【英飞凌DIY】反激电源

Design Example Report

Title	Flyback power supply Engineering report
Specification	Input : 100Vac ~ 250Vac ，47-63Hz Output : 12V@1A
Application	AC/DC converter
Author
Date	2017,12,20
Revision	Rev1

1. Introduction

This document describes the performances of a 20W evaluation board, with wide range operation voltage for input and power factor correction. The demo board is used a single chip solution. The demo board is designed for a universal AC/DC solution based on UC3842.
This demo board utilizes a common UC3842 IC and a current transformer to control a traditional Flyback topology which can get high efficiency and reduces the components count a lot. The topology operates at a fixed frequency with the input voltage. This demo board optimized the ratio of performance and price, design is quite easy. The demo board mainly utilized Cool MOSFET from Infineon 

Description	Symbol	Min	Typ.	Max	Unit
Input	Voltage	Vin	100	220	250	V
Frequency	Flin	47	50	63
PowerFactors	PF
Output	Voltage	Vo	10	12	13	V
Current	Io		1.5	3	A
Power	Po		20		W
Efficiency	ƞ		86		%

3. Electrical requirements

Input Characteristics

3.1 AC Input Voltage

The power will operate over the entire input voltage range (85‐305 VAC). 

Minimum	Maximum	Nominal/Rated
100V	250V	100-250 VAC

3.2 Frequency

The input frequency range will be 47Hz to 63Hz.

3.3 Input Current

The input current will not exceed 0.5Amp(rms.) for 100V_AC.

3.4 Efficiency

The power efficiency (watts output/watts input) will not be less than 80% typically at full load condition (230VAC)

3.5 Output Characteristics

DC Load Characteristics 

Output Voltage	Minimum Current	Maximum Current
12VDC	0.0A	3A

4. Schematic

5.PCB Layout

This PCB is single side board made of FR4 with 1Oz copper.(unit mm)

Top silkscreen

Top layer

Bottom layer

8.Bill Of Material 

Bill of Materials
Source Data From:	UC3842反激式开关电源.Sch
Project:	Free Documents
Variant:		None
Creation Date:	2017/12/19 16:12:47
Print Date:	43088	43088.67577
Footprint	Comment	LibRef	Designator	Description	Quantity
FIX_POINT_3MM		FIX_POINT_3MM	1, 2		2
RADIATOR_12MM*35MM		RADIATOR_12MM*35MM	1,  2		2
FIX_POINT_3MM		FIX_POINT_3MM	3,  4		2
CD6	1000u	ELECTRO2	C17, C18, C19, C20, C21	Electrolytic Capacitor	5
CB2	103	CAP	C22, C24	Capacitor	2
CB1	103	CAP	C23	Capacitor	1
CD12	10U	ELECTRO2	C25	Electrolytic Capacitor	1
CB1	102	CAP	C26, C27	Capacitor	2
CB1	472	CAP	C28	Capacitor	1
CB1	104	CAP	C29	Capacitor	1
CD6	10u	ELECTRO1	C30	Electrolytic Capacitor	1
CD6	1000u/16	ELECTRO2	C31	Electrolytic Capacitor	1
CD6	100u	ELECTRO2	C32	Electrolytic Capacitor	1
4007	1N5819	DIODE	D13, D14, D15, D16, D17, D18	Diode	6
4007	4007	DIODE	D19, D20, D21, D22	Diode	4
4007	UF4007	DIODE	D23	Diode	1
4007	FR107	DIODE	D24	Diode	1
0805	FUSE2	FUSE2	F2	Fuse	1
XH2.54_6P	12V	HEADER 6	JP1		1
XH2.54_2P	5V	HEADER 2	JP6		1
XH2.54_2P	AC	HEADER 2	JP7		1
XH2.54_3P	+-12V	HEADER 3	JP8		1
EMI_9MM*9MM	EMI_L	EMI_L	L2		1
CON1_1MM	TIP	TIP	P1		1
CON1_1MM	TIP3	TIP	P6		1
CON1_1MM	TIP4	TIP	P7		1
CON1_1MM	-12	TIP	P8		1
CON1_1MM	TIP1	TIP	P9		1
CON1_1MM	TIP2	TIP	P10		1
TO220L	2N60	MOSFET N	Q2		1
RT	5	RT	R17		1
RP3	47k	POT2	R18	Potentiometer	1
1/4W	47K	RES2	R19		1
1/4W	10K	RES2	R20		1
2W	10K	RES5	R21		1
2W	120K	RES5	R22		1
1/4W	20	RES2	R26		1
1/4W	20K	RES2	R29		1
1/4W	5.1K	RES2	R30		1
1/4W	1K	RES2	R31		1
1/4W	1	RES2	R32		1
EE19L	EE19	EE19	T2		1
DIP8	UC3842	UC3842	U3		1
TO220L	7805	78**	U4		1
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