Dual +12V/-12V @ 400mA Regulated Linear Power Supply with AC input

Rajkumar Sharma
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SKU: EL113014
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The project presented here is a dual output linear power supply. This power supply provides low ripple low noise DC regulated output. It is a very useful tool to power Audio, Video, OPAMP-based circuits, and projects. The circuit provides regulated +/-12V DC output @ 400mA + 400mA. The project supports AC input supply 230V or 115V. On-board jumpers are provided for AC230V or AC115V selection. Besides regulated output, the board also has provisions to output the unregulated supply using CN2.

Parts Explanation

Connector CN1: 230V/115V AC Input
Jumper J2: 230V Selection
Jumper J1, J3: 115V Selection
Transformer-Step Down T1: 230/115V AC IN, 12VAC-0V-12VAC 0.83A
Bridge Rectifier BR1: Bridge Rectifier
Capacitor C2, C5: DC Filter Capacitors
Connector CN2: Unregulated DC Output
Regulator U1: +12V Regulator
Regulator U2: -12V Regulator
C1,C3,C4, C6 : DC Filter Capacitors
LED D1: +12V LED
LED D2: -12V LED
Connector CN3, and CN4: +/-12V Regulated Output
Resistor R1, R2: Current Limiting Resistors for LEDs

Note1: This power supply supports 230V AC or 115V AC input, remove input power cable while changing Jumper selection.

Note 2: This power supply contains hazardous voltage at the input, PCB must be installed in an encloser that prevents accidental contact. Use Plastic screws to mount the power supply.

Note 3: Power supply also can be used as Dual Regulated +/-15V DC Output. In this case replace U1 LM7815, U2 LM7915

Note 4: Heatsink is a must for regulators U1 and U2 @ full load. The heatsink should be mounted with plastic screws and should not touch the ground plane of the PCB.

Input Voltage Selection

For 230V AC Input: Close Jumper J2 Jumper J1 and J3 Open,
For 115V AC Input: Close Jumper J1 and J3 Open Jumper J2

Other Similar AC to DC Power Supplies

Features

Input 230V or 115V AC (Use Jumpers to Select 230V or 115V AC)
Output +/-12V DC (Dual Output)
Unregulated Output Approx. +/-17V (CN2)
Output Ripple Approx. 5mV
Maximum Load Current 800mA (+12V@400mA, -12V@400mA)
2 x Power LEDs, for 12V and -12V
Screw Terminal for AC Input
Screw Terminal for Regulated DC Output
3 Pin Male Header Provides Unregulated DC Output
4 Pin Male Header for Regulated DC Output
PCB Dimensions 99.06 x 58.74 mm

Schematic

Parts List

NO	QNTY.	REF.	DESC.	MANUFACTURER	SUPPLIER	SUPPLIER PART NO
1	1	BR1	BRIDGE GBL08 OR GBL06	VISHAY	DIGIKEY	GBL06-E3/45GI-ND
2	1	CN1	3 PIN SCREW TERMINAL PITCH 5.08MM	PHOENIX	DIGIKEY	277-1248-ND
3	1	CN2	3 PIN MALE HEADER PITCH 2.54MM	WURTH	DIGIKEY	732-5316-ND
4	1	CN3	4 PIN MALE HEADER PITCH 2.54MM	WURTH	DIGIKEY	732-5317-ND
5	1	CN4	3 PIN SCREW TERMINAL PITCH 5.08MM	PHOENIX	DIGIKEY	277-1248-ND
6	2	C1,C4	0.1uF/50V SMD SIZE 0805	MURATA/YAGEO	DIGIKEY
7	2	C2,C5	2200uF/25V	RUBYCON	DIGIKEY	1189-3651-ND
8	2	C3,C6	10uF/25V SMD SIZE 1206	MURATA/YAGEO	DIGIKEY
9	1	D1	RED LED SMD SIZE 0805	LITE ON	DIGIKEY	160-1427-1-ND
10	1	D2	GREEN LED SMD SIZE 0805	DIALIGHT	DIGIKEY	350-2044-1-ND
11	3	J1,J2,J3	JUMPER 2 PIN MALE HEADER PITCH 2.54MM	WURTH	DIGIKEY	732-5315-ND
12	2	R1,R2	1.5K 5% SMD SIZE 0805	MURATA/YAGEO	DIGIKEY
13	1	T1	VPP24–830 TRANSFORMER 12V-0-12VAC	TRIAD	DIGIKEY	237-1071-ND
14	1	U1	LM7812	TI	DIGIKEY	296-50628-ND
15	1	U2	LM7912	TI	DIGIKEY	LM7912CT/NOPB-ND
16	2	SHUNT	SHUNT FOR JUMPPERS J1,J2,J3	SULLINS	DIGIKEY	S9001-ND
17	2	HT	HEATSINK	AVID	DIGIKEY	HS106-ND
18	2	SC	M3 SCREW X 10MM L	IO AUDIO	DIGIKEY	1937-IO-M3X10/M3HN-50-ND