)

MAXIMUM VOLTAGE BETWEEN WINDINGS <60V

VIEW FROM SIDE OF PART

SHOWING OUTER FOIL SCREEN

WINDING DETAILS

			No PER	ID	OD	START	END	NOTES
WINDING	TURNS	WIRE DETAILS	CABLE			PIN #	PIN #

PRIMARY2	16	ENAMELLED COPPER WIRE	1	0.8mm	0.86mm	3	2	SPACE WINDING ACROSS WHOLE BOBBIN WIDTH

SCREEN 2		INSULATED 2mil COPPER FOIL				1		SCREEN TO HAVE NO OVERLAP AT ENDS

SECONDARY3	22	ENAMELLED COPPER WIRE	1	0.25mm	0.3mm	11	12	WIND ACROSS WHOLE BOBBIN WIDTH BETWEEN GAPS IN SEC4

SECONDARY4	14	ENAMELLED COPPER WIRE	1	0.66mm	0.72mm	9	10	SPACE WINDING ACROSS WHOLE BOBBIN WIDTH

SECONDARY5	10	ENAMELLED COPPER WIRE (BIFILAR)	2	0.66mm	0.72mm	7	8	WIND AS A BIFILAR PAIR ACROSS WHOLE BOBBIN WIDTH

SHORTED TURN FOIL SCREEN TO BE ELECTRICALLY CONNECTED TO CORE CLAMP CONDUCTIVE ADHESIVE FOIL MAY BE USED FOIL TO BE COVERED IN A LAYER OF MYLAR TAPE

6 to 8mm 10THOU COPPER

OUTER SCREEN

SECONDARY1	41	ENAMELLED COPPER WIRE	1	0.25mm	0.3mm	4	5	WIND SEC1 AND SEC2 AS A BIFILAR PAIR ACROSS
								WIND SEC1 AND SEC2 AS A BIFILAR PAIR ACROSS
SECONDARY2	41	ENAMELLED COPPER WIRE	1	0.25mm	0.3mm	5	6	WHOLE BOBBIN WIDTH
SECONDARY2	41	ENAMELLED COPPER WIRE	1	0.25mm	0.3mm	5	6

SCREEN 1		INSULATED 2mil COPPER FOIL				1		SCREEN TO HAVE NO OVERLAP AT ENDS

ELECTRICAL REPRESENTATION

SEE VIEW GIVING PIN LENGTH DIMENSIONS

PRIMARY1

ENAMELLED COPPER WIRE

0.8mm 0.86mm

SPACE WINDING ACROSS WHOLE BOBBIN WIDTH

TX2

Ferrite Switch Mode

L925TX

41T SECONDARY1

VIEW FROM TOP OF PART WITH PART INSTALLED IN PCB

WINDING ARRANGEMENT ON BOBBIN

		5
		41T	SECONDARY2
		6
	1	11
PRIMARY1	16T	22T	SECONDARY3
PRIMARY1		12
	2	12
	2	9
		9
PRIMARY2	16T	14T	SECONDARY4
	16T	14T	SECONDARY4

PIN 1 TO BE MARKED

1.1 INCH

1	12
2	11
3	10

4	9
5	8
6	7

2 LAYERS MYLAR TAPE PRIMARY2

SCREEN2 SECONDARY4 + SECONDARY3

SECONDARY5

SECONDARY1 + SECONDARY2

SCREEN1

PRIMARY1

1 FULL LAYER

WIND SECONDARY 4 FIRST THEN SECONDARY 3 IN THE GAPS

1 FULL LAYER WIND AS BIFILAR PAIR

SEC1 AND 2 WOUND AS BIFILAR PAIR ACROSS FULL WIDTH

1 FULL LAYER

3	10
	7
	10T SECONDARY5
	8
SCR

VIEW FROM SIDE OF PART

SHOWING PIN LENGTH DIMENSIONS

MATING FACE OF TX 7 REF.

PCB

2.5 MAX

1.2 INCH

NOTE PIN NUMBERING CONVENTION	MATERIALS
NOTE PIN NUMBERING CONVENTION
	CORE	PQ32/30 in PC44 MATERIAL (OR EQUIVALENT)
		CORE TO BE GAPPED IN CENTRE LEG TO GIVE REQUIRED Lpri (GAP APPROX 0.4mm)
		(Lpri = 450uH +/- 10% PRIMARY INDUCTANCE MEASURED FROM PIN 1 TO 3 )
		PART NUMBER TDK PC44PQ32/30Z-12 (OR EQUIVALENT)
	BOBBIN	PART NUMBER TDK BPQ32/30-1112CP (OR EQUIVALENT)
	CLAMP	PART NUMBER TDK FPQ32/30-A (OR EQUIVALENT)

ARRANGEMENT OF INTERNAL FOIL SCREENS

ASSEMBLY DETAILS

WIRE

PART TO BE MARKED WITH PART NUMBER / ISSUE NUMBER

INTERNAL SCREENS TO BE FULL WIDTH. CONNECTION TO SCREEN VIA SOLDER JOINT TO COPPER (SEE DIAGRAM)

FOIL (2mil OR THINNER)

SOLDER JOINT TO BE ARRANGED TO PRODUCE A LUMP IN THE CORE WINDOW

INSULATOR

SOLDER JOINT TO MADE MADE TO CLEAN COPPER AND JOINT TO BE TAPED.

FULL WINDING WIDTH

SOLDER JOINT TO BE MADE HALF WAY ALONG LENGTH OF THE FOIL

SCREEN TO BE HIGHEST POSSIBLE RESISTANCE FOIL FOR LOWEST LOSSES. (I.E. FOIL AS THIN AS POSSIBLE)

SOLDER JOINT TO BE COVERED IN TAPE

SCREEN TO BE MADE FROM MAXIMUM 0.05mm (2MIL) FOIL

JOINT MUST BE MADE TO CLEAN COPPER

WINDINGS WILL BE A TIGHT FIT ON BOBBIN. NOTES AND WINDING ARRANGEMENT SPECIFIED TO BE ADOPTED.

(I.E. NOT THROUGH MYLAR INSULATOR)

4TRANSFORMER TO BE FITTED WITH AN OUTER COPPER SCREEN WRAPPED AROUND THE OUTSIDE OF THE OF THE TRANSFORMER CORE AND CONTACTING THE METAL CORE CLAMP THUS FORMING A SHORTED TURN

TO LEAKAGE FLUX. SEE DIAGRAM

SCREEN TO BE 10THOU COPPER STRIP 6 to 8mm WIDE AND FITTED OVER THE JOIN OF THE CORE HALVES.

1 BUMP FROM SCREEN JOINT TO BE

SCREEN TO BE COVERED IN A LAYER OF TAPE.

ADJACENT TO CORE WINDOW

5 PIN 1 ON BOBBIN TO BE MARKED WITH WHITE PAINT (OR OTHERWISE)

TO MINIMISE LOSS OF WINDING HEIGHT

THIS MARKING TO BE USED TO ORIENTATE TX DURING WINDING PHASE TEST

2 MAXIMUM OVERLAP ON ENDS OF

6 100% PHASE TEST AND ISOLATION TEST TO BE CARRIED OUT ON ALL WINDINGS.

SCREENS TO BE LESS THAN 1mm

TO MINIMISE CAPACITIVE COUPLING

WHICH WOULD PRODUCE SHORTED

DRAWING TITLE

DV78 450uH FLYBACK TX

TURN FOR HIGH FREQUENCY CURRENTS

03_E290

SLS

06-10-03

'VIEW FROM SIDE OF PART SHOWING PIN LENGTH DIMS' added.

1.1

3 SOLDER JOINTS TO BE MADE HALF WAY